[PATCH v7 00/39] btrfs: zoned block device support

[PATCH v7 00/39] btrfs: zoned block device support

[Naohiro Aota]

This series adds zoned block device support to btrfs.

Changes from v6:
 - Use zone append write command instead of normal write command
   - Bio issuing order does not matter
   - No need to use lock anymore
   - Can use asynchronous checksum
 - Removed RAID support for now
 - Rename HMZONED to ZONED
 - Split some patches
 - Rebased on kdave/for-5.9-rc3 + iomap direct IO

Userland series will follow.

This version of ZONED btrfs switched from normal write command to zone
append write command. You do not need to specify LBA (at the write pointer)
to write for zone append write command. Instead, you only select a zone to
write with its start LBA. Then the device (NVMe ZNS), or the emulation of
zone append command in the sd driver in the case of SAS or SATA HDDs,
automatically writes the data at the write pointer position and return the
written LBA as a command reply.

The benefit of using the zone append write command is that write command
issuing order does not matter. So, we can eliminate block group lock and
utilize asynchronous checksum, which can reorder the IOs.

Eliminating the lock improves performance. In particular, on a workload
with massive competing to the same zone [1], we observed 36% performance
improvement compared to normal write.

[1] Fio running 16 jobs with 4KB random writes for 5 minutes

However, there are some limitations. We cannot use the non-SINGLE profile.
Supporting non-SINGLE profile with zone append writing is not trivial. For
example, in the DUP profile, we send a zone append writing IO to two zones
on a device. The device reply with written LBAs for the IOs. If the offsets
of the returned addresses from the beginning of the zone are different,
then it results in different logical addresses.

For the same reason, we cannot issue multiple IOs for one ordered extent.
Thus, the size of an ordered extent is limited under max_zone_append_size.
This limitation will cause fragmentation and increased usage of metadata.
In the future, we can add optimization to merge ordered extents after
end_bio.

* Patch series description

A zoned block device consists of a number of zones. Zones are either
conventional and accepting random writes or sequential and requiring
that writes be issued in LBA order from each zone write pointer
position. This patch series ensures that the sequential write
constraint of sequential zones is respected while fundamentally not
changing BtrFS block and I/O management for block stored in
conventional zones.

To achieve this, the default chunk size of btrfs is changed on zoned
block devices so that chunks are always aligned to a zone. Allocation
of blocks within a chunk is changed so that the allocation is always
sequential from the beginning of the chunks. To do so, an allocation
pointer is added to block groups and used as the allocation hint.  The
allocation changes also ensure that blocks freed below the allocation
pointer are ignored, resulting in sequential block allocation
regardless of the chunk usage.

The zone of a chunk is reset to allow reuse of the zone only when the
block group is being freed, that is, when all the chunks of the block
group are unused.

For btrfs volumes composed of multiple zoned disks, a restriction is
added to ensure that all disks have the same zone size. This
restriction matches the existing constraint that all chunks in a block
group must have the same size.

* Enabling tree-log

The tree-log feature does not work on ZONED mode as is. Blocks for a
tree-log tree are allocated mixed with other metadata blocks, and btrfs
writes and syncs the tree-log blocks to devices at the time of fsync(),
which is different timing than a global transaction commit. As a result,
both writing tree-log blocks and writing other metadata blocks become
non-sequential writes which ZONED mode must avoid.

This series introduces a dedicated block group for tree-log blocks to
create two metadata writing streams, one for tree-log blocks and the
other for metadata blocks. As a result, each write stream can now be
written to devices separately and sequentially.

* Log-structured superblock

Superblock (and its copies) is the only data structure in btrfs which
has a fixed location on a device. Since we cannot overwrite in a
sequential write required zone, we cannot place superblock in the
zone.

This series implements superblock log writing. It uses two zones as a
circular buffer to write updated superblocks. Once the first zone is filled
up, start writing into the second zone. The first zone will be reset once
both zones are filled. We can determine the postion of the latest
superblock by reading the write pointer information from a device.

* Patch series organization

Patch 1 introduces the ZONED incompatible feature flag to indicate that the
btrfs volume was formatted for use on zoned block devices.

Patches 2 to 4 implement functions to gather information on the zones of
the device (zones type, write pointer position, and max_zone_append_size).

Patches 5 to 9 disable features which are not compatible with the
sequential write constraints of zoned block devices. These includes
space_cache, NODATACOW, fallocate, MIXED_BG and inode cache.

Patch 10 implements the log-structured superblock writing.

Patches 11 and 12 tweak the device extent allocation for ZONED mode and add
verification to check if a device extent is properly aligned to zones.

Patches 13 to 16 implements sequential block allocator for ZONED mode.

Patch 17 implement a zone reset for unused block groups.

Patches 18 to 28 implement the writing path for several types of IO
(non-compressed data, direct IO, and metadata). These include re-dirtying
once-freed metadata blocks to prevent write holes.

Patches 29 to 38 tweak some btrfs features work with ZONED mode. These
include device-replace, relocation, repairing IO error, and tree-log.

Finally, patch 28 adds the ZONED feature to the list of supported features.

* Patch testing note

This series is based on kdave/for-5.5.

** Zone-aware util-linux

Since the log-structured superblock feature changed the location of
superblock magic, the current util-linux (libblkid) cannot detect ZONED
btrfs anymore. You need to apply a to-be posted patch to util-linux to make
it "zone aware".

** Testing device

You need devices with zone append writing command support to run ZONED
btrfs.

Other than real devices, null_blk supports zone append write command. You
can use memory backed null_blk to run the test on it. Following script
creates 12800 MB /dev/nullb0.

    sysfs=/sys/kernel/config/nullb/nullb0
    size=12800 # MB
    
    # drop nullb0
    if [[ -d $sysfs ]]; then
            echo 0 > "${sysfs}"/power
            rmdir $sysfs
    fi
    lsmod | grep -q null_blk && rmmod null_blk
    modprobe null_blk nr_devices=0
    
    mkdir "${sysfs}"
    
    echo "${size}" > "${sysfs}"/size
    echo 1 > "${sysfs}"/zoned
    echo 0 > "${sysfs}"/zone_nr_conv
    echo 1 > "${sysfs}"/memory_backed
    
    echo 1 > "${sysfs}"/power
    udevadm settle

Zoned SCSI devices such as SMR HDDs or scsi_debug also support the zone
append command as an emulated command within the SCSI sd driver. This
emulation is completely transparent to the user and provides the same
semantic as a NVMe ZNS native drive support.

Also, there is a qemu patch available to enable NVMe ZNS device.

** xfstests

We ran xfstests on ZONED btrfs, and, if we omit some cases that are known
to fail currently, all test cases pass.

Cases that can be ignored:
1) failing also with the regular btrfs on regular devices,
2) trying to test fallocate feature without testing with
   "_require_xfs_io_command "falloc"",
3) trying to test incompatible features for ZONED btrfs (e.g. RAID5/6)
4) trying to use incompatible setup for ZONED btrfs (e.g. dm-linear not
   aligned to zone boundary, swap)
5) trying to create a file system with too small size, (we require at least
   9 zones to initiate a ZONED btrfs)
6) dropping original MKFS_OPTIONS ("-O zoned"), so it cannot create ZONED
   btrfs (btrfs/003)
7) having ENOSPC which incurred by larger metadata block group size

I will send a patch series for xfstests to handle these cases (2-6)
properly.

Also, you need to apply the following patch if you run xfstests with
tcmu devices. xfstests btrfs/003 failed to "_devmgt_add" after
"_devmgt_remove" without this patch.

https://marc.info/?l=linux-scsi&m=156498625421698&w=2

v6 https://lore.kernel.org/linux-btrfs/20191213040915.3502922-1-naohiro.aota@wdc.com/
v5 https://lore.kernel.org/linux-btrfs/20191204082513.857320-1-naohiro.aota@wdc.com/
v4 https://lwn.net/Articles/797061/
v3 https://lore.kernel.org/linux-btrfs/20190808093038.4163421-1-naohiro.aota@wdc.com/
v2 https://lore.kernel.org/linux-btrfs/20190607131025.31996-1-naohiro.aota@wdc.com/
v1 https://lore.kernel.org/linux-btrfs/20180809180450.5091-1-naota@elisp.net/

Changelog
v6:
 - Use bitmap helpers (Johannes)
 - Code cleanup (Johannes)
 - Rebased on kdave/for-5.5
 - Enable the tree-log feature.
 - Treat conventional zones as sequential zones, so we can now allow
   mixed allocation of conventional zone and sequential write required
   zone to construct a block group.
 - Implement log-structured superblock
   - No need for one conventional zone at the beginning of a device.
 - Fix deadlock of direct IO writing
 - Fix building with !CONFIG_BLK_DEV_ZONED (Johannes)
 - Fix leak of zone_info (Johannes)
v5:
 - Rebased on kdave/for-5.5
 - Enable the tree-log feature.
 - Treat conventional zones as sequential zones, so we can now allow
   mixed allocation of conventional zone and sequential write required
   zone to construct a block group.
 - Implement log-structured superblock
   - No need for one conventional zone at the beginning of a device.
 - Fix deadlock of direct IO writing
 - Fix building with !CONFIG_BLK_DEV_ZONED (Johannes)
 - Fix leak of zone_info (Johannes)
v4:
 - Move memory allcation of zone informattion out of
   btrfs_get_dev_zones() (Anand)
 - Add disabled features table in commit log (Anand)
 - Ensure "max_chunk_size >= devs_min * data_stripes * zone_size"
v3:
 - Serialize allocation and submit_bio instead of bio buffering in
   btrfs_map_bio().
 -- Disable async checksum/submit in HMZONED mode
 - Introduce helper functions and hmzoned.c/h (Josef, David)
 - Add support for repairing IO failure
 - Add support for NOCOW direct IO write (Josef)
 - Disable preallocation entirely
 -- Disable INODE_MAP_CACHE
 -- relocation is reworked not to rely on preallocation in HMZONED mode
 - Disable NODATACOW
 -Disable MIXED_BG
 - Device extent that cover super block position is banned (David)
v2:
 - Add support for dev-replace
 -- To support dev-replace, moved submit_buffer one layer up. It now
    handles bio instead of btrfs_bio.
 -- Mark unmirrored Block Group readonly only when there are writable
    mirrored BGs. Necessary to handle degraded RAID.
 - Expire worker use vanilla delayed_work instead of btrfs's async-thread
 - Device extent allocator now ensure that region is on the same zone type.
 - Add delayed allocation shrinking.
 - Rename btrfs_drop_dev_zonetypes() to btrfs_destroy_dev_zonetypes
 - Fix
 -- Use SECTOR_SHIFT (Nikolay)
 -- Use btrfs_err (Nikolay)


Naohiro Aota (39):
  btrfs: introduce ZONED feature flag
  btrfs: Get zone information of zoned block devices
  btrfs: Check and enable ZONED mode
  btrfs: introduce max_zone_append_size
  btrfs: disallow space_cache in ZONED mode
  btrfs: disallow NODATACOW in ZONED mode
  btrfs: disable fallocate in ZONED mode
  btrfs: disallow mixed-bg in ZONED mode
  btrfs: disallow inode_cache in ZONED mode
  btrfs: implement log-structured superblock for ZONED mode
  btrfs: implement zoned chunk allocator
  btrfs: verify device extent is aligned to zone
  btrfs: load zone's alloction offset
  btrfs: emulate write pointer for conventional zones
  btrfs: track unusable bytes for zones
  btrfs: do sequential extent allocation in ZONED mode
  btrfs: reset zones of unused block groups
  btrfs: redirty released extent buffers in ZONED mode
  btrfs: limit bio size under max_zone_append_size
  btrfs: limit ordered extent size to max_zone_append_size
  btrfs: extend btrfs_rmap_block for specifying a device
  btrfs: use ZONE_APPEND write for ZONED btrfs
  btrfs: handle REQ_OP_ZONE_APPEND as writing
  btrfs: enable zone append writing for direct IO
  btrfs: introduce dedicated data write path for ZONED mode
  btrfs: serialize meta IOs on ZONED mode
  btrfs: wait existing extents before truncating
  btrfs: avoid async metadata checksum on ZONED mode
  btrfs: mark block groups to copy for device-replace
  btrfs: implement cloning for ZONED device-replace
  btrfs: implement copying for ZONED device-replace
  btrfs: support dev-replace in ZONED mode
  btrfs: enable relocation in ZONED mode
  btrfs: relocate block group to repair IO failure in ZONED
  btrfs: split alloc_log_tree()
  btrfs: extend zoned allocator to use dedicated tree-log block group
  btrfs: serialize log transaction on ZONED mode
  btrfs: reorder log node allocation
  btrfs: enable to mount ZONED incompat flag

 fs/btrfs/Makefile           |    1 +
 fs/btrfs/block-group.c      |   85 ++-
 fs/btrfs/block-group.h      |   13 +
 fs/btrfs/ctree.h            |   12 +-
 fs/btrfs/dev-replace.c      |  187 +++++
 fs/btrfs/dev-replace.h      |    3 +
 fs/btrfs/disk-io.c          |   82 ++-
 fs/btrfs/disk-io.h          |    2 +
 fs/btrfs/extent-tree.c      |  206 +++++-
 fs/btrfs/extent_io.c        |   48 +-
 fs/btrfs/extent_io.h        |    2 +
 fs/btrfs/file.c             |    4 +
 fs/btrfs/free-space-cache.c |   58 ++
 fs/btrfs/free-space-cache.h |    4 +
 fs/btrfs/inode.c            |   72 +-
 fs/btrfs/ioctl.c            |    3 +
 fs/btrfs/ordered-data.c     |    3 +
 fs/btrfs/ordered-data.h     |    4 +
 fs/btrfs/relocation.c       |   35 +-
 fs/btrfs/scrub.c            |  145 ++++
 fs/btrfs/space-info.c       |   13 +-
 fs/btrfs/space-info.h       |    4 +-
 fs/btrfs/super.c            |   13 +-
 fs/btrfs/sysfs.c            |    4 +
 fs/btrfs/transaction.c      |   10 +
 fs/btrfs/transaction.h      |    3 +
 fs/btrfs/tree-log.c         |   50 +-
 fs/btrfs/volumes.c          |  307 ++++++++-
 fs/btrfs/volumes.h          |    7 +
 fs/btrfs/zoned.c            | 1279 +++++++++++++++++++++++++++++++++++
 fs/btrfs/zoned.h            |  281 ++++++++
 include/uapi/linux/btrfs.h  |    1 +
 32 files changed, 2864 insertions(+), 77 deletions(-)
 create mode 100644 fs/btrfs/zoned.c
 create mode 100644 fs/btrfs/zoned.h

-- 
2.27.0

[PATCH v7 01/39] btrfs: introduce ZONED feature flag

[Naohiro Aota]

This patch introduces the ZONED incompat flag. The flag indicates that the
volume management will satisfy the constraints imposed by host-managed
zoned block devices.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/sysfs.c           | 2 ++
 include/uapi/linux/btrfs.h | 1 +
 2 files changed, 3 insertions(+)

diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index c8df2edafd85..38c7a57789d8 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -262,6 +262,7 @@ BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES);
 BTRFS_FEAT_ATTR_INCOMPAT(metadata_uuid, METADATA_UUID);
 BTRFS_FEAT_ATTR_COMPAT_RO(free_space_tree, FREE_SPACE_TREE);
 BTRFS_FEAT_ATTR_INCOMPAT(raid1c34, RAID1C34);
+BTRFS_FEAT_ATTR_INCOMPAT(zoned, ZONED);
 
 static struct attribute *btrfs_supported_feature_attrs[] = {
 	BTRFS_FEAT_ATTR_PTR(mixed_backref),
@@ -277,6 +278,7 @@ static struct attribute *btrfs_supported_feature_attrs[] = {
 	BTRFS_FEAT_ATTR_PTR(metadata_uuid),
 	BTRFS_FEAT_ATTR_PTR(free_space_tree),
 	BTRFS_FEAT_ATTR_PTR(raid1c34),
+	BTRFS_FEAT_ATTR_PTR(zoned),
 	NULL
 };
 
diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
index 2c39d15a2beb..5df73001aad4 100644
--- a/include/uapi/linux/btrfs.h
+++ b/include/uapi/linux/btrfs.h
@@ -307,6 +307,7 @@ struct btrfs_ioctl_fs_info_args {
 #define BTRFS_FEATURE_INCOMPAT_NO_HOLES		(1ULL << 9)
 #define BTRFS_FEATURE_INCOMPAT_METADATA_UUID	(1ULL << 10)
 #define BTRFS_FEATURE_INCOMPAT_RAID1C34		(1ULL << 11)
+#define BTRFS_FEATURE_INCOMPAT_ZONED		(1ULL << 12)
 
 struct btrfs_ioctl_feature_flags {
 	__u64 compat_flags;
-- 
2.27.0

[PATCH v7 02/39] btrfs: Get zone information of zoned block devices

[Naohiro Aota]

If a zoned block device is found, get its zone information (number of zones
and zone size) using the new helper function btrfs_get_dev_zone_info().  To
avoid costly run-time zone report commands to test the device zones type
during block allocation, attach the seq_zones bitmap to the device
structure to indicate if a zone is sequential or accept random writes. Also
it attaches the empty_zones bitmap to indicate if a zone is empty or not.

This patch also introduces the helper function btrfs_dev_is_sequential() to
test if the zone storing a block is a sequential write required zone and
btrfs_dev_is_empty_zone() to test if the zone is a empty zone.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/Makefile      |   1 +
 fs/btrfs/dev-replace.c |   5 ++
 fs/btrfs/volumes.c     |  18 ++++-
 fs/btrfs/volumes.h     |   4 +
 fs/btrfs/zoned.c       | 179 +++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/zoned.h       |  92 +++++++++++++++++++++
 6 files changed, 297 insertions(+), 2 deletions(-)
 create mode 100644 fs/btrfs/zoned.c
 create mode 100644 fs/btrfs/zoned.h

diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
index e738f6206ea5..0497fdc37f90 100644
--- a/fs/btrfs/Makefile
+++ b/fs/btrfs/Makefile
@@ -16,6 +16,7 @@ btrfs-y += super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \
 btrfs-$(CONFIG_BTRFS_FS_POSIX_ACL) += acl.o
 btrfs-$(CONFIG_BTRFS_FS_CHECK_INTEGRITY) += check-integrity.o
 btrfs-$(CONFIG_BTRFS_FS_REF_VERIFY) += ref-verify.o
+btrfs-$(CONFIG_BLK_DEV_ZONED) += zoned.o
 
 btrfs-$(CONFIG_BTRFS_FS_RUN_SANITY_TESTS) += tests/free-space-tests.o \
 	tests/extent-buffer-tests.o tests/btrfs-tests.o \
diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index db93909b25e0..83ee7371136c 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -21,6 +21,7 @@
 #include "rcu-string.h"
 #include "dev-replace.h"
 #include "sysfs.h"
+#include "zoned.h"
 
 /*
  * Device replace overview
@@ -297,6 +298,10 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
 	set_blocksize(device->bdev, BTRFS_BDEV_BLOCKSIZE);
 	device->fs_devices = fs_info->fs_devices;
 
+	ret = btrfs_get_dev_zone_info(device);
+	if (ret)
+		goto error;
+
 	mutex_lock(&fs_info->fs_devices->device_list_mutex);
 	list_add(&device->dev_list, &fs_info->fs_devices->devices);
 	fs_info->fs_devices->num_devices++;
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 214856c4ccb1..ce612cb900cd 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -30,6 +30,7 @@
 #include "space-info.h"
 #include "block-group.h"
 #include "discard.h"
+#include "zoned.h"
 
 const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
 	[BTRFS_RAID_RAID10] = {
@@ -372,6 +373,7 @@ void btrfs_free_device(struct btrfs_device *device)
 	rcu_string_free(device->name);
 	extent_io_tree_release(&device->alloc_state);
 	bio_put(device->flush_bio);
+	btrfs_destroy_dev_zone_info(device);
 	kfree(device);
 }
 
@@ -666,6 +668,11 @@ static int btrfs_open_one_device(struct btrfs_fs_devices *fs_devices,
 	clear_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state);
 	device->mode = flags;
 
+	/* Get zone type information of zoned block devices */
+	ret = btrfs_get_dev_zone_info(device);
+	if (ret != 0)
+		goto error_free_page;
+
 	fs_devices->open_devices++;
 	if (test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state) &&
 	    device->devid != BTRFS_DEV_REPLACE_DEVID) {
@@ -2553,6 +2560,14 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path
 	}
 	rcu_assign_pointer(device->name, name);
 
+	device->fs_info = fs_info;
+	device->bdev = bdev;
+
+	/* Get zone type information of zoned block devices */
+	ret = btrfs_get_dev_zone_info(device);
+	if (ret)
+		goto error_free_device;
+
 	trans = btrfs_start_transaction(root, 0);
 	if (IS_ERR(trans)) {
 		ret = PTR_ERR(trans);
@@ -2569,8 +2584,6 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path
 					 fs_info->sectorsize);
 	device->disk_total_bytes = device->total_bytes;
 	device->commit_total_bytes = device->total_bytes;
-	device->fs_info = fs_info;
-	device->bdev = bdev;
 	set_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state);
 	clear_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state);
 	device->mode = FMODE_EXCL;
@@ -2713,6 +2726,7 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path
 		sb->s_flags |= SB_RDONLY;
 	if (trans)
 		btrfs_end_transaction(trans);
+	btrfs_destroy_dev_zone_info(device);
 error_free_device:
 	btrfs_free_device(device);
 error:
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 5eea93916fbf..a7ae1a02c6d2 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -51,6 +51,8 @@ struct btrfs_io_geometry {
 #define BTRFS_DEV_STATE_REPLACE_TGT	(3)
 #define BTRFS_DEV_STATE_FLUSH_SENT	(4)
 
+struct btrfs_zoned_device_info;
+
 struct btrfs_device {
 	struct list_head dev_list; /* device_list_mutex */
 	struct list_head dev_alloc_list; /* chunk mutex */
@@ -64,6 +66,8 @@ struct btrfs_device {
 
 	struct block_device *bdev;
 
+	struct btrfs_zoned_device_info *zone_info;
+
 	/* the mode sent to blkdev_get */
 	fmode_t mode;
 
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
new file mode 100644
index 000000000000..0c908f0e9469
--- /dev/null
+++ b/fs/btrfs/zoned.c
@@ -0,0 +1,179 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ * Authors:
+ *	Naohiro Aota	<naohiro.aota@wdc.com>
+ *	Damien Le Moal	<damien.lemoal@wdc.com>
+ */
+
+#include <linux/slab.h>
+#include <linux/blkdev.h>
+#include "ctree.h"
+#include "volumes.h"
+#include "zoned.h"
+#include "rcu-string.h"
+
+/* Maximum number of zones to report per blkdev_report_zones() call */
+#define BTRFS_REPORT_NR_ZONES   4096
+
+static int copy_zone_info_cb(struct blk_zone *zone, unsigned int idx,
+			     void *data)
+{
+	struct blk_zone *zones = data;
+
+	memcpy(&zones[idx], zone, sizeof(*zone));
+
+	return 0;
+}
+
+static int btrfs_get_dev_zones(struct btrfs_device *device, u64 pos,
+			       struct blk_zone *zones, unsigned int *nr_zones)
+{
+	int ret;
+
+	if (!*nr_zones)
+		return 0;
+
+	ret = blkdev_report_zones(device->bdev, pos >> SECTOR_SHIFT, *nr_zones,
+				  copy_zone_info_cb, zones);
+	if (ret < 0) {
+		btrfs_err_in_rcu(device->fs_info,
+				 "get zone at %llu on %s failed %d", pos,
+				 rcu_str_deref(device->name), ret);
+		return ret;
+	}
+	*nr_zones = ret;
+	if (!ret)
+		return -EIO;
+
+	return 0;
+}
+
+int btrfs_get_dev_zone_info(struct btrfs_device *device)
+{
+	struct btrfs_zoned_device_info *zone_info = NULL;
+	struct block_device *bdev = device->bdev;
+	sector_t nr_sectors = bdev->bd_part->nr_sects;
+	sector_t sector = 0;
+	struct blk_zone *zones = NULL;
+	unsigned int i, nreported = 0, nr_zones;
+	unsigned int zone_sectors;
+	int ret;
+	char devstr[sizeof(device->fs_info->sb->s_id) +
+		    sizeof(" (device )") - 1];
+
+	if (!bdev_is_zoned(bdev))
+		return 0;
+
+	zone_info = kzalloc(sizeof(*zone_info), GFP_KERNEL);
+	if (!zone_info)
+		return -ENOMEM;
+
+	zone_sectors = bdev_zone_sectors(bdev);
+	ASSERT(is_power_of_2(zone_sectors));
+	zone_info->zone_size = (u64)zone_sectors << SECTOR_SHIFT;
+	zone_info->zone_size_shift = ilog2(zone_info->zone_size);
+	zone_info->nr_zones = nr_sectors >> ilog2(bdev_zone_sectors(bdev));
+	if (!IS_ALIGNED(nr_sectors, zone_sectors))
+		zone_info->nr_zones++;
+
+	zone_info->seq_zones = bitmap_zalloc(zone_info->nr_zones, GFP_KERNEL);
+	if (!zone_info->seq_zones) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	zone_info->empty_zones = bitmap_zalloc(zone_info->nr_zones, GFP_KERNEL);
+	if (!zone_info->empty_zones) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	zones = kcalloc(BTRFS_REPORT_NR_ZONES,
+			sizeof(struct blk_zone), GFP_KERNEL);
+	if (!zones) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	/* Get zones type */
+	while (sector < nr_sectors) {
+		nr_zones = BTRFS_REPORT_NR_ZONES;
+		ret = btrfs_get_dev_zones(device, sector << SECTOR_SHIFT, zones,
+					  &nr_zones);
+		if (ret)
+			goto out;
+
+		for (i = 0; i < nr_zones; i++) {
+			if (zones[i].type == BLK_ZONE_TYPE_SEQWRITE_REQ)
+				set_bit(nreported, zone_info->seq_zones);
+			if (zones[i].cond == BLK_ZONE_COND_EMPTY)
+				set_bit(nreported, zone_info->empty_zones);
+			nreported++;
+		}
+		sector = zones[nr_zones - 1].start + zones[nr_zones - 1].len;
+	}
+
+	if (nreported != zone_info->nr_zones) {
+		btrfs_err_in_rcu(device->fs_info,
+				 "inconsistent number of zones on %s (%u / %u)",
+				 rcu_str_deref(device->name), nreported,
+				 zone_info->nr_zones);
+		ret = -EIO;
+		goto out;
+	}
+
+	kfree(zones);
+
+	device->zone_info = zone_info;
+
+	devstr[0] = 0;
+	if (device->fs_info)
+		snprintf(devstr, sizeof(devstr), " (device %s)",
+			 device->fs_info->sb->s_id);
+
+	rcu_read_lock();
+	pr_info(
+"BTRFS info%s: host-%s zoned block device %s, %u zones of %llu sectors",
+		devstr,
+		bdev_zoned_model(bdev) == BLK_ZONED_HM ? "managed" : "aware",
+		rcu_str_deref(device->name), zone_info->nr_zones,
+		zone_info->zone_size >> SECTOR_SHIFT);
+	rcu_read_unlock();
+
+	return 0;
+
+out:
+	kfree(zones);
+	bitmap_free(zone_info->empty_zones);
+	bitmap_free(zone_info->seq_zones);
+	kfree(zone_info);
+
+	return ret;
+}
+
+void btrfs_destroy_dev_zone_info(struct btrfs_device *device)
+{
+	struct btrfs_zoned_device_info *zone_info = device->zone_info;
+
+	if (!zone_info)
+		return;
+
+	bitmap_free(zone_info->seq_zones);
+	bitmap_free(zone_info->empty_zones);
+	kfree(zone_info);
+	device->zone_info = NULL;
+}
+
+int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
+		       struct blk_zone *zone)
+{
+	unsigned int nr_zones = 1;
+	int ret;
+
+	ret = btrfs_get_dev_zones(device, pos, zone, &nr_zones);
+	if (ret != 0 || !nr_zones)
+		return ret ? ret : -EIO;
+
+	return 0;
+}
diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h
new file mode 100644
index 000000000000..e4a08ae0a96b
--- /dev/null
+++ b/fs/btrfs/zoned.h
@@ -0,0 +1,92 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ * Authors:
+ *	Naohiro Aota	<naohiro.aota@wdc.com>
+ *	Damien Le Moal	<damien.lemoal@wdc.com>
+ */
+
+#ifndef BTRFS_ZONED_H
+#define BTRFS_ZONED_H
+
+struct btrfs_zoned_device_info {
+	/*
+	 * Number of zones, zone size and types of zones if bdev is a
+	 * zoned block device.
+	 */
+	u64 zone_size;
+	u8  zone_size_shift;
+	u32 nr_zones;
+	unsigned long *seq_zones;
+	unsigned long *empty_zones;
+};
+
+#ifdef CONFIG_BLK_DEV_ZONED
+int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
+		       struct blk_zone *zone);
+int btrfs_get_dev_zone_info(struct btrfs_device *device);
+void btrfs_destroy_dev_zone_info(struct btrfs_device *device);
+#else /* CONFIG_BLK_DEV_ZONED */
+static inline int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
+				     struct blk_zone *zone)
+{
+	return 0;
+}
+static inline int btrfs_get_dev_zone_info(struct btrfs_device *device)
+{
+	return 0;
+}
+static inline void btrfs_destroy_dev_zone_info(struct btrfs_device *device) { }
+#endif
+
+static inline bool btrfs_dev_is_sequential(struct btrfs_device *device, u64 pos)
+{
+	struct btrfs_zoned_device_info *zone_info = device->zone_info;
+
+	if (!zone_info)
+		return false;
+
+	return test_bit(pos >> zone_info->zone_size_shift,
+			zone_info->seq_zones);
+}
+
+static inline bool btrfs_dev_is_empty_zone(struct btrfs_device *device, u64 pos)
+{
+	struct btrfs_zoned_device_info *zone_info = device->zone_info;
+
+	if (!zone_info)
+		return true;
+
+	return test_bit(pos >> zone_info->zone_size_shift,
+			zone_info->empty_zones);
+}
+
+static inline void btrfs_dev_set_empty_zone_bit(struct btrfs_device *device,
+						u64 pos, bool set)
+{
+	struct btrfs_zoned_device_info *zone_info = device->zone_info;
+	unsigned int zno;
+
+	if (!zone_info)
+		return;
+
+	zno = pos >> zone_info->zone_size_shift;
+	if (set)
+		set_bit(zno, zone_info->empty_zones);
+	else
+		clear_bit(zno, zone_info->empty_zones);
+}
+
+static inline void btrfs_dev_set_zone_empty(struct btrfs_device *device,
+					    u64 pos)
+{
+	btrfs_dev_set_empty_zone_bit(device, pos, true);
+}
+
+static inline void btrfs_dev_clear_zone_empty(struct btrfs_device *device,
+					      u64 pos)
+{
+	btrfs_dev_set_empty_zone_bit(device, pos, false);
+}
+
+#endif
-- 
2.27.0

[PATCH v7 03/39] btrfs: Check and enable ZONED mode

[Naohiro Aota]

This commit introduces the function btrfs_check_zoned_mode() to check if
ZONED flag is enabled on the file system and if the file system consists of
zoned devices with equal zone size.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/ctree.h       |  3 ++
 fs/btrfs/dev-replace.c |  7 ++++
 fs/btrfs/disk-io.c     |  9 +++++
 fs/btrfs/super.c       |  1 +
 fs/btrfs/volumes.c     |  5 +++
 fs/btrfs/zoned.c       | 78 ++++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/zoned.h       | 26 ++++++++++++++
 7 files changed, 129 insertions(+)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 4455eb3f3683..f5ed8f5519dd 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -580,6 +580,9 @@ struct btrfs_fs_info {
 	struct btrfs_root *free_space_root;
 	struct btrfs_root *data_reloc_root;
 
+	/* Zone size when in ZONED mode */
+	u64 zone_size;
+
 	/* the log root tree is a directory of all the other log roots */
 	struct btrfs_root *log_root_tree;
 
diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index 83ee7371136c..18a36973f973 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -243,6 +243,13 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
 		return PTR_ERR(bdev);
 	}
 
+	if (!btrfs_check_device_zone_type(fs_info, bdev)) {
+		btrfs_err(fs_info,
+			  "zone type of target device mismatch with the filesystem!");
+		ret = -EINVAL;
+		goto error;
+	}
+
 	sync_blockdev(bdev);
 
 	devices = &fs_info->fs_devices->devices;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 465bc8372e09..f7c2d1d26026 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -42,6 +42,7 @@
 #include "block-group.h"
 #include "discard.h"
 #include "space-info.h"
+#include "zoned.h"
 
 #define BTRFS_SUPER_FLAG_SUPP	(BTRFS_HEADER_FLAG_WRITTEN |\
 				 BTRFS_HEADER_FLAG_RELOC |\
@@ -3212,7 +3213,15 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
 
 	btrfs_free_extra_devids(fs_devices, 1);
 
+	ret = btrfs_check_zoned_mode(fs_info);
+	if (ret) {
+		btrfs_err(fs_info, "failed to init ZONED mode: %d",
+				ret);
+		goto fail_block_groups;
+	}
+
 	ret = btrfs_sysfs_add_fsid(fs_devices);
+
 	if (ret) {
 		btrfs_err(fs_info, "failed to init sysfs fsid interface: %d",
 				ret);
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 25967ecaaf0a..27a3a053f330 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -44,6 +44,7 @@
 #include "backref.h"
 #include "space-info.h"
 #include "sysfs.h"
+#include "zoned.h"
 #include "tests/btrfs-tests.h"
 #include "block-group.h"
 #include "discard.h"
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index ce612cb900cd..d736d5391fac 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2527,6 +2527,11 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path
 	if (IS_ERR(bdev))
 		return PTR_ERR(bdev);
 
+	if (!btrfs_check_device_zone_type(fs_info, bdev)) {
+		ret = -EINVAL;
+		goto error;
+	}
+
 	if (fs_devices->seeding) {
 		seeding_dev = 1;
 		down_write(&sb->s_umount);
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 0c908f0e9469..7509888b457a 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -177,3 +177,81 @@ int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
 
 	return 0;
 }
+
+int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info)
+{
+	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
+	struct btrfs_device *device;
+	u64 hmzoned_devices = 0;
+	u64 nr_devices = 0;
+	u64 zone_size = 0;
+	int incompat_zoned = btrfs_fs_incompat(fs_info, ZONED);
+	int ret = 0;
+
+	/* Count zoned devices */
+	list_for_each_entry(device, &fs_devices->devices, dev_list) {
+		enum blk_zoned_model model;
+
+		if (!device->bdev)
+			continue;
+
+		model = bdev_zoned_model(device->bdev);
+		if (model == BLK_ZONED_HM ||
+		    (model == BLK_ZONED_HA && incompat_zoned)) {
+			hmzoned_devices++;
+			if (!zone_size) {
+				zone_size = device->zone_info->zone_size;
+			} else if (device->zone_info->zone_size != zone_size) {
+				btrfs_err(fs_info,
+					  "Zoned block devices must have equal zone sizes");
+				ret = -EINVAL;
+				goto out;
+			}
+		}
+		nr_devices++;
+	}
+
+	if (!hmzoned_devices && !incompat_zoned)
+		goto out;
+
+	if (!hmzoned_devices && incompat_zoned) {
+		/* No zoned block device found on ZONED FS */
+		btrfs_err(fs_info,
+			  "ZONED enabled file system should have zoned devices");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (hmzoned_devices && !incompat_zoned) {
+		btrfs_err(fs_info,
+			  "Enable ZONED mode to mount HMZONED device");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (hmzoned_devices != nr_devices) {
+		btrfs_err(fs_info,
+			  "zoned devices cannot be mixed with regular devices");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/*
+	 * stripe_size is always aligned to BTRFS_STRIPE_LEN in
+	 * __btrfs_alloc_chunk(). Since we want stripe_len == zone_size,
+	 * check the alignment here.
+	 */
+	if (!IS_ALIGNED(zone_size, BTRFS_STRIPE_LEN)) {
+		btrfs_err(fs_info,
+			  "zone size is not aligned to BTRFS_STRIPE_LEN");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	fs_info->zone_size = zone_size;
+
+	btrfs_info(fs_info, "ZONED mode enabled, zone size %llu B",
+		   fs_info->zone_size);
+out:
+	return ret;
+}
diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h
index e4a08ae0a96b..4341630cb756 100644
--- a/fs/btrfs/zoned.h
+++ b/fs/btrfs/zoned.h
@@ -9,6 +9,8 @@
 #ifndef BTRFS_ZONED_H
 #define BTRFS_ZONED_H
 
+#include <linux/blkdev.h>
+
 struct btrfs_zoned_device_info {
 	/*
 	 * Number of zones, zone size and types of zones if bdev is a
@@ -26,6 +28,7 @@ int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
 		       struct blk_zone *zone);
 int btrfs_get_dev_zone_info(struct btrfs_device *device);
 void btrfs_destroy_dev_zone_info(struct btrfs_device *device);
+int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info);
 #else /* CONFIG_BLK_DEV_ZONED */
 static inline int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
 				     struct blk_zone *zone)
@@ -37,6 +40,14 @@ static inline int btrfs_get_dev_zone_info(struct btrfs_device *device)
 	return 0;
 }
 static inline void btrfs_destroy_dev_zone_info(struct btrfs_device *device) { }
+static inline int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info)
+{
+	if (!btrfs_fs_incompat(fs_info, ZONED))
+		return 0;
+
+	btrfs_err(fs_info, "Zoned block devices support is not enabled");
+	return -EOPNOTSUPP;
+}
 #endif
 
 static inline bool btrfs_dev_is_sequential(struct btrfs_device *device, u64 pos)
@@ -89,4 +100,19 @@ static inline void btrfs_dev_clear_zone_empty(struct btrfs_device *device,
 	btrfs_dev_set_empty_zone_bit(device, pos, false);
 }
 
+static inline bool btrfs_check_device_zone_type(struct btrfs_fs_info *fs_info,
+						struct block_device *bdev)
+{
+	u64 zone_size;
+
+	if (btrfs_fs_incompat(fs_info, ZONED)) {
+		zone_size = (u64)bdev_zone_sectors(bdev) << SECTOR_SHIFT;
+		/* Do not allow non-zoned device */
+		return bdev_is_zoned(bdev) && fs_info->zone_size == zone_size;
+	}
+
+	/* Do not allow Host Manged zoned device */
+	return bdev_zoned_model(bdev) != BLK_ZONED_HM;
+}
+
 #endif
-- 
2.27.0

[PATCH v7 04/39] btrfs: introduce max_zone_append_size

[Naohiro Aota]

Zone append write command has a maximum IO size restriction it accepts.
Introduce max_zone_append_size to zone_info and fs_into to track the value.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/ctree.h |  2 ++
 fs/btrfs/zoned.c | 17 +++++++++++++++--
 fs/btrfs/zoned.h |  1 +
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index f5ed8f5519dd..54c22ad0d633 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -582,6 +582,8 @@ struct btrfs_fs_info {
 
 	/* Zone size when in ZONED mode */
 	u64 zone_size;
+	/* max size to emit ZONE_APPEND write command */
+	u64 max_zone_append_size;
 
 	/* the log root tree is a directory of all the other log roots */
 	struct btrfs_root *log_root_tree;
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 7509888b457a..2e12fce81abf 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -53,6 +53,7 @@ int btrfs_get_dev_zone_info(struct btrfs_device *device)
 {
 	struct btrfs_zoned_device_info *zone_info = NULL;
 	struct block_device *bdev = device->bdev;
+	struct request_queue *q = bdev_get_queue(bdev);
 	sector_t nr_sectors = bdev->bd_part->nr_sects;
 	sector_t sector = 0;
 	struct blk_zone *zones = NULL;
@@ -73,6 +74,8 @@ int btrfs_get_dev_zone_info(struct btrfs_device *device)
 	ASSERT(is_power_of_2(zone_sectors));
 	zone_info->zone_size = (u64)zone_sectors << SECTOR_SHIFT;
 	zone_info->zone_size_shift = ilog2(zone_info->zone_size);
+	zone_info->max_zone_append_size =
+		(u64)queue_max_zone_append_sectors(q) << SECTOR_SHIFT;
 	zone_info->nr_zones = nr_sectors >> ilog2(bdev_zone_sectors(bdev));
 	if (!IS_ALIGNED(nr_sectors, zone_sectors))
 		zone_info->nr_zones++;
@@ -185,6 +188,7 @@ int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info)
 	u64 hmzoned_devices = 0;
 	u64 nr_devices = 0;
 	u64 zone_size = 0;
+	u64 max_zone_append_size = 0;
 	int incompat_zoned = btrfs_fs_incompat(fs_info, ZONED);
 	int ret = 0;
 
@@ -198,15 +202,23 @@ int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info)
 		model = bdev_zoned_model(device->bdev);
 		if (model == BLK_ZONED_HM ||
 		    (model == BLK_ZONED_HA && incompat_zoned)) {
+			struct btrfs_zoned_device_info *zone_info =
+				device->zone_info;
+
 			hmzoned_devices++;
 			if (!zone_size) {
-				zone_size = device->zone_info->zone_size;
-			} else if (device->zone_info->zone_size != zone_size) {
+				zone_size = zone_info->zone_size;
+			} else if (zone_info->zone_size != zone_size) {
 				btrfs_err(fs_info,
 					  "Zoned block devices must have equal zone sizes");
 				ret = -EINVAL;
 				goto out;
 			}
+			if (!max_zone_append_size ||
+			    (zone_info->max_zone_append_size &&
+			     zone_info->max_zone_append_size < max_zone_append_size))
+				max_zone_append_size =
+					zone_info->max_zone_append_size;
 		}
 		nr_devices++;
 	}
@@ -249,6 +261,7 @@ int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info)
 	}
 
 	fs_info->zone_size = zone_size;
+	fs_info->max_zone_append_size = max_zone_append_size;
 
 	btrfs_info(fs_info, "ZONED mode enabled, zone size %llu B",
 		   fs_info->zone_size);
diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h
index 4341630cb756..f200b46a71fb 100644
--- a/fs/btrfs/zoned.h
+++ b/fs/btrfs/zoned.h
@@ -18,6 +18,7 @@ struct btrfs_zoned_device_info {
 	 */
 	u64 zone_size;
 	u8  zone_size_shift;
+	u64 max_zone_append_size;
 	u32 nr_zones;
 	unsigned long *seq_zones;
 	unsigned long *empty_zones;
-- 
2.27.0

[PATCH v7 05/39] btrfs: disallow space_cache in ZONED mode

[Naohiro Aota]

As updates to the space cache v1 are in-place, the space cache cannot be
located over sequential zones and there is no guarantees that the device
will have enough conventional zones to store this cache. Resolve this
problem by disabling completely the space cache v1.  This does not
introduces any problems with sequential block groups: all the free space is
located after the allocation pointer and no free space before the pointer.
There is no need to have such cache.

Note: we can technically use free-space-tree (space cache v2) on ZONED
mode. But, since ZONED mode now always allocate extents in a block group
sequentially regardless of underlying device zone type, it's no use to
enable and maintain the tree.

For the same reason, NODATACOW is also disabled.

Also INODE_MAP_CACHE is also disabled to avoid preallocation in the
INODE_MAP_CACHE inode.

In summary, ZONED will disable:

| Disabled features | Reason                                              |
|-------------------+-----------------------------------------------------|
| RAID/Dup          | Cannot handle two zone append writes to different   |
|                   | zones                                               |
|-------------------+-----------------------------------------------------|
| space_cache (v1)  | In-place updating                                   |
| NODATACOW         | In-place updating                                   |
|-------------------+-----------------------------------------------------|
| fallocate         | Reserved extent will be a write hole                |
| INODE_MAP_CACHE   | Need pre-allocation. (and will be deprecated?)      |
|-------------------+-----------------------------------------------------|
| MIXED_BG          | Allocated metadata region will be write holes for   |
|                   | data writes                                         |

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/super.c | 12 ++++++++++--
 fs/btrfs/zoned.c | 18 ++++++++++++++++++
 fs/btrfs/zoned.h |  5 +++++
 3 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 27a3a053f330..3fbffc7ce42b 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -525,8 +525,14 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
 	cache_gen = btrfs_super_cache_generation(info->super_copy);
 	if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
 		btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
-	else if (cache_gen)
-		btrfs_set_opt(info->mount_opt, SPACE_CACHE);
+	else if (cache_gen) {
+		if (btrfs_fs_incompat(info, ZONED)) {
+			btrfs_info(info,
+			"clearring existing space cache in ZONED mode");
+			btrfs_set_super_cache_generation(info->super_copy, 0);
+		} else
+			btrfs_set_opt(info->mount_opt, SPACE_CACHE);
+	}
 
 	/*
 	 * Even the options are empty, we still need to do extra check
@@ -985,6 +991,8 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
 		ret = -EINVAL;
 
 	}
+	if (!ret)
+		ret = btrfs_check_mountopts_zoned(info);
 	if (!ret && btrfs_test_opt(info, SPACE_CACHE))
 		btrfs_info(info, "disk space caching is enabled");
 	if (!ret && btrfs_test_opt(info, FREE_SPACE_TREE))
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 2e12fce81abf..1629e585ba8c 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -268,3 +268,21 @@ int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info)
 out:
 	return ret;
 }
+
+int btrfs_check_mountopts_zoned(struct btrfs_fs_info *info)
+{
+	if (!btrfs_fs_incompat(info, ZONED))
+		return 0;
+
+	/*
+	 * SPACE CACHE writing is not CoWed. Disable that to avoid write
+	 * errors in sequential zones.
+	 */
+	if (btrfs_test_opt(info, SPACE_CACHE)) {
+		btrfs_err(info,
+			  "space cache v1 not supportted in ZONED mode");
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h
index f200b46a71fb..2e1983188e6f 100644
--- a/fs/btrfs/zoned.h
+++ b/fs/btrfs/zoned.h
@@ -30,6 +30,7 @@ int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
 int btrfs_get_dev_zone_info(struct btrfs_device *device);
 void btrfs_destroy_dev_zone_info(struct btrfs_device *device);
 int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info);
+int btrfs_check_mountopts_zoned(struct btrfs_fs_info *info);
 #else /* CONFIG_BLK_DEV_ZONED */
 static inline int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
 				     struct blk_zone *zone)
@@ -49,6 +50,10 @@ static inline int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info)
 	btrfs_err(fs_info, "Zoned block devices support is not enabled");
 	return -EOPNOTSUPP;
 }
+static inline int btrfs_check_mountopts_zoned(struct btrfs_fs_info *info)
+{
+	return 0;
+}
 #endif
 
 static inline bool btrfs_dev_is_sequential(struct btrfs_device *device, u64 pos)
-- 
2.27.0

[PATCH v7 06/39] btrfs: disallow NODATACOW in ZONED mode

[Naohiro Aota]

NODATACOW implies overwriting the file data on a device, which is
impossible in sequential required zones. Disable NODATACOW globally with
mount option and per-file NODATACOW attribute by masking FS_NOCOW_FL.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/ioctl.c | 3 +++
 fs/btrfs/zoned.c | 6 ++++++
 2 files changed, 9 insertions(+)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index ac45f022b495..548692cdc5df 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -91,6 +91,9 @@ struct btrfs_ioctl_send_args_32 {
 static unsigned int btrfs_mask_fsflags_for_type(struct inode *inode,
 		unsigned int flags)
 {
+	if (btrfs_fs_incompat(btrfs_sb(inode->i_sb), ZONED))
+		flags &= ~FS_NOCOW_FL;
+
 	if (S_ISDIR(inode->i_mode))
 		return flags;
 	else if (S_ISREG(inode->i_mode))
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 1629e585ba8c..6bce654bb0e8 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -284,5 +284,11 @@ int btrfs_check_mountopts_zoned(struct btrfs_fs_info *info)
 		return -EOPNOTSUPP;
 	}
 
+	if (btrfs_test_opt(info, NODATACOW)) {
+		btrfs_err(info,
+		  "cannot enable nodatacow with ZONED mode");
+		return -EOPNOTSUPP;
+	}
+
 	return 0;
 }
-- 
2.27.0

[PATCH v7 07/39] btrfs: disable fallocate in ZONED mode

[Naohiro Aota]

fallocate() is implemented by reserving actual extent instead of
reservations. This can result in exposing the sequential write constraint
of host-managed zoned block devices to the application, which would break
the POSIX semantic for the fallocated file.  To avoid this, report
fallocate() as not supported when in ZONED mode for now.

In the future, we may be able to implement "in-memory" fallocate() in ZONED
mode by utilizing space_info->bytes_may_use or so.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/file.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 1395e537ad32..8843696c7f74 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -3309,6 +3309,10 @@ static long btrfs_fallocate(struct file *file, int mode,
 	alloc_end = round_up(offset + len, blocksize);
 	cur_offset = alloc_start;
 
+	/* Do not allow fallocate in ZONED mode */
+	if (btrfs_fs_incompat(btrfs_sb(inode->i_sb), ZONED))
+		return -EOPNOTSUPP;
+
 	/* Make sure we aren't being give some crap mode */
 	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
 		     FALLOC_FL_ZERO_RANGE))
-- 
2.27.0

[PATCH v7 08/39] btrfs: disallow mixed-bg in ZONED mode

[Naohiro Aota]

Placing both data and metadata in a block group is impossible in ZONED
mode. For data, we can allocate a space for it and write it immediately
after the allocation. For metadata, however, we cannot do so, because the
logical addresses are recorded in other metadata buffers to build up the
trees. As a result, a data buffer can be placed after a metadata buffer,
which is not written yet. Writing out the data buffer will break the
sequential write rule.

This commit check and disallow MIXED_BG with ZONED mode.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/zoned.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 6bce654bb0e8..8cd43d2d5611 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -260,6 +260,13 @@ int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info)
 		goto out;
 	}
 
+	if (btrfs_fs_incompat(fs_info, MIXED_GROUPS)) {
+		btrfs_err(fs_info,
+			  "ZONED mode is not allowed for mixed block groups");
+		ret = -EINVAL;
+		goto out;
+	}
+
 	fs_info->zone_size = zone_size;
 	fs_info->max_zone_append_size = max_zone_append_size;
 
-- 
2.27.0

[PATCH v7 09/39] btrfs: disallow inode_cache in ZONED mode

[Naohiro Aota]

inode_cache use pre-allocation to write its cache data. However,
pre-allocation is completely disabled in ZONED mode.

We can technically enable inode_cache in the same way as relocation.
However, inode_cache is rarely used and the man page discourage using it.
So, let's just disable it for now.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/zoned.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 8cd43d2d5611..e47698d313a5 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -297,5 +297,11 @@ int btrfs_check_mountopts_zoned(struct btrfs_fs_info *info)
 		return -EOPNOTSUPP;
 	}
 
+	if (btrfs_test_pending(info, SET_INODE_MAP_CACHE)) {
+		btrfs_err(info,
+		  "cannot enable inode map caching with ZONED mode");
+		return -EOPNOTSUPP;
+	}
+
 	return 0;
 }
-- 
2.27.0

[PATCH v7 10/39] btrfs: implement log-structured superblock for ZONED mode

[Naohiro Aota]

Superblock (and its copies) is the only data structure in btrfs which has a
fixed location on a device. Since we cannot overwrite in a sequential write
required zone, we cannot place superblock in the zone. One easy solution is
limiting superblock and copies to be placed only in conventional zones.
However, this method has two downsides: one is reduced number of superblock
copies. The location of the second copy of superblock is 256GB, which is in
a sequential write required zone on typical devices in the market today.
So, the number of superblock and copies is limited to be two.  Second
downside is that we cannot support devices which have no conventional zones
at all.

To solve these two problems, we employ superblock log writing. It uses two
zones as a circular buffer to write updated superblocks. Once the first
zone is filled up, start writing into the second buffer. Then, when the
both zones are filled up and before start writing to the first zone again,
it reset the first zone.

We can determine the position of the latest superblock by reading write
pointer information from a device. One corner case is when the both zones
are full. For this situation, we read out the last superblock of each
zone, and compare them to determine which zone is older.

The following zones are reserved as the circular buffer on ZONED btrfs.

- The primary superblock: zones 0 and 1
- The first copy: zones 16 and 17
- The second copy: zones 1024 or zone at 256GB which is minimum, and next
  to it

If these reserved zones are conventional, superblock is written fixed at
the start of the zone without logging.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/block-group.c |   9 ++
 fs/btrfs/disk-io.c     |  41 +++++-
 fs/btrfs/scrub.c       |   3 +
 fs/btrfs/volumes.c     |  21 ++-
 fs/btrfs/zoned.c       | 313 +++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/zoned.h       |  42 ++++++
 6 files changed, 417 insertions(+), 12 deletions(-)

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index ea8aaf36647e..4ac4aacfae04 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -1723,6 +1723,7 @@ int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
 static int exclude_super_stripes(struct btrfs_block_group *cache)
 {
 	struct btrfs_fs_info *fs_info = cache->fs_info;
+	bool zoned = btrfs_fs_incompat(fs_info, ZONED);
 	u64 bytenr;
 	u64 *logical;
 	int stripe_len;
@@ -1744,6 +1745,14 @@ static int exclude_super_stripes(struct btrfs_block_group *cache)
 		if (ret)
 			return ret;
 
+		/* shouldn't have super stripes in sequential zones */
+		if (zoned && nr) {
+			btrfs_err(fs_info,
+				  "Zoned btrfs's block group %llu should not have super blocks",
+				  cache->start);
+			return -EUCLEAN;
+		}
+
 		while (nr--) {
 			u64 len = min_t(u64, stripe_len,
 				cache->start + cache->length - logical[nr]);
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index f7c2d1d26026..362799403285 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3501,10 +3501,17 @@ struct btrfs_super_block *btrfs_read_dev_one_super(struct block_device *bdev,
 {
 	struct btrfs_super_block *super;
 	struct page *page;
-	u64 bytenr;
+	u64 bytenr, bytenr_orig;
 	struct address_space *mapping = bdev->bd_inode->i_mapping;
+	int ret;
+
+	bytenr_orig = btrfs_sb_offset(copy_num);
+	ret = btrfs_sb_log_location_bdev(bdev, copy_num, READ, &bytenr);
+	if (ret == -ENOENT)
+		return ERR_PTR(-EINVAL);
+	else if (ret)
+		return ERR_PTR(ret);
 
-	bytenr = btrfs_sb_offset(copy_num);
 	if (bytenr + BTRFS_SUPER_INFO_SIZE >= i_size_read(bdev->bd_inode))
 		return ERR_PTR(-EINVAL);
 
@@ -3513,7 +3520,7 @@ struct btrfs_super_block *btrfs_read_dev_one_super(struct block_device *bdev,
 		return ERR_CAST(page);
 
 	super = page_address(page);
-	if (btrfs_super_bytenr(super) != bytenr ||
+	if (btrfs_super_bytenr(super) != bytenr_orig ||
 		    btrfs_super_magic(super) != BTRFS_MAGIC) {
 		btrfs_release_disk_super(super);
 		return ERR_PTR(-EINVAL);
@@ -3569,7 +3576,8 @@ static int write_dev_supers(struct btrfs_device *device,
 	SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
 	int i;
 	int errors = 0;
-	u64 bytenr;
+	int ret;
+	u64 bytenr, bytenr_orig;
 
 	if (max_mirrors == 0)
 		max_mirrors = BTRFS_SUPER_MIRROR_MAX;
@@ -3581,12 +3589,21 @@ static int write_dev_supers(struct btrfs_device *device,
 		struct bio *bio;
 		struct btrfs_super_block *disk_super;
 
-		bytenr = btrfs_sb_offset(i);
+		bytenr_orig = btrfs_sb_offset(i);
+		ret = btrfs_sb_log_location(device, i, WRITE, &bytenr);
+		if (ret == -ENOENT)
+			continue;
+		else if (ret < 0) {
+			btrfs_err(device->fs_info, "couldn't get super block location for mirror %d",
+				  i);
+			errors++;
+			continue;
+		}
 		if (bytenr + BTRFS_SUPER_INFO_SIZE >=
 		    device->commit_total_bytes)
 			break;
 
-		btrfs_set_super_bytenr(sb, bytenr);
+		btrfs_set_super_bytenr(sb, bytenr_orig);
 
 		crypto_shash_digest(shash, (const char *)sb + BTRFS_CSUM_SIZE,
 				    BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE,
@@ -3631,6 +3648,7 @@ static int write_dev_supers(struct btrfs_device *device,
 			bio->bi_opf |= REQ_FUA;
 
 		btrfsic_submit_bio(bio);
+		btrfs_advance_sb_log(device, i);
 	}
 	return errors < i ? 0 : -1;
 }
@@ -3647,6 +3665,7 @@ static int wait_dev_supers(struct btrfs_device *device, int max_mirrors)
 	int i;
 	int errors = 0;
 	bool primary_failed = false;
+	int ret;
 	u64 bytenr;
 
 	if (max_mirrors == 0)
@@ -3655,7 +3674,15 @@ static int wait_dev_supers(struct btrfs_device *device, int max_mirrors)
 	for (i = 0; i < max_mirrors; i++) {
 		struct page *page;
 
-		bytenr = btrfs_sb_offset(i);
+		ret = btrfs_sb_log_location(device, i, READ, &bytenr);
+		if (ret == -ENOENT)
+			break;
+		else if (ret < 0) {
+			errors++;
+			if (i == 0)
+				primary_failed = true;
+			continue;
+		}
 		if (bytenr + BTRFS_SUPER_INFO_SIZE >=
 		    device->commit_total_bytes)
 			break;
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 354ab9985a34..e46c91188a75 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -20,6 +20,7 @@
 #include "rcu-string.h"
 #include "raid56.h"
 #include "block-group.h"
+#include "zoned.h"
 
 /*
  * This is only the first step towards a full-features scrub. It reads all
@@ -3704,6 +3705,8 @@ static noinline_for_stack int scrub_supers(struct scrub_ctx *sctx,
 		if (bytenr + BTRFS_SUPER_INFO_SIZE >
 		    scrub_dev->commit_total_bytes)
 			break;
+		if (!btrfs_check_super_location(scrub_dev, bytenr))
+			continue;
 
 		ret = scrub_pages(sctx, bytenr, BTRFS_SUPER_INFO_SIZE, bytenr,
 				  scrub_dev, BTRFS_EXTENT_FLAG_SUPER, gen, i,
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index d736d5391fac..22384c803ead 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1273,7 +1273,8 @@ void btrfs_release_disk_super(struct btrfs_super_block *super)
 }
 
 static struct btrfs_super_block *btrfs_read_disk_super(struct block_device *bdev,
-						       u64 bytenr)
+						       u64 bytenr,
+						       u64 bytenr_orig)
 {
 	struct btrfs_super_block *disk_super;
 	struct page *page;
@@ -1304,7 +1305,7 @@ static struct btrfs_super_block *btrfs_read_disk_super(struct block_device *bdev
 	/* align our pointer to the offset of the super block */
 	disk_super = p + offset_in_page(bytenr);
 
-	if (btrfs_super_bytenr(disk_super) != bytenr ||
+	if (btrfs_super_bytenr(disk_super) != bytenr_orig ||
 	    btrfs_super_magic(disk_super) != BTRFS_MAGIC) {
 		btrfs_release_disk_super(p);
 		return ERR_PTR(-EINVAL);
@@ -1339,7 +1340,8 @@ struct btrfs_device *btrfs_scan_one_device(const char *path, fmode_t flags,
 	bool new_device_added = false;
 	struct btrfs_device *device = NULL;
 	struct block_device *bdev;
-	u64 bytenr;
+	u64 bytenr, bytenr_orig;
+	int ret;
 
 	lockdep_assert_held(&uuid_mutex);
 
@@ -1349,14 +1351,18 @@ struct btrfs_device *btrfs_scan_one_device(const char *path, fmode_t flags,
 	 * So, we need to add a special mount option to scan for
 	 * later supers, using BTRFS_SUPER_MIRROR_MAX instead
 	 */
-	bytenr = btrfs_sb_offset(0);
 	flags |= FMODE_EXCL;
 
 	bdev = blkdev_get_by_path(path, flags, holder);
 	if (IS_ERR(bdev))
 		return ERR_CAST(bdev);
 
-	disk_super = btrfs_read_disk_super(bdev, bytenr);
+	bytenr_orig = btrfs_sb_offset(0);
+	ret = btrfs_sb_log_location_bdev(bdev, 0, READ, &bytenr);
+	if (ret)
+		return ERR_PTR(ret);
+
+	disk_super = btrfs_read_disk_super(bdev, bytenr, bytenr_orig);
 	if (IS_ERR(disk_super)) {
 		device = ERR_CAST(disk_super);
 		goto error_bdev_put;
@@ -2023,6 +2029,11 @@ static void btrfs_scratch_superblocks(struct btrfs_fs_info *fs_info,
 		if (IS_ERR(disk_super))
 			continue;
 
+		if (bdev_is_zoned(bdev)) {
+			btrfs_reset_sb_log_zones(bdev, copy_num);
+			continue;
+		}
+
 		memset(&disk_super->magic, 0, sizeof(disk_super->magic));
 
 		page = virt_to_page(disk_super);
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index e47698d313a5..6912b66f3130 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -26,6 +26,27 @@ static int copy_zone_info_cb(struct blk_zone *zone, unsigned int idx,
 	return 0;
 }
 
+static int sb_write_pointer(struct block_device *bdev, struct blk_zone *zone,
+			    u64 *wp_ret);
+
+static inline u32 sb_zone_number(u64 zone_size, int mirror)
+{
+	ASSERT(mirror < BTRFS_SUPER_MIRROR_MAX);
+
+	switch (mirror) {
+	case 0:
+		return 0;
+	case 1:
+		return 16;
+	case 2:
+		return min(btrfs_sb_offset(mirror) / zone_size, 1024ULL);
+	default:
+		BUG();
+	}
+
+	return 0;
+}
+
 static int btrfs_get_dev_zones(struct btrfs_device *device, u64 pos,
 			       struct blk_zone *zones, unsigned int *nr_zones)
 {
@@ -126,6 +147,40 @@ int btrfs_get_dev_zone_info(struct btrfs_device *device)
 		goto out;
 	}
 
+	nr_zones = 2;
+	for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
+		u32 sb_zone = sb_zone_number(zone_info->zone_size, i);
+		u64 sb_wp;
+
+		if (sb_zone + 1 >= zone_info->nr_zones)
+			continue;
+
+		sector = sb_zone << (zone_info->zone_size_shift - SECTOR_SHIFT);
+		ret = btrfs_get_dev_zones(device, sector << SECTOR_SHIFT,
+					  &zone_info->sb_zones[2 * i],
+					  &nr_zones);
+		if (ret)
+			goto out;
+		if (nr_zones != 2) {
+			btrfs_err_in_rcu(device->fs_info,
+			"failed to read SB log zone info at device %s zone %u",
+					 rcu_str_deref(device->name), sb_zone);
+			ret = -EIO;
+			goto out;
+		}
+
+		ret = sb_write_pointer(device->bdev,
+				       &zone_info->sb_zones[2 * i], &sb_wp);
+		if (ret != -ENOENT && ret) {
+			btrfs_err_in_rcu(device->fs_info,
+				"SB log zone corrupted: device %s zone %u",
+					 rcu_str_deref(device->name), sb_zone);
+			ret = -EUCLEAN;
+			goto out;
+		}
+	}
+
+
 	kfree(zones);
 
 	device->zone_info = zone_info;
@@ -305,3 +360,261 @@ int btrfs_check_mountopts_zoned(struct btrfs_fs_info *info)
 
 	return 0;
 }
+
+static int sb_write_pointer(struct block_device *bdev, struct blk_zone *zones,
+			    u64 *wp_ret)
+{
+	bool empty[2];
+	bool full[2];
+	sector_t sector;
+
+	ASSERT(zones[0].type != BLK_ZONE_TYPE_CONVENTIONAL &&
+	       zones[1].type != BLK_ZONE_TYPE_CONVENTIONAL);
+	if (zones[0].type == BLK_ZONE_TYPE_CONVENTIONAL) {
+		*wp_ret = zones[0].start << SECTOR_SHIFT;
+		return -ENOENT;
+	}
+
+	empty[0] = zones[0].cond == BLK_ZONE_COND_EMPTY;
+	empty[1] = zones[1].cond == BLK_ZONE_COND_EMPTY;
+	full[0] = zones[0].cond == BLK_ZONE_COND_FULL;
+	full[1] = zones[1].cond == BLK_ZONE_COND_FULL;
+
+	/*
+	 * Possible state of log buffer zones
+	 *
+	 *   E I F
+	 * E * x 0
+	 * I 0 x 0
+	 * F 1 1 C
+	 *
+	 * Row: zones[0]
+	 * Col: zones[1]
+	 * State:
+	 *   E: Empty, I: In-Use, F: Full
+	 * Log position:
+	 *   *: Special case, no superblock is written
+	 *   0: Use write pointer of zones[0]
+	 *   1: Use write pointer of zones[1]
+	 *   C: Compare SBs from zones[0] and zones[1], use the newer one
+	 *   x: Invalid state
+	 */
+
+	if (empty[0] && empty[1]) {
+		/* special case to distinguish no superblock to read */
+		*wp_ret = zones[0].start << SECTOR_SHIFT;
+		return -ENOENT;
+	} else if (full[0] && full[1]) {
+		/* Compare two super blocks */
+		struct address_space *mapping = bdev->bd_inode->i_mapping;
+		struct page *page[2];
+		struct btrfs_super_block *super[2];
+		u64 bytenr[2];
+		int i;
+
+		for (i = 0; i < 2; i++) {
+			bytenr[i] = ((zones[i].start + zones[i].len) << SECTOR_SHIFT) -
+				BTRFS_SUPER_INFO_SIZE;
+			page[i] = read_cache_page_gfp(mapping,
+						      bytenr[i] >> PAGE_SHIFT,
+						      GFP_NOFS);
+			if (IS_ERR(page[i])) {
+				if (i == 1)
+					btrfs_release_disk_super(super[0]);
+				return PTR_ERR(page[i]);
+			}
+			super[i] = page_address(page[i]);
+		}
+
+		if (super[0]->generation > super[1]->generation)
+			sector = zones[1].start;
+		else
+			sector = zones[0].start;
+
+		for (i = 0; i < 2; i++)
+			btrfs_release_disk_super(super[i]);
+	} else if (!full[0] && (empty[1] || full[1])) {
+		sector = zones[0].wp;
+	} else if (full[0]) {
+		sector = zones[1].wp;
+	} else {
+		return -EUCLEAN;
+	}
+	*wp_ret = sector << SECTOR_SHIFT;
+	return 0;
+}
+
+static int sb_log_location(struct block_device *bdev, struct blk_zone *zones,
+			   int rw, u64 *bytenr_ret)
+{
+	u64 wp;
+	int ret;
+
+	if (zones[0].type == BLK_ZONE_TYPE_CONVENTIONAL) {
+		*bytenr_ret = zones[0].start << SECTOR_SHIFT;
+		return 0;
+	}
+
+	ret = sb_write_pointer(bdev, zones, &wp);
+	if (ret != -ENOENT && ret < 0)
+		return ret;
+
+	if (rw == WRITE) {
+		struct blk_zone *reset = NULL;
+
+		if (wp == zones[0].start << SECTOR_SHIFT)
+			reset = &zones[0];
+		else if (wp == zones[1].start << SECTOR_SHIFT)
+			reset = &zones[1];
+
+		if (reset) {
+			ASSERT(reset->cond == BLK_ZONE_COND_FULL);
+
+			ret = blkdev_zone_mgmt(bdev, REQ_OP_ZONE_RESET,
+					       reset->start, reset->len,
+					       GFP_NOFS);
+			if (ret)
+				return ret;
+
+			reset->cond = BLK_ZONE_COND_EMPTY;
+			reset->wp = reset->start;
+		}
+	} else if (ret != -ENOENT) {
+		/* For READ, we want the precious one */
+		if (wp == zones[0].start << SECTOR_SHIFT)
+			wp = (zones[1].start + zones[1].len) << SECTOR_SHIFT;
+		wp -= BTRFS_SUPER_INFO_SIZE;
+	}
+
+	*bytenr_ret = wp;
+	return 0;
+
+}
+
+int btrfs_sb_log_location_bdev(struct block_device *bdev, int mirror, int rw,
+			       u64 *bytenr_ret)
+{
+	struct blk_zone zones[2];
+	unsigned int zone_sectors;
+	u32 sb_zone;
+	int ret;
+	u64 zone_size;
+	u8 zone_sectors_shift;
+	sector_t nr_sectors = bdev->bd_part->nr_sects;
+	u32 nr_zones;
+
+	if (!bdev_is_zoned(bdev)) {
+		*bytenr_ret = btrfs_sb_offset(mirror);
+		return 0;
+	}
+
+	ASSERT(rw == READ || rw == WRITE);
+
+	zone_sectors = bdev_zone_sectors(bdev);
+	if (!is_power_of_2(zone_sectors))
+		return -EINVAL;
+	zone_size = zone_sectors << SECTOR_SHIFT;
+	zone_sectors_shift = ilog2(zone_sectors);
+	nr_zones = nr_sectors >> zone_sectors_shift;
+
+	sb_zone = sb_zone_number(zone_size, mirror);
+	if (sb_zone + 1 >= nr_zones)
+		return -ENOENT;
+
+	ret = blkdev_report_zones(bdev, sb_zone << zone_sectors_shift, 2,
+				  copy_zone_info_cb, zones);
+	if (ret < 0)
+		return ret;
+	if (ret != 2)
+		return -EIO;
+
+	return sb_log_location(bdev, zones, rw, bytenr_ret);
+}
+
+int btrfs_sb_log_location(struct btrfs_device *device, int mirror, int rw,
+			  u64 *bytenr_ret)
+{
+	struct btrfs_zoned_device_info *zinfo = device->zone_info;
+	u32 zone_num;
+
+	if (!zinfo) {
+		*bytenr_ret = btrfs_sb_offset(mirror);
+		return 0;
+	}
+
+	zone_num = sb_zone_number(zinfo->zone_size, mirror);
+	if (zone_num + 1 >= zinfo->nr_zones)
+		return -ENOENT;
+
+	return sb_log_location(device->bdev, &zinfo->sb_zones[2 * mirror], rw,
+			       bytenr_ret);
+}
+
+static inline bool is_sb_log_zone(struct btrfs_zoned_device_info *zinfo,
+				  int mirror)
+{
+	u32 zone_num;
+
+	if (!zinfo)
+		return false;
+
+	zone_num = sb_zone_number(zinfo->zone_size, mirror);
+	if (zone_num + 1 >= zinfo->nr_zones)
+		return false;
+
+	if (!test_bit(zone_num, zinfo->seq_zones))
+		return false;
+
+	return true;
+}
+
+int btrfs_advance_sb_log(struct btrfs_device *device, int mirror)
+{
+	struct btrfs_zoned_device_info *zinfo = device->zone_info;
+	struct blk_zone *zone;
+	int ret;
+
+	if (!is_sb_log_zone(zinfo, mirror))
+		return 0;
+
+	zone = &zinfo->sb_zones[2 * mirror];
+	if (zone->cond != BLK_ZONE_COND_FULL) {
+		if (zone->cond == BLK_ZONE_COND_EMPTY)
+			zone->cond = BLK_ZONE_COND_IMP_OPEN;
+		zone->wp += (BTRFS_SUPER_INFO_SIZE >> SECTOR_SHIFT);
+		if (zone->wp == zone->start + zone->len)
+			zone->cond = BLK_ZONE_COND_FULL;
+		return 0;
+	}
+
+	zone++;
+	ASSERT(zone->cond != BLK_ZONE_COND_FULL);
+	if (zone->cond == BLK_ZONE_COND_EMPTY)
+		zone->cond = BLK_ZONE_COND_IMP_OPEN;
+	zone->wp += (BTRFS_SUPER_INFO_SIZE >> SECTOR_SHIFT);
+	if (zone->wp == zone->start + zone->len)
+		zone->cond = BLK_ZONE_COND_FULL;
+
+	return ret;
+}
+
+int btrfs_reset_sb_log_zones(struct block_device *bdev, int mirror)
+{
+	sector_t zone_sectors;
+	sector_t nr_sectors = bdev->bd_part->nr_sects;
+	u8 zone_sectors_shift;
+	u32 sb_zone;
+	u32 nr_zones;
+
+	zone_sectors = bdev_zone_sectors(bdev);
+	zone_sectors_shift = ilog2(zone_sectors);
+	nr_zones = nr_sectors >> zone_sectors_shift;
+
+	sb_zone = sb_zone_number(zone_sectors << SECTOR_SHIFT, mirror);
+	if (sb_zone + 1 >= nr_zones)
+		return -ENOENT;
+
+	return blkdev_zone_mgmt(bdev, REQ_OP_ZONE_RESET,
+				sb_zone << zone_sectors_shift, zone_sectors * 2,
+				GFP_NOFS);
+}
diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h
index 2e1983188e6f..e33c0e409b7d 100644
--- a/fs/btrfs/zoned.h
+++ b/fs/btrfs/zoned.h
@@ -10,6 +10,8 @@
 #define BTRFS_ZONED_H
 
 #include <linux/blkdev.h>
+#include "volumes.h"
+#include "disk-io.h"
 
 struct btrfs_zoned_device_info {
 	/*
@@ -22,6 +24,7 @@ struct btrfs_zoned_device_info {
 	u32 nr_zones;
 	unsigned long *seq_zones;
 	unsigned long *empty_zones;
+	struct blk_zone sb_zones[2 * BTRFS_SUPER_MIRROR_MAX];
 };
 
 #ifdef CONFIG_BLK_DEV_ZONED
@@ -31,6 +34,12 @@ int btrfs_get_dev_zone_info(struct btrfs_device *device);
 void btrfs_destroy_dev_zone_info(struct btrfs_device *device);
 int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info);
 int btrfs_check_mountopts_zoned(struct btrfs_fs_info *info);
+int btrfs_sb_log_location_bdev(struct block_device *bdev, int mirror, int rw,
+			       u64 *bytenr_ret);
+int btrfs_sb_log_location(struct btrfs_device *device, int mirror, int rw,
+			  u64 *bytenr_ret);
+int btrfs_advance_sb_log(struct btrfs_device *device, int mirror);
+int btrfs_reset_sb_log_zones(struct block_device *bdev, int mirror);
 #else /* CONFIG_BLK_DEV_ZONED */
 static inline int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
 				     struct blk_zone *zone)
@@ -54,6 +63,28 @@ static inline int btrfs_check_mountopts_zoned(struct btrfs_fs_info *info)
 {
 	return 0;
 }
+static inline int btrfs_sb_log_location_bdev(struct block_device *bdev,
+					     int mirror, int rw,
+					     u64 *bytenr_ret)
+{
+	*bytenr_ret = btrfs_sb_offset(mirror);
+	return 0;
+}
+static inline int btrfs_sb_log_location(struct btrfs_device *device, int mirror,
+					int rw, u64 *bytenr_ret)
+{
+	*bytenr_ret = btrfs_sb_offset(mirror);
+	return 0;
+}
+static inline int btrfs_advance_sb_log(struct btrfs_device *device, int mirror)
+{
+	return 0;
+}
+static inline int btrfs_reset_sb_log_zones(struct block_device *bdev,
+					   int mirror)
+{
+	return 0;
+}
 #endif
 
 static inline bool btrfs_dev_is_sequential(struct btrfs_device *device, u64 pos)
@@ -121,4 +152,15 @@ static inline bool btrfs_check_device_zone_type(struct btrfs_fs_info *fs_info,
 	return bdev_zoned_model(bdev) != BLK_ZONED_HM;
 }
 
+static inline bool btrfs_check_super_location(struct btrfs_device *device,
+					      u64 pos)
+{
+	/*
+	 * On a non-zoned device, any address is OK. On a zoned device,
+	 * non-SEQUENTIAL WRITE REQUIRED zones are capable.
+	 */
+	return device->zone_info == NULL ||
+	       !btrfs_dev_is_sequential(device, pos);
+}
+
 #endif
-- 
2.27.0

[PATCH v7 11/39] btrfs: implement zoned chunk allocator

[Naohiro Aota]

This commit implements zoned chunk/dev_extent allocator. The zoned
allocator align the device extents to zone boundaries so that a zone
reset affects only the device extent and does not change the state of
blocks in the neighbor device extents.

Also, it checks that a region allocation is not over any locations of
super block zones, and ensures the region is empty.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/volumes.c | 133 +++++++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/volumes.h |   1 +
 fs/btrfs/zoned.c   | 128 +++++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/zoned.h   |  30 ++++++++++
 4 files changed, 292 insertions(+)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 22384c803ead..8c439d1ae4c5 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1407,6 +1407,14 @@ static bool contains_pending_extent(struct btrfs_device *device, u64 *start,
 	return false;
 }
 
+static inline u64 dev_extent_search_start_zoned(struct btrfs_device *device,
+						u64 start)
+{
+	start = max_t(u64, start,
+		      max_t(u64, device->zone_info->zone_size, SZ_1M));
+	return btrfs_zone_align(device, start);
+}
+
 static u64 dev_extent_search_start(struct btrfs_device *device, u64 start)
 {
 	switch (device->fs_devices->chunk_alloc_policy) {
@@ -1417,11 +1425,57 @@ static u64 dev_extent_search_start(struct btrfs_device *device, u64 start)
 		 * make sure to start at an offset of at least 1MB.
 		 */
 		return max_t(u64, start, SZ_1M);
+	case BTRFS_CHUNK_ALLOC_ZONED:
+		return dev_extent_search_start_zoned(device, start);
 	default:
 		BUG();
 	}
 }
 
+static bool dev_extent_hole_check_zoned(struct btrfs_device *device,
+					u64 *hole_start, u64 *hole_size,
+					u64 num_bytes)
+{
+	u64 zone_size = device->zone_info->zone_size;
+	u64 pos;
+	int ret;
+	int changed = 0;
+
+	ASSERT(IS_ALIGNED(*hole_start, zone_size));
+
+	while (*hole_size > 0) {
+		pos = btrfs_find_allocatable_zones(device, *hole_start,
+						   *hole_start + *hole_size,
+						   num_bytes);
+		if (pos != *hole_start) {
+			*hole_size = *hole_start + *hole_size - pos;
+			*hole_start = pos;
+			changed = 1;
+			if (*hole_size < num_bytes)
+				break;
+		}
+
+		ret = btrfs_ensure_empty_zones(device, pos, num_bytes);
+
+		/* range is ensured to be empty */
+		if (!ret)
+			return changed;
+
+		/* given hole range was invalid (outside of device) */
+		if (ret == -ERANGE) {
+			*hole_start += *hole_size;
+			*hole_size = 0;
+			return 1;
+		}
+
+		*hole_start += zone_size;
+		*hole_size -= zone_size;
+		changed = 1;
+	}
+
+	return changed;
+}
+
 /**
  * dev_extent_hole_check - check if specified hole is suitable for allocation
  * @device:	the device which we have the hole
@@ -1454,6 +1508,10 @@ static bool dev_extent_hole_check(struct btrfs_device *device, u64 *hole_start,
 	case BTRFS_CHUNK_ALLOC_REGULAR:
 		/* No extra check */
 		break;
+	case BTRFS_CHUNK_ALLOC_ZONED:
+		changed |= dev_extent_hole_check_zoned(device, hole_start,
+						       hole_size, num_bytes);
+		break;
 	default:
 		BUG();
 	}
@@ -1508,6 +1566,9 @@ static int find_free_dev_extent_start(struct btrfs_device *device,
 
 	search_start = dev_extent_search_start(device, search_start);
 
+	WARN_ON(device->zone_info &&
+		!IS_ALIGNED(num_bytes, device->zone_info->zone_size));
+
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
@@ -4912,6 +4973,39 @@ static void init_alloc_chunk_ctl_policy_regular(
 	ctl->dev_extent_min = BTRFS_STRIPE_LEN * ctl->dev_stripes;
 }
 
+static void
+init_alloc_chunk_ctl_policy_zoned(struct btrfs_fs_devices *fs_devices,
+				  struct alloc_chunk_ctl *ctl)
+{
+	u64 zone_size = fs_devices->fs_info->zone_size;
+	u64 limit;
+	int min_num_stripes = ctl->devs_min * ctl->dev_stripes;
+	int min_data_stripes = (min_num_stripes - ctl->nparity) / ctl->ncopies;
+	u64 min_chunk_size = min_data_stripes * zone_size;
+	u64 type = ctl->type;
+
+	ctl->max_stripe_size = zone_size;
+	if (type & BTRFS_BLOCK_GROUP_DATA) {
+		ctl->max_chunk_size = round_down(BTRFS_MAX_DATA_CHUNK_SIZE,
+						 zone_size);
+	} else if (type & BTRFS_BLOCK_GROUP_METADATA) {
+		ctl->max_chunk_size = ctl->max_stripe_size;
+	} else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
+		ctl->max_chunk_size = 2 * ctl->max_stripe_size;
+		ctl->devs_max = min_t(int, ctl->devs_max,
+				      BTRFS_MAX_DEVS_SYS_CHUNK);
+	} else {
+		BUG();
+	}
+
+	/* We don't want a chunk larger than 10% of writable space */
+	limit = max(round_down(div_factor(fs_devices->total_rw_bytes, 1),
+			       zone_size),
+		    min_chunk_size);
+	ctl->max_chunk_size = min(limit, ctl->max_chunk_size);
+	ctl->dev_extent_min = zone_size * ctl->dev_stripes;
+}
+
 static void init_alloc_chunk_ctl(struct btrfs_fs_devices *fs_devices,
 				 struct alloc_chunk_ctl *ctl)
 {
@@ -4932,6 +5026,9 @@ static void init_alloc_chunk_ctl(struct btrfs_fs_devices *fs_devices,
 	case BTRFS_CHUNK_ALLOC_REGULAR:
 		init_alloc_chunk_ctl_policy_regular(fs_devices, ctl);
 		break;
+	case BTRFS_CHUNK_ALLOC_ZONED:
+		init_alloc_chunk_ctl_policy_zoned(fs_devices, ctl);
+		break;
 	default:
 		BUG();
 	}
@@ -5058,6 +5155,40 @@ static int decide_stripe_size_regular(struct alloc_chunk_ctl *ctl,
 	return 0;
 }
 
+static int decide_stripe_size_zoned(struct alloc_chunk_ctl *ctl,
+				    struct btrfs_device_info *devices_info)
+{
+	u64 zone_size = devices_info[0].dev->zone_info->zone_size;
+	int data_stripes;	/* number of stripes that count for
+				   block group size */
+
+	/*
+	 * It should hold because:
+	 *    dev_extent_min == dev_extent_want == zone_size * dev_stripes
+	 */
+	ASSERT(devices_info[ctl->ndevs - 1].max_avail == ctl->dev_extent_min);
+
+	ctl->stripe_size = zone_size;
+	ctl->num_stripes = ctl->ndevs * ctl->dev_stripes;
+	data_stripes = (ctl->num_stripes - ctl->nparity) / ctl->ncopies;
+
+	/*
+	 * stripe_size is fixed in ZONED. Reduce ndevs instead.
+	 */
+	if (ctl->stripe_size * data_stripes > ctl->max_chunk_size) {
+		ctl->ndevs = div_u64(div_u64(ctl->max_chunk_size * ctl->ncopies,
+					     ctl->stripe_size) + ctl->nparity,
+				     ctl->dev_stripes);
+		ctl->num_stripes = ctl->ndevs * ctl->dev_stripes;
+		data_stripes = (ctl->num_stripes - ctl->nparity) / ctl->ncopies;
+		ASSERT(ctl->stripe_size * data_stripes <= ctl->max_chunk_size);
+	}
+
+	ctl->chunk_size = ctl->stripe_size * data_stripes;
+
+	return 0;
+}
+
 static int decide_stripe_size(struct btrfs_fs_devices *fs_devices,
 			      struct alloc_chunk_ctl *ctl,
 			      struct btrfs_device_info *devices_info)
@@ -5085,6 +5216,8 @@ static int decide_stripe_size(struct btrfs_fs_devices *fs_devices,
 	switch (fs_devices->chunk_alloc_policy) {
 	case BTRFS_CHUNK_ALLOC_REGULAR:
 		return decide_stripe_size_regular(ctl, devices_info);
+	case BTRFS_CHUNK_ALLOC_ZONED:
+		return decide_stripe_size_zoned(ctl, devices_info);
 	default:
 		BUG();
 	}
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index a7ae1a02c6d2..88b1d59fbc12 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -213,6 +213,7 @@ BTRFS_DEVICE_GETSET_FUNCS(bytes_used);
 
 enum btrfs_chunk_allocation_policy {
 	BTRFS_CHUNK_ALLOC_REGULAR,
+	BTRFS_CHUNK_ALLOC_ZONED,
 };
 
 struct btrfs_fs_devices {
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 6912b66f3130..916d358dea27 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -6,12 +6,16 @@
  *	Damien Le Moal	<damien.lemoal@wdc.com>
  */
 
+#include "asm-generic/bitops/find.h"
+#include "linux/blk_types.h"
+#include "linux/kernel.h"
 #include <linux/slab.h>
 #include <linux/blkdev.h>
 #include "ctree.h"
 #include "volumes.h"
 #include "zoned.h"
 #include "rcu-string.h"
+#include "disk-io.h"
 
 /* Maximum number of zones to report per blkdev_report_zones() call */
 #define BTRFS_REPORT_NR_ZONES   4096
@@ -324,6 +328,7 @@ int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info)
 
 	fs_info->zone_size = zone_size;
 	fs_info->max_zone_append_size = max_zone_append_size;
+	fs_info->fs_devices->chunk_alloc_policy = BTRFS_CHUNK_ALLOC_ZONED;
 
 	btrfs_info(fs_info, "ZONED mode enabled, zone size %llu B",
 		   fs_info->zone_size);
@@ -618,3 +623,126 @@ int btrfs_reset_sb_log_zones(struct block_device *bdev, int mirror)
 				sb_zone << zone_sectors_shift, zone_sectors * 2,
 				GFP_NOFS);
 }
+
+/*
+ * btrfs_check_allocatable_zones - find allocatable zones within give region
+ * @device:	the device to allocate a region
+ * @hole_start: the position of the hole to allocate the region
+ * @num_bytes:	the size of wanted region
+ * @hole_size:	the size of hole
+ *
+ * Allocatable region should not contain any superblock locations.
+ */
+u64 btrfs_find_allocatable_zones(struct btrfs_device *device, u64 hole_start,
+				 u64 hole_end, u64 num_bytes)
+{
+	struct btrfs_zoned_device_info *zinfo = device->zone_info;
+	u8 shift = zinfo->zone_size_shift;
+	u64 nzones = num_bytes >> shift;
+	u64 pos = hole_start;
+	u64 begin, end;
+	u64 sb_pos;
+	bool have_sb;
+	int i;
+
+	ASSERT(IS_ALIGNED(hole_start, zinfo->zone_size));
+	ASSERT(IS_ALIGNED(num_bytes, zinfo->zone_size));
+
+	while (pos < hole_end) {
+		begin = pos >> shift;
+		end = begin + nzones;
+
+		if (end > zinfo->nr_zones)
+			return hole_end;
+
+		/* check if zones in the region are all empty */
+		if (btrfs_dev_is_sequential(device, pos) &&
+		    find_next_zero_bit(zinfo->empty_zones, end, begin) != end) {
+			pos += zinfo->zone_size;
+			continue;
+		}
+
+		have_sb = false;
+		for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
+			sb_pos = sb_zone_number(zinfo->zone_size, i);
+			if (!(end < sb_pos || sb_pos + 1 < begin)) {
+				have_sb = true;
+				pos = (sb_pos + 2) << shift;
+				break;
+			}
+		}
+		if (!have_sb)
+			break;
+	}
+
+	return pos;
+}
+
+int btrfs_reset_device_zone(struct btrfs_device *device, u64 physical,
+			    u64 length, u64 *bytes)
+{
+	int ret;
+
+	*bytes = 0;
+	ret = blkdev_zone_mgmt(device->bdev, REQ_OP_ZONE_RESET,
+			       physical >> SECTOR_SHIFT, length >> SECTOR_SHIFT,
+			       GFP_NOFS);
+	if (ret)
+		return ret;
+
+	*bytes = length;
+	while (length) {
+		btrfs_dev_set_zone_empty(device, physical);
+		physical += device->zone_info->zone_size;
+		length -= device->zone_info->zone_size;
+	}
+
+	return 0;
+}
+
+int btrfs_ensure_empty_zones(struct btrfs_device *device, u64 start, u64 size)
+{
+	struct btrfs_zoned_device_info *zinfo = device->zone_info;
+	u8 shift = zinfo->zone_size_shift;
+	unsigned long begin = start >> shift;
+	unsigned long end = (start + size) >> shift;
+	u64 pos;
+	int ret;
+
+	ASSERT(IS_ALIGNED(start, zinfo->zone_size));
+	ASSERT(IS_ALIGNED(size, zinfo->zone_size));
+
+	if (end > zinfo->nr_zones)
+		return -ERANGE;
+
+	/* all the zones are conventional */
+	if (find_next_bit(zinfo->seq_zones, begin, end) == end)
+		return 0;
+
+	/* all the zones are sequential and empty */
+	if (find_next_zero_bit(zinfo->seq_zones, begin, end) == end &&
+	    find_next_zero_bit(zinfo->empty_zones, begin, end) == end)
+		return 0;
+
+	for (pos = start; pos < start + size; pos += zinfo->zone_size) {
+		u64 reset_bytes;
+
+		if (!btrfs_dev_is_sequential(device, pos) ||
+		    btrfs_dev_is_empty_zone(device, pos))
+			continue;
+
+		/* free regions should be empty */
+		btrfs_warn_in_rcu(
+			device->fs_info,
+			"resetting device %s zone %llu for allocation",
+			rcu_str_deref(device->name), pos >> shift);
+		WARN_ON_ONCE(1);
+
+		ret = btrfs_reset_device_zone(device, pos, zinfo->zone_size,
+					      &reset_bytes);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h
index e33c0e409b7d..0be58861d922 100644
--- a/fs/btrfs/zoned.h
+++ b/fs/btrfs/zoned.h
@@ -40,6 +40,11 @@ int btrfs_sb_log_location(struct btrfs_device *device, int mirror, int rw,
 			  u64 *bytenr_ret);
 int btrfs_advance_sb_log(struct btrfs_device *device, int mirror);
 int btrfs_reset_sb_log_zones(struct block_device *bdev, int mirror);
+u64 btrfs_find_allocatable_zones(struct btrfs_device *device, u64 hole_start,
+				 u64 hole_end, u64 num_bytes);
+int btrfs_reset_device_zone(struct btrfs_device *device, u64 physical,
+			    u64 length, u64 *bytes);
+int btrfs_ensure_empty_zones(struct btrfs_device *device, u64 start, u64 size);
 #else /* CONFIG_BLK_DEV_ZONED */
 static inline int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
 				     struct blk_zone *zone)
@@ -85,6 +90,23 @@ static inline int btrfs_reset_sb_log_zones(struct block_device *bdev,
 {
 	return 0;
 }
+static inline u64 btrfs_find_allocatable_zones(struct btrfs_device *device,
+					       u64 hole_start, u64 hole_end,
+					       u64 num_bytes)
+{
+	return hole_start;
+}
+static inline int btrfs_reset_device_zone(struct btrfs_device *device,
+					  u64 physical, u64 length, u64 *bytes)
+{
+	*bytes = 0;
+	return 0;
+}
+static inline int btrfs_ensure_empty_zones(struct btrfs_device *device,
+					   u64 start, u64 size)
+{
+	return 0;
+}
 #endif
 
 static inline bool btrfs_dev_is_sequential(struct btrfs_device *device, u64 pos)
@@ -163,4 +185,12 @@ static inline bool btrfs_check_super_location(struct btrfs_device *device,
 	       !btrfs_dev_is_sequential(device, pos);
 }
 
+static inline u64 btrfs_zone_align(struct btrfs_device *device, u64 pos)
+{
+	if (!device->zone_info)
+		return pos;
+
+	return ALIGN(pos, device->zone_info->zone_size);
+}
+
 #endif
-- 
2.27.0

[PATCH v7 12/39] btrfs: verify device extent is aligned to zone

[Naohiro Aota]

This patch add a verification in verify_one_dev_extent() to check if the
device extent is aligned to zone boundary.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/volumes.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 8c439d1ae4c5..086cd308e5b6 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -7765,6 +7765,20 @@ static int verify_one_dev_extent(struct btrfs_fs_info *fs_info,
 		ret = -EUCLEAN;
 		goto out;
 	}
+
+	if (dev->zone_info) {
+		u64 zone_size = dev->zone_info->zone_size;
+
+		if (!IS_ALIGNED(physical_offset, zone_size) ||
+		    !IS_ALIGNED(physical_len, zone_size)) {
+			btrfs_err(fs_info,
+"dev extent devid %llu physical offset %llu len %llu is not aligned to device zone",
+				  devid, physical_offset, physical_len);
+			ret = -EUCLEAN;
+			goto out;
+		}
+	}
+
 out:
 	free_extent_map(em);
 	return ret;
-- 
2.27.0

[PATCH v7 13/39] btrfs: load zone's alloction offset

[Naohiro Aota]

Zoned btrfs must allocate blocks at the zones' write pointer. The device's
write pointer position can be mapped to a logical address within a block
group. This commit adds "alloc_offset" to track the logical address.

This logical address is populated in btrfs_load_block-group_zone_info()
from write pointers of corresponding zones.

For now, zoned btrfs only support the SINGLE profile. Supporting non-SINGLE
profile with zone append writing is not trivial. For example, in the DUP
profile, we send a zone append writing IO to two zones on a device. The
device reply with written LBAs for the IOs. If the offsets of the returned
addresses from the beginning of the zone are different, then it results in
different logical addresses.

We need fine-grained logical to physical mapping to support such separated
physical address issue. Since it should require additional metadata type,
disable non-SINGLE profiles for now.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/block-group.c |  15 ++++
 fs/btrfs/block-group.h |   6 ++
 fs/btrfs/zoned.c       | 153 +++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/zoned.h       |   6 ++
 4 files changed, 180 insertions(+)

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 4ac4aacfae04..3ce685a10631 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -15,6 +15,7 @@
 #include "delalloc-space.h"
 #include "discard.h"
 #include "raid56.h"
+#include "zoned.h"
 
 /*
  * Return target flags in extended format or 0 if restripe for this chunk_type
@@ -1945,6 +1946,13 @@ static int read_one_block_group(struct btrfs_fs_info *info,
 			goto error;
 	}
 
+	ret = btrfs_load_block_group_zone_info(cache);
+	if (ret) {
+		btrfs_err(info, "failed to load zone info of bg %llu",
+			  cache->start);
+		goto error;
+	}
+
 	/*
 	 * We need to exclude the super stripes now so that the space info has
 	 * super bytes accounted for, otherwise we'll think we have more space
@@ -2148,6 +2156,13 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans, u64 bytes_used,
 	cache->last_byte_to_unpin = (u64)-1;
 	cache->cached = BTRFS_CACHE_FINISHED;
 	cache->needs_free_space = 1;
+
+	ret = btrfs_load_block_group_zone_info(cache);
+	if (ret) {
+		btrfs_put_block_group(cache);
+		return ret;
+	}
+
 	ret = exclude_super_stripes(cache);
 	if (ret) {
 		/* We may have excluded something, so call this just in case */
diff --git a/fs/btrfs/block-group.h b/fs/btrfs/block-group.h
index adfd7583a17b..14e3043c9ce7 100644
--- a/fs/btrfs/block-group.h
+++ b/fs/btrfs/block-group.h
@@ -183,6 +183,12 @@ struct btrfs_block_group {
 
 	/* Record locked full stripes for RAID5/6 block group */
 	struct btrfs_full_stripe_locks_tree full_stripe_locks_root;
+
+	/*
+	 * Allocation offset for the block group to implement sequential
+	 * allocation. This is used only with ZONED mode enabled.
+	 */
+	u64 alloc_offset;
 };
 
 static inline u64 btrfs_block_group_end(struct btrfs_block_group *block_group)
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 916d358dea27..cc6bc45729b4 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -11,14 +11,20 @@
 #include "linux/kernel.h"
 #include <linux/slab.h>
 #include <linux/blkdev.h>
+#include <linux/sched/mm.h>
 #include "ctree.h"
 #include "volumes.h"
 #include "zoned.h"
 #include "rcu-string.h"
 #include "disk-io.h"
+#include "block-group.h"
 
 /* Maximum number of zones to report per blkdev_report_zones() call */
 #define BTRFS_REPORT_NR_ZONES   4096
+/* Invalid allocation pointer value for missing devices */
+#define WP_MISSING_DEV ((u64)-1)
+/* Pseudo write pointer value for conventional zone */
+#define WP_CONVENTIONAL ((u64)-2)
 
 static int copy_zone_info_cb(struct blk_zone *zone, unsigned int idx,
 			     void *data)
@@ -746,3 +752,150 @@ int btrfs_ensure_empty_zones(struct btrfs_device *device, u64 start, u64 size)
 
 	return 0;
 }
+
+int btrfs_load_block_group_zone_info(struct btrfs_block_group *cache)
+{
+	struct btrfs_fs_info *fs_info = cache->fs_info;
+	struct extent_map_tree *em_tree = &fs_info->mapping_tree;
+	struct extent_map *em;
+	struct map_lookup *map;
+	struct btrfs_device *device;
+	u64 logical = cache->start;
+	u64 length = cache->length;
+	u64 physical = 0;
+	int ret;
+	int i;
+	unsigned int nofs_flag;
+	u64 *alloc_offsets = NULL;
+	u32 num_sequential = 0, num_conventional = 0;
+
+	if (!btrfs_fs_incompat(fs_info, ZONED))
+		return 0;
+
+	/* Sanity check */
+	if (!IS_ALIGNED(length, fs_info->zone_size)) {
+		btrfs_err(fs_info, "unaligned block group at %llu + %llu",
+			  logical, length);
+		return -EIO;
+	}
+
+	/* Get the chunk mapping */
+	read_lock(&em_tree->lock);
+	em = lookup_extent_mapping(em_tree, logical, length);
+	read_unlock(&em_tree->lock);
+
+	if (!em)
+		return -EINVAL;
+
+	map = em->map_lookup;
+
+	/*
+	 * Get the zone type: if the group is mapped to a non-sequential zone,
+	 * there is no need for the allocation offset (fit allocation is OK).
+	 */
+	alloc_offsets = kcalloc(map->num_stripes, sizeof(*alloc_offsets),
+				GFP_NOFS);
+	if (!alloc_offsets) {
+		free_extent_map(em);
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < map->num_stripes; i++) {
+		bool is_sequential;
+		struct blk_zone zone;
+
+		device = map->stripes[i].dev;
+		physical = map->stripes[i].physical;
+
+		if (device->bdev == NULL) {
+			alloc_offsets[i] = WP_MISSING_DEV;
+			continue;
+		}
+
+		is_sequential = btrfs_dev_is_sequential(device, physical);
+		if (is_sequential)
+			num_sequential++;
+		else
+			num_conventional++;
+
+		if (!is_sequential) {
+			alloc_offsets[i] = WP_CONVENTIONAL;
+			continue;
+		}
+
+		/*
+		 * This zone will be used for allocation, so mark this
+		 * zone non-empty.
+		 */
+		btrfs_dev_clear_zone_empty(device, physical);
+
+		/*
+		 * The group is mapped to a sequential zone. Get the zone write
+		 * pointer to determine the allocation offset within the zone.
+		 */
+		WARN_ON(!IS_ALIGNED(physical, fs_info->zone_size));
+		nofs_flag = memalloc_nofs_save();
+		ret = btrfs_get_dev_zone(device, physical, &zone);
+		memalloc_nofs_restore(nofs_flag);
+		if (ret == -EIO || ret == -EOPNOTSUPP) {
+			ret = 0;
+			alloc_offsets[i] = WP_MISSING_DEV;
+			continue;
+		} else if (ret) {
+			goto out;
+		}
+
+		switch (zone.cond) {
+		case BLK_ZONE_COND_OFFLINE:
+		case BLK_ZONE_COND_READONLY:
+			btrfs_err(fs_info, "Offline/readonly zone %llu",
+				  physical >> device->zone_info->zone_size_shift);
+			alloc_offsets[i] = WP_MISSING_DEV;
+			break;
+		case BLK_ZONE_COND_EMPTY:
+			alloc_offsets[i] = 0;
+			break;
+		case BLK_ZONE_COND_FULL:
+			alloc_offsets[i] = fs_info->zone_size;
+			break;
+		default:
+			/* Partially used zone */
+			alloc_offsets[i] =
+				((zone.wp - zone.start) << SECTOR_SHIFT);
+			break;
+		}
+	}
+
+	if (num_conventional > 0) {
+		/*
+		 * Since conventional zones does not have write pointer, we
+		 * cannot determine alloc_offset from the pointer
+		 */
+		ret = -EINVAL;
+		goto out;
+	}
+
+	switch (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
+	case 0: /* single */
+		cache->alloc_offset = alloc_offsets[0];
+		break;
+	case BTRFS_BLOCK_GROUP_DUP:
+	case BTRFS_BLOCK_GROUP_RAID1:
+	case BTRFS_BLOCK_GROUP_RAID0:
+	case BTRFS_BLOCK_GROUP_RAID10:
+	case BTRFS_BLOCK_GROUP_RAID5:
+	case BTRFS_BLOCK_GROUP_RAID6:
+		/* non-SINGLE profiles are not supported yet */
+	default:
+		btrfs_err(fs_info, "Unsupported profile on ZONED %s",
+			  btrfs_bg_type_to_raid_name(map->type));
+		ret = -EINVAL;
+		goto out;
+	}
+
+out:
+	kfree(alloc_offsets);
+	free_extent_map(em);
+
+	return ret;
+}
diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h
index 0be58861d922..1fd7cad19e18 100644
--- a/fs/btrfs/zoned.h
+++ b/fs/btrfs/zoned.h
@@ -45,6 +45,7 @@ u64 btrfs_find_allocatable_zones(struct btrfs_device *device, u64 hole_start,
 int btrfs_reset_device_zone(struct btrfs_device *device, u64 physical,
 			    u64 length, u64 *bytes);
 int btrfs_ensure_empty_zones(struct btrfs_device *device, u64 start, u64 size);
+int btrfs_load_block_group_zone_info(struct btrfs_block_group *cache);
 #else /* CONFIG_BLK_DEV_ZONED */
 static inline int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
 				     struct blk_zone *zone)
@@ -107,6 +108,11 @@ static inline int btrfs_ensure_empty_zones(struct btrfs_device *device,
 {
 	return 0;
 }
+static inline int btrfs_load_block_group_zone_info(
+	struct btrfs_block_group *cache)
+{
+	return 0;
+}
 #endif
 
 static inline bool btrfs_dev_is_sequential(struct btrfs_device *device, u64 pos)
-- 
2.27.0

[PATCH v7 14/39] btrfs: emulate write pointer for conventional zones

[Naohiro Aota]

Conventional zones do not have a write pointer. So, we cannot use it to
determine the allocation offset if a block group contains a conventional
zone. Instead, we can consider the end of the last allocated extent int the
block group as an allocation offset.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/zoned.c | 119 ++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 113 insertions(+), 6 deletions(-)

diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index cc6bc45729b4..ca090a5cdc6e 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -753,6 +753,104 @@ int btrfs_ensure_empty_zones(struct btrfs_device *device, u64 start, u64 size)
 	return 0;
 }
 
+static int emulate_write_pointer(struct btrfs_block_group *cache,
+				 u64 *offset_ret)
+{
+	struct btrfs_fs_info *fs_info = cache->fs_info;
+	struct btrfs_root *root = fs_info->extent_root;
+	struct btrfs_path *path;
+	struct extent_buffer *leaf;
+	struct btrfs_key search_key;
+	struct btrfs_key found_key;
+	int slot;
+	int ret;
+	u64 length;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	search_key.objectid = cache->start + cache->length;
+	search_key.type = 0;
+	search_key.offset = 0;
+
+	ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
+	if (ret < 0)
+		goto out;
+	ASSERT(ret != 0);
+	slot = path->slots[0];
+	leaf = path->nodes[0];
+	ASSERT(slot != 0);
+	slot--;
+	btrfs_item_key_to_cpu(leaf, &found_key, slot);
+
+	if (found_key.objectid < cache->start) {
+		*offset_ret = 0;
+	} else if (found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
+		struct btrfs_key extent_item_key;
+
+		if (found_key.objectid != cache->start) {
+			ret = -EUCLEAN;
+			goto out;
+		}
+
+		length = 0;
+
+		/* metadata may have METADATA_ITEM_KEY */
+		if (slot == 0) {
+			btrfs_set_path_blocking(path);
+			ret = btrfs_prev_leaf(root, path);
+			if (ret < 0)
+				goto out;
+			if (ret == 0) {
+				slot = btrfs_header_nritems(leaf) - 1;
+				btrfs_item_key_to_cpu(leaf, &extent_item_key,
+						      slot);
+			}
+		} else {
+			btrfs_item_key_to_cpu(leaf, &extent_item_key, slot - 1);
+			ret = 0;
+		}
+
+		if (ret == 0 &&
+		    extent_item_key.objectid == cache->start) {
+			if (extent_item_key.type == BTRFS_METADATA_ITEM_KEY)
+				length = fs_info->nodesize;
+			else if (extent_item_key.type == BTRFS_EXTENT_ITEM_KEY)
+				length = extent_item_key.offset;
+			else {
+				ret = -EUCLEAN;
+				goto out;
+			}
+		}
+
+		*offset_ret = length;
+	} else if (found_key.type == BTRFS_EXTENT_ITEM_KEY ||
+		   found_key.type == BTRFS_METADATA_ITEM_KEY) {
+
+		if (found_key.type == BTRFS_EXTENT_ITEM_KEY)
+			length = found_key.offset;
+		else
+			length = fs_info->nodesize;
+
+		if (!(found_key.objectid >= cache->start &&
+		       found_key.objectid + length <=
+		       cache->start + cache->length)) {
+			ret = -EUCLEAN;
+			goto out;
+		}
+		*offset_ret = found_key.objectid + length - cache->start;
+	} else {
+		ret = -EUCLEAN;
+		goto out;
+	}
+	ret = 0;
+
+out:
+	btrfs_free_path(path);
+	return ret;
+}
+
 int btrfs_load_block_group_zone_info(struct btrfs_block_group *cache)
 {
 	struct btrfs_fs_info *fs_info = cache->fs_info;
@@ -767,6 +865,7 @@ int btrfs_load_block_group_zone_info(struct btrfs_block_group *cache)
 	int i;
 	unsigned int nofs_flag;
 	u64 *alloc_offsets = NULL;
+	u64 emulated_offset = 0;
 	u32 num_sequential = 0, num_conventional = 0;
 
 	if (!btrfs_fs_incompat(fs_info, ZONED))
@@ -867,12 +966,12 @@ int btrfs_load_block_group_zone_info(struct btrfs_block_group *cache)
 	}
 
 	if (num_conventional > 0) {
-		/*
-		 * Since conventional zones does not have write pointer, we
-		 * cannot determine alloc_offset from the pointer
-		 */
-		ret = -EINVAL;
-		goto out;
+		ret = emulate_write_pointer(cache, &emulated_offset);
+		if (ret || map->num_stripes == num_conventional) {
+			if (!ret)
+				cache->alloc_offset = emulated_offset;
+			goto out;
+		}
 	}
 
 	switch (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
@@ -894,6 +993,14 @@ int btrfs_load_block_group_zone_info(struct btrfs_block_group *cache)
 	}
 
 out:
+	/* an extent is allocated after the write pointer */
+	if (num_conventional && emulated_offset > cache->alloc_offset) {
+		btrfs_err(fs_info,
+			  "got wrong write pointer in BG %llu: %llu > %llu",
+			  logical, emulated_offset, cache->alloc_offset);
+		ret = -EIO;
+	}
+
 	kfree(alloc_offsets);
 	free_extent_map(em);
 
-- 
2.27.0

[PATCH v7 15/39] btrfs: track unusable bytes for zones

[Naohiro Aota]

In zoned btrfs, once written, then freed region is never usable until
resetting underlying zones. We need to distinguish such unusable space from
usable free space. So, this commit introduces "zone_unusable" to block
group, and "bytes_zone_unusable" to space_info to track the unusable space.

Pinned bytes are always reclaimed to the unsable space. But, when an
allocated region is returned before using e.g., the block group becomes
read-only between allocation time and reservation time, we can safely
return the region to the block group. For the situation, this commit
introduces "btrfs_add_free_space_unused". This behave as the same as
btrfs_add_free_space() on regular btrfs. On zoned btrfs, it rewinds the
allocation offset.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/block-group.c      | 19 +++++++++-----
 fs/btrfs/block-group.h      |  1 +
 fs/btrfs/extent-tree.c      | 15 ++++++++---
 fs/btrfs/free-space-cache.c | 52 +++++++++++++++++++++++++++++++++++++
 fs/btrfs/free-space-cache.h |  4 +++
 fs/btrfs/space-info.c       | 13 ++++++----
 fs/btrfs/space-info.h       |  4 ++-
 fs/btrfs/sysfs.c            |  2 ++
 fs/btrfs/zoned.c            | 22 ++++++++++++++++
 fs/btrfs/zoned.h            |  2 ++
 10 files changed, 118 insertions(+), 16 deletions(-)

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 3ce685a10631..324a1ef1bf04 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -1080,12 +1080,15 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 		WARN_ON(block_group->space_info->total_bytes
 			< block_group->length);
 		WARN_ON(block_group->space_info->bytes_readonly
-			< block_group->length);
+			< block_group->length - block_group->zone_unusable);
+		WARN_ON(block_group->space_info->bytes_zone_unusable
+			< block_group->zone_unusable);
 		WARN_ON(block_group->space_info->disk_total
 			< block_group->length * factor);
 	}
 	block_group->space_info->total_bytes -= block_group->length;
-	block_group->space_info->bytes_readonly -= block_group->length;
+	block_group->space_info->bytes_readonly -=
+		(block_group->length - block_group->zone_unusable);
 	block_group->space_info->disk_total -= block_group->length * factor;
 
 	spin_unlock(&block_group->space_info->lock);
@@ -1229,7 +1232,7 @@ static int inc_block_group_ro(struct btrfs_block_group *cache, int force)
 	}
 
 	num_bytes = cache->length - cache->reserved - cache->pinned -
-		    cache->bytes_super - cache->used;
+		    cache->bytes_super - cache->zone_unusable - cache->used;
 
 	/*
 	 * Data never overcommits, even in mixed mode, so do just the straight
@@ -1983,6 +1986,8 @@ static int read_one_block_group(struct btrfs_fs_info *info,
 		btrfs_free_excluded_extents(cache);
 	}
 
+	btrfs_calc_zone_unusable(cache);
+
 	ret = btrfs_add_block_group_cache(info, cache);
 	if (ret) {
 		btrfs_remove_free_space_cache(cache);
@@ -1990,7 +1995,8 @@ static int read_one_block_group(struct btrfs_fs_info *info,
 	}
 	trace_btrfs_add_block_group(info, cache, 0);
 	btrfs_update_space_info(info, cache->flags, cache->length,
-				cache->used, cache->bytes_super, &space_info);
+				cache->used, cache->bytes_super,
+				cache->zone_unusable, &space_info);
 
 	cache->space_info = space_info;
 
@@ -2204,7 +2210,7 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans, u64 bytes_used,
 	 */
 	trace_btrfs_add_block_group(fs_info, cache, 1);
 	btrfs_update_space_info(fs_info, cache->flags, size, bytes_used,
-				cache->bytes_super, &cache->space_info);
+				cache->bytes_super, 0, &cache->space_info);
 	btrfs_update_global_block_rsv(fs_info);
 
 	link_block_group(cache);
@@ -2312,7 +2318,8 @@ void btrfs_dec_block_group_ro(struct btrfs_block_group *cache)
 	spin_lock(&cache->lock);
 	if (!--cache->ro) {
 		num_bytes = cache->length - cache->reserved -
-			    cache->pinned - cache->bytes_super - cache->used;
+			    cache->pinned - cache->bytes_super -
+			    cache->zone_unusable - cache->used;
 		sinfo->bytes_readonly -= num_bytes;
 		list_del_init(&cache->ro_list);
 	}
diff --git a/fs/btrfs/block-group.h b/fs/btrfs/block-group.h
index 14e3043c9ce7..5be47f4bfea7 100644
--- a/fs/btrfs/block-group.h
+++ b/fs/btrfs/block-group.h
@@ -189,6 +189,7 @@ struct btrfs_block_group {
 	 * allocation. This is used only with ZONED mode enabled.
 	 */
 	u64 alloc_offset;
+	u64 zone_unusable;
 };
 
 static inline u64 btrfs_block_group_end(struct btrfs_block_group *block_group)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index e9eedc053fc5..4f486277fb6e 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -34,6 +34,7 @@
 #include "block-group.h"
 #include "discard.h"
 #include "rcu-string.h"
+#include "zoned.h"
 
 #undef SCRAMBLE_DELAYED_REFS
 
@@ -2790,9 +2791,11 @@ static int unpin_extent_range(struct btrfs_fs_info *fs_info,
 			cache = btrfs_lookup_block_group(fs_info, start);
 			BUG_ON(!cache); /* Logic error */
 
-			cluster = fetch_cluster_info(fs_info,
-						     cache->space_info,
-						     &empty_cluster);
+			if (!btrfs_fs_incompat(fs_info, ZONED))
+				cluster = fetch_cluster_info(fs_info,
+							     cache->space_info,
+							     &empty_cluster);
+
 			empty_cluster <<= 1;
 		}
 
@@ -2829,7 +2832,11 @@ static int unpin_extent_range(struct btrfs_fs_info *fs_info,
 		space_info->max_extent_size = 0;
 		percpu_counter_add_batch(&space_info->total_bytes_pinned,
 			    -len, BTRFS_TOTAL_BYTES_PINNED_BATCH);
-		if (cache->ro) {
+		if (btrfs_fs_incompat(fs_info, ZONED)) {
+			/* need reset before reusing in zoned Block Group */
+			space_info->bytes_zone_unusable += len;
+			readonly = true;
+		} else if (cache->ro) {
 			space_info->bytes_readonly += len;
 			readonly = true;
 		}
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index dc82fd0c80cb..7701b39b4d57 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -2470,6 +2470,8 @@ int __btrfs_add_free_space(struct btrfs_fs_info *fs_info,
 	int ret = 0;
 	u64 filter_bytes = bytes;
 
+	ASSERT(!btrfs_fs_incompat(fs_info, ZONED));
+
 	info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
 	if (!info)
 		return -ENOMEM;
@@ -2527,11 +2529,44 @@ int __btrfs_add_free_space(struct btrfs_fs_info *fs_info,
 	return ret;
 }
 
+int __btrfs_add_free_space_zoned(struct btrfs_block_group *block_group,
+				 u64 bytenr, u64 size, bool used)
+{
+	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
+	u64 offset = bytenr - block_group->start;
+	u64 to_free, to_unusable;
+
+	spin_lock(&ctl->tree_lock);
+	if (!used)
+		to_free = size;
+	else if (offset >= block_group->alloc_offset)
+		to_free = size;
+	else if (offset + size <= block_group->alloc_offset)
+		to_free = 0;
+	else
+		to_free = offset + size - block_group->alloc_offset;
+	to_unusable = size - to_free;
+
+	ctl->free_space += to_free;
+	block_group->zone_unusable += to_unusable;
+	spin_unlock(&ctl->tree_lock);
+	if (!used) {
+		spin_lock(&block_group->lock);
+		block_group->alloc_offset -= size;
+		spin_unlock(&block_group->lock);
+	}
+	return 0;
+}
+
 int btrfs_add_free_space(struct btrfs_block_group *block_group,
 			 u64 bytenr, u64 size)
 {
 	enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
 
+	if (btrfs_fs_incompat(block_group->fs_info, ZONED))
+		return __btrfs_add_free_space_zoned(block_group, bytenr, size,
+						    true);
+
 	if (btrfs_test_opt(block_group->fs_info, DISCARD_SYNC))
 		trim_state = BTRFS_TRIM_STATE_TRIMMED;
 
@@ -2540,6 +2575,16 @@ int btrfs_add_free_space(struct btrfs_block_group *block_group,
 				      bytenr, size, trim_state);
 }
 
+int btrfs_add_free_space_unused(struct btrfs_block_group *block_group,
+				u64 bytenr, u64 size)
+{
+	if (btrfs_fs_incompat(block_group->fs_info, ZONED))
+		return __btrfs_add_free_space_zoned(block_group, bytenr, size,
+						    false);
+
+	return btrfs_add_free_space(block_group, bytenr, size);
+}
+
 /*
  * This is a subtle distinction because when adding free space back in general,
  * we want it to be added as untrimmed for async. But in the case where we add
@@ -2550,6 +2595,10 @@ int btrfs_add_free_space_async_trimmed(struct btrfs_block_group *block_group,
 {
 	enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
 
+	if (btrfs_fs_incompat(block_group->fs_info, ZONED))
+		return __btrfs_add_free_space_zoned(block_group, bytenr, size,
+						    true);
+
 	if (btrfs_test_opt(block_group->fs_info, DISCARD_SYNC) ||
 	    btrfs_test_opt(block_group->fs_info, DISCARD_ASYNC))
 		trim_state = BTRFS_TRIM_STATE_TRIMMED;
@@ -2567,6 +2616,9 @@ int btrfs_remove_free_space(struct btrfs_block_group *block_group,
 	int ret;
 	bool re_search = false;
 
+	if (btrfs_fs_incompat(block_group->fs_info, ZONED))
+		return 0;
+
 	spin_lock(&ctl->tree_lock);
 
 again:
diff --git a/fs/btrfs/free-space-cache.h b/fs/btrfs/free-space-cache.h
index e3d5e0ad8f8e..7081216257a8 100644
--- a/fs/btrfs/free-space-cache.h
+++ b/fs/btrfs/free-space-cache.h
@@ -114,8 +114,12 @@ int __btrfs_add_free_space(struct btrfs_fs_info *fs_info,
 			   struct btrfs_free_space_ctl *ctl,
 			   u64 bytenr, u64 size,
 			   enum btrfs_trim_state trim_state);
+int __btrfs_add_free_space_zoned(struct btrfs_block_group *block_group,
+				 u64 bytenr, u64 size, bool used);
 int btrfs_add_free_space(struct btrfs_block_group *block_group,
 			 u64 bytenr, u64 size);
+int btrfs_add_free_space_unused(struct btrfs_block_group *block_group,
+				u64 bytenr, u64 size);
 int btrfs_add_free_space_async_trimmed(struct btrfs_block_group *block_group,
 				       u64 bytenr, u64 size);
 int btrfs_remove_free_space(struct btrfs_block_group *block_group,
diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c
index 475968ccbd1d..bcf7c41746d8 100644
--- a/fs/btrfs/space-info.c
+++ b/fs/btrfs/space-info.c
@@ -163,6 +163,7 @@ u64 __pure btrfs_space_info_used(struct btrfs_space_info *s_info,
 	ASSERT(s_info);
 	return s_info->bytes_used + s_info->bytes_reserved +
 		s_info->bytes_pinned + s_info->bytes_readonly +
+		s_info->bytes_zone_unusable +
 		(may_use_included ? s_info->bytes_may_use : 0);
 }
 
@@ -259,7 +260,7 @@ int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
 
 void btrfs_update_space_info(struct btrfs_fs_info *info, u64 flags,
 			     u64 total_bytes, u64 bytes_used,
-			     u64 bytes_readonly,
+			     u64 bytes_readonly, u64 bytes_zone_unusable,
 			     struct btrfs_space_info **space_info)
 {
 	struct btrfs_space_info *found;
@@ -275,6 +276,7 @@ void btrfs_update_space_info(struct btrfs_fs_info *info, u64 flags,
 	found->bytes_used += bytes_used;
 	found->disk_used += bytes_used * factor;
 	found->bytes_readonly += bytes_readonly;
+	found->bytes_zone_unusable += bytes_zone_unusable;
 	if (total_bytes > 0)
 		found->full = 0;
 	btrfs_try_granting_tickets(info, found);
@@ -433,10 +435,10 @@ static void __btrfs_dump_space_info(struct btrfs_fs_info *fs_info,
 		   info->total_bytes - btrfs_space_info_used(info, true),
 		   info->full ? "" : "not ");
 	btrfs_info(fs_info,
-		"space_info total=%llu, used=%llu, pinned=%llu, reserved=%llu, may_use=%llu, readonly=%llu",
+		"space_info total=%llu, used=%llu, pinned=%llu, reserved=%llu, may_use=%llu, readonly=%llu zone_unusable=%llu",
 		info->total_bytes, info->bytes_used, info->bytes_pinned,
 		info->bytes_reserved, info->bytes_may_use,
-		info->bytes_readonly);
+		info->bytes_readonly, info->bytes_zone_unusable);
 
 	DUMP_BLOCK_RSV(fs_info, global_block_rsv);
 	DUMP_BLOCK_RSV(fs_info, trans_block_rsv);
@@ -465,9 +467,10 @@ void btrfs_dump_space_info(struct btrfs_fs_info *fs_info,
 	list_for_each_entry(cache, &info->block_groups[index], list) {
 		spin_lock(&cache->lock);
 		btrfs_info(fs_info,
-			"block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %s",
+			"block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %llu zone_unusable %s",
 			cache->start, cache->length, cache->used, cache->pinned,
-			cache->reserved, cache->ro ? "[readonly]" : "");
+			cache->reserved, cache->zone_unusable,
+			cache->ro ? "[readonly]" : "");
 		spin_unlock(&cache->lock);
 		btrfs_dump_free_space(cache, bytes);
 	}
diff --git a/fs/btrfs/space-info.h b/fs/btrfs/space-info.h
index c3c64019950a..3799b703f0eb 100644
--- a/fs/btrfs/space-info.h
+++ b/fs/btrfs/space-info.h
@@ -17,6 +17,8 @@ struct btrfs_space_info {
 	u64 bytes_may_use;	/* number of bytes that may be used for
 				   delalloc/allocations */
 	u64 bytes_readonly;	/* total bytes that are read only */
+	u64 bytes_zone_unusable;	/* total bytes that are unusable until
+					   resetting the device zone */
 
 	u64 max_extent_size;	/* This will hold the maximum extent size of
 				   the space info if we had an ENOSPC in the
@@ -119,7 +121,7 @@ DECLARE_SPACE_INFO_UPDATE(bytes_pinned, "pinned");
 int btrfs_init_space_info(struct btrfs_fs_info *fs_info);
 void btrfs_update_space_info(struct btrfs_fs_info *info, u64 flags,
 			     u64 total_bytes, u64 bytes_used,
-			     u64 bytes_readonly,
+			     u64 bytes_readonly, u64 bytes_zone_unusable,
 			     struct btrfs_space_info **space_info);
 struct btrfs_space_info *btrfs_find_space_info(struct btrfs_fs_info *info,
 					       u64 flags);
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 38c7a57789d8..1709f5e0e375 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -626,6 +626,7 @@ SPACE_INFO_ATTR(bytes_pinned);
 SPACE_INFO_ATTR(bytes_reserved);
 SPACE_INFO_ATTR(bytes_may_use);
 SPACE_INFO_ATTR(bytes_readonly);
+SPACE_INFO_ATTR(bytes_zone_unusable);
 SPACE_INFO_ATTR(disk_used);
 SPACE_INFO_ATTR(disk_total);
 BTRFS_ATTR(space_info, total_bytes_pinned,
@@ -639,6 +640,7 @@ static struct attribute *space_info_attrs[] = {
 	BTRFS_ATTR_PTR(space_info, bytes_reserved),
 	BTRFS_ATTR_PTR(space_info, bytes_may_use),
 	BTRFS_ATTR_PTR(space_info, bytes_readonly),
+	BTRFS_ATTR_PTR(space_info, bytes_zone_unusable),
 	BTRFS_ATTR_PTR(space_info, disk_used),
 	BTRFS_ATTR_PTR(space_info, disk_total),
 	BTRFS_ATTR_PTR(space_info, total_bytes_pinned),
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index ca090a5cdc6e..68f8224d74c3 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -1006,3 +1006,25 @@ int btrfs_load_block_group_zone_info(struct btrfs_block_group *cache)
 
 	return ret;
 }
+
+void btrfs_calc_zone_unusable(struct btrfs_block_group *cache)
+{
+	u64 unusable, free;
+
+	if (!btrfs_fs_incompat(cache->fs_info, ZONED))
+		return;
+
+	WARN_ON(cache->bytes_super != 0);
+	unusable = cache->alloc_offset - cache->used;
+	free = cache->length - cache->alloc_offset;
+	/* we only need ->free_space in ALLOC_SEQ BGs */
+	cache->last_byte_to_unpin = (u64)-1;
+	cache->cached = BTRFS_CACHE_FINISHED;
+	cache->free_space_ctl->free_space = free;
+	cache->zone_unusable = unusable;
+	/*
+	 * Should not have any excluded extents. Just
+	 * in case, though.
+	 */
+	btrfs_free_excluded_extents(cache);
+}
diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h
index 1fd7cad19e18..3e3eff8dd0b4 100644
--- a/fs/btrfs/zoned.h
+++ b/fs/btrfs/zoned.h
@@ -46,6 +46,7 @@ int btrfs_reset_device_zone(struct btrfs_device *device, u64 physical,
 			    u64 length, u64 *bytes);
 int btrfs_ensure_empty_zones(struct btrfs_device *device, u64 start, u64 size);
 int btrfs_load_block_group_zone_info(struct btrfs_block_group *cache);
+void btrfs_calc_zone_unusable(struct btrfs_block_group *cache);
 #else /* CONFIG_BLK_DEV_ZONED */
 static inline int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
 				     struct blk_zone *zone)
@@ -113,6 +114,7 @@ static inline int btrfs_load_block_group_zone_info(
 {
 	return 0;
 }
+static inline void btrfs_calc_zone_unusable(struct btrfs_block_group *cache) { }
 #endif
 
 static inline bool btrfs_dev_is_sequential(struct btrfs_device *device, u64 pos)
-- 
2.27.0

[PATCH v7 16/39] btrfs: do sequential extent allocation in ZONED mode

[Naohiro Aota]

This commit implement sequential extent allocator for ZONED mode. The
allocator just need to check if there is enough space in the block group.
Since the allocator never manage bitmap or cluster. This commit also add
ASSERTs to the corresponding functions.

Actually, with zone append writing, it is unnecessary to track the
allocation offset. It only needs to check space availability. But, by
tracking the offset and returning the offset as an allocated region, we can
skip modification of ordered extents and checksum information when there is
no IO reordering.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/block-group.c      |  4 ++
 fs/btrfs/extent-tree.c      | 82 ++++++++++++++++++++++++++++++++++---
 fs/btrfs/free-space-cache.c |  6 +++
 3 files changed, 86 insertions(+), 6 deletions(-)

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 324a1ef1bf04..9df83e687b92 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -683,6 +683,10 @@ int btrfs_cache_block_group(struct btrfs_block_group *cache, int load_cache_only
 	struct btrfs_caching_control *caching_ctl;
 	int ret = 0;
 
+	/* Allocator for ZONED btrfs do not use the cache at all */
+	if (btrfs_fs_incompat(fs_info, ZONED))
+		return 0;
+
 	caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 	if (!caching_ctl)
 		return -ENOMEM;
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 4f486277fb6e..5f86d552c6cb 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3412,6 +3412,7 @@ btrfs_release_block_group(struct btrfs_block_group *cache,
 
 enum btrfs_extent_allocation_policy {
 	BTRFS_EXTENT_ALLOC_CLUSTERED,
+	BTRFS_EXTENT_ALLOC_ZONED,
 };
 
 /*
@@ -3664,6 +3665,55 @@ static int do_allocation_clustered(struct btrfs_block_group *block_group,
 	return find_free_extent_unclustered(block_group, ffe_ctl);
 }
 
+/*
+ * Simple allocator for sequential only block group. It only allows
+ * sequential allocation. No need to play with trees. This function
+ * also reserve the bytes as in btrfs_add_reserved_bytes.
+ */
+static int do_allocation_zoned(struct btrfs_block_group *block_group,
+			       struct find_free_extent_ctl *ffe_ctl,
+			       struct btrfs_block_group **bg_ret)
+{
+	struct btrfs_space_info *space_info = block_group->space_info;
+	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
+	u64 start = block_group->start;
+	u64 num_bytes = ffe_ctl->num_bytes;
+	u64 avail;
+	int ret = 0;
+
+	ASSERT(btrfs_fs_incompat(block_group->fs_info, ZONED));
+
+	spin_lock(&space_info->lock);
+	spin_lock(&block_group->lock);
+
+	if (block_group->ro) {
+		ret = 1;
+		goto out;
+	}
+
+	avail = block_group->length - block_group->alloc_offset;
+	if (avail < num_bytes) {
+		ffe_ctl->max_extent_size = avail;
+		ret = 1;
+		goto out;
+	}
+
+	ffe_ctl->found_offset = start + block_group->alloc_offset;
+	block_group->alloc_offset += num_bytes;
+	spin_lock(&ctl->tree_lock);
+	ctl->free_space -= num_bytes;
+	spin_unlock(&ctl->tree_lock);
+
+	ASSERT(IS_ALIGNED(ffe_ctl->found_offset,
+			  block_group->fs_info->stripesize));
+	ffe_ctl->search_start = ffe_ctl->found_offset;
+
+out:
+	spin_unlock(&block_group->lock);
+	spin_unlock(&space_info->lock);
+	return ret;
+}
+
 static int do_allocation(struct btrfs_block_group *block_group,
 			 struct find_free_extent_ctl *ffe_ctl,
 			 struct btrfs_block_group **bg_ret)
@@ -3671,6 +3721,8 @@ static int do_allocation(struct btrfs_block_group *block_group,
 	switch (ffe_ctl->policy) {
 	case BTRFS_EXTENT_ALLOC_CLUSTERED:
 		return do_allocation_clustered(block_group, ffe_ctl, bg_ret);
+	case BTRFS_EXTENT_ALLOC_ZONED:
+		return do_allocation_zoned(block_group, ffe_ctl, bg_ret);
 	default:
 		BUG();
 	}
@@ -3685,6 +3737,9 @@ static void release_block_group(struct btrfs_block_group *block_group,
 		ffe_ctl->retry_clustered = false;
 		ffe_ctl->retry_unclustered = false;
 		break;
+	case BTRFS_EXTENT_ALLOC_ZONED:
+		/* nothing to do */
+		break;
 	default:
 		BUG();
 	}
@@ -3713,6 +3768,9 @@ static void found_extent(struct find_free_extent_ctl *ffe_ctl,
 	case BTRFS_EXTENT_ALLOC_CLUSTERED:
 		found_extent_clustered(ffe_ctl, ins);
 		break;
+	case BTRFS_EXTENT_ALLOC_ZONED:
+		/* nothing to do */
+		break;
 	default:
 		BUG();
 	}
@@ -3728,6 +3786,9 @@ static int chunk_allocation_failed(struct find_free_extent_ctl *ffe_ctl)
 		 */
 		ffe_ctl->loop = LOOP_NO_EMPTY_SIZE;
 		return 0;
+	case BTRFS_EXTENT_ALLOC_ZONED:
+		/* give up here */
+		return -ENOSPC;
 	default:
 		BUG();
 	}
@@ -3896,6 +3957,9 @@ static int prepare_allocation(struct btrfs_fs_info *fs_info,
 	case BTRFS_EXTENT_ALLOC_CLUSTERED:
 		return prepare_allocation_clustered(fs_info, ffe_ctl,
 						    space_info, ins);
+	case BTRFS_EXTENT_ALLOC_ZONED:
+		/* nothing to do */
+		return 0;
 	default:
 		BUG();
 	}
@@ -3958,6 +4022,9 @@ static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
 	ffe_ctl.last_ptr = NULL;
 	ffe_ctl.use_cluster = true;
 
+	if (btrfs_fs_incompat(fs_info, ZONED))
+		ffe_ctl.policy = BTRFS_EXTENT_ALLOC_ZONED;
+
 	ins->type = BTRFS_EXTENT_ITEM_KEY;
 	ins->objectid = 0;
 	ins->offset = 0;
@@ -4100,20 +4167,23 @@ static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
 		/* move on to the next group */
 		if (ffe_ctl.search_start + num_bytes >
 		    block_group->start + block_group->length) {
-			btrfs_add_free_space(block_group, ffe_ctl.found_offset,
-					     num_bytes);
+			btrfs_add_free_space_unused(block_group,
+						    ffe_ctl.found_offset,
+						    num_bytes);
 			goto loop;
 		}
 
 		if (ffe_ctl.found_offset < ffe_ctl.search_start)
-			btrfs_add_free_space(block_group, ffe_ctl.found_offset,
-				ffe_ctl.search_start - ffe_ctl.found_offset);
+			btrfs_add_free_space_unused(block_group,
+						    ffe_ctl.found_offset,
+						    ffe_ctl.search_start - ffe_ctl.found_offset);
 
 		ret = btrfs_add_reserved_bytes(block_group, ram_bytes,
 				num_bytes, delalloc);
 		if (ret == -EAGAIN) {
-			btrfs_add_free_space(block_group, ffe_ctl.found_offset,
-					     num_bytes);
+			btrfs_add_free_space_unused(block_group,
+						    ffe_ctl.found_offset,
+						    num_bytes);
 			goto loop;
 		}
 		btrfs_inc_block_group_reservations(block_group);
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 7701b39b4d57..2df8ffd1ef8b 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -2906,6 +2906,8 @@ u64 btrfs_find_space_for_alloc(struct btrfs_block_group *block_group,
 	u64 align_gap_len = 0;
 	enum btrfs_trim_state align_gap_trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
 
+	ASSERT(!btrfs_fs_incompat(block_group->fs_info, ZONED));
+
 	spin_lock(&ctl->tree_lock);
 	entry = find_free_space(ctl, &offset, &bytes_search,
 				block_group->full_stripe_len, max_extent_size);
@@ -3037,6 +3039,8 @@ u64 btrfs_alloc_from_cluster(struct btrfs_block_group *block_group,
 	struct rb_node *node;
 	u64 ret = 0;
 
+	ASSERT(!btrfs_fs_incompat(block_group->fs_info, ZONED));
+
 	spin_lock(&cluster->lock);
 	if (bytes > cluster->max_size)
 		goto out;
@@ -3813,6 +3817,8 @@ int btrfs_trim_block_group(struct btrfs_block_group *block_group,
 	int ret;
 	u64 rem = 0;
 
+	ASSERT(!btrfs_fs_incompat(block_group->fs_info, ZONED));
+
 	*trimmed = 0;
 
 	spin_lock(&block_group->lock);
-- 
2.27.0

[PATCH v7 17/39] btrfs: reset zones of unused block groups

[Naohiro Aota]

For an ZONED volume, a block group maps to a zone of the device. For
deleted unused block groups, the zone of the block group can be reset to
rewind the zone write pointer at the start of the zone.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/block-group.c |  8 ++++++--
 fs/btrfs/extent-tree.c | 17 ++++++++++++-----
 fs/btrfs/zoned.h       | 16 ++++++++++++++++
 3 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 9df83e687b92..fbc22f0a6744 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -1468,8 +1468,12 @@ void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
 		if (!async_trim_enabled && btrfs_test_opt(fs_info, DISCARD_ASYNC))
 			goto flip_async;
 
-		/* DISCARD can flip during remount */
-		trimming = btrfs_test_opt(fs_info, DISCARD_SYNC);
+		/*
+		 * DISCARD can flip during remount. In ZONED mode, we need
+		 * to reset sequential required zones.
+		 */
+		trimming = btrfs_test_opt(fs_info, DISCARD_SYNC) ||
+				btrfs_fs_incompat(fs_info, ZONED);
 
 		/* Implicit trim during transaction commit. */
 		if (trimming)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 5f86d552c6cb..7fe5b6e3b207 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -1317,6 +1317,9 @@ int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
 
 		stripe = bbio->stripes;
 		for (i = 0; i < bbio->num_stripes; i++, stripe++) {
+			struct btrfs_device *dev = stripe->dev;
+			u64 physical = stripe->physical;
+			u64 length = stripe->length;
 			u64 bytes;
 			struct request_queue *req_q;
 
@@ -1324,14 +1327,18 @@ int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
 				ASSERT(btrfs_test_opt(fs_info, DEGRADED));
 				continue;
 			}
+
 			req_q = bdev_get_queue(stripe->dev->bdev);
-			if (!blk_queue_discard(req_q))
+			/* zone reset in ZONED mode */
+			if (btrfs_can_zone_reset(dev, physical, length))
+				ret = btrfs_reset_device_zone(dev, physical,
+							      length, &bytes);
+			else if (blk_queue_discard(req_q))
+				ret = btrfs_issue_discard(dev->bdev, physical,
+							  length, &bytes);
+			else
 				continue;
 
-			ret = btrfs_issue_discard(stripe->dev->bdev,
-						  stripe->physical,
-						  stripe->length,
-						  &bytes);
 			if (!ret) {
 				discarded_bytes += bytes;
 			} else if (ret != -EOPNOTSUPP) {
diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h
index 3e3eff8dd0b4..ccfb63a455dc 100644
--- a/fs/btrfs/zoned.h
+++ b/fs/btrfs/zoned.h
@@ -201,4 +201,20 @@ static inline u64 btrfs_zone_align(struct btrfs_device *device, u64 pos)
 	return ALIGN(pos, device->zone_info->zone_size);
 }
 
+static inline bool btrfs_can_zone_reset(struct btrfs_device *device,
+					u64 physical, u64 length)
+{
+	u64 zone_size;
+
+	if (!btrfs_dev_is_sequential(device, physical))
+		return false;
+
+	zone_size = device->zone_info->zone_size;
+	if (!IS_ALIGNED(physical, zone_size) ||
+	    !IS_ALIGNED(length, zone_size))
+		return false;
+
+	return true;
+}
+
 #endif
-- 
2.27.0

[PATCH v7 18/39] btrfs: redirty released extent buffers in ZONED mode

[Naohiro Aota]

Tree manipulating operations like merging nodes often release
once-allocated tree nodes. Btrfs cleans such nodes so that pages in the
node are not uselessly written out. On ZONED volumes, however, such
optimization blocks the following IOs as the cancellation of the write out
of the freed blocks breaks the sequential write sequence expected by the
device.

This patch introduces a list of clean and unwritten extent buffers that
have been released in a transaction. Btrfs redirty the buffer so that
btree_write_cache_pages() can send proper bios to the devices.

Besides it clears the entire content of the extent buffer not to confuse
raw block scanners e.g. btrfsck. By clearing the content,
csum_dirty_buffer() complains about bytenr mismatch, so avoid the checking
and checksum using newly introduced buffer flag EXTENT_BUFFER_NO_CHECK.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/disk-io.c     |  8 ++++++++
 fs/btrfs/extent-tree.c | 12 +++++++++++-
 fs/btrfs/extent_io.c   |  3 +++
 fs/btrfs/extent_io.h   |  2 ++
 fs/btrfs/transaction.c | 10 ++++++++++
 fs/btrfs/transaction.h |  3 +++
 fs/btrfs/tree-log.c    |  6 ++++++
 fs/btrfs/zoned.c       | 37 +++++++++++++++++++++++++++++++++++++
 fs/btrfs/zoned.h       |  6 ++++++
 9 files changed, 86 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 362799403285..d766cb0e1a52 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -510,6 +510,12 @@ static int csum_dirty_buffer(struct btrfs_fs_info *fs_info, struct page *page)
 		return 0;
 
 	found_start = btrfs_header_bytenr(eb);
+
+	if (test_bit(EXTENT_BUFFER_NO_CHECK, &eb->bflags)) {
+		WARN_ON(found_start != 0);
+		return 0;
+	}
+
 	/*
 	 * Please do not consolidate these warnings into a single if.
 	 * It is useful to know what went wrong.
@@ -4689,6 +4695,8 @@ void btrfs_cleanup_one_transaction(struct btrfs_transaction *cur_trans,
 				     EXTENT_DIRTY);
 	btrfs_destroy_pinned_extent(fs_info, &cur_trans->pinned_extents);
 
+	btrfs_free_redirty_list(cur_trans);
+
 	cur_trans->state =TRANS_STATE_COMPLETED;
 	wake_up(&cur_trans->commit_wait);
 }
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 7fe5b6e3b207..81b9b58d7a9d 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3271,8 +3271,10 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
 
 		if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
 			ret = check_ref_cleanup(trans, buf->start);
-			if (!ret)
+			if (!ret) {
+				btrfs_redirty_list_add(trans->transaction, buf);
 				goto out;
+			}
 		}
 
 		pin = 0;
@@ -3284,6 +3286,13 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
 			goto out;
 		}
 
+		if (btrfs_fs_incompat(fs_info, ZONED)) {
+			btrfs_redirty_list_add(trans->transaction, buf);
+			pin_down_extent(trans, cache, buf->start, buf->len, 1);
+			btrfs_put_block_group(cache);
+			goto out;
+		}
+
 		WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
 
 		btrfs_add_free_space(cache, buf->start, buf->len);
@@ -4615,6 +4624,7 @@ btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 	btrfs_tree_lock(buf);
 	btrfs_clean_tree_block(buf);
 	clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
+	clear_bit(EXTENT_BUFFER_NO_CHECK, &buf->bflags);
 
 	btrfs_set_lock_blocking_write(buf);
 	set_extent_buffer_uptodate(buf);
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index c15ab6c1897f..53bac37bc4ac 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -24,6 +24,7 @@
 #include "rcu-string.h"
 #include "backref.h"
 #include "disk-io.h"
+#include "zoned.h"
 
 static struct kmem_cache *extent_state_cache;
 static struct kmem_cache *extent_buffer_cache;
@@ -4994,6 +4995,7 @@ __alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
 
 	btrfs_leak_debug_add(&fs_info->eb_leak_lock, &eb->leak_list,
 			     &fs_info->allocated_ebs);
+	INIT_LIST_HEAD(&eb->release_list);
 
 	spin_lock_init(&eb->refs_lock);
 	atomic_set(&eb->refs, 1);
@@ -5756,6 +5758,7 @@ void write_extent_buffer(const struct extent_buffer *eb, const void *srcv,
 
 	WARN_ON(start > eb->len);
 	WARN_ON(start + len > eb->start + eb->len);
+	WARN_ON(test_bit(EXTENT_BUFFER_NO_CHECK, &eb->bflags));
 
 	offset = offset_in_page(start);
 
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 30794ae58498..29dbb21a5c9a 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -30,6 +30,7 @@ enum {
 	EXTENT_BUFFER_IN_TREE,
 	/* write IO error */
 	EXTENT_BUFFER_WRITE_ERR,
+	EXTENT_BUFFER_NO_CHECK,
 };
 
 /* these are flags for __process_pages_contig */
@@ -119,6 +120,7 @@ struct extent_buffer {
 	 */
 	wait_queue_head_t read_lock_wq;
 	struct page *pages[INLINE_EXTENT_BUFFER_PAGES];
+	struct list_head release_list;
 #ifdef CONFIG_BTRFS_DEBUG
 	int spinning_writers;
 	atomic_t spinning_readers;
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 951b10364fd0..1414b3ade2db 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -22,6 +22,7 @@
 #include "qgroup.h"
 #include "block-group.h"
 #include "space-info.h"
+#include "zoned.h"
 
 #define BTRFS_ROOT_TRANS_TAG 0
 
@@ -334,6 +335,8 @@ static noinline int join_transaction(struct btrfs_fs_info *fs_info,
 	spin_lock_init(&cur_trans->dirty_bgs_lock);
 	INIT_LIST_HEAD(&cur_trans->deleted_bgs);
 	spin_lock_init(&cur_trans->dropped_roots_lock);
+	INIT_LIST_HEAD(&cur_trans->releasing_ebs);
+	spin_lock_init(&cur_trans->releasing_ebs_lock);
 	list_add_tail(&cur_trans->list, &fs_info->trans_list);
 	extent_io_tree_init(fs_info, &cur_trans->dirty_pages,
 			IO_TREE_TRANS_DIRTY_PAGES, fs_info->btree_inode);
@@ -2334,6 +2337,13 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
 		goto scrub_continue;
 	}
 
+	/*
+	 * At this point, we should have written the all tree blocks
+	 * allocated in this transaction. So it's now safe to free the
+	 * redirtyied extent buffers.
+	 */
+	btrfs_free_redirty_list(cur_trans);
+
 	ret = write_all_supers(fs_info, 0);
 	/*
 	 * the super is written, we can safely allow the tree-loggers
diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h
index d60b055b8695..d274b6d9798c 100644
--- a/fs/btrfs/transaction.h
+++ b/fs/btrfs/transaction.h
@@ -85,6 +85,9 @@ struct btrfs_transaction {
 	spinlock_t dropped_roots_lock;
 	struct btrfs_delayed_ref_root delayed_refs;
 	struct btrfs_fs_info *fs_info;
+
+	spinlock_t releasing_ebs_lock;
+	struct list_head releasing_ebs;
 };
 
 #define __TRANS_FREEZABLE	(1U << 0)
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 39da9db35278..4b6a68a81eac 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -20,6 +20,7 @@
 #include "inode-map.h"
 #include "block-group.h"
 #include "space-info.h"
+#include "zoned.h"
 
 /* magic values for the inode_only field in btrfs_log_inode:
  *
@@ -2746,6 +2747,8 @@ static noinline int walk_down_log_tree(struct btrfs_trans_handle *trans,
 						free_extent_buffer(next);
 						return ret;
 					}
+					btrfs_redirty_list_add(
+						trans->transaction, next);
 				} else {
 					if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &next->bflags))
 						clear_extent_buffer_dirty(next);
@@ -3281,6 +3284,9 @@ static void free_log_tree(struct btrfs_trans_handle *trans,
 	clear_extent_bits(&log->dirty_log_pages, 0, (u64)-1,
 			  EXTENT_DIRTY | EXTENT_NEW | EXTENT_NEED_WAIT);
 	extent_io_tree_release(&log->log_csum_range);
+
+	if (trans && log->node)
+		btrfs_redirty_list_add(trans->transaction, log->node);
 	btrfs_put_root(log);
 }
 
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 68f8224d74c3..855acbc61d47 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -18,6 +18,7 @@
 #include "rcu-string.h"
 #include "disk-io.h"
 #include "block-group.h"
+#include "transaction.h"
 
 /* Maximum number of zones to report per blkdev_report_zones() call */
 #define BTRFS_REPORT_NR_ZONES   4096
@@ -1028,3 +1029,39 @@ void btrfs_calc_zone_unusable(struct btrfs_block_group *cache)
 	 */
 	btrfs_free_excluded_extents(cache);
 }
+
+void btrfs_redirty_list_add(struct btrfs_transaction *trans,
+			    struct extent_buffer *eb)
+{
+	struct btrfs_fs_info *fs_info = eb->fs_info;
+
+	if (!btrfs_fs_incompat(fs_info, ZONED) ||
+	    btrfs_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN) ||
+	    !list_empty(&eb->release_list))
+		return;
+
+	set_extent_buffer_dirty(eb);
+	set_extent_bits_nowait(&trans->dirty_pages, eb->start,
+			       eb->start + eb->len - 1, EXTENT_DIRTY);
+	memzero_extent_buffer(eb, 0, eb->len);
+	set_bit(EXTENT_BUFFER_NO_CHECK, &eb->bflags);
+
+	spin_lock(&trans->releasing_ebs_lock);
+	list_add_tail(&eb->release_list, &trans->releasing_ebs);
+	spin_unlock(&trans->releasing_ebs_lock);
+	atomic_inc(&eb->refs);
+}
+
+void btrfs_free_redirty_list(struct btrfs_transaction *trans)
+{
+	spin_lock(&trans->releasing_ebs_lock);
+	while (!list_empty(&trans->releasing_ebs)) {
+		struct extent_buffer *eb;
+
+		eb = list_first_entry(&trans->releasing_ebs,
+				      struct extent_buffer, release_list);
+		list_del_init(&eb->release_list);
+		free_extent_buffer(eb);
+	}
+	spin_unlock(&trans->releasing_ebs_lock);
+}
diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h
index ccfb63a455dc..cdb84c758a61 100644
--- a/fs/btrfs/zoned.h
+++ b/fs/btrfs/zoned.h
@@ -47,6 +47,9 @@ int btrfs_reset_device_zone(struct btrfs_device *device, u64 physical,
 int btrfs_ensure_empty_zones(struct btrfs_device *device, u64 start, u64 size);
 int btrfs_load_block_group_zone_info(struct btrfs_block_group *cache);
 void btrfs_calc_zone_unusable(struct btrfs_block_group *cache);
+void btrfs_redirty_list_add(struct btrfs_transaction *trans,
+			    struct extent_buffer *eb);
+void btrfs_free_redirty_list(struct btrfs_transaction *trans);
 #else /* CONFIG_BLK_DEV_ZONED */
 static inline int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
 				     struct blk_zone *zone)
@@ -115,6 +118,9 @@ static inline int btrfs_load_block_group_zone_info(
 	return 0;
 }
 static inline void btrfs_calc_zone_unusable(struct btrfs_block_group *cache) { }
+static inline void btrfs_redirty_list_add(struct btrfs_transaction *trans,
+					  struct extent_buffer *eb) { }
+static inline void btrfs_free_redirty_list(struct btrfs_transaction *trans) { }
 #endif
 
 static inline bool btrfs_dev_is_sequential(struct btrfs_device *device, u64 pos)
-- 
2.27.0

[PATCH v7 19/39] btrfs: limit bio size under max_zone_append_size

[Naohiro Aota]

Zone append write command cannot exceed the max zone append size. This
commit limits the page merging into a bio.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/extent_io.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 53bac37bc4ac..63cdf67e6885 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3041,6 +3041,7 @@ static int submit_extent_page(unsigned int opf,
 	size_t page_size = min_t(size_t, size, PAGE_SIZE);
 	sector_t sector = offset >> 9;
 	struct extent_io_tree *tree = &BTRFS_I(page->mapping->host)->io_tree;
+	struct btrfs_fs_info *fs_info = tree->fs_info;
 
 	ASSERT(bio_ret);
 
@@ -3058,6 +3059,11 @@ static int submit_extent_page(unsigned int opf,
 		if (btrfs_bio_fits_in_stripe(page, page_size, bio, bio_flags))
 			can_merge = false;
 
+		if (fs_info->max_zone_append_size &&
+		    bio_op(bio) == REQ_OP_WRITE &&
+		    bio->bi_iter.bi_size + size > fs_info->max_zone_append_size)
+			can_merge = false;
+
 		if (prev_bio_flags != bio_flags || !contig || !can_merge ||
 		    force_bio_submit ||
 		    bio_add_page(bio, page, page_size, pg_offset) < page_size) {
-- 
2.27.0

[PATCH v7 20/39] btrfs: limit ordered extent size to max_zone_append_size

[Naohiro Aota]

With zone append writing, the logical address must be modified to match the
actual written physical address. If multiple bios serve one ordered extent,
the bios can reside in a non-contiguous physical region, resulting in the
non-contiguous logical region. It is troublesome to handle such a case, so
one ordered extent must be served by one bio, limited to
max_zone_apend_size. Thus, this commit limits the size of an ordered extent
as well.

This size limitation results in file extents fragmentation. In the future,
we can merge contiguous ordered extents as an optimization.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/extent_io.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 63cdf67e6885..c21d1dbe314e 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1865,6 +1865,7 @@ noinline_for_stack bool find_lock_delalloc_range(struct inode *inode,
 				    u64 *end)
 {
 	struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
+	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 	u64 max_bytes = BTRFS_MAX_EXTENT_SIZE;
 	u64 delalloc_start;
 	u64 delalloc_end;
@@ -1873,6 +1874,10 @@ noinline_for_stack bool find_lock_delalloc_range(struct inode *inode,
 	int ret;
 	int loops = 0;
 
+	if (fs_info && fs_info->max_zone_append_size)
+		max_bytes = ALIGN_DOWN(fs_info->max_zone_append_size,
+				       PAGE_SIZE);
+
 again:
 	/* step one, find a bunch of delalloc bytes starting at start */
 	delalloc_start = *start;
-- 
2.27.0

[PATCH v7 21/39] btrfs: extend btrfs_rmap_block for specifying a device

[Naohiro Aota]

btrfs_rmap_block currently reverse-map the physical address on all devices
to logical addresses. This commit extends the function to match to a
specified device. You can still query all devices by specifying NULL as a
device.

This commit also exporet the function for later use.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/block-group.c | 23 ++++++++++++++++++-----
 fs/btrfs/block-group.h |  3 +++
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index fbc22f0a6744..be5394c8ec3a 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -1655,9 +1655,9 @@ static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
  * Used primarily to exclude those portions of a block group that contain super
  * block copies.
  */
-EXPORT_FOR_TESTS
-int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
-		     u64 physical, u64 **logical, int *naddrs, int *stripe_len)
+int __btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
+		       struct block_device *bdev, u64 physical, u64 **logical,
+		       int *naddrs, int *stripe_len)
 {
 	struct extent_map *em;
 	struct map_lookup *map;
@@ -1675,6 +1675,7 @@ int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
 	map = em->map_lookup;
 	data_stripe_length = em->orig_block_len;
 	io_stripe_size = map->stripe_len;
+	chunk_start = em->start;
 
 	/* For RAID5/6 adjust to a full IO stripe length */
 	if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
@@ -1689,14 +1690,18 @@ int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
 	for (i = 0; i < map->num_stripes; i++) {
 		bool already_inserted = false;
 		u64 stripe_nr;
+		u64 offset;
 		int j;
 
 		if (!in_range(physical, map->stripes[i].physical,
 			      data_stripe_length))
 			continue;
 
+		if (bdev && map->stripes[i].dev->bdev != bdev)
+			continue;
+
 		stripe_nr = physical - map->stripes[i].physical;
-		stripe_nr = div64_u64(stripe_nr, map->stripe_len);
+		stripe_nr = div64_u64_rem(stripe_nr, map->stripe_len, &offset);
 
 		if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
 			stripe_nr = stripe_nr * map->num_stripes + i;
@@ -1710,7 +1715,7 @@ int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
 		 * instead of map->stripe_len
 		 */
 
-		bytenr = chunk_start + stripe_nr * io_stripe_size;
+		bytenr = chunk_start + stripe_nr * io_stripe_size + offset;
 
 		/* Ensure we don't add duplicate addresses */
 		for (j = 0; j < nr; j++) {
@@ -1732,6 +1737,14 @@ int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
 	return ret;
 }
 
+EXPORT_FOR_TESTS
+int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
+		     u64 physical, u64 **logical, int *naddrs, int *stripe_len)
+{
+	return __btrfs_rmap_block(fs_info, chunk_start, NULL, physical, logical,
+				  naddrs, stripe_len);
+}
+
 static int exclude_super_stripes(struct btrfs_block_group *cache)
 {
 	struct btrfs_fs_info *fs_info = cache->fs_info;
diff --git a/fs/btrfs/block-group.h b/fs/btrfs/block-group.h
index 5be47f4bfea7..401e9bcefaec 100644
--- a/fs/btrfs/block-group.h
+++ b/fs/btrfs/block-group.h
@@ -275,6 +275,9 @@ void check_system_chunk(struct btrfs_trans_handle *trans, const u64 type);
 u64 btrfs_get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags);
 void btrfs_put_block_group_cache(struct btrfs_fs_info *info);
 int btrfs_free_block_groups(struct btrfs_fs_info *info);
+int __btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
+		       struct block_device *bdev, u64 physical, u64 **logical,
+		       int *naddrs, int *stripe_len);
 
 static inline u64 btrfs_data_alloc_profile(struct btrfs_fs_info *fs_info)
 {
-- 
2.27.0

[PATCH v7 22/39] btrfs: use ZONE_APPEND write for ZONED btrfs

[Naohiro Aota]

This commit enables zone append writing for zoned btrfs. Three parts are
necessary to enable it. First, it modifies bio to use REQ_OP_ZONE_APPEND in
btrfs_submit_bio_hook() and adjust the bi_sector to point the beginning of
the zone.

Second, it records returned physical address (and disk/partno) to
the ordered extent in end_bio_extent_writepage().

Finally, it rewrites logical addresses of the extent mapping and checksum
data according to the physical address (using __btrfs_rmap_block). If the
returned address match to the originaly allocated address, we can skip the
rewriting process.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/extent_io.c    |  4 +++
 fs/btrfs/inode.c        | 12 ++++++-
 fs/btrfs/ordered-data.c |  3 ++
 fs/btrfs/ordered-data.h |  4 +++
 fs/btrfs/volumes.c      |  9 ++++++
 fs/btrfs/zoned.c        | 70 +++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/zoned.h        |  9 ++++++
 7 files changed, 110 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index c21d1dbe314e..00a07cefffeb 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2749,6 +2749,10 @@ static void end_bio_extent_writepage(struct bio *bio)
 	u64 end;
 	struct bvec_iter_all iter_all;
 
+	btrfs_record_physical_zoned(bio_iovec(bio).bv_page->mapping->host,
+				    page_offset(bio_iovec(bio).bv_page) + bio_iovec(bio).bv_offset,
+				    bio);
+
 	ASSERT(!bio_flagged(bio, BIO_CLONED));
 	bio_for_each_segment_all(bvec, bio, iter_all) {
 		struct page *page = bvec->bv_page;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index ca0be689e7ad..7fe28a77f9b8 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -49,6 +49,7 @@
 #include "delalloc-space.h"
 #include "block-group.h"
 #include "space-info.h"
+#include "zoned.h"
 
 struct btrfs_iget_args {
 	u64 ino;
@@ -2198,7 +2199,13 @@ static blk_status_t btrfs_submit_bio_hook(struct inode *inode, struct bio *bio,
 	if (btrfs_is_free_space_inode(BTRFS_I(inode)))
 		metadata = BTRFS_WQ_ENDIO_FREE_SPACE;
 
-	if (bio_op(bio) != REQ_OP_WRITE) {
+	if (bio_op(bio) == REQ_OP_WRITE && btrfs_fs_incompat(fs_info, ZONED)) {
+		/* use zone append writing */
+		bio->bi_opf &= ~REQ_OP_MASK;
+		bio->bi_opf |= REQ_OP_ZONE_APPEND;
+	}
+
+	if (bio_op(bio) != REQ_OP_WRITE && bio_op(bio) != REQ_OP_ZONE_APPEND) {
 		ret = btrfs_bio_wq_end_io(fs_info, bio, metadata);
 		if (ret)
 			goto out;
@@ -2594,6 +2601,9 @@ static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
 	bool clear_reserved_extent = true;
 	unsigned int clear_bits;
 
+	if (ordered_extent->disk)
+		btrfs_rewrite_logical_zoned(ordered_extent);
+
 	start = ordered_extent->file_offset;
 	end = start + ordered_extent->num_bytes - 1;
 
diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index ebac13389e7e..3cb0d92a3bcf 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -199,6 +199,9 @@ static int __btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset
 	entry->compress_type = compress_type;
 	entry->truncated_len = (u64)-1;
 	entry->qgroup_rsv = ret;
+	entry->physical = (u64)-1;
+	entry->disk = NULL;
+	entry->partno = (u8)-1;
 	if (type != BTRFS_ORDERED_IO_DONE && type != BTRFS_ORDERED_COMPLETE)
 		set_bit(type, &entry->flags);
 
diff --git a/fs/btrfs/ordered-data.h b/fs/btrfs/ordered-data.h
index d61ea9c880a3..7872d566ae1b 100644
--- a/fs/btrfs/ordered-data.h
+++ b/fs/btrfs/ordered-data.h
@@ -118,6 +118,10 @@ struct btrfs_ordered_extent {
 	struct completion completion;
 	struct btrfs_work flush_work;
 	struct list_head work_list;
+
+	u64 physical;
+	struct gendisk *disk;
+	u8 partno;
 };
 
 /*
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 086cd308e5b6..6337ce95a088 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -6505,6 +6505,15 @@ static void submit_stripe_bio(struct btrfs_bio *bbio, struct bio *bio,
 	btrfs_io_bio(bio)->device = dev;
 	bio->bi_end_io = btrfs_end_bio;
 	bio->bi_iter.bi_sector = physical >> 9;
+	/*
+	 * For zone append writing, bi_sector must point the beginning of the
+	 * zone
+	 */
+	if (bio_op(bio) == REQ_OP_ZONE_APPEND) {
+		u64 zone_start = round_down(physical, fs_info->zone_size);
+
+		bio->bi_iter.bi_sector = zone_start >> SECTOR_SHIFT;
+	}
 	btrfs_debug_in_rcu(fs_info,
 	"btrfs_map_bio: rw %d 0x%x, sector=%llu, dev=%lu (%s id %llu), size=%u",
 		bio_op(bio), bio->bi_opf, (u64)bio->bi_iter.bi_sector,
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 855acbc61d47..1744e2649087 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -1065,3 +1065,73 @@ void btrfs_free_redirty_list(struct btrfs_transaction *trans)
 	}
 	spin_unlock(&trans->releasing_ebs_lock);
 }
+
+void btrfs_record_physical_zoned(struct inode *inode, u64 file_offset,
+				 struct bio *bio)
+{
+	struct btrfs_ordered_extent *ordered;
+	struct bio_vec bvec = bio_iovec(bio);
+	u64 physical = ((u64)bio->bi_iter.bi_sector << SECTOR_SHIFT) +
+		bvec.bv_offset;
+
+	if (bio_op(bio) != REQ_OP_ZONE_APPEND)
+		return;
+
+	ordered = btrfs_lookup_ordered_extent(BTRFS_I(inode), file_offset);
+	if (WARN_ON(!ordered))
+		return;
+
+	ordered->physical = physical;
+	ordered->disk = bio->bi_disk;
+	ordered->partno = bio->bi_partno;
+
+	btrfs_put_ordered_extent(ordered);
+}
+
+void btrfs_rewrite_logical_zoned(struct btrfs_ordered_extent *ordered)
+{
+	struct extent_map_tree *em_tree;
+	struct extent_map *em;
+	struct inode *inode = ordered->inode;
+	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+	struct btrfs_ordered_sum *sum;
+	struct block_device *bdev;
+	u64 orig_logical = ordered->disk_bytenr;
+	u64 *logical = NULL;
+	int nr, stripe_len;
+
+	bdev = bdget_disk(ordered->disk, ordered->partno);
+	if (WARN_ON(!bdev))
+		return;
+
+	if (WARN_ON(__btrfs_rmap_block(fs_info, orig_logical, bdev,
+				       ordered->physical, &logical, &nr,
+				       &stripe_len)))
+		goto out;
+
+	WARN_ON(nr != 1);
+
+	if (orig_logical == *logical)
+		goto out;
+
+	ordered->disk_bytenr = *logical;
+
+	em_tree = &BTRFS_I(inode)->extent_tree;
+	write_lock(&em_tree->lock);
+	em = search_extent_mapping(em_tree, ordered->file_offset,
+				   ordered->num_bytes);
+	em->block_start = *logical;
+	free_extent_map(em);
+	write_unlock(&em_tree->lock);
+
+	list_for_each_entry(sum, &ordered->list, list) {
+		if (*logical < orig_logical)
+			sum->bytenr -= orig_logical - *logical;
+		else
+			sum->bytenr += *logical - orig_logical;
+	}
+
+out:
+	kfree(logical);
+	bdput(bdev);
+}
diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h
index cdb84c758a61..5f4bc746e3e2 100644
--- a/fs/btrfs/zoned.h
+++ b/fs/btrfs/zoned.h
@@ -50,6 +50,9 @@ void btrfs_calc_zone_unusable(struct btrfs_block_group *cache);
 void btrfs_redirty_list_add(struct btrfs_transaction *trans,
 			    struct extent_buffer *eb);
 void btrfs_free_redirty_list(struct btrfs_transaction *trans);
+void btrfs_record_physical_zoned(struct inode *inode, u64 file_offset,
+				 struct bio *bio);
+void btrfs_rewrite_logical_zoned(struct btrfs_ordered_extent *ordered);
 #else /* CONFIG_BLK_DEV_ZONED */
 static inline int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
 				     struct blk_zone *zone)
@@ -121,6 +124,12 @@ static inline void btrfs_calc_zone_unusable(struct btrfs_block_group *cache) { }
 static inline void btrfs_redirty_list_add(struct btrfs_transaction *trans,
 					  struct extent_buffer *eb) { }
 static inline void btrfs_free_redirty_list(struct btrfs_transaction *trans) { }
+static inline void btrfs_record_physical_zoned(struct inode *inode,
+					       u64 file_offset, struct bio *bio)
+{
+}
+static inline void
+btrfs_rewrite_logical_zoned(struct btrfs_ordered_extent *ordered) { }
 #endif
 
 static inline bool btrfs_dev_is_sequential(struct btrfs_device *device, u64 pos)
-- 
2.27.0

[PATCH v7 23/39] btrfs: handle REQ_OP_ZONE_APPEND as writing

[Naohiro Aota]

ZONED btrfs uses REQ_OP_ZONE_APPEND for a bio going to actual devices. Let
btrfs_end_bio() and btrfs_op, who faces the bios, aware of it.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/volumes.c | 3 ++-
 fs/btrfs/volumes.h | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 6337ce95a088..ca139c63f63c 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -6453,7 +6453,8 @@ static void btrfs_end_bio(struct bio *bio)
 			struct btrfs_device *dev = btrfs_io_bio(bio)->device;
 
 			ASSERT(dev->bdev);
-			if (bio_op(bio) == REQ_OP_WRITE)
+			if (bio_op(bio) == REQ_OP_WRITE ||
+			    bio_op(bio) == REQ_OP_ZONE_APPEND)
 				btrfs_dev_stat_inc_and_print(dev,
 						BTRFS_DEV_STAT_WRITE_ERRS);
 			else if (!(bio->bi_opf & REQ_RAHEAD))
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 88b1d59fbc12..fc03b386bb8c 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -410,6 +410,7 @@ static inline enum btrfs_map_op btrfs_op(struct bio *bio)
 	case REQ_OP_DISCARD:
 		return BTRFS_MAP_DISCARD;
 	case REQ_OP_WRITE:
+	case REQ_OP_ZONE_APPEND:
 		return BTRFS_MAP_WRITE;
 	default:
 		WARN_ON_ONCE(1);
-- 
2.27.0

[PATCH v7 24/39] btrfs: enable zone append writing for direct IO

[Naohiro Aota]

This commit enables zone append writing as same as in buffered write.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/inode.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 7fe28a77f9b8..422940d7bb4b 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -7351,6 +7351,11 @@ static int btrfs_dio_iomap_begin(struct inode *inode, loff_t start,
 	u64 len = length;
 	bool unlock_extents = false;
 
+	if (write && fs_info->max_zone_append_size) {
+		length = min_t(u64, length, fs_info->max_zone_append_size);
+		len = length;
+	}
+
 	if (!write)
 		len = min_t(u64, len, fs_info->sectorsize);
 
@@ -7692,6 +7697,8 @@ static void btrfs_end_dio_bio(struct bio *bio)
 	if (err)
 		dip->dio_bio->bi_status = err;
 
+	btrfs_record_physical_zoned(dip->inode, dip->logical_offset, bio);
+
 	bio_put(bio);
 	btrfs_dio_private_put(dip);
 }
@@ -7701,7 +7708,8 @@ static inline blk_status_t btrfs_submit_dio_bio(struct bio *bio,
 {
 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 	struct btrfs_dio_private *dip = bio->bi_private;
-	bool write = bio_op(bio) == REQ_OP_WRITE;
+	bool write = bio_op(bio) == REQ_OP_WRITE ||
+		     bio_op(bio) == REQ_OP_ZONE_APPEND;
 	blk_status_t ret;
 
 	/* Check btrfs_submit_bio_hook() for rules about async submit. */
@@ -7846,6 +7854,12 @@ static blk_qc_t btrfs_submit_direct(struct inode *inode, struct iomap *iomap,
 		bio->bi_end_io = btrfs_end_dio_bio;
 		btrfs_io_bio(bio)->logical = file_offset;
 
+		if (write && btrfs_fs_incompat(fs_info, ZONED) &&
+		    fs_info->max_zone_append_size) {
+			bio->bi_opf &= ~REQ_OP_MASK;
+			bio->bi_opf |= REQ_OP_ZONE_APPEND;
+		}
+
 		ASSERT(submit_len >= clone_len);
 		submit_len -= clone_len;
 
-- 
2.27.0

[PATCH v7 25/39] btrfs: introduce dedicated data write path for ZONED mode

[Naohiro Aota]

If more than one IO is issued for one file extent, these IO can be written
in a separate region on a device. Since we cannot map one file extent to
such a separate area, we need to follow the "one IO == one ordered extent"
rule.

Normal (buffered, uncompressed, not pre-allocated) write path (=
cow_file_range()) sometime does not follow the rule. It can write a part of
an ordered extent when specified a region to write e.g., called from
fdatasync().

This commit introduces a dedicated (uncompressed buffered) data write path
for ZONED mode. This write path CoW the region and write the region at
once.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/inode.c | 34 ++++++++++++++++++++++++++++++++--
 1 file changed, 32 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 422940d7bb4b..2bd001df4a75 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1355,6 +1355,29 @@ static int cow_file_range_async(struct btrfs_inode *inode,
 	return 0;
 }
 
+static noinline int run_delalloc_zoned(struct btrfs_inode *inode,
+				       struct page *locked_page, u64 start,
+				       u64 end, int *page_started,
+				       unsigned long *nr_written)
+{
+	int ret;
+
+	ret = cow_file_range(inode, locked_page, start, end,
+			     page_started, nr_written, 0);
+	if (ret)
+		return ret;
+
+	if (*page_started)
+		return 0;
+
+	__set_page_dirty_nobuffers(locked_page);
+	account_page_redirty(locked_page);
+	extent_write_locked_range(&inode->vfs_inode, start, end, WB_SYNC_ALL);
+	*page_started = 1;
+
+	return 0;
+}
+
 static noinline int csum_exist_in_range(struct btrfs_fs_info *fs_info,
 					u64 bytenr, u64 num_bytes)
 {
@@ -1825,17 +1848,24 @@ int btrfs_run_delalloc_range(struct btrfs_inode *inode, struct page *locked_page
 {
 	int ret;
 	int force_cow = need_force_cow(inode, start, end);
+	int do_compress = inode_can_compress(inode) &&
+		inode_need_compress(inode, start, end);
+	bool zoned = btrfs_fs_incompat(inode->root->fs_info, ZONED);
 
 	if (inode->flags & BTRFS_INODE_NODATACOW && !force_cow) {
+		ASSERT(!zoned);
 		ret = run_delalloc_nocow(inode, locked_page, start, end,
 					 page_started, 1, nr_written);
 	} else if (inode->flags & BTRFS_INODE_PREALLOC && !force_cow) {
+		ASSERT(!zoned);
 		ret = run_delalloc_nocow(inode, locked_page, start, end,
 					 page_started, 0, nr_written);
-	} else if (!inode_can_compress(inode) ||
-		   !inode_need_compress(inode, start, end)) {
+	} else if (!do_compress && !zoned) {
 		ret = cow_file_range(inode, locked_page, start, end,
 				     page_started, nr_written, 1);
+	} else if (!do_compress && zoned) {
+		ret = run_delalloc_zoned(inode, locked_page, start, end,
+					 page_started, nr_written);
 	} else {
 		set_bit(BTRFS_INODE_HAS_ASYNC_EXTENT, &inode->runtime_flags);
 		ret = cow_file_range_async(inode, wbc, locked_page, start, end,
-- 
2.27.0

[PATCH v7 26/39] btrfs: serialize meta IOs on ZONED mode

[Naohiro Aota]

We cannot use zone append writing for metadata, because the B-tree nodes
have references to each other using the logical address. Without knowing
the address in advance, we cannot construct the tree in the first place.
Thus, we need to serialize write IOs for metadata.

We cannot add mutex around allocation and submit because metadata blocks
are allocated in an earlier stage to build up B-trees.

Thus, this commit add zoned_meta_io_lock and hold it during metadata IO
submission in btree_write_cache_pages() to serialize IOs. Furthermore, this
commit add per-block group metadata IO submission pointer
"meta_write_pointer" to ensure sequential writing, which can be caused when
writing back blocks in a not finished transaction.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/block-group.h |  1 +
 fs/btrfs/ctree.h       |  2 ++
 fs/btrfs/disk-io.c     |  1 +
 fs/btrfs/extent_io.c   | 27 ++++++++++++++++++++++-
 fs/btrfs/zoned.c       | 50 ++++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/zoned.h       | 31 ++++++++++++++++++++++++++
 6 files changed, 111 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/block-group.h b/fs/btrfs/block-group.h
index 401e9bcefaec..b2a8a3beceac 100644
--- a/fs/btrfs/block-group.h
+++ b/fs/btrfs/block-group.h
@@ -190,6 +190,7 @@ struct btrfs_block_group {
 	 */
 	u64 alloc_offset;
 	u64 zone_unusable;
+	u64 meta_write_pointer;
 };
 
 static inline u64 btrfs_block_group_end(struct btrfs_block_group *block_group)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 54c22ad0d633..e08fe341cd81 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -941,6 +941,8 @@ struct btrfs_fs_info {
 	 */
 	int send_in_progress;
 
+	struct mutex zoned_meta_io_lock;
+
 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 	spinlock_t ref_verify_lock;
 	struct rb_root block_tree;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index d766cb0e1a52..a50436d89d30 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2732,6 +2732,7 @@ void btrfs_init_fs_info(struct btrfs_fs_info *fs_info)
 	mutex_init(&fs_info->delete_unused_bgs_mutex);
 	mutex_init(&fs_info->reloc_mutex);
 	mutex_init(&fs_info->delalloc_root_mutex);
+	mutex_init(&fs_info->zoned_meta_io_lock);
 	seqlock_init(&fs_info->profiles_lock);
 
 	INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 00a07cefffeb..b660921af935 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -25,6 +25,7 @@
 #include "backref.h"
 #include "disk-io.h"
 #include "zoned.h"
+#include "block-group.h"
 
 static struct kmem_cache *extent_state_cache;
 static struct kmem_cache *extent_buffer_cache;
@@ -3986,6 +3987,7 @@ int btree_write_cache_pages(struct address_space *mapping,
 				   struct writeback_control *wbc)
 {
 	struct extent_buffer *eb, *prev_eb = NULL;
+	struct btrfs_block_group *cache = NULL;
 	struct extent_page_data epd = {
 		.bio = NULL,
 		.extent_locked = 0,
@@ -4020,6 +4022,7 @@ int btree_write_cache_pages(struct address_space *mapping,
 		tag = PAGECACHE_TAG_TOWRITE;
 	else
 		tag = PAGECACHE_TAG_DIRTY;
+	btrfs_zoned_meta_io_lock(fs_info);
 retry:
 	if (wbc->sync_mode == WB_SYNC_ALL)
 		tag_pages_for_writeback(mapping, index, end);
@@ -4062,12 +4065,30 @@ int btree_write_cache_pages(struct address_space *mapping,
 			if (!ret)
 				continue;
 
+			if (!btrfs_check_meta_write_pointer(fs_info, eb,
+							    &cache)) {
+				/*
+				 * If for_sync, this hole will be filled with
+				 * trasnsaction commit.
+				 */
+				if (wbc->sync_mode == WB_SYNC_ALL &&
+				    !wbc->for_sync)
+					ret = -EAGAIN;
+				else
+					ret = 0;
+				done = 1;
+				free_extent_buffer(eb);
+				break;
+			}
+
 			prev_eb = eb;
 			ret = lock_extent_buffer_for_io(eb, &epd);
 			if (!ret) {
+				btrfs_revert_meta_write_pointer(cache, eb);
 				free_extent_buffer(eb);
 				continue;
 			} else if (ret < 0) {
+				btrfs_revert_meta_write_pointer(cache, eb);
 				done = 1;
 				free_extent_buffer(eb);
 				break;
@@ -4100,10 +4121,12 @@ int btree_write_cache_pages(struct address_space *mapping,
 		index = 0;
 		goto retry;
 	}
+	if (cache)
+		btrfs_put_block_group(cache);
 	ASSERT(ret <= 0);
 	if (ret < 0) {
 		end_write_bio(&epd, ret);
-		return ret;
+		goto out;
 	}
 	/*
 	 * If something went wrong, don't allow any metadata write bio to be
@@ -4138,6 +4161,8 @@ int btree_write_cache_pages(struct address_space *mapping,
 		ret = -EROFS;
 		end_write_bio(&epd, ret);
 	}
+out:
+	btrfs_zoned_meta_io_unlock(fs_info);
 	return ret;
 }
 
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 1744e2649087..0f790f3a54e5 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -1002,6 +1002,9 @@ int btrfs_load_block_group_zone_info(struct btrfs_block_group *cache)
 		ret = -EIO;
 	}
 
+	if (!ret)
+		cache->meta_write_pointer = cache->alloc_offset + cache->start;
+
 	kfree(alloc_offsets);
 	free_extent_map(em);
 
@@ -1135,3 +1138,50 @@ void btrfs_rewrite_logical_zoned(struct btrfs_ordered_extent *ordered)
 	kfree(logical);
 	bdput(bdev);
 }
+
+bool btrfs_check_meta_write_pointer(struct btrfs_fs_info *fs_info,
+				    struct extent_buffer *eb,
+				    struct btrfs_block_group **cache_ret)
+{
+	struct btrfs_block_group *cache;
+
+	if (!btrfs_fs_incompat(fs_info, ZONED))
+		return true;
+
+	cache = *cache_ret;
+
+	if (cache && (eb->start < cache->start ||
+		      cache->start + cache->length <= eb->start)) {
+		btrfs_put_block_group(cache);
+		cache = NULL;
+		*cache_ret = NULL;
+	}
+
+	if (!cache)
+		cache = btrfs_lookup_block_group(fs_info, eb->start);
+
+	if (cache) {
+		*cache_ret = cache;
+
+		if (cache->meta_write_pointer != eb->start) {
+			btrfs_put_block_group(cache);
+			cache = NULL;
+			*cache_ret = NULL;
+			return false;
+		}
+
+		cache->meta_write_pointer = eb->start + eb->len;
+	}
+
+	return true;
+}
+
+void btrfs_revert_meta_write_pointer(struct btrfs_block_group *cache,
+				     struct extent_buffer *eb)
+{
+	if (!btrfs_fs_incompat(eb->fs_info, ZONED) || !cache)
+		return;
+
+	ASSERT(cache->meta_write_pointer == eb->start + eb->len);
+	cache->meta_write_pointer = eb->start;
+}
diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h
index 5f4bc746e3e2..5d4b132a4d95 100644
--- a/fs/btrfs/zoned.h
+++ b/fs/btrfs/zoned.h
@@ -53,6 +53,11 @@ void btrfs_free_redirty_list(struct btrfs_transaction *trans);
 void btrfs_record_physical_zoned(struct inode *inode, u64 file_offset,
 				 struct bio *bio);
 void btrfs_rewrite_logical_zoned(struct btrfs_ordered_extent *ordered);
+bool btrfs_check_meta_write_pointer(struct btrfs_fs_info *fs_info,
+				    struct extent_buffer *eb,
+				    struct btrfs_block_group **cache_ret);
+void btrfs_revert_meta_write_pointer(struct btrfs_block_group *cache,
+				     struct extent_buffer *eb);
 #else /* CONFIG_BLK_DEV_ZONED */
 static inline int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
 				     struct blk_zone *zone)
@@ -130,6 +135,18 @@ static inline void btrfs_record_physical_zoned(struct inode *inode,
 }
 static inline void
 btrfs_rewrite_logical_zoned(struct btrfs_ordered_extent *ordered) { }
+static inline bool
+btrfs_check_meta_write_pointer(struct btrfs_fs_info *fs_info,
+			       struct extent_buffer *eb,
+			       struct btrfs_block_group **cache_ret)
+{
+	return true;
+}
+static inline void
+btrfs_revert_meta_write_pointer(struct btrfs_block_group *cache,
+				struct extent_buffer *eb)
+{
+}
 #endif
 
 static inline bool btrfs_dev_is_sequential(struct btrfs_device *device, u64 pos)
@@ -232,4 +249,18 @@ static inline bool btrfs_can_zone_reset(struct btrfs_device *device,
 	return true;
 }
 
+static inline void btrfs_zoned_meta_io_lock(struct btrfs_fs_info *fs_info)
+{
+	if (!btrfs_fs_incompat(fs_info, ZONED))
+		return;
+	mutex_lock(&fs_info->zoned_meta_io_lock);
+}
+
+static inline void btrfs_zoned_meta_io_unlock(struct btrfs_fs_info *fs_info)
+{
+	if (!btrfs_fs_incompat(fs_info, ZONED))
+		return;
+	mutex_unlock(&fs_info->zoned_meta_io_lock);
+}
+
 #endif
-- 
2.27.0

[PATCH v7 27/39] btrfs: wait existing extents before truncating

[Naohiro Aota]

When truncating a file, file buffers which have already been allocated but
not yet written may be truncated.  Truncating these buffers could cause
breakage of a sequential write pattern in a block group if the truncated
blocks are for example followed by blocks allocated to another file. To
avoid this problem, always wait for write out of all unwritten buffers
before proceeding with the truncate execution.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/inode.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 2bd001df4a75..7e1a0a5a6e55 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4883,6 +4883,16 @@ static int btrfs_setsize(struct inode *inode, struct iattr *attr)
 		btrfs_drew_write_unlock(&root->snapshot_lock);
 		btrfs_end_transaction(trans);
 	} else {
+		struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+
+		if (btrfs_fs_incompat(fs_info, ZONED)) {
+			ret = btrfs_wait_ordered_range(
+				inode,
+				ALIGN(newsize, fs_info->sectorsize),
+				(u64)-1);
+			if (ret)
+				return ret;
+		}
 
 		/*
 		 * We're truncating a file that used to have good data down to
-- 
2.27.0

[PATCH v7 28/39] btrfs: avoid async metadata checksum on ZONED mode

[Naohiro Aota]

In ZONED, btrfs uses per-FS zoned_meta_io_lock to serialize the metadata
write IOs.

Even with these serialization, write bios sent from btree_write_cache_pages
can be reordered by async checksum workers as these workers are per CPU and
not per zone.

To preserve write BIO ordering, we can disable async metadata checksum on
ZONED.  This does not result in lower performance with HDDs as a single CPU
core is fast enough to do checksum for a single zone write stream with the
maximum possible bandwidth of the device. If multiple zones are being
written simultaneously, HDD seek overhead lowers the achievable maximum
bandwidth, resulting again in a per zone checksum serialization not
affecting performance.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/disk-io.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index a50436d89d30..cd768030b7bb 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -865,6 +865,8 @@ static blk_status_t btree_submit_bio_start(void *private_data, struct bio *bio,
 static int check_async_write(struct btrfs_fs_info *fs_info,
 			     struct btrfs_inode *bi)
 {
+	if (btrfs_fs_incompat(fs_info, ZONED))
+		return 0;
 	if (atomic_read(&bi->sync_writers))
 		return 0;
 	if (test_bit(BTRFS_FS_CSUM_IMPL_FAST, &fs_info->flags))
-- 
2.27.0

[PATCH v7 29/39] btrfs: mark block groups to copy for device-replace

[Naohiro Aota]

This is the 1/4 patch to support device-replace in ZONED mode.

We have two types of I/Os during the device-replace process. One is an I/O
to "copy" (by the scrub functions) all the device extents on the source
device to the destination device.  The other one is an I/O to "clone" (by
handle_ops_on_dev_replace()) new incoming write I/Os from users to the
source device into the target device.

Cloning incoming I/Os can break the sequential write rule in the target
device. When writing is mapped in the middle of a block group, the I/O is
directed in the middle of a target device zone, which breaks the sequential
write rule.

However, the cloning function cannot be merely disabled since incoming I/Os
targeting already copied device extents must be cloned so that the I/O is
executed on the target device.

We cannot use dev_replace->cursor_{left,right} to determine whether bio is
going to not yet copied region.  Since we have a time gap between finishing
btrfs_scrub_dev() and rewriting the mapping tree in
btrfs_dev_replace_finishing(), we can have a newly allocated device extent
which is never cloned nor copied.

So the point is to copy only already existing device extents. This patch
introduces mark_block_group_to_copy() to mark existing block groups as a
target of copying. Then, handle_ops_on_dev_replace() and dev-replace can
check the flag to do their job.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/block-group.h |   1 +
 fs/btrfs/dev-replace.c | 175 +++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/dev-replace.h |   3 +
 fs/btrfs/scrub.c       |  17 ++++
 4 files changed, 196 insertions(+)

diff --git a/fs/btrfs/block-group.h b/fs/btrfs/block-group.h
index b2a8a3beceac..e91123495d68 100644
--- a/fs/btrfs/block-group.h
+++ b/fs/btrfs/block-group.h
@@ -95,6 +95,7 @@ struct btrfs_block_group {
 	unsigned int iref:1;
 	unsigned int has_caching_ctl:1;
 	unsigned int removed:1;
+	unsigned int to_copy:1;
 
 	int disk_cache_state;
 
diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index 18a36973f973..d2db963be985 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -22,6 +22,7 @@
 #include "dev-replace.h"
 #include "sysfs.h"
 #include "zoned.h"
+#include "block-group.h"
 
 /*
  * Device replace overview
@@ -443,6 +444,176 @@ static char* btrfs_dev_name(struct btrfs_device *device)
 		return rcu_str_deref(device->name);
 }
 
+static int mark_block_group_to_copy(struct btrfs_fs_info *fs_info,
+				    struct btrfs_device *src_dev)
+{
+	struct btrfs_path *path;
+	struct btrfs_key key;
+	struct btrfs_key found_key;
+	struct btrfs_root *root = fs_info->dev_root;
+	struct btrfs_dev_extent *dev_extent = NULL;
+	struct btrfs_block_group *cache;
+	struct extent_buffer *l;
+	struct btrfs_trans_handle *trans;
+	int slot;
+	int ret = 0;
+	u64 chunk_offset, length;
+
+	/* Do not use "to_copy" on non-ZONED for now */
+	if (!btrfs_fs_incompat(fs_info, ZONED))
+		return 0;
+
+	mutex_lock(&fs_info->chunk_mutex);
+
+	/* ensulre we don't have pending new block group */
+	while (fs_info->running_transaction &&
+	       !list_empty(&fs_info->running_transaction->dev_update_list)) {
+		mutex_unlock(&fs_info->chunk_mutex);
+		trans = btrfs_attach_transaction(root);
+		if (IS_ERR(trans)) {
+			ret = PTR_ERR(trans);
+			mutex_lock(&fs_info->chunk_mutex);
+			if (ret == -ENOENT)
+				continue;
+			else
+				goto out;
+		}
+
+		ret = btrfs_commit_transaction(trans);
+		mutex_lock(&fs_info->chunk_mutex);
+		if (ret)
+			goto out;
+	}
+
+	path = btrfs_alloc_path();
+	if (!path) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	path->reada = READA_FORWARD;
+	path->search_commit_root = 1;
+	path->skip_locking = 1;
+
+	key.objectid = src_dev->devid;
+	key.offset = 0ull;
+	key.type = BTRFS_DEV_EXTENT_KEY;
+
+	while (1) {
+		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+		if (ret < 0)
+			break;
+		if (ret > 0) {
+			if (path->slots[0] >=
+			    btrfs_header_nritems(path->nodes[0])) {
+				ret = btrfs_next_leaf(root, path);
+				if (ret < 0)
+					break;
+				if (ret > 0) {
+					ret = 0;
+					break;
+				}
+			} else {
+				ret = 0;
+			}
+		}
+
+		l = path->nodes[0];
+		slot = path->slots[0];
+
+		btrfs_item_key_to_cpu(l, &found_key, slot);
+
+		if (found_key.objectid != src_dev->devid)
+			break;
+
+		if (found_key.type != BTRFS_DEV_EXTENT_KEY)
+			break;
+
+		if (found_key.offset < key.offset)
+			break;
+
+		dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
+		length = btrfs_dev_extent_length(l, dev_extent);
+
+		chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
+
+		cache = btrfs_lookup_block_group(fs_info, chunk_offset);
+		if (!cache)
+			goto skip;
+
+		spin_lock(&cache->lock);
+		cache->to_copy = 1;
+		spin_unlock(&cache->lock);
+
+		btrfs_put_block_group(cache);
+
+skip:
+		key.offset = found_key.offset + length;
+		btrfs_release_path(path);
+	}
+
+	btrfs_free_path(path);
+out:
+	mutex_unlock(&fs_info->chunk_mutex);
+
+	return ret;
+}
+
+bool btrfs_finish_block_group_to_copy(struct btrfs_device *srcdev,
+				      struct btrfs_block_group *cache,
+				      u64 physical)
+{
+	struct btrfs_fs_info *fs_info = cache->fs_info;
+	struct extent_map *em;
+	struct map_lookup *map;
+	u64 chunk_offset = cache->start;
+	int num_extents, cur_extent;
+	int i;
+
+	/* Do not use "to_copy" on non-ZONED for now */
+	if (!btrfs_fs_incompat(fs_info, ZONED))
+		return true;
+
+	spin_lock(&cache->lock);
+	if (cache->removed) {
+		spin_unlock(&cache->lock);
+		return true;
+	}
+	spin_unlock(&cache->lock);
+
+	em = btrfs_get_chunk_map(fs_info, chunk_offset, 1);
+	BUG_ON(IS_ERR(em));
+	map = em->map_lookup;
+
+	num_extents = cur_extent = 0;
+	for (i = 0; i < map->num_stripes; i++) {
+		/* we have more device extent to copy */
+		if (srcdev != map->stripes[i].dev)
+			continue;
+
+		num_extents++;
+		if (physical == map->stripes[i].physical)
+			cur_extent = i;
+	}
+
+	free_extent_map(em);
+
+	if (num_extents > 1 && cur_extent < num_extents - 1) {
+		/*
+		 * Has more stripes on this device. Keep this BG
+		 * readonly until we finish all the stripes.
+		 */
+		return false;
+	}
+
+	/* last stripe on this device */
+	spin_lock(&cache->lock);
+	cache->to_copy = 0;
+	spin_unlock(&cache->lock);
+
+	return true;
+}
+
 static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
 		const char *tgtdev_name, u64 srcdevid, const char *srcdev_name,
 		int read_src)
@@ -484,6 +655,10 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
 	if (ret)
 		return ret;
 
+	ret = mark_block_group_to_copy(fs_info, src_device);
+	if (ret)
+		return ret;
+
 	down_write(&dev_replace->rwsem);
 	switch (dev_replace->replace_state) {
 	case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
diff --git a/fs/btrfs/dev-replace.h b/fs/btrfs/dev-replace.h
index 60b70dacc299..3911049a5f23 100644
--- a/fs/btrfs/dev-replace.h
+++ b/fs/btrfs/dev-replace.h
@@ -18,5 +18,8 @@ int btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info);
 void btrfs_dev_replace_suspend_for_unmount(struct btrfs_fs_info *fs_info);
 int btrfs_resume_dev_replace_async(struct btrfs_fs_info *fs_info);
 int __pure btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace);
+bool btrfs_finish_block_group_to_copy(struct btrfs_device *srcdev,
+				      struct btrfs_block_group *cache,
+				      u64 physical);
 
 #endif
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index e46c91188a75..f7d750b32cfb 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -3500,6 +3500,17 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx,
 		if (!cache)
 			goto skip;
 
+
+		if (sctx->is_dev_replace && btrfs_fs_incompat(fs_info, ZONED)) {
+			spin_lock(&cache->lock);
+			if (!cache->to_copy) {
+				spin_unlock(&cache->lock);
+				ro_set = 0;
+				goto done;
+			}
+			spin_unlock(&cache->lock);
+		}
+
 		/*
 		 * Make sure that while we are scrubbing the corresponding block
 		 * group doesn't get its logical address and its device extents
@@ -3631,6 +3642,12 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx,
 
 		scrub_pause_off(fs_info);
 
+		if (sctx->is_dev_replace &&
+		    !btrfs_finish_block_group_to_copy(dev_replace->srcdev,
+						      cache, found_key.offset))
+			ro_set = 0;
+
+done:
 		down_write(&dev_replace->rwsem);
 		dev_replace->cursor_left = dev_replace->cursor_right;
 		dev_replace->item_needs_writeback = 1;
-- 
2.27.0

[PATCH v7 30/39] btrfs: implement cloning for ZONED device-replace

[Naohiro Aota]

This is 2/4 patch to implement device-replace for ZONED mode.

On zoned mode, a block group must be either copied (from the source device
to the destination device) or cloned (to the both device).

This commit implements the cloning part. If a block group targeted by an IO
is marked to copy, we should not clone the IO to the destination device,
because the block group is eventually copied by the replace process.

This commit also handles cloning of device reset.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/extent-tree.c | 20 ++++++++++++++++++--
 fs/btrfs/volumes.c     | 33 +++++++++++++++++++++++++++++++--
 fs/btrfs/zoned.c       | 11 +++++++++++
 3 files changed, 60 insertions(+), 4 deletions(-)

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 81b9b58d7a9d..79ac8fcc5c35 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -35,6 +35,7 @@
 #include "discard.h"
 #include "rcu-string.h"
 #include "zoned.h"
+#include "dev-replace.h"
 
 #undef SCRAMBLE_DELAYED_REFS
 
@@ -1322,6 +1323,8 @@ int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
 			u64 length = stripe->length;
 			u64 bytes;
 			struct request_queue *req_q;
+			struct btrfs_dev_replace *dev_replace =
+				&fs_info->dev_replace;
 
 			if (!stripe->dev->bdev) {
 				ASSERT(btrfs_test_opt(fs_info, DEGRADED));
@@ -1330,15 +1333,28 @@ int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
 
 			req_q = bdev_get_queue(stripe->dev->bdev);
 			/* zone reset in ZONED mode */
-			if (btrfs_can_zone_reset(dev, physical, length))
+			if (btrfs_can_zone_reset(dev, physical, length)) {
 				ret = btrfs_reset_device_zone(dev, physical,
 							      length, &bytes);
-			else if (blk_queue_discard(req_q))
+				if (ret)
+					goto next;
+				if (!btrfs_dev_replace_is_ongoing(
+					    dev_replace) ||
+				    dev != dev_replace->srcdev)
+					goto next;
+
+				discarded_bytes += bytes;
+				/* send to replace target as well */
+				ret = btrfs_reset_device_zone(
+					dev_replace->tgtdev,
+					physical, length, &bytes);
+			} else if (blk_queue_discard(req_q))
 				ret = btrfs_issue_discard(dev->bdev, physical,
 							  length, &bytes);
 			else
 				continue;
 
+next:
 			if (!ret) {
 				discarded_bytes += bytes;
 			} else if (ret != -EOPNOTSUPP) {
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index ca139c63f63c..779ee0452c1b 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -5971,9 +5971,29 @@ static int get_extra_mirror_from_replace(struct btrfs_fs_info *fs_info,
 	return ret;
 }
 
+static bool is_block_group_to_copy(struct btrfs_fs_info *fs_info, u64 logical)
+{
+	struct btrfs_block_group *cache;
+	bool ret;
+
+	/* non-ZONED mode does not use "to_copy" flag */
+	if (!btrfs_fs_incompat(fs_info, ZONED))
+		return false;
+
+	cache = btrfs_lookup_block_group(fs_info, logical);
+
+	spin_lock(&cache->lock);
+	ret = cache->to_copy;
+	spin_unlock(&cache->lock);
+
+	btrfs_put_block_group(cache);
+	return ret;
+}
+
 static void handle_ops_on_dev_replace(enum btrfs_map_op op,
 				      struct btrfs_bio **bbio_ret,
 				      struct btrfs_dev_replace *dev_replace,
+				      u64 logical,
 				      int *num_stripes_ret, int *max_errors_ret)
 {
 	struct btrfs_bio *bbio = *bbio_ret;
@@ -5986,6 +6006,15 @@ static void handle_ops_on_dev_replace(enum btrfs_map_op op,
 	if (op == BTRFS_MAP_WRITE) {
 		int index_where_to_add;
 
+		/*
+		 * a block group which have "to_copy" set will
+		 * eventually copied by dev-replace process. We can
+		 * avoid cloning IO here.
+		 */
+		if (is_block_group_to_copy(dev_replace->srcdev->fs_info,
+					   logical))
+			return;
+
 		/*
 		 * duplicate the write operations while the dev replace
 		 * procedure is running. Since the copying of the old disk to
@@ -6381,8 +6410,8 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
 
 	if (dev_replace_is_ongoing && dev_replace->tgtdev != NULL &&
 	    need_full_stripe(op)) {
-		handle_ops_on_dev_replace(op, &bbio, dev_replace, &num_stripes,
-					  &max_errors);
+		handle_ops_on_dev_replace(op, &bbio, dev_replace, logical,
+					  &num_stripes, &max_errors);
 	}
 
 	*bbio_ret = bbio;
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 0f790f3a54e5..2fe659bb0709 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -19,6 +19,7 @@
 #include "disk-io.h"
 #include "block-group.h"
 #include "transaction.h"
+#include "dev-replace.h"
 
 /* Maximum number of zones to report per blkdev_report_zones() call */
 #define BTRFS_REPORT_NR_ZONES   4096
@@ -903,6 +904,8 @@ int btrfs_load_block_group_zone_info(struct btrfs_block_group *cache)
 	for (i = 0; i < map->num_stripes; i++) {
 		bool is_sequential;
 		struct blk_zone zone;
+		struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
+		int dev_replace_is_ongoing = 0;
 
 		device = map->stripes[i].dev;
 		physical = map->stripes[i].physical;
@@ -929,6 +932,14 @@ int btrfs_load_block_group_zone_info(struct btrfs_block_group *cache)
 		 */
 		btrfs_dev_clear_zone_empty(device, physical);
 
+		down_read(&dev_replace->rwsem);
+		dev_replace_is_ongoing =
+			btrfs_dev_replace_is_ongoing(dev_replace);
+		if (dev_replace_is_ongoing && dev_replace->tgtdev != NULL)
+			btrfs_dev_clear_zone_empty(dev_replace->tgtdev,
+						   physical);
+		up_read(&dev_replace->rwsem);
+
 		/*
 		 * The group is mapped to a sequential zone. Get the zone write
 		 * pointer to determine the allocation offset within the zone.
-- 
2.27.0

[PATCH v7 31/39] btrfs: implement copying for ZONED device-replace

[Naohiro Aota]

This is 3/4 patch to implement device-replace on ZONED mode.

This commit implement copying. So, it track the write pointer during device
replace process. Device-replace's copying is smart to copy only used
extents on source device, we have to fill the gap to honor the sequential
write rule in the target device.

Device-replace process in ZONED mode must copy or clone all the extents in
the source device exactly once.  So, we need to use to ensure allocations
started just before the dev-replace process to have their corresponding
extent information in the B-trees. finish_extent_writes_for_zoned()
implements that functionality, which basically is the removed code in the
commit 042528f8d840 ("Btrfs: fix block group remaining RO forever after
error during device replace").

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/scrub.c | 86 ++++++++++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/zoned.c | 12 +++++++
 fs/btrfs/zoned.h |  7 ++++
 3 files changed, 105 insertions(+)

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index f7d750b32cfb..568d90214446 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -169,6 +169,7 @@ struct scrub_ctx {
 	int			pages_per_rd_bio;
 
 	int			is_dev_replace;
+	u64			write_pointer;
 
 	struct scrub_bio        *wr_curr_bio;
 	struct mutex            wr_lock;
@@ -1623,6 +1624,25 @@ static int scrub_write_page_to_dev_replace(struct scrub_block *sblock,
 	return scrub_add_page_to_wr_bio(sblock->sctx, spage);
 }
 
+static int fill_writer_pointer_gap(struct scrub_ctx *sctx, u64 physical)
+{
+	int ret = 0;
+	u64 length;
+
+	if (!btrfs_fs_incompat(sctx->fs_info, ZONED))
+		return 0;
+
+	if (sctx->write_pointer < physical) {
+		length = physical - sctx->write_pointer;
+
+		ret = btrfs_zoned_issue_zeroout(sctx->wr_tgtdev,
+						sctx->write_pointer, length);
+		if (!ret)
+			sctx->write_pointer = physical;
+	}
+	return ret;
+}
+
 static int scrub_add_page_to_wr_bio(struct scrub_ctx *sctx,
 				    struct scrub_page *spage)
 {
@@ -1645,6 +1665,13 @@ static int scrub_add_page_to_wr_bio(struct scrub_ctx *sctx,
 	if (sbio->page_count == 0) {
 		struct bio *bio;
 
+		ret = fill_writer_pointer_gap(sctx,
+					      spage->physical_for_dev_replace);
+		if (ret) {
+			mutex_unlock(&sctx->wr_lock);
+			return ret;
+		}
+
 		sbio->physical = spage->physical_for_dev_replace;
 		sbio->logical = spage->logical;
 		sbio->dev = sctx->wr_tgtdev;
@@ -1706,6 +1733,10 @@ static void scrub_wr_submit(struct scrub_ctx *sctx)
 	 * doubled the write performance on spinning disks when measured
 	 * with Linux 3.5 */
 	btrfsic_submit_bio(sbio->bio);
+
+	if (btrfs_fs_incompat(sctx->fs_info, ZONED))
+		sctx->write_pointer = sbio->physical +
+			sbio->page_count * PAGE_SIZE;
 }
 
 static void scrub_wr_bio_end_io(struct bio *bio)
@@ -2973,6 +3004,21 @@ static noinline_for_stack int scrub_raid56_parity(struct scrub_ctx *sctx,
 	return ret < 0 ? ret : 0;
 }
 
+static void sync_replace_for_zoned(struct scrub_ctx *sctx)
+{
+	if (!btrfs_fs_incompat(sctx->fs_info, ZONED))
+		return;
+
+	sctx->flush_all_writes = true;
+	scrub_submit(sctx);
+	mutex_lock(&sctx->wr_lock);
+	scrub_wr_submit(sctx);
+	mutex_unlock(&sctx->wr_lock);
+
+	wait_event(sctx->list_wait,
+		   atomic_read(&sctx->bios_in_flight) == 0);
+}
+
 static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
 					   struct map_lookup *map,
 					   struct btrfs_device *scrub_dev,
@@ -3105,6 +3151,14 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
 	 */
 	blk_start_plug(&plug);
 
+	if (sctx->is_dev_replace &&
+	    btrfs_dev_is_sequential(sctx->wr_tgtdev, physical)) {
+		mutex_lock(&sctx->wr_lock);
+		sctx->write_pointer = physical;
+		mutex_unlock(&sctx->wr_lock);
+		sctx->flush_all_writes = true;
+	}
+
 	/*
 	 * now find all extents for each stripe and scrub them
 	 */
@@ -3292,6 +3346,9 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
 			if (ret)
 				goto out;
 
+			if (sctx->is_dev_replace)
+				sync_replace_for_zoned(sctx);
+
 			if (extent_logical + extent_len <
 			    key.objectid + bytes) {
 				if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
@@ -3414,6 +3471,25 @@ static noinline_for_stack int scrub_chunk(struct scrub_ctx *sctx,
 	return ret;
 }
 
+static int finish_extent_writes_for_zoned(struct btrfs_root *root,
+					  struct btrfs_block_group *cache)
+{
+	struct btrfs_fs_info *fs_info = cache->fs_info;
+	struct btrfs_trans_handle *trans;
+
+	if (!btrfs_fs_incompat(fs_info, ZONED))
+		return 0;
+
+	btrfs_wait_block_group_reservations(cache);
+	btrfs_wait_nocow_writers(cache);
+	btrfs_wait_ordered_roots(fs_info, U64_MAX, cache->start, cache->length);
+
+	trans = btrfs_join_transaction(root);
+	if (IS_ERR(trans))
+		return PTR_ERR(trans);
+	return btrfs_commit_transaction(trans);
+}
+
 static noinline_for_stack
 int scrub_enumerate_chunks(struct scrub_ctx *sctx,
 			   struct btrfs_device *scrub_dev, u64 start, u64 end)
@@ -3569,6 +3645,16 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx,
 		 * group is not RO.
 		 */
 		ret = btrfs_inc_block_group_ro(cache, sctx->is_dev_replace);
+		if (!ret && sctx->is_dev_replace) {
+			ret = finish_extent_writes_for_zoned(root, cache);
+			if (ret) {
+				btrfs_dec_block_group_ro(cache);
+				scrub_pause_off(fs_info);
+				btrfs_put_block_group(cache);
+				break;
+			}
+		}
+
 		if (ret == 0) {
 			ro_set = 1;
 		} else if (ret == -ENOSPC && !sctx->is_dev_replace) {
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 2fe659bb0709..ac88d26f1119 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -1196,3 +1196,15 @@ void btrfs_revert_meta_write_pointer(struct btrfs_block_group *cache,
 	ASSERT(cache->meta_write_pointer == eb->start + eb->len);
 	cache->meta_write_pointer = eb->start;
 }
+
+int btrfs_zoned_issue_zeroout(struct btrfs_device *device, u64 physical,
+			      u64 length)
+{
+	if (!btrfs_dev_is_sequential(device, physical))
+		return -EOPNOTSUPP;
+
+	return blkdev_issue_zeroout(device->bdev,
+				    physical >> SECTOR_SHIFT,
+				    length >> SECTOR_SHIFT,
+				    GFP_NOFS, 0);
+}
diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h
index 5d4b132a4d95..dea313a61a3e 100644
--- a/fs/btrfs/zoned.h
+++ b/fs/btrfs/zoned.h
@@ -58,6 +58,8 @@ bool btrfs_check_meta_write_pointer(struct btrfs_fs_info *fs_info,
 				    struct btrfs_block_group **cache_ret);
 void btrfs_revert_meta_write_pointer(struct btrfs_block_group *cache,
 				     struct extent_buffer *eb);
+int btrfs_zoned_issue_zeroout(struct btrfs_device *device, u64 physical,
+			      u64 length);
 #else /* CONFIG_BLK_DEV_ZONED */
 static inline int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
 				     struct blk_zone *zone)
@@ -147,6 +149,11 @@ btrfs_revert_meta_write_pointer(struct btrfs_block_group *cache,
 				struct extent_buffer *eb)
 {
 }
+static inline int btrfs_zoned_issue_zeroout(struct btrfs_device *device,
+					    u64 physical, u64 length)
+{
+	return -EOPNOTSUPP;
+}
 #endif
 
 static inline bool btrfs_dev_is_sequential(struct btrfs_device *device, u64 pos)
-- 
2.27.0

[PATCH v7 32/39] btrfs: support dev-replace in ZONED mode

[Naohiro Aota]

This is 4/4 patch to implement device-replace on ZONED mode.

Even after the copying is done, the write pointers of the source device and
the destination device may not be synchronized. For example, when the last
allocated extent is freed before device-replace process, the extent is not
copied, leaving a hole there.

This patch synchronize the write pointers by writing zeros to the
destination device.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/scrub.c | 36 +++++++++++++++++++++++++
 fs/btrfs/zoned.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/zoned.h |  8 ++++++
 3 files changed, 113 insertions(+)

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 568d90214446..2356e6d90690 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -3019,6 +3019,31 @@ static void sync_replace_for_zoned(struct scrub_ctx *sctx)
 		   atomic_read(&sctx->bios_in_flight) == 0);
 }
 
+static int sync_write_pointer_for_zoned(struct scrub_ctx *sctx, u64 logical,
+					u64 physical, u64 physical_end)
+{
+	struct btrfs_fs_info *fs_info = sctx->fs_info;
+	int ret = 0;
+
+	if (!btrfs_fs_incompat(fs_info, ZONED))
+		return 0;
+
+	wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0);
+
+	mutex_lock(&sctx->wr_lock);
+	if (sctx->write_pointer < physical_end) {
+		ret = btrfs_sync_zone_write_pointer(sctx->wr_tgtdev, logical,
+						    physical,
+						    sctx->write_pointer);
+		if (ret)
+			btrfs_err(fs_info, "failed to recover write pointer");
+	}
+	mutex_unlock(&sctx->wr_lock);
+	btrfs_dev_clear_zone_empty(sctx->wr_tgtdev, physical);
+
+	return ret;
+}
+
 static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
 					   struct map_lookup *map,
 					   struct btrfs_device *scrub_dev,
@@ -3416,6 +3441,17 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
 	blk_finish_plug(&plug);
 	btrfs_free_path(path);
 	btrfs_free_path(ppath);
+
+	if (sctx->is_dev_replace && ret >= 0) {
+		int ret2;
+
+		ret2 = sync_write_pointer_for_zoned(sctx, base + offset,
+						    map->stripes[num].physical,
+						    physical_end);
+		if (ret2)
+			ret = ret2;
+	}
+
 	return ret < 0 ? ret : 0;
 }
 
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index ac88d26f1119..576f8e333f16 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -20,6 +20,7 @@
 #include "block-group.h"
 #include "transaction.h"
 #include "dev-replace.h"
+#include "space-info.h"
 
 /* Maximum number of zones to report per blkdev_report_zones() call */
 #define BTRFS_REPORT_NR_ZONES   4096
@@ -1208,3 +1209,71 @@ int btrfs_zoned_issue_zeroout(struct btrfs_device *device, u64 physical,
 				    length >> SECTOR_SHIFT,
 				    GFP_NOFS, 0);
 }
+
+static int read_zone_info(struct btrfs_fs_info *fs_info, u64 logical,
+			  struct blk_zone *zone)
+{
+	struct btrfs_bio *bbio = NULL;
+	u64 mapped_length = PAGE_SIZE;
+	unsigned int nofs_flag;
+	int nmirrors;
+	int i, ret;
+
+	ret = btrfs_map_sblock(fs_info, BTRFS_MAP_GET_READ_MIRRORS, logical,
+			       &mapped_length, &bbio);
+	if (ret || !bbio || mapped_length < PAGE_SIZE) {
+		btrfs_put_bbio(bbio);
+		return -EIO;
+	}
+
+	if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK)
+		return -EINVAL;
+
+	nofs_flag = memalloc_nofs_save();
+	nmirrors = (int)bbio->num_stripes;
+	for (i = 0; i < nmirrors; i++) {
+		u64 physical = bbio->stripes[i].physical;
+		struct btrfs_device *dev = bbio->stripes[i].dev;
+
+		/* missing device */
+		if (!dev->bdev)
+			continue;
+
+		ret = btrfs_get_dev_zone(dev, physical, zone);
+		/* failing device */
+		if (ret == -EIO || ret == -EOPNOTSUPP)
+			continue;
+		break;
+	}
+	memalloc_nofs_restore(nofs_flag);
+
+	return ret;
+}
+
+int btrfs_sync_zone_write_pointer(struct btrfs_device *tgt_dev, u64 logical,
+				    u64 physical_start, u64 physical_pos)
+{
+	struct btrfs_fs_info *fs_info = tgt_dev->fs_info;
+	struct blk_zone zone;
+	u64 length;
+	u64 wp;
+	int ret;
+
+	if (!btrfs_dev_is_sequential(tgt_dev, physical_pos))
+		return 0;
+
+	ret = read_zone_info(fs_info, logical, &zone);
+	if (ret)
+		return ret;
+
+	wp = physical_start + ((zone.wp - zone.start) << SECTOR_SHIFT);
+
+	if (physical_pos == wp)
+		return 0;
+
+	if (physical_pos > wp)
+		return -EUCLEAN;
+
+	length = wp - physical_pos;
+	return btrfs_zoned_issue_zeroout(tgt_dev, physical_pos, length);
+}
diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h
index dea313a61a3e..61388381c679 100644
--- a/fs/btrfs/zoned.h
+++ b/fs/btrfs/zoned.h
@@ -60,6 +60,8 @@ void btrfs_revert_meta_write_pointer(struct btrfs_block_group *cache,
 				     struct extent_buffer *eb);
 int btrfs_zoned_issue_zeroout(struct btrfs_device *device, u64 physical,
 			      u64 length);
+int btrfs_sync_zone_write_pointer(struct btrfs_device *tgt_dev, u64 logical,
+				  u64 physical_start, u64 physical_pos);
 #else /* CONFIG_BLK_DEV_ZONED */
 static inline int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
 				     struct blk_zone *zone)
@@ -154,6 +156,12 @@ static inline int btrfs_zoned_issue_zeroout(struct btrfs_device *device,
 {
 	return -EOPNOTSUPP;
 }
+static inline int btrfs_sync_zone_write_pointer(struct btrfs_device *tgt_dev,
+						u64 logical, u64 physical_start,
+						u64 physical_pos)
+{
+	return -EOPNOTSUPP;
+}
 #endif
 
 static inline bool btrfs_dev_is_sequential(struct btrfs_device *device, u64 pos)
-- 
2.27.0

[PATCH v7 33/39] btrfs: enable relocation in ZONED mode

[Naohiro Aota]

To serialize allocation and submit_bio, we introduced mutex around them. As
a result, preallocation must be completely disabled to avoid a deadlock.

Since current relocation process relies on preallocation to move file data
extents, it must be handled in another way. In ZONED mode, we just truncate
the inode to the size that we wanted to pre-allocate. Then, we flush dirty
pages on the file before finishing relocation process.
run_delalloc_zoned() will handle all the allocation and submit IOs to the
underlying layers.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/relocation.c | 35 +++++++++++++++++++++++++++++++++--
 1 file changed, 33 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 4ba1ab9cc76d..5bd1f2e61062 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -2600,6 +2600,32 @@ static noinline_for_stack int prealloc_file_extent_cluster(
 	if (ret)
 		return ret;
 
+	/*
+	 * In ZONED mode, we cannot preallocate the file region. Instead, we
+	 * dirty and fiemap_write the region.
+	 */
+
+	if (btrfs_fs_incompat(inode->root->fs_info, ZONED)) {
+		struct btrfs_root *root = inode->root;
+		struct btrfs_trans_handle *trans;
+
+		end = cluster->end - offset + 1;
+		trans = btrfs_start_transaction(root, 1);
+		if (IS_ERR(trans))
+			return PTR_ERR(trans);
+
+		inode->vfs_inode.i_ctime = current_time(&inode->vfs_inode);
+		i_size_write(&inode->vfs_inode, end);
+		ret = btrfs_update_inode(trans, root, &inode->vfs_inode);
+		if (ret) {
+			btrfs_abort_transaction(trans, ret);
+			btrfs_end_transaction(trans);
+			return ret;
+		}
+
+		return btrfs_end_transaction(trans);
+	}
+
 	inode_lock(&inode->vfs_inode);
 	for (nr = 0; nr < cluster->nr; nr++) {
 		start = cluster->boundary[nr] - offset;
@@ -2796,6 +2822,8 @@ static int relocate_file_extent_cluster(struct inode *inode,
 		}
 	}
 	WARN_ON(nr != cluster->nr);
+	if (btrfs_fs_incompat(fs_info, ZONED) && !ret)
+		ret = btrfs_wait_ordered_range(inode, 0, (u64)-1);
 out:
 	kfree(ra);
 	return ret;
@@ -3431,8 +3459,12 @@ static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
 	struct btrfs_path *path;
 	struct btrfs_inode_item *item;
 	struct extent_buffer *leaf;
+	u64 flags = BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC;
 	int ret;
 
+	if (btrfs_fs_incompat(trans->fs_info, ZONED))
+		flags &= ~BTRFS_INODE_PREALLOC;
+
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
@@ -3447,8 +3479,7 @@ static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
 	btrfs_set_inode_generation(leaf, item, 1);
 	btrfs_set_inode_size(leaf, item, 0);
 	btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
-	btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
-					  BTRFS_INODE_PREALLOC);
+	btrfs_set_inode_flags(leaf, item, flags);
 	btrfs_mark_buffer_dirty(leaf);
 out:
 	btrfs_free_path(path);
-- 
2.27.0

[PATCH v7 34/39] btrfs: relocate block group to repair IO failure in ZONED

[Naohiro Aota]

When btrfs find a checksum error and if the file system has a mirror of the
damaged data, btrfs read the correct data from the mirror and write the
data to damaged blocks. This repairing, however, is against the sequential
write required rule.

We can consider three methods to repair an IO failure in ZONED mode:
(1) Reset and rewrite the damaged zone
(2) Allocate new device extent and replace the damaged device extent to the
    new extent
(3) Relocate the corresponding block group

Method (1) is most similar to a behavior done with regular devices.
However, it also wipes non-damaged data in the same device extent, and so
it unnecessary degrades non-damaged data.

Method (2) is much like device replacing but done in the same device. It is
safe because it keeps the device extent until the replacing finish.
However, extending device replacing is non-trivial. It assumes
"src_dev->physical == dst_dev->physical". Also, the extent mapping
replacing function should be extended to support replacing device extent
position in one device.

Method (3) invokes relocation of the damaged block group, so it is
straightforward to implement. It relocates all the mirrored device extents,
so it is, potentially, a more costly operation than method (1) or (2). But
it relocates only using extents which reduce the total IO size.

Let's apply method (3) for now. In the future, we can extend device-replace
and apply method (2).

For protecting a block group gets relocated multiple time with multiple IO
errors, this commit introduces "relocating_repair" bit to show it's now
relocating to repair IO failures. Also it uses a new kthread
"btrfs-relocating-repair", not to block IO path with relocating process.

This commit also supports repairing in the scrub process.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/block-group.h |  1 +
 fs/btrfs/extent_io.c   |  3 ++
 fs/btrfs/scrub.c       |  3 ++
 fs/btrfs/volumes.c     | 71 ++++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/volumes.h     |  1 +
 5 files changed, 79 insertions(+)

diff --git a/fs/btrfs/block-group.h b/fs/btrfs/block-group.h
index e91123495d68..50e5ddb0a19b 100644
--- a/fs/btrfs/block-group.h
+++ b/fs/btrfs/block-group.h
@@ -96,6 +96,7 @@ struct btrfs_block_group {
 	unsigned int has_caching_ctl:1;
 	unsigned int removed:1;
 	unsigned int to_copy:1;
+	unsigned int relocating_repair:1;
 
 	int disk_cache_state;
 
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index b660921af935..2fcb78147330 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2273,6 +2273,9 @@ int repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 start,
 	ASSERT(!(fs_info->sb->s_flags & SB_RDONLY));
 	BUG_ON(!mirror_num);
 
+	if (btrfs_fs_incompat(fs_info, ZONED))
+		return btrfs_repair_one_zone(fs_info, logical);
+
 	bio = btrfs_io_bio_alloc(1);
 	bio->bi_iter.bi_size = 0;
 	map_length = length;
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 2356e6d90690..3c59e551b894 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -861,6 +861,9 @@ static int scrub_handle_errored_block(struct scrub_block *sblock_to_check)
 	have_csum = sblock_to_check->pagev[0]->have_csum;
 	dev = sblock_to_check->pagev[0]->dev;
 
+	if (btrfs_fs_incompat(fs_info, ZONED) && !sctx->is_dev_replace)
+		return btrfs_repair_one_zone(fs_info, logical);
+
 	/*
 	 * We must use GFP_NOFS because the scrub task might be waiting for a
 	 * worker task executing this function and in turn a transaction commit
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 779ee0452c1b..9e82cf28662f 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -7961,3 +7961,74 @@ bool btrfs_pinned_by_swapfile(struct btrfs_fs_info *fs_info, void *ptr)
 	spin_unlock(&fs_info->swapfile_pins_lock);
 	return node != NULL;
 }
+
+static int relocating_repair_kthread(void *data)
+{
+	struct btrfs_block_group *cache = (struct btrfs_block_group *) data;
+	struct btrfs_fs_info *fs_info = cache->fs_info;
+	u64 target;
+	int ret = 0;
+
+	target = cache->start;
+	btrfs_put_block_group(cache);
+
+	if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
+		btrfs_info(fs_info,
+			   "skip relocating block group %llu to repair: EBUSY",
+			   target);
+		return -EBUSY;
+	}
+
+	mutex_lock(&fs_info->delete_unused_bgs_mutex);
+
+	/* ensure Block Group still exists */
+	cache = btrfs_lookup_block_group(fs_info, target);
+	if (!cache)
+		goto out;
+
+	if (!cache->relocating_repair)
+		goto out;
+
+	ret = btrfs_may_alloc_data_chunk(fs_info, target);
+	if (ret < 0)
+		goto out;
+
+	btrfs_info(fs_info, "relocating block group %llu to repair IO failure",
+		   target);
+	ret = btrfs_relocate_chunk(fs_info, target);
+
+out:
+	if (cache)
+		btrfs_put_block_group(cache);
+	mutex_unlock(&fs_info->delete_unused_bgs_mutex);
+	clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
+
+	return ret;
+}
+
+int btrfs_repair_one_zone(struct btrfs_fs_info *fs_info, u64 logical)
+{
+	struct btrfs_block_group *cache;
+
+	/* do not attempt to repair in degraded state */
+	if (btrfs_test_opt(fs_info, DEGRADED))
+		return 0;
+
+	cache = btrfs_lookup_block_group(fs_info, logical);
+	if (!cache)
+		return 0;
+
+	spin_lock(&cache->lock);
+	if (cache->relocating_repair) {
+		spin_unlock(&cache->lock);
+		btrfs_put_block_group(cache);
+		return 0;
+	}
+	cache->relocating_repair = 1;
+	spin_unlock(&cache->lock);
+
+	kthread_run(relocating_repair_kthread, cache,
+		    "btrfs-relocating-repair");
+
+	return 0;
+}
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index fc03b386bb8c..25814628e2d5 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -583,5 +583,6 @@ bool btrfs_check_rw_degradable(struct btrfs_fs_info *fs_info,
 int btrfs_bg_type_to_factor(u64 flags);
 const char *btrfs_bg_type_to_raid_name(u64 flags);
 int btrfs_verify_dev_extents(struct btrfs_fs_info *fs_info);
+int btrfs_repair_one_zone(struct btrfs_fs_info *fs_info, u64 logical);
 
 #endif
-- 
2.27.0

[PATCH v7 35/39] btrfs: split alloc_log_tree()

[Naohiro Aota]

This is a preparation for the next patch. This commit split
alloc_log_tree() to allocating tree structure part (remains in
alloc_log_tree()) and allocating tree node part (moved in
btrfs_alloc_log_tree_node()). The latter part is also exported to be used
in the next patch.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/disk-io.c | 27 ++++++++++++++++++++++++---
 fs/btrfs/disk-io.h |  2 ++
 2 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index cd768030b7bb..4d1851e72031 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1269,7 +1269,6 @@ static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
 					 struct btrfs_fs_info *fs_info)
 {
 	struct btrfs_root *root;
-	struct extent_buffer *leaf;
 
 	root = btrfs_alloc_root(fs_info, BTRFS_TREE_LOG_OBJECTID, GFP_NOFS);
 	if (!root)
@@ -1279,6 +1278,14 @@ static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
 	root->root_key.type = BTRFS_ROOT_ITEM_KEY;
 	root->root_key.offset = BTRFS_TREE_LOG_OBJECTID;
 
+	return root;
+}
+
+int btrfs_alloc_log_tree_node(struct btrfs_trans_handle *trans,
+			      struct btrfs_root *root)
+{
+	struct extent_buffer *leaf;
+
 	/*
 	 * DON'T set SHAREABLE bit for log trees.
 	 *
@@ -1293,24 +1300,31 @@ static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
 			NULL, 0, 0, 0);
 	if (IS_ERR(leaf)) {
 		btrfs_put_root(root);
-		return ERR_CAST(leaf);
+		return PTR_ERR(leaf);
 	}
 
 	root->node = leaf;
 
 	btrfs_mark_buffer_dirty(root->node);
 	btrfs_tree_unlock(root->node);
-	return root;
+
+	return 0;
 }
 
 int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
 			     struct btrfs_fs_info *fs_info)
 {
 	struct btrfs_root *log_root;
+	int ret;
 
 	log_root = alloc_log_tree(trans, fs_info);
 	if (IS_ERR(log_root))
 		return PTR_ERR(log_root);
+	ret = btrfs_alloc_log_tree_node(trans, log_root);
+	if (ret) {
+		kfree(log_root);
+		return ret;
+	}
 	WARN_ON(fs_info->log_root_tree);
 	fs_info->log_root_tree = log_root;
 	return 0;
@@ -1322,11 +1336,18 @@ int btrfs_add_log_tree(struct btrfs_trans_handle *trans,
 	struct btrfs_fs_info *fs_info = root->fs_info;
 	struct btrfs_root *log_root;
 	struct btrfs_inode_item *inode_item;
+	int ret;
 
 	log_root = alloc_log_tree(trans, fs_info);
 	if (IS_ERR(log_root))
 		return PTR_ERR(log_root);
 
+	ret = btrfs_alloc_log_tree_node(trans, log_root);
+	if (ret) {
+		kfree(log_root);
+		return ret;
+	}
+
 	log_root->last_trans = trans->transid;
 	log_root->root_key.offset = root->root_key.objectid;
 
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index 00dc39d47ed3..85c7d4de765e 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -111,6 +111,8 @@ blk_status_t btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio,
 			extent_submit_bio_start_t *submit_bio_start);
 blk_status_t btrfs_submit_bio_done(void *private_data, struct bio *bio,
 			  int mirror_num);
+int btrfs_alloc_log_tree_node(struct btrfs_trans_handle *trans,
+			      struct btrfs_root *root);
 int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
 			     struct btrfs_fs_info *fs_info);
 int btrfs_add_log_tree(struct btrfs_trans_handle *trans,
-- 
2.27.0

[PATCH v7 36/39] btrfs: extend zoned allocator to use dedicated tree-log block group

[Naohiro Aota]

This is the 1/3 patch to enable tree log on ZONED mode.

The tree-log feature does not work on ZONED mode as is. Blocks for a
tree-log tree are allocated mixed with other metadata blocks, and btrfs
writes and syncs the tree-log blocks to devices at the time of fsync(),
which is different timing from a global transaction commit. As a result,
both writing tree-log blocks and writing other metadata blocks become
non-sequential writes that ZONED mode must avoid.

We can introduce a dedicated block group for tree-log blocks so that
tree-log blocks and other metadata blocks can be separated write streams.
As a result, each write stream can now be written to devices separately.
"fs_info->treelog_bg" tracks the dedicated block group and btrfs assign
"treelog_bg" on-demand on tree-log block allocation time.

This commit extends the zoned block allocator to use the block group.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/block-group.c |  7 +++++
 fs/btrfs/ctree.h       |  2 ++
 fs/btrfs/extent-tree.c | 68 +++++++++++++++++++++++++++++++++++++-----
 3 files changed, 70 insertions(+), 7 deletions(-)

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index be5394c8ec3a..d30eba3c484a 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -939,6 +939,13 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 	btrfs_return_cluster_to_free_space(block_group, cluster);
 	spin_unlock(&cluster->refill_lock);
 
+	if (btrfs_fs_incompat(fs_info, ZONED)) {
+		spin_lock(&fs_info->treelog_bg_lock);
+		if (fs_info->treelog_bg == block_group->start)
+			fs_info->treelog_bg = 0;
+		spin_unlock(&fs_info->treelog_bg_lock);
+	}
+
 	path = btrfs_alloc_path();
 	if (!path) {
 		ret = -ENOMEM;
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index e08fe341cd81..6e05eb180a77 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -942,6 +942,8 @@ struct btrfs_fs_info {
 	int send_in_progress;
 
 	struct mutex zoned_meta_io_lock;
+	spinlock_t treelog_bg_lock;
+	u64 treelog_bg;
 
 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 	spinlock_t ref_verify_lock;
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 79ac8fcc5c35..9e576977f416 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3506,6 +3506,9 @@ struct find_free_extent_ctl {
 
 	/* Allocation policy */
 	enum btrfs_extent_allocation_policy policy;
+
+	/* Allocation is called for tree-log */
+	bool for_treelog;
 };
 
 
@@ -3706,23 +3709,54 @@ static int do_allocation_zoned(struct btrfs_block_group *block_group,
 			       struct find_free_extent_ctl *ffe_ctl,
 			       struct btrfs_block_group **bg_ret)
 {
+	struct btrfs_fs_info *fs_info = block_group->fs_info;
 	struct btrfs_space_info *space_info = block_group->space_info;
 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
 	u64 start = block_group->start;
 	u64 num_bytes = ffe_ctl->num_bytes;
 	u64 avail;
+	u64 bytenr = block_group->start;
+	u64 log_bytenr;
 	int ret = 0;
+	bool skip;
 
 	ASSERT(btrfs_fs_incompat(block_group->fs_info, ZONED));
 
+	/*
+	 * Do not allow non-tree-log blocks in the dedicated tree-log block
+	 * group, and vice versa.
+	 */
+	spin_lock(&fs_info->treelog_bg_lock);
+	log_bytenr = fs_info->treelog_bg;
+	skip = log_bytenr && ((ffe_ctl->for_treelog && bytenr != log_bytenr) ||
+			      (!ffe_ctl->for_treelog && bytenr == log_bytenr));
+	spin_unlock(&fs_info->treelog_bg_lock);
+	if (skip)
+		return 1;
+
 	spin_lock(&space_info->lock);
 	spin_lock(&block_group->lock);
+	spin_lock(&fs_info->treelog_bg_lock);
+
+	ASSERT(!ffe_ctl->for_treelog ||
+	       block_group->start == fs_info->treelog_bg ||
+	       fs_info->treelog_bg == 0);
 
 	if (block_group->ro) {
 		ret = 1;
 		goto out;
 	}
 
+	/*
+	 * Do not allow currently using block group to be tree-log dedicated
+	 * block group.
+	 */
+	if (ffe_ctl->for_treelog && !fs_info->treelog_bg &&
+	    (block_group->used || block_group->reserved)) {
+		ret = 1;
+		goto out;
+	}
+
 	avail = block_group->length - block_group->alloc_offset;
 	if (avail < num_bytes) {
 		ffe_ctl->max_extent_size = avail;
@@ -3730,6 +3764,9 @@ static int do_allocation_zoned(struct btrfs_block_group *block_group,
 		goto out;
 	}
 
+	if (ffe_ctl->for_treelog && !fs_info->treelog_bg)
+		fs_info->treelog_bg = block_group->start;
+
 	ffe_ctl->found_offset = start + block_group->alloc_offset;
 	block_group->alloc_offset += num_bytes;
 	spin_lock(&ctl->tree_lock);
@@ -3737,10 +3774,13 @@ static int do_allocation_zoned(struct btrfs_block_group *block_group,
 	spin_unlock(&ctl->tree_lock);
 
 	ASSERT(IS_ALIGNED(ffe_ctl->found_offset,
-			  block_group->fs_info->stripesize));
+			  fs_info->stripesize));
 	ffe_ctl->search_start = ffe_ctl->found_offset;
 
 out:
+	if (ret && ffe_ctl->for_treelog)
+		fs_info->treelog_bg = 0;
+	spin_unlock(&fs_info->treelog_bg_lock);
 	spin_unlock(&block_group->lock);
 	spin_unlock(&space_info->lock);
 	return ret;
@@ -3990,7 +4030,12 @@ static int prepare_allocation(struct btrfs_fs_info *fs_info,
 		return prepare_allocation_clustered(fs_info, ffe_ctl,
 						    space_info, ins);
 	case BTRFS_EXTENT_ALLOC_ZONED:
-		/* nothing to do */
+		if (ffe_ctl->for_treelog) {
+			spin_lock(&fs_info->treelog_bg_lock);
+			if (fs_info->treelog_bg)
+				ffe_ctl->hint_byte = fs_info->treelog_bg;
+			spin_unlock(&fs_info->treelog_bg_lock);
+		}
 		return 0;
 	default:
 		BUG();
@@ -4025,7 +4070,7 @@ static int prepare_allocation(struct btrfs_fs_info *fs_info,
 static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
 				u64 ram_bytes, u64 num_bytes, u64 empty_size,
 				u64 hint_byte_orig, struct btrfs_key *ins,
-				u64 flags, int delalloc)
+				u64 flags, int delalloc, bool for_treelog)
 {
 	int ret = 0;
 	int cache_block_group_error = 0;
@@ -4046,6 +4091,7 @@ static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
 	ffe_ctl.orig_have_caching_bg = false;
 	ffe_ctl.found_offset = 0;
 	ffe_ctl.hint_byte = hint_byte_orig;
+	ffe_ctl.for_treelog = for_treelog;
 	ffe_ctl.policy = BTRFS_EXTENT_ALLOC_CLUSTERED;
 
 	/* For clustered allocation */
@@ -4120,8 +4166,15 @@ static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
 		struct btrfs_block_group *bg_ret;
 
 		/* If the block group is read-only, we can skip it entirely. */
-		if (unlikely(block_group->ro))
+		if (unlikely(block_group->ro)) {
+			if (btrfs_fs_incompat(fs_info, ZONED) && for_treelog) {
+				spin_lock(&fs_info->treelog_bg_lock);
+				if (block_group->start == fs_info->treelog_bg)
+					fs_info->treelog_bg = 0;
+				spin_unlock(&fs_info->treelog_bg_lock);
+			}
 			continue;
+		}
 
 		btrfs_grab_block_group(block_group, delalloc);
 		ffe_ctl.search_start = block_group->start;
@@ -4309,12 +4362,13 @@ int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes,
 	bool final_tried = num_bytes == min_alloc_size;
 	u64 flags;
 	int ret;
+	bool for_treelog = root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID;
 
 	flags = get_alloc_profile_by_root(root, is_data);
 again:
 	WARN_ON(num_bytes < fs_info->sectorsize);
 	ret = find_free_extent(fs_info, ram_bytes, num_bytes, empty_size,
-			       hint_byte, ins, flags, delalloc);
+			       hint_byte, ins, flags, delalloc, for_treelog);
 	if (!ret && !is_data) {
 		btrfs_dec_block_group_reservations(fs_info, ins->objectid);
 	} else if (ret == -ENOSPC) {
@@ -4332,8 +4386,8 @@ int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes,
 
 			sinfo = btrfs_find_space_info(fs_info, flags);
 			btrfs_err(fs_info,
-				  "allocation failed flags %llu, wanted %llu",
-				  flags, num_bytes);
+			"allocation failed flags %llu, wanted %llu treelog %d",
+				  flags, num_bytes, for_treelog);
 			if (sinfo)
 				btrfs_dump_space_info(fs_info, sinfo,
 						      num_bytes, 1);
-- 
2.27.0

[PATCH v7 37/39] btrfs: serialize log transaction on ZONED mode

[Naohiro Aota]

This is the 2/3 patch to enable tree-log on ZONED mode.

Since we can start more than one log transactions per subvolume
simultaneously, nodes from multiple transactions can be allocated
interleaved. Such mixed allocation results in non-sequential writes at the
time of log transaction commit. The nodes of the global log root tree
(fs_info->log_root_tree), also have the same mixed allocation problem.

This patch serializes log transactions by waiting for a committing
transaction when someone tries to start a new transaction, to avoid the
mixed allocation problem. We must also wait for running log transactions
from another subvolume, but there is no easy way to detect which subvolume
root is running a log transaction. So, this patch forbids starting a new
log transaction when other subvolumes already allocated the global log root
tree.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/tree-log.c | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 4b6a68a81eac..1ffb9a0341e2 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -108,6 +108,7 @@ static noinline int replay_dir_deletes(struct btrfs_trans_handle *trans,
 				       struct btrfs_root *log,
 				       struct btrfs_path *path,
 				       u64 dirid, int del_all);
+static void wait_log_commit(struct btrfs_root *root, int transid);
 
 /*
  * tree logging is a special write ahead log used to make sure that
@@ -142,16 +143,25 @@ static int start_log_trans(struct btrfs_trans_handle *trans,
 			   struct btrfs_log_ctx *ctx)
 {
 	struct btrfs_fs_info *fs_info = root->fs_info;
+	bool zoned = btrfs_fs_incompat(fs_info, ZONED);
 	int ret = 0;
 
 	mutex_lock(&root->log_mutex);
 
+again:
 	if (root->log_root) {
+		int index = (root->log_transid + 1) % 2;
+
 		if (btrfs_need_log_full_commit(trans)) {
 			ret = -EAGAIN;
 			goto out;
 		}
 
+		if (zoned && atomic_read(&root->log_commit[index])) {
+			wait_log_commit(root, root->log_transid - 1);
+			goto again;
+		}
+
 		if (!root->log_start_pid) {
 			clear_bit(BTRFS_ROOT_MULTI_LOG_TASKS, &root->state);
 			root->log_start_pid = current->pid;
@@ -160,8 +170,13 @@ static int start_log_trans(struct btrfs_trans_handle *trans,
 		}
 	} else {
 		mutex_lock(&fs_info->tree_log_mutex);
-		if (!fs_info->log_root_tree)
+		if (zoned && fs_info->log_root_tree) {
+			ret = -EAGAIN;
+			mutex_unlock(&fs_info->tree_log_mutex);
+			goto out;
+		} else if (!fs_info->log_root_tree) {
 			ret = btrfs_init_log_root_tree(trans, fs_info);
+		}
 		mutex_unlock(&fs_info->tree_log_mutex);
 		if (ret)
 			goto out;
@@ -195,14 +210,22 @@ static int start_log_trans(struct btrfs_trans_handle *trans,
  */
 static int join_running_log_trans(struct btrfs_root *root)
 {
+	bool zoned = btrfs_fs_incompat(root->fs_info, ZONED);
 	int ret = -ENOENT;
 
 	if (!test_bit(BTRFS_ROOT_HAS_LOG_TREE, &root->state))
 		return ret;
 
 	mutex_lock(&root->log_mutex);
+again:
 	if (root->log_root) {
+		int index = (root->log_transid + 1) % 2;
+
 		ret = 0;
+		if (zoned && atomic_read(&root->log_commit[index])) {
+			wait_log_commit(root, root->log_transid - 1);
+			goto again;
+		}
 		atomic_inc(&root->log_writers);
 	}
 	mutex_unlock(&root->log_mutex);
-- 
2.27.0

[PATCH v7 38/39] btrfs: reorder log node allocation

[Naohiro Aota]

This is the 3/3 patch to enable tree-log on ZONED mode.

The allocation order of nodes of "fs_info->log_root_tree" and nodes of
"root->log_root" is not the same as the writing order of them. So, the
writing causes unaligned write errors.

This patch reorders the allocation of them by delaying allocation of the
root node of "fs_info->log_root_tree," so that the node buffers can go out
sequentially to devices.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/disk-io.c  |  6 ------
 fs/btrfs/tree-log.c | 19 +++++++++++++------
 2 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 4d1851e72031..0884412977a0 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1315,16 +1315,10 @@ int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
 			     struct btrfs_fs_info *fs_info)
 {
 	struct btrfs_root *log_root;
-	int ret;
 
 	log_root = alloc_log_tree(trans, fs_info);
 	if (IS_ERR(log_root))
 		return PTR_ERR(log_root);
-	ret = btrfs_alloc_log_tree_node(trans, log_root);
-	if (ret) {
-		kfree(log_root);
-		return ret;
-	}
 	WARN_ON(fs_info->log_root_tree);
 	fs_info->log_root_tree = log_root;
 	return 0;
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 1ffb9a0341e2..087c1d0c7307 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -3147,6 +3147,11 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans,
 	list_add_tail(&root_log_ctx.list, &log_root_tree->log_ctxs[index2]);
 	root_log_ctx.log_transid = log_root_tree->log_transid;
 
+	mutex_lock(&fs_info->tree_log_mutex);
+	if (!log_root_tree->node)
+		btrfs_alloc_log_tree_node(trans, log_root_tree);
+	mutex_unlock(&fs_info->tree_log_mutex);
+
 	/*
 	 * Now we are safe to update the log_root_tree because we're under the
 	 * log_mutex, and we're a current writer so we're holding the commit
@@ -3296,12 +3301,14 @@ static void free_log_tree(struct btrfs_trans_handle *trans,
 		.process_func = process_one_buffer
 	};
 
-	ret = walk_log_tree(trans, log, &wc);
-	if (ret) {
-		if (trans)
-			btrfs_abort_transaction(trans, ret);
-		else
-			btrfs_handle_fs_error(log->fs_info, ret, NULL);
+	if (log->node) {
+		ret = walk_log_tree(trans, log, &wc);
+		if (ret) {
+			if (trans)
+				btrfs_abort_transaction(trans, ret);
+			else
+				btrfs_handle_fs_error(log->fs_info, ret, NULL);
+		}
 	}
 
 	clear_extent_bits(&log->dirty_log_pages, 0, (u64)-1,
-- 
2.27.0

[PATCH v7 39/39] btrfs: enable to mount ZONED incompat flag

[Naohiro Aota]

This final patch adds the ZONED incompat flag to
BTRFS_FEATURE_INCOMPAT_SUPP and enables btrfs to mount ZONED flagged file
system.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/ctree.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 6e05eb180a77..e8639f6f7dec 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -303,7 +303,8 @@ struct btrfs_super_block {
 	 BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA |	\
 	 BTRFS_FEATURE_INCOMPAT_NO_HOLES	|	\
 	 BTRFS_FEATURE_INCOMPAT_METADATA_UUID	|	\
-	 BTRFS_FEATURE_INCOMPAT_RAID1C34)
+	 BTRFS_FEATURE_INCOMPAT_RAID1C34	|	\
+	 BTRFS_FEATURE_INCOMPAT_ZONED)
 
 #define BTRFS_FEATURE_INCOMPAT_SAFE_SET			\
 	(BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF)
-- 
2.27.0

Re: [PATCH v7 19/39] btrfs: limit bio size under max_zone_append_size

[Christoph Hellwig]

On Fri, Sep 11, 2020 at 09:32:39PM +0900, Naohiro Aota wrote:
> +		if (fs_info->max_zone_append_size &&
> +		    bio_op(bio) == REQ_OP_WRITE &&
> +		    bio->bi_iter.bi_size + size > fs_info->max_zone_append_size)
> +			can_merge = false;
> +
>  		if (prev_bio_flags != bio_flags || !contig || !can_merge ||
>  		    force_bio_submit ||
>  		    bio_add_page(bio, page, page_size, pg_offset) < page_size) {

For zoned devices you need to use bio_add_hw_page instead of so that all
the hardware restrictions are applied.  bio_add_hw_page asso gets the
lenght limited passed as the last parameter so we won't need a separate
check.

Re: [PATCH v7 19/39] btrfs: limit bio size under max_zone_append_size

[Naohiro Aota]

On Fri, Sep 11, 2020 at 03:17:19PM +0100, Christoph Hellwig wrote:
>On Fri, Sep 11, 2020 at 09:32:39PM +0900, Naohiro Aota wrote:
>> +		if (fs_info->max_zone_append_size &&
>> +		    bio_op(bio) == REQ_OP_WRITE &&
>> +		    bio->bi_iter.bi_size + size > fs_info->max_zone_append_size)
>> +			can_merge = false;
>> +
>>  		if (prev_bio_flags != bio_flags || !contig || !can_merge ||
>>  		    force_bio_submit ||
>>  		    bio_add_page(bio, page, page_size, pg_offset) < page_size) {
>
>For zoned devices you need to use bio_add_hw_page instead of so that all
>the hardware restrictions are applied.  bio_add_hw_page asso gets the
>lenght limited passed as the last parameter so we won't need a separate
>check.

I think we can't use it here. This bio is built for btrfs's logical space,
so the corresponding request queue is not available here.

Technically, we can use fs_devices->lateste_bdev. But considering this bio
can map to multiple bios to multiple devices, limiting the size of this bio
under the minimum queue_max_zone_appends_sectors() among devices is
feasible.

Re: [PATCH v7 19/39] btrfs: limit bio size under max_zone_append_size

[Christoph Hellwig]

On Sat, Sep 12, 2020 at 01:14:24PM +0900, Naohiro Aota wrote:
> > For zoned devices you need to use bio_add_hw_page instead of so that all
> > the hardware restrictions are applied.  bio_add_hw_page asso gets the
> > lenght limited passed as the last parameter so we won't need a separate
> > check.
> 
> I think we can't use it here. This bio is built for btrfs's logical space,
> so the corresponding request queue is not available here.
> 
> Technically, we can use fs_devices->lateste_bdev. But considering this bio
> can map to multiple bios to multiple devices, limiting the size of this bio
> under the minimum queue_max_zone_appends_sectors() among devices is
> feasible.

Well, how do you then ensure the bio actually fits all the other
device limits as well?  e.g. max segment size, no SG gaps policy,
etc?

Re: [PATCH v7 18/39] btrfs: redirty released extent buffers in ZONED mode

[Johannes Thumshirn]

On 11/09/2020 19:42, Naohiro Aota wrote:
> Tree manipulating operations like merging nodes often release
> once-allocated tree nodes. Btrfs cleans such nodes so that pages in the
> node are not uselessly written out. On ZONED volumes, however, such
> optimization blocks the following IOs as the cancellation of the write out
> of the freed blocks breaks the sequential write sequence expected by the
> device.
> 
> This patch introduces a list of clean and unwritten extent buffers that
> have been released in a transaction. Btrfs redirty the buffer so that
> btree_write_cache_pages() can send proper bios to the devices.
> 
> Besides it clears the entire content of the extent buffer not to confuse
> raw block scanners e.g. btrfsck. By clearing the content,
> csum_dirty_buffer() complains about bytenr mismatch, so avoid the checking
> and checksum using newly introduced buffer flag EXTENT_BUFFER_NO_CHECK.

That one doesn't apply cleanly on current misc-next.

Re: [PATCH v7 00/39] btrfs: zoned block device support

[David Sterba]

On Fri, Sep 11, 2020 at 09:32:20PM +0900, Naohiro Aota wrote:
> Changelog
> v6:
>  - Use bitmap helpers (Johannes)
>  - Code cleanup (Johannes)
>  - Rebased on kdave/for-5.5
>  - Enable the tree-log feature.
>  - Treat conventional zones as sequential zones, so we can now allow
>    mixed allocation of conventional zone and sequential write required
>    zone to construct a block group.
>  - Implement log-structured superblock
>    - No need for one conventional zone at the beginning of a device.
>  - Fix deadlock of direct IO writing
>  - Fix building with !CONFIG_BLK_DEV_ZONED (Johannes)
>  - Fix leak of zone_info (Johannes)

I did a quick check to see if the patchset passes the default VM tests
and there's use after free short after the fstests start. No zoned
devices or such. I had to fix some conflicts when rebasing on misc-next
but I tried to base it on the last iomap-dio patch ("btrfs: switch to
iomap for direct IO"), same result so it's something in the zoned
patches.

The reported pointer 0x6b6b6b6b6d1918eb contains the use-after-free
poison (0x6b) (CONFIG_PAGE_POISONING=y).

MKFS_OPTIONS  -- -f -K --csum xxhash /dev/vdb
MOUNT_OPTIONS -- -o discard /dev/vdb /tmp/scratch

[   19.928844] BTRFS: device fsid 663b9b17-ab02-4021-92bf-dc24c3e4351a devid 1 transid 5 /dev/vdb scanned by mkfs.btrfs (398)
[   19.974176] BTRFS info (device vdb): turning on sync discard
[   19.977035] BTRFS info (device vdb): disk space caching is enabled
[   19.979965] BTRFS info (device vdb): has skinny extents
[   19.982586] BTRFS info (device vdb): flagging fs with big metadata feature
[   19.991757] BTRFS info (device vdb): checking UUID tree
[   20.002740] general protection fault, probably for non-canonical address 0x6b6b6b6b6d1918eb: 0000 [#1] SMP
[   20.006949] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.9.0-rc5-default+ #1260
[   20.009746] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba527-rebuilt.opensuse.org 04/01/2014
[   20.013566] RIP: 0010:end_bio_extent_writepage+0x51/0x180 [btrfs]
[   20.015873] Code: 8b 54 24 2c 41 8b 74 24 30 41 89 c5 48 c1 e2 04 49 03 54 24 60 03 72 0c 89 f0 81 e6 ff 0f 00 00 c1 e8 0c 48 c1 e0 06 48 03 02 <48> 8b 50 20 48 8b 40 18 48 c1 e2 0c 48 8b 38 48 01 d6 4c 89 e2 e8
[   20.022029] RSP: 0018:ffff93fc800b8e20 EFLAGS: 00010206
[   20.023615] RAX: 6b6b6b6b6d1918eb RBX: ffff8eceaf630378 RCX: 0000000000000020
[   20.025565] RDX: ffff8eceb297da00 RSI: 0000000000000b6b RDI: 0000000000000000
[   20.027289] RBP: ffff93fc800b8e80 R08: 00000004a84169d3 R09: 0000000000000000
[   20.028634] R10: 0000000000000000 R11: 0000000000000246 R12: ffff8eceaf630378
[   20.030569] R13: 0000000000000000 R14: 0000000000010000 R15: ffff8ecebaf62280
[   20.032607] FS:  0000000000000000(0000) GS:ffff8ecebd800000(0000) knlGS:0000000000000000
[   20.035314] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   20.036641] CR2: 00007f9bc3b5a990 CR3: 000000005fa3a005 CR4: 0000000000170ea0
[   20.038523] Call Trace:
[   20.039527]  <IRQ>
[   20.040378]  ? sched_clock_cpu+0x15/0x130
[   20.041619]  ? bio_endio+0x120/0x2c0
[   20.042880]  btrfs_end_bio+0x83/0x130 [btrfs]
[   20.044172]  blk_update_request+0x230/0x710
[   20.045368]  blk_mq_end_request+0x1c/0x130
[   20.046594]  blk_done_softirq+0x9f/0xd0
[   20.047754]  __do_softirq+0x1eb/0x56c
[   20.048917]  asm_call_on_stack+0xf/0x20
[   20.050185]  </IRQ>
[   20.051035]  do_softirq_own_stack+0x52/0x60
[   20.052368]  irq_exit_rcu+0x98/0xb0
[   20.053533]  sysvec_call_function_single+0x43/0xa0
[   20.054887]  asm_sysvec_call_function_single+0x12/0x20
[   20.056545] RIP: 0010:default_idle+0x1d/0x20
[   20.057961] Code: cc cc cc cc cc cc cc cc cc cc cc cc cc 0f 1f 44 00 00 e8 26 4d 9e ff 8b 05 f0 0e 03 01 85 c0 7e 07 0f 00 2d 67 1d 46 00 fb f4 <c3> 66 90 0f 1f 44 00 00 65 48 8b 04 25 00 8e 01 00 f0 80 48 02 20
[   20.063377] RSP: 0018:ffff93fc80073ed0 EFLAGS: 00000246
[   20.064915] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   20.066743] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff9b7a5c6a
[   20.068656] RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000001
[   20.070530] R10: 0000000000000000 R11: 0000000000000046 R12: ffff8ecebd330040
[   20.072439] R13: ffff8ecebd330040 R14: 0000000000000000 R15: 0000000000000000
[   20.074408]  ? default_idle+0xa/0x20
[   20.075564]  default_idle_call+0x52/0x230
[   20.076849]  do_idle+0x201/0x210
[   20.077993]  cpu_startup_entry+0x19/0x1b
[   20.079301]  secondary_startup_64+0xa4/0xb0
[   20.080685] Modules linked in: xxhash_generic btrfs blake2b_generic libcrc32c crc32c_intel xor zstd_decompress zstd_compress xxhash lzo_compress lzo_decompress raid6_pq loop
[   20.085376] ---[ end trace fb99f1646d553ef6 ]---
[   20.087627] RIP: 0010:end_bio_extent_writepage+0x51/0x180 [btrfs]
[   20.090290] Code: 8b 54 24 2c 41 8b 74 24 30 41 89 c5 48 c1 e2 04 49 03 54 24 60 03 72 0c 89 f0 81 e6 ff 0f 00 00 c1 e8 0c 48 c1 e0 06 48 03 02 <48> 8b 50 20 48 8b 40 18 48 c1 e2 0c 48 8b 38 48 01 d6 4c 89 e2 e8
[   20.096561] RSP: 0018:ffff93fc800b8e20 EFLAGS: 00010206
[   20.098468] RAX: 6b6b6b6b6d1918eb RBX: ffff8eceaf630378 RCX: 0000000000000020
[   20.100883] RDX: ffff8eceb297da00 RSI: 0000000000000b6b RDI: 0000000000000000
[   20.103124] RBP: ffff93fc800b8e80 R08: 00000004a84169d3 R09: 0000000000000000
[   20.105312] R10: 0000000000000000 R11: 0000000000000246 R12: ffff8eceaf630378
[   20.107553] R13: 0000000000000000 R14: 0000000000010000 R15: ffff8ecebaf62280
[   20.109464] FS:  0000000000000000(0000) GS:ffff8ecebd800000(0000) knlGS:0000000000000000
[   20.112286] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   20.114048] CR2: 00007f9bc3b5a990 CR3: 000000005fa3a005 CR4: 0000000000170ea0
[   20.115946] Kernel panic - not syncing: Fatal exception in interrupt
[   20.117851] Kernel Offset: 0x1a000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
[   20.120788] Rebooting in 90 seconds..

Re: [PATCH v7 00/39] btrfs: zoned block device support

[Johannes Thumshirn]

On 15/09/2020 10:25, David Sterba wrote:
> On Fri, Sep 11, 2020 at 09:32:20PM +0900, Naohiro Aota wrote:
>> Changelog
>> v6:
>>  - Use bitmap helpers (Johannes)
>>  - Code cleanup (Johannes)
>>  - Rebased on kdave/for-5.5
>>  - Enable the tree-log feature.
>>  - Treat conventional zones as sequential zones, so we can now allow
>>    mixed allocation of conventional zone and sequential write required
>>    zone to construct a block group.
>>  - Implement log-structured superblock
>>    - No need for one conventional zone at the beginning of a device.
>>  - Fix deadlock of direct IO writing
>>  - Fix building with !CONFIG_BLK_DEV_ZONED (Johannes)
>>  - Fix leak of zone_info (Johannes)
> 
> I did a quick check to see if the patchset passes the default VM tests
> and there's use after free short after the fstests start. No zoned
> devices or such. I had to fix some conflicts when rebasing on misc-next
> but I tried to base it on the last iomap-dio patch ("btrfs: switch to
> iomap for direct IO"), same result so it's something in the zoned
> patches.
> 
> The reported pointer 0x6b6b6b6b6d1918eb contains the use-after-free
> poison (0x6b) (CONFIG_PAGE_POISONING=y).
> 
> MKFS_OPTIONS  -- -f -K --csum xxhash /dev/vdb
> MOUNT_OPTIONS -- -o discard /dev/vdb /tmp/scratch

Hi David,

Can you check if this on top of the series fixes the issue? According
to Keith we can't call bio_iovec() from endio() as the iterator is already
advanced (see req_bio_endio()).


diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index bda4e02b5eab..311956697682 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2753,10 +2753,6 @@ static void end_bio_extent_writepage(struct bio *bio)
        u64 end;
        struct bvec_iter_all iter_all;
 
-       btrfs_record_physical_zoned(bio_iovec(bio).bv_page->mapping->host,
-                                   page_offset(bio_iovec(bio).bv_page) + bio_iovec(bio).bv_offset,
-                                   bio);
-
        ASSERT(!bio_flagged(bio, BIO_CLONED));
        bio_for_each_segment_all(bvec, bio, iter_all) {
                struct page *page = bvec->bv_page;
@@ -2782,6 +2778,7 @@ static void end_bio_extent_writepage(struct bio *bio)
                start = page_offset(page);
                end = start + bvec->bv_offset + bvec->bv_len - 1;
 
+               btrfs_record_physical_zoned(inode, start, bio);
                end_extent_writepage(page, error, start, end);
                end_page_writeback(page);
        }
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 576f8e333f16..6fdb21029ea9 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -1086,8 +1086,7 @@ void btrfs_record_physical_zoned(struct inode *inode, u64 file_offset,
 {
        struct btrfs_ordered_extent *ordered;
        struct bio_vec bvec = bio_iovec(bio);
-       u64 physical = ((u64)bio->bi_iter.bi_sector << SECTOR_SHIFT) +
-               bvec.bv_offset;
+       u64 physical = (u64)bio->bi_iter.bi_sector << SECTOR_SHIFT;
 
        if (bio_op(bio) != REQ_OP_ZONE_APPEND)
                return;

Re: [PATCH v7 00/39] btrfs: zoned block device support

[David Sterba]

On Wed, Sep 16, 2020 at 05:42:50PM +0000, Johannes Thumshirn wrote:
> On 15/09/2020 10:25, David Sterba wrote:
> > On Fri, Sep 11, 2020 at 09:32:20PM +0900, Naohiro Aota wrote:
> >> Changelog
> >> v6:
> >>  - Use bitmap helpers (Johannes)
> >>  - Code cleanup (Johannes)
> >>  - Rebased on kdave/for-5.5
> >>  - Enable the tree-log feature.
> >>  - Treat conventional zones as sequential zones, so we can now allow
> >>    mixed allocation of conventional zone and sequential write required
> >>    zone to construct a block group.
> >>  - Implement log-structured superblock
> >>    - No need for one conventional zone at the beginning of a device.
> >>  - Fix deadlock of direct IO writing
> >>  - Fix building with !CONFIG_BLK_DEV_ZONED (Johannes)
> >>  - Fix leak of zone_info (Johannes)
> > 
> > I did a quick check to see if the patchset passes the default VM tests
> > and there's use after free short after the fstests start. No zoned
> > devices or such. I had to fix some conflicts when rebasing on misc-next
> > but I tried to base it on the last iomap-dio patch ("btrfs: switch to
> > iomap for direct IO"), same result so it's something in the zoned
> > patches.
> > 
> > The reported pointer 0x6b6b6b6b6d1918eb contains the use-after-free
> > poison (0x6b) (CONFIG_PAGE_POISONING=y).
> > 
> > MKFS_OPTIONS  -- -f -K --csum xxhash /dev/vdb
> > MOUNT_OPTIONS -- -o discard /dev/vdb /tmp/scratch
> 
> Hi David,
> 
> Can you check if this on top of the series fixes the issue? According
> to Keith we can't call bio_iovec() from endio() as the iterator is already
> advanced (see req_bio_endio()).

It booted and is past the point it crashed before.

Re: [PATCH v7 00/39] btrfs: zoned block device support

[Johannes Thumshirn]

On 16/09/2020 21:48, David Sterba wrote:
>> Can you check if this on top of the series fixes the issue? According
>> to Keith we can't call bio_iovec() from endio() as the iterator is already
>> advanced (see req_bio_endio()).
> It booted and is past the point it crashed before.
> 

Thanks a lot for confirming

Re: [PATCH v7 19/39] btrfs: limit bio size under max_zone_append_size

[Naohiro Aota]

On Sat, Sep 12, 2020 at 06:30:56AM +0100, Christoph Hellwig wrote:
>On Sat, Sep 12, 2020 at 01:14:24PM +0900, Naohiro Aota wrote:
>> > For zoned devices you need to use bio_add_hw_page instead of so that all
>> > the hardware restrictions are applied.  bio_add_hw_page asso gets the
>> > lenght limited passed as the last parameter so we won't need a separate
>> > check.
>>
>> I think we can't use it here. This bio is built for btrfs's logical space,
>> so the corresponding request queue is not available here.
>>
>> Technically, we can use fs_devices->lateste_bdev. But considering this bio
>> can map to multiple bios to multiple devices, limiting the size of this bio
>> under the minimum queue_max_zone_appends_sectors() among devices is
>> feasible.
>
>Well, how do you then ensure the bio actually fits all the other
>device limits as well?  e.g. max segment size, no SG gaps policy,
>etc?

Yeah, that's problematic, and I realized we could not deal with all the
restrictions in this manner. I'm reimplementing this patch basing on
bio_add_hw_page().

Regards,

Re: [PATCH v7 00/39] btrfs: zoned block device support

[Naohiro Aota]

On Wed, Sep 16, 2020 at 05:42:50PM +0000, Johannes Thumshirn wrote:
>On 15/09/2020 10:25, David Sterba wrote:
>> On Fri, Sep 11, 2020 at 09:32:20PM +0900, Naohiro Aota wrote:
>>> Changelog
>>> v6:
>>>  - Use bitmap helpers (Johannes)
>>>  - Code cleanup (Johannes)
>>>  - Rebased on kdave/for-5.5
>>>  - Enable the tree-log feature.
>>>  - Treat conventional zones as sequential zones, so we can now allow
>>>    mixed allocation of conventional zone and sequential write required
>>>    zone to construct a block group.
>>>  - Implement log-structured superblock
>>>    - No need for one conventional zone at the beginning of a device.
>>>  - Fix deadlock of direct IO writing
>>>  - Fix building with !CONFIG_BLK_DEV_ZONED (Johannes)
>>>  - Fix leak of zone_info (Johannes)
>>
>> I did a quick check to see if the patchset passes the default VM tests
>> and there's use after free short after the fstests start. No zoned
>> devices or such. I had to fix some conflicts when rebasing on misc-next
>> but I tried to base it on the last iomap-dio patch ("btrfs: switch to
>> iomap for direct IO"), same result so it's something in the zoned
>> patches.
>>
>> The reported pointer 0x6b6b6b6b6d1918eb contains the use-after-free
>> poison (0x6b) (CONFIG_PAGE_POISONING=y).
>>
>> MKFS_OPTIONS  -- -f -K --csum xxhash /dev/vdb
>> MOUNT_OPTIONS -- -o discard /dev/vdb /tmp/scratch
>
>Hi David,
>
>Can you check if this on top of the series fixes the issue? According
>to Keith we can't call bio_iovec() from endio() as the iterator is already
>advanced (see req_bio_endio()).
>
>

Thank you for fixing this.

>diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
>index bda4e02b5eab..311956697682 100644
>--- a/fs/btrfs/extent_io.c
>+++ b/fs/btrfs/extent_io.c
>@@ -2753,10 +2753,6 @@ static void end_bio_extent_writepage(struct bio *bio)
>        u64 end;
>        struct bvec_iter_all iter_all;
>
>-       btrfs_record_physical_zoned(bio_iovec(bio).bv_page->mapping->host,
>-                                   page_offset(bio_iovec(bio).bv_page) + bio_iovec(bio).bv_offset,
>-                                   bio);
>-
>        ASSERT(!bio_flagged(bio, BIO_CLONED));
>        bio_for_each_segment_all(bvec, bio, iter_all) {
>                struct page *page = bvec->bv_page;
>@@ -2782,6 +2778,7 @@ static void end_bio_extent_writepage(struct bio *bio)
>                start = page_offset(page);
>                end = start + bvec->bv_offset + bvec->bv_len - 1;
>
>+               btrfs_record_physical_zoned(inode, start, bio);

We need to record the physical address only once per an ordered extent.
So, this should be like:

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index c21d1dbe314e..0bbe6e52ea0d 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2748,6 +2748,7 @@ static void end_bio_extent_writepage(struct bio *bio)
         u64 start;
         u64 end;
         struct bvec_iter_all iter_all;
+       bool first_bvec = true;

         ASSERT(!bio_flagged(bio, BIO_CLONED));
         bio_for_each_segment_all(bvec, bio, iter_all) {
@@ -2774,6 +2775,11 @@ static void end_bio_extent_writepage(struct bio *bio)
                 start = page_offset(page);
                 end = start + bvec->bv_offset + bvec->bv_len - 1;

+               if (first_bvec) {
+                       btrfs_record_physical_zoned(inode, start, bio);
+                       first_bvec = false;
+               }
+
                 end_extent_writepage(page, error, start, end);
                 end_page_writeback(page);
         }


>                end_extent_writepage(page, error, start, end);
>                end_page_writeback(page);
>        }
>diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
>index 576f8e333f16..6fdb21029ea9 100644
>--- a/fs/btrfs/zoned.c
>+++ b/fs/btrfs/zoned.c
>@@ -1086,8 +1086,7 @@ void btrfs_record_physical_zoned(struct inode *inode, u64 file_offset,
> {
>        struct btrfs_ordered_extent *ordered;
>        struct bio_vec bvec = bio_iovec(bio);
>-       u64 physical = ((u64)bio->bi_iter.bi_sector << SECTOR_SHIFT) +
>-               bvec.bv_offset;
>+       u64 physical = (u64)bio->bi_iter.bi_sector << SECTOR_SHIFT;
>
>        if (bio_op(bio) != REQ_OP_ZONE_APPEND)
>                return;
>

Re: [PATCH v7 00/39] btrfs: zoned block device support

[Johannes Thumshirn]

On 17/09/2020 07:40, Naohiro Aota wrote:
> Thank you for fixing this.

Well it was you who had the idea, I just sent it.

>> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
>> index bda4e02b5eab..311956697682 100644
>> --- a/fs/btrfs/extent_io.c
>> +++ b/fs/btrfs/extent_io.c
>> @@ -2753,10 +2753,6 @@ static void end_bio_extent_writepage(struct bio *bio)
>>        u64 end;
>>        struct bvec_iter_all iter_all;
>>
>> -       btrfs_record_physical_zoned(bio_iovec(bio).bv_page->mapping->host,
>> -                                   page_offset(bio_iovec(bio).bv_page) + bio_iovec(bio).bv_offset,
>> -                                   bio);
>> -
>>        ASSERT(!bio_flagged(bio, BIO_CLONED));
>>        bio_for_each_segment_all(bvec, bio, iter_all) {
>>                struct page *page = bvec->bv_page;
>> @@ -2782,6 +2778,7 @@ static void end_bio_extent_writepage(struct bio *bio)
>>                start = page_offset(page);
>>                end = start + bvec->bv_offset + bvec->bv_len - 1;
>>
>> +               btrfs_record_physical_zoned(inode, start, bio);
> We need to record the physical address only once per an ordered extent.
> So, this should be like:
> 

Right, this would save us a lot of unneeded function calls for the non-zoned
version of btrfs as well.

> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> index c21d1dbe314e..0bbe6e52ea0d 100644
> --- a/fs/btrfs/extent_io.c
> +++ b/fs/btrfs/extent_io.c
> @@ -2748,6 +2748,7 @@ static void end_bio_extent_writepage(struct bio *bio)
>          u64 start;
>          u64 end;
>          struct bvec_iter_all iter_all;
> +       bool first_bvec = true;
> 
>          ASSERT(!bio_flagged(bio, BIO_CLONED));
>          bio_for_each_segment_all(bvec, bio, iter_all) {
> @@ -2774,6 +2775,11 @@ static void end_bio_extent_writepage(struct bio *bio)
>                  start = page_offset(page);
>                  end = start + bvec->bv_offset + bvec->bv_len - 1;
> 
> +               if (first_bvec) {
> +                       btrfs_record_physical_zoned(inode, start, bio);
> +                       first_bvec = false;
> +               }
> +
>                  end_extent_writepage(page, error, start, end);
>                  end_page_writeback(page);
>          }
> 
> 
>>                end_extent_writepage(page, error, start, end);
>>                end_page_writeback(page);
>>        }
>> diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
>> index 576f8e333f16..6fdb21029ea9 100644
>> --- a/fs/btrfs/zoned.c
>> +++ b/fs/btrfs/zoned.c
>> @@ -1086,8 +1086,7 @@ void btrfs_record_physical_zoned(struct inode *inode, u64 file_offset,
>> {
>>        struct btrfs_ordered_extent *ordered;
>>        struct bio_vec bvec = bio_iovec(bio);
>> -       u64 physical = ((u64)bio->bi_iter.bi_sector << SECTOR_SHIFT) +
>> -               bvec.bv_offset;
>> +       u64 physical = (u64)bio->bi_iter.bi_sector << SECTOR_SHIFT;
>>
>>        if (bio_op(bio) != REQ_OP_ZONE_APPEND)
>>                return;
>>