From: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
To: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org
Cc: Ojaswin Mujoo <ojaswin@linux.ibm.com>, Jan Kara <jack@suse.cz>,
Theodore Ts'o <tytso@mit.edu>,
Matthew Wilcox <willy@infradead.org>,
"Darrick J . Wong" <djwong@kernel.org>,
Luis Chamberlain <mcgrof@kernel.org>,
John Garry <john.g.garry@oracle.com>,
linux-kernel@vger.kernel.org,
"Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Subject: [RFC 4/8] ext4: Add statx and other atomic write helper routines
Date: Sat, 2 Mar 2024 13:12:01 +0530 [thread overview]
Message-ID: <9def15d6ffb88f7352713c65292513fab532112a.1709361537.git.ritesh.list@gmail.com> (raw)
In-Reply-To: <555cc3e262efa77ee5648196362f415a1efc018d.1709361537.git.ritesh.list@gmail.com>
This patch adds the statx (STATX_WRITE_ATOMIC) support in ext4_getattr()
to query for atomic_write_unit_min(awu_min), awu_max and other
attributes for atomic writes.
This adds a new runtime mount flag (EXT4_MF_ATOMIC_WRITE_FSAWU),
for querying whether ext4 supports atomic write using fsawu
(filesystem atomic write unit).
Co-developed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
---
fs/ext4/ext4.h | 53 ++++++++++++++++++++++++++++++++++++++++++++++++-
fs/ext4/inode.c | 16 +++++++++++++++
2 files changed, 68 insertions(+), 1 deletion(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 023571f8dd1b..1d2bce26e616 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1817,7 +1817,8 @@ static inline int ext4_valid_inum(struct super_block *sb, unsigned long ino)
*/
enum {
EXT4_MF_MNTDIR_SAMPLED,
- EXT4_MF_FC_INELIGIBLE /* Fast commit ineligible */
+ EXT4_MF_FC_INELIGIBLE, /* Fast commit ineligible */
+ EXT4_MF_ATOMIC_WRITE_FSAWU /* Atomic write via FSAWU */
};
static inline void ext4_set_mount_flag(struct super_block *sb, int bit)
@@ -3839,6 +3840,56 @@ static inline int ext4_buffer_uptodate(struct buffer_head *bh)
return buffer_uptodate(bh);
}
+#define ext4_can_atomic_write_fsawu(sb) \
+ ext4_test_mount_flag(sb, EXT4_MF_ATOMIC_WRITE_FSAWU)
+
+/**
+ * ext4_atomic_write_fsawu Returns EXT4 filesystem atomic write unit.
+ * @sb super_block
+ * This returns the filesystem min|max atomic write units.
+ * For !bigalloc it is filesystem blocksize (fsawu_min)
+ * For bigalloc it should be either blocksize or multiple of blocksize
+ * (fsawu_min)
+ */
+static inline void ext4_atomic_write_fsawu(struct super_block *sb,
+ unsigned int *fsawu_min,
+ unsigned int *fsawu_max)
+{
+ u8 blkbits = sb->s_blocksize_bits;
+ unsigned int blocksize = 1U << blkbits;
+ unsigned int clustersize = blocksize;
+ struct block_device *bdev = sb->s_bdev;
+ unsigned int awu_min =
+ queue_atomic_write_unit_min_bytes(bdev->bd_queue);
+ unsigned int awu_max =
+ queue_atomic_write_unit_max_bytes(bdev->bd_queue);
+
+ if (ext4_has_feature_bigalloc(sb))
+ clustersize = 1U << (EXT4_SB(sb)->s_cluster_bits + blkbits);
+
+ /* fs min|max should respect awu_[min|max] units */
+ if (unlikely(awu_min > clustersize || awu_max < blocksize))
+ goto not_supported;
+
+ /* in case of !bigalloc fsawu_[min|max] should be same as blocksize */
+ if (!ext4_has_feature_bigalloc(sb)) {
+ *fsawu_min = blocksize;
+ *fsawu_max = blocksize;
+ return;
+ }
+
+ /* bigalloc can support write in blocksize units. So advertize it */
+ *fsawu_min = max(blocksize, awu_min);
+ *fsawu_max = min(clustersize, awu_max);
+
+ /* This should never happen, but let's keep a WARN_ON_ONCE */
+ WARN_ON_ONCE(!IS_ALIGNED(clustersize, *fsawu_min));
+ return;
+not_supported:
+ *fsawu_min = 0;
+ *fsawu_max = 0;
+}
+
#endif /* __KERNEL__ */
#define EFSBADCRC EBADMSG /* Bad CRC detected */
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 2ccf3b5e3a7c..ea009ca9085d 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5536,6 +5536,22 @@ int ext4_getattr(struct mnt_idmap *idmap, const struct path *path,
}
}
+ if (request_mask & STATX_WRITE_ATOMIC) {
+ unsigned int fsawu_min = 0, fsawu_max = 0;
+
+ /*
+ * Get fsawu_[min|max] value which we can advertise to userspace
+ * in statx call, if we support atomic writes using
+ * EXT4_MF_ATOMIC_WRITE_FSAWU.
+ */
+ if (ext4_can_atomic_write_fsawu(inode->i_sb)) {
+ ext4_atomic_write_fsawu(inode->i_sb, &fsawu_min,
+ &fsawu_max);
+ }
+
+ generic_fill_statx_atomic_writes(stat, fsawu_min, fsawu_max);
+ }
+
flags = ei->i_flags & EXT4_FL_USER_VISIBLE;
if (flags & EXT4_APPEND_FL)
stat->attributes |= STATX_ATTR_APPEND;
--
2.43.0
next prev parent reply other threads:[~2024-03-02 7:42 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-02 7:41 [RFC 0/9] ext4: Add direct-io atomic write support using fsawu Ritesh Harjani (IBM)
2024-03-02 7:41 ` [RFC 1/8] fs: Add FS_XFLAG_ATOMICWRITES flag Ritesh Harjani (IBM)
2024-03-02 7:41 ` [RFC 2/8] fs: Reserve inode flag FS_ATOMICWRITES_FL for atomic writes Ritesh Harjani (IBM)
2024-03-04 0:59 ` Dave Chinner
2024-03-08 7:19 ` Ojaswin Mujoo
2024-03-02 7:42 ` [RFC 3/8] iomap: Add atomic write support for direct-io Ritesh Harjani (IBM)
2024-03-04 1:16 ` Dave Chinner
2024-03-04 5:33 ` Ritesh Harjani
2024-03-04 8:49 ` John Garry
2024-03-04 10:31 ` Ritesh Harjani
2024-03-04 20:56 ` Dave Chinner
2024-03-02 7:42 ` Ritesh Harjani (IBM) [this message]
2024-03-06 11:14 ` [RFC 4/8] ext4: Add statx and other atomic write helper routines John Garry
2024-03-08 8:10 ` Ritesh Harjani
2024-03-02 7:42 ` [RFC 5/8] ext4: Adds direct-io atomic writes checks Ritesh Harjani (IBM)
2024-03-02 7:42 ` [RFC 6/8] ext4: Add an inode flag for atomic writes Ritesh Harjani (IBM)
2024-03-04 20:34 ` Dave Chinner
2024-03-08 8:02 ` Ritesh Harjani
2024-03-02 7:42 ` [RFC 7/8] ext4: Enable FMODE_CAN_ATOMIC_WRITE in open for direct-io Ritesh Harjani (IBM)
2024-03-02 7:42 ` [RFC 8/8] ext4: Adds atomic writes using fsawu Ritesh Harjani (IBM)
2024-03-02 7:42 ` [RFC 9/9] e2fsprogs/chattr: Supports atomic writes attribute Ritesh Harjani (IBM)
2024-03-06 11:22 ` [RFC 0/9] ext4: Add direct-io atomic write support using fsawu John Garry
2024-03-06 13:13 ` Ritesh Harjani
2024-03-08 20:25 ` [RFC] ext4: Add support for ext4_map_blocks_atomic() Ritesh Harjani (IBM)
2024-03-09 2:37 ` Ritesh Harjani
2024-03-13 18:40 ` John Garry
2024-03-14 15:52 ` Ritesh Harjani
2024-03-18 8:22 ` John Garry
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