[PATCH 3/6] xfs: don't stall cowblocks scan if we can't take locks
From: "Darrick J. Wong" <djwong@kernel.org>
Date: 2021-01-12 00:30:29
Subsystem:
filesystems (vfs and infrastructure), the rest, xfs filesystem · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds, Carlos Maiolino
From: Darrick J. Wong <djwong@kernel.org> Don't stall the cowblocks scan on a locked inode if we possibly can. We'd much rather the background scanner keep moving. Signed-off-by: Darrick J. Wong <djwong@kernel.org> --- fs/xfs/xfs_icache.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-)
diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index 66af84c578b5..4e226827b33d 100644
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c@@ -1624,17 +1624,31 @@ xfs_inode_free_cowblocks( void *args) { struct xfs_eofblocks *eofb = args; + bool wait; int ret = 0; + wait = eofb && (eofb->eof_flags & XFS_EOF_FLAGS_SYNC); + if (!xfs_prep_free_cowblocks(ip)) return 0; if (!xfs_inode_matches_eofb(ip, eofb)) return 0; - /* Free the CoW blocks */ - xfs_ilock(ip, XFS_IOLOCK_EXCL); - xfs_ilock(ip, XFS_MMAPLOCK_EXCL); + /* + * If the caller is waiting, return -EAGAIN to keep the background + * scanner moving and revisit the inode in a subsequent pass. + */ + if (!xfs_ilock_nowait(ip, XFS_IOLOCK_EXCL)) { + if (wait) + return -EAGAIN; + return 0; + } + if (!xfs_ilock_nowait(ip, XFS_MMAPLOCK_EXCL)) { + if (wait) + ret = -EAGAIN; + goto out_iolock; + } /* * Check again, nobody else should be able to dirty blocks or change
@@ -1644,6 +1658,7 @@ xfs_inode_free_cowblocks( ret = xfs_reflink_cancel_cow_range(ip, 0, NULLFILEOFF, false); xfs_iunlock(ip, XFS_MMAPLOCK_EXCL); +out_iolock: xfs_iunlock(ip, XFS_IOLOCK_EXCL); return ret;