diff mbox series

[8/9] xfs_scrub: request fewer bmaps when we can

Message ID 157177007451.1459098.7077839567802348147.stgit@magnolia (mailing list archive)
State Accepted
Headers show
Series xfs_scrub: fix IO error reporting | expand

Commit Message

Darrick J. Wong Oct. 22, 2019, 6:47 p.m. UTC 
From: Darrick J. Wong <darrick.wong@oracle.com>

In xfs_iterate_filemaps, we query the number of bmaps for a given file
that we're going to iterate, so feed that information to bmap so that
the kernel won't waste time allocating in-kernel memory unnecessarily.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 scrub/filemap.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

Comments

Eric Sandeen Nov. 1, 2019, 8:31 p.m. UTC | #1 
On 10/22/19 1:47 PM, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> In xfs_iterate_filemaps, we query the number of bmaps for a given file
> that we're going to iterate, so feed that information to bmap so that
> the kernel won't waste time allocating in-kernel memory unnecessarily.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Reviewed-by: Eric Sandeen <sandeen@redhat.com>
diff mbox series

Patch

diff --git a/scrub/filemap.c b/scrub/filemap.c
index bdc6d8f9..f92e9620 100644
--- a/scrub/filemap.c
+++ b/scrub/filemap.c
@@ -71,7 +71,6 @@  xfs_iterate_filemaps(
 		map->bmv_length = ULLONG_MAX;
 	else
 		map->bmv_length = BTOBB(key->bm_length);
-	map->bmv_count = BMAP_NR;
 	map->bmv_iflags = BMV_IF_NO_DMAPI_READ | BMV_IF_PREALLOC |
 			  BMV_IF_NO_HOLES;
 	switch (whichfork) {
@@ -97,6 +96,13 @@  xfs_iterate_filemaps(
 		goto out;
 	}
 
+	if (fsx.fsx_nextents == 0) {
+		moveon = true;
+		goto out;
+	}
+
+	map->bmv_count = min(fsx.fsx_nextents + 1, BMAP_NR);
+
 	while ((error = ioctl(fd, XFS_IOC_GETBMAPX, map)) == 0) {
 		for (i = 0, p = &map[i + 1]; i < map->bmv_entries; i++, p++) {
 			bmap.bm_offset = BBTOB(p->bmv_offset);