diff mbox series

[1/2] xfs: don't take m_sb_lock in xfs_fs_statfs

Message ID 20250113043259.2054322-1-hch@lst.de (mailing list archive)
State Accepted, archived
Headers show
Series [1/2] xfs: don't take m_sb_lock in xfs_fs_statfs | expand

Commit Message

Christoph Hellwig Jan. 13, 2025, 4:32 a.m. UTC 
The only non-constant value read under m_sb_lock in xfs_fs_statfs is
sb_dblocks, and it could become stale right after dropping the lock
anyway.  Remove the thus pointless lock section.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
---
 fs/xfs/xfs_super.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Comments

Carlos Maiolino Jan. 14, 2025, 10:30 a.m. UTC | #1 
On Mon, 13 Jan 2025 05:32:58 +0100, Christoph Hellwig wrote:
> The only non-constant value read under m_sb_lock in xfs_fs_statfs is
> sb_dblocks, and it could become stale right after dropping the lock
> anyway.  Remove the thus pointless lock section.
> 
> 

Applied to for-next, thanks!

[1/2] xfs: don't take m_sb_lock in xfs_fs_statfs
      commit: 72843ca62417a0587ca98791b172e4c3b3f8d3a8
[2/2] xfs: refactor xfs_fs_statfs
      commit: dd324cb79e54d3a61621f09c346ee050315a4d2e

Best regards,
diff mbox series

Patch

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 7c3f996cd39e..20cc00b992a6 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -850,11 +850,13 @@  xfs_fs_statfs(
 	ifree = percpu_counter_sum(&mp->m_ifree);
 	fdblocks = percpu_counter_sum(&mp->m_fdblocks);
 
-	spin_lock(&mp->m_sb_lock);
 	statp->f_bsize = sbp->sb_blocksize;
 	lsize = sbp->sb_logstart ? sbp->sb_logblocks : 0;
+	/*
+	 * sb_dblocks can change during growfs, but nothing cares about reporting
+	 * the old or new value during growfs.
+	 */
 	statp->f_blocks = sbp->sb_dblocks - lsize;
-	spin_unlock(&mp->m_sb_lock);
 
 	/* make sure statp->f_bfree does not underflow */
 	statp->f_bfree = max_t(int64_t, 0,