[PATCH AUTOSEL 5.7 067/274] btrfs: account for trans_block_rsv in may_commit_transaction

[PATCH AUTOSEL 5.7 067/274] btrfs: account for trans_block_rsv in may_commit_transaction

[Sasha Levin]

From: Josef Bacik <josef@toxicpanda.com>

[ Upstream commit bb4f58a747f0421b10645fbf75a6acc88da0de50 ]

On ppc64le with 64k page size (respectively 64k block size) generic/320
was failing and debug output showed we were getting a premature ENOSPC
with a bunch of space in btrfs_fs_info::trans_block_rsv.

This meant there were still open transaction handles holding space, yet
the flusher didn't commit the transaction because it deemed the freed
space won't be enough to satisfy the current reserve ticket. Fix this
by accounting for space in trans_block_rsv when deciding whether the
current transaction should be committed or not.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/btrfs/space-info.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c
index ff17a4420358..3c0e9999bfd7 100644
--- a/fs/btrfs/space-info.c
+++ b/fs/btrfs/space-info.c
@@ -626,6 +626,7 @@ static int may_commit_transaction(struct btrfs_fs_info *fs_info,
 	struct reserve_ticket *ticket = NULL;
 	struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_block_rsv;
 	struct btrfs_block_rsv *delayed_refs_rsv = &fs_info->delayed_refs_rsv;
+	struct btrfs_block_rsv *trans_rsv = &fs_info->trans_block_rsv;
 	struct btrfs_trans_handle *trans;
 	u64 bytes_needed;
 	u64 reclaim_bytes = 0;
@@ -688,6 +689,11 @@ static int may_commit_transaction(struct btrfs_fs_info *fs_info,
 	spin_lock(&delayed_refs_rsv->lock);
 	reclaim_bytes += delayed_refs_rsv->reserved;
 	spin_unlock(&delayed_refs_rsv->lock);
+
+	spin_lock(&trans_rsv->lock);
+	reclaim_bytes += trans_rsv->reserved;
+	spin_unlock(&trans_rsv->lock);
+
 	if (reclaim_bytes >= bytes_needed)
 		goto commit;
 	bytes_needed -= reclaim_bytes;
-- 
2.25.1

[PATCH AUTOSEL 5.7 068/274] btrfs: do not ignore error from btrfs_next_leaf() when inserting checksums

[Sasha Levin]

From: Filipe Manana <fdmanana@suse.com>

[ Upstream commit 7e4a3f7ed5d54926ec671bbb13e171cfe179cc50 ]

We are currently treating any non-zero return value from btrfs_next_leaf()
the same way, by going to the code that inserts a new checksum item in the
tree. However if btrfs_next_leaf() returns an error (a value < 0), we
should just stop and return the error, and not behave as if nothing has
happened, since in that case we do not have a way to know if there is a
next leaf or we are currently at the last leaf already.

So fix that by returning the error from btrfs_next_leaf().

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/btrfs/file-item.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index b618ad5339ba..a88a8bf4b12c 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -887,10 +887,12 @@ int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
 		nritems = btrfs_header_nritems(path->nodes[0]);
 		if (!nritems || (path->slots[0] >= nritems - 1)) {
 			ret = btrfs_next_leaf(root, path);
-			if (ret == 1)
+			if (ret < 0) {
+				goto out;
+			} else if (ret > 0) {
 				found_next = 1;
-			if (ret != 0)
 				goto insert;
+			}
 			slot = path->slots[0];
 		}
 		btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
-- 
2.25.1

[PATCH AUTOSEL 5.7 232/274] btrfs: improve global reserve stealing logic

[Sasha Levin]

From: Josef Bacik <josef@toxicpanda.com>

[ Upstream commit 7f9fe614407692f670601a634621138233ac00d7 ]

For unlink transactions and block group removal
btrfs_start_transaction_fallback_global_rsv will first try to start an
ordinary transaction and if it fails it will fall back to reserving the
required amount by stealing from the global reserve. This is problematic
because of all the same reasons we had with previous iterations of the
ENOSPC handling, thundering herd.  We get a bunch of failures all at
once, everybody tries to allocate from the global reserve, some win and
some lose, we get an ENSOPC.

Fix this behavior by introducing BTRFS_RESERVE_FLUSH_ALL_STEAL. It's
used to mark unlink reservation. To fix this we need to integrate this
logic into the normal ENOSPC infrastructure.  We still go through all of
the normal flushing work, and at the moment we begin to fail all the
tickets we try to satisfy any tickets that are allowed to steal by
stealing from the global reserve.  If this works we start the flushing
system over again just like we would with a normal ticket satisfaction.
This serializes our global reserve stealing, so we don't have the
thundering herd problem.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/btrfs/block-group.c |  2 +-
 fs/btrfs/ctree.h       |  1 +
 fs/btrfs/inode.c       |  2 +-
 fs/btrfs/space-info.c  | 37 ++++++++++++++++++++++++++++++++++++-
 fs/btrfs/space-info.h  |  1 +
 fs/btrfs/transaction.c | 42 +++++-------------------------------------
 fs/btrfs/transaction.h |  3 +--
 7 files changed, 46 insertions(+), 42 deletions(-)

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 696f47103cfc..233c5663f233 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -1175,7 +1175,7 @@ struct btrfs_trans_handle *btrfs_start_trans_remove_block_group(
 	free_extent_map(em);
 
 	return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
-							   num_items, 1);
+							   num_items);
 }
 
 /*
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 8aa7b9dac405..3510e33706c1 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2512,6 +2512,7 @@ enum btrfs_reserve_flush_enum {
 	BTRFS_RESERVE_FLUSH_LIMIT,
 	BTRFS_RESERVE_FLUSH_EVICT,
 	BTRFS_RESERVE_FLUSH_ALL,
+	BTRFS_RESERVE_FLUSH_ALL_STEAL,
 };
 
 enum btrfs_flush_state {
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 320d1062068d..259239b33370 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3618,7 +3618,7 @@ static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir)
 	 * 1 for the inode ref
 	 * 1 for the inode
 	 */
-	return btrfs_start_transaction_fallback_global_rsv(root, 5, 5);
+	return btrfs_start_transaction_fallback_global_rsv(root, 5);
 }
 
 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c
index 3c0e9999bfd7..eee6748c49e4 100644
--- a/fs/btrfs/space-info.c
+++ b/fs/btrfs/space-info.c
@@ -862,6 +862,34 @@ static inline int need_do_async_reclaim(struct btrfs_fs_info *fs_info,
 		!test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state));
 }
 
+static bool steal_from_global_rsv(struct btrfs_fs_info *fs_info,
+				  struct btrfs_space_info *space_info,
+				  struct reserve_ticket *ticket)
+{
+	struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
+	u64 min_bytes;
+
+	if (global_rsv->space_info != space_info)
+		return false;
+
+	spin_lock(&global_rsv->lock);
+	min_bytes = div_factor(global_rsv->size, 5);
+	if (global_rsv->reserved < min_bytes + ticket->bytes) {
+		spin_unlock(&global_rsv->lock);
+		return false;
+	}
+	global_rsv->reserved -= ticket->bytes;
+	ticket->bytes = 0;
+	list_del_init(&ticket->list);
+	wake_up(&ticket->wait);
+	space_info->tickets_id++;
+	if (global_rsv->reserved < global_rsv->size)
+		global_rsv->full = 0;
+	spin_unlock(&global_rsv->lock);
+
+	return true;
+}
+
 /*
  * maybe_fail_all_tickets - we've exhausted our flushing, start failing tickets
  * @fs_info - fs_info for this fs
@@ -894,6 +922,10 @@ static bool maybe_fail_all_tickets(struct btrfs_fs_info *fs_info,
 		ticket = list_first_entry(&space_info->tickets,
 					  struct reserve_ticket, list);
 
+		if (ticket->steal &&
+		    steal_from_global_rsv(fs_info, space_info, ticket))
+			return true;
+
 		/*
 		 * may_commit_transaction will avoid committing the transaction
 		 * if it doesn't feel like the space reclaimed by the commit
@@ -1110,6 +1142,7 @@ static int handle_reserve_ticket(struct btrfs_fs_info *fs_info,
 
 	switch (flush) {
 	case BTRFS_RESERVE_FLUSH_ALL:
+	case BTRFS_RESERVE_FLUSH_ALL_STEAL:
 		wait_reserve_ticket(fs_info, space_info, ticket);
 		break;
 	case BTRFS_RESERVE_FLUSH_LIMIT:
@@ -1209,7 +1242,9 @@ static int __reserve_metadata_bytes(struct btrfs_fs_info *fs_info,
 		ticket.error = 0;
 		space_info->reclaim_size += ticket.bytes;
 		init_waitqueue_head(&ticket.wait);
-		if (flush == BTRFS_RESERVE_FLUSH_ALL) {
+		ticket.steal = (flush == BTRFS_RESERVE_FLUSH_ALL_STEAL);
+		if (flush == BTRFS_RESERVE_FLUSH_ALL ||
+		    flush == BTRFS_RESERVE_FLUSH_ALL_STEAL) {
 			list_add_tail(&ticket.list, &space_info->tickets);
 			if (!space_info->flush) {
 				space_info->flush = 1;
diff --git a/fs/btrfs/space-info.h b/fs/btrfs/space-info.h
index 0a5001ef1481..c3c64019950a 100644
--- a/fs/btrfs/space-info.h
+++ b/fs/btrfs/space-info.h
@@ -78,6 +78,7 @@ struct btrfs_space_info {
 struct reserve_ticket {
 	u64 bytes;
 	int error;
+	bool steal;
 	struct list_head list;
 	wait_queue_head_t wait;
 };
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 2d5498136e5e..b5da5d8342dc 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -563,7 +563,8 @@ start_transaction(struct btrfs_root *root, unsigned int num_items,
 		 * refill that amount for whatever is missing in the reserve.
 		 */
 		num_bytes = btrfs_calc_insert_metadata_size(fs_info, num_items);
-		if (delayed_refs_rsv->full == 0) {
+		if (flush == BTRFS_RESERVE_FLUSH_ALL &&
+		    delayed_refs_rsv->full == 0) {
 			delayed_refs_bytes = num_bytes;
 			num_bytes <<= 1;
 		}
@@ -699,43 +700,10 @@ struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
 
 struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv(
 					struct btrfs_root *root,
-					unsigned int num_items,
-					int min_factor)
+					unsigned int num_items)
 {
-	struct btrfs_fs_info *fs_info = root->fs_info;
-	struct btrfs_trans_handle *trans;
-	u64 num_bytes;
-	int ret;
-
-	/*
-	 * We have two callers: unlink and block group removal.  The
-	 * former should succeed even if we will temporarily exceed
-	 * quota and the latter operates on the extent root so
-	 * qgroup enforcement is ignored anyway.
-	 */
-	trans = start_transaction(root, num_items, TRANS_START,
-				  BTRFS_RESERVE_FLUSH_ALL, false);
-	if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
-		return trans;
-
-	trans = btrfs_start_transaction(root, 0);
-	if (IS_ERR(trans))
-		return trans;
-
-	num_bytes = btrfs_calc_insert_metadata_size(fs_info, num_items);
-	ret = btrfs_cond_migrate_bytes(fs_info, &fs_info->trans_block_rsv,
-				       num_bytes, min_factor);
-	if (ret) {
-		btrfs_end_transaction(trans);
-		return ERR_PTR(ret);
-	}
-
-	trans->block_rsv = &fs_info->trans_block_rsv;
-	trans->bytes_reserved = num_bytes;
-	trace_btrfs_space_reservation(fs_info, "transaction",
-				      trans->transid, num_bytes, 1);
-
-	return trans;
+	return start_transaction(root, num_items, TRANS_START,
+				 BTRFS_RESERVE_FLUSH_ALL_STEAL, false);
 }
 
 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h
index 31ae8d273065..bf102e64bfb2 100644
--- a/fs/btrfs/transaction.h
+++ b/fs/btrfs/transaction.h
@@ -193,8 +193,7 @@ struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
 						   unsigned int num_items);
 struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv(
 					struct btrfs_root *root,
-					unsigned int num_items,
-					int min_factor);
+					unsigned int num_items);
 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root);
 struct btrfs_trans_handle *btrfs_join_transaction_spacecache(struct btrfs_root *root);
 struct btrfs_trans_handle *btrfs_join_transaction_nostart(struct btrfs_root *root);
-- 
2.25.1

[PATCH AUTOSEL 5.7 233/274] btrfs: qgroup: mark qgroup inconsistent if we're inherting snapshot to a new qgroup

[Sasha Levin]

From: Qu Wenruo <wqu@suse.com>

[ Upstream commit cbab8ade585a18c4334b085564d9d046e01a3f70 ]

[BUG]
For the following operation, qgroup is guaranteed to be screwed up due
to snapshot adding to a new qgroup:

  # mkfs.btrfs -f $dev
  # mount $dev $mnt
  # btrfs qgroup en $mnt
  # btrfs subv create $mnt/src
  # xfs_io -f -c "pwrite 0 1m" $mnt/src/file
  # sync
  # btrfs qgroup create 1/0 $mnt/src
  # btrfs subv snapshot -i 1/0 $mnt/src $mnt/snapshot
  # btrfs qgroup show -prce $mnt/src
  qgroupid         rfer         excl     max_rfer     max_excl parent  child
  --------         ----         ----     --------     -------- ------  -----
  0/5          16.00KiB     16.00KiB         none         none ---     ---
  0/257         1.02MiB     16.00KiB         none         none ---     ---
  0/258         1.02MiB     16.00KiB         none         none 1/0     ---
  1/0             0.00B        0.00B         none         none ---     0/258
	        ^^^^^^^^^^^^^^^^^^^^

[CAUSE]
The problem is in btrfs_qgroup_inherit(), we don't have good enough
check to determine if the new relation would break the existing
accounting.

Unlike btrfs_add_qgroup_relation(), which has proper check to determine
if we can do quick update without a rescan, in btrfs_qgroup_inherit() we
can even assign a snapshot to multiple qgroups.

[FIX]
Fix it by manually marking qgroup inconsistent for snapshot inheritance.

For subvolume creation, since all its extents are exclusively owned, we
don't need to rescan.

In theory, we should call relation check like quick_update_accounting()
when doing qgroup inheritance and inform user about qgroup accounting
inconsistency.

But we don't have good mechanism to relay that back to the user in the
snapshot creation context, thus we can only silently mark the qgroup
inconsistent.

Anyway, user shouldn't use qgroup inheritance during snapshot creation,
and should add qgroup relationship after snapshot creation by 'btrfs
qgroup assign', which has a much better UI to inform user about qgroup
inconsistent and kick in rescan automatically.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/btrfs/qgroup.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index c3888fb367e7..5bd4089ad0e1 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -2622,6 +2622,7 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid,
 	struct btrfs_root *quota_root;
 	struct btrfs_qgroup *srcgroup;
 	struct btrfs_qgroup *dstgroup;
+	bool need_rescan = false;
 	u32 level_size = 0;
 	u64 nums;
 
@@ -2765,6 +2766,13 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid,
 				goto unlock;
 		}
 		++i_qgroups;
+
+		/*
+		 * If we're doing a snapshot, and adding the snapshot to a new
+		 * qgroup, the numbers are guaranteed to be incorrect.
+		 */
+		if (srcid)
+			need_rescan = true;
 	}
 
 	for (i = 0; i <  inherit->num_ref_copies; ++i, i_qgroups += 2) {
@@ -2784,6 +2792,9 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid,
 
 		dst->rfer = src->rfer - level_size;
 		dst->rfer_cmpr = src->rfer_cmpr - level_size;
+
+		/* Manually tweaking numbers certainly needs a rescan */
+		need_rescan = true;
 	}
 	for (i = 0; i <  inherit->num_excl_copies; ++i, i_qgroups += 2) {
 		struct btrfs_qgroup *src;
@@ -2802,6 +2813,7 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid,
 
 		dst->excl = src->excl + level_size;
 		dst->excl_cmpr = src->excl_cmpr + level_size;
+		need_rescan = true;
 	}
 
 unlock:
@@ -2809,6 +2821,8 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid,
 out:
 	if (!committing)
 		mutex_unlock(&fs_info->qgroup_ioctl_lock);
+	if (need_rescan)
+		fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
 	return ret;
 }
 
-- 
2.25.1