diff mbox series

[02/11] xfs: don't stall cowblocks scan if we can't take locks

Message ID 161100792917.88816.7369361459458348804.stgit@magnolia (mailing list archive)
State Superseded
Headers show
Series xfs: try harder to reclaim space when we run out | expand

Commit Message

Darrick J. Wong Jan. 18, 2021, 10:12 p.m. UTC
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(-)

Comments

Christoph Hellwig Jan. 19, 2021, 6:49 a.m. UTC | #1
On Mon, Jan 18, 2021 at 02:12:09PM -0800, Darrick J. Wong wrote:
> 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>

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>
diff mbox series

Patch

diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index c71eb15e3835..89f9e692fde7 100644
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -1605,17 +1605,31 @@  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
@@ -1625,6 +1639,7 @@  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;