summaryrefslogtreecommitdiff
path: root/fs/xfs/xfs_trans_bmap.c
diff options
context:
space:
mode:
authorDarrick J. Wong <darrick.wong@oracle.com>2017-06-15 07:25:57 +0300
committerDarrick J. Wong <darrick.wong@oracle.com>2017-06-19 18:59:10 +0300
commite1a4e37cc7b665b6804fba812aca2f4d7402c249 (patch)
treec00ee8beef512215b72dd24a92f02c37012dcaba /fs/xfs/xfs_trans_bmap.c
parentd205a7d0ec47d11977882b5e910ad35f7be912b4 (diff)
downloadlinux-e1a4e37cc7b665b6804fba812aca2f4d7402c249.tar.xz
xfs: try to avoid blowing out the transaction reservation when bunmaping a shared extent
In a pathological scenario where we are trying to bunmapi a single extent in which every other block is shared, it's possible that trying to unmap the entire large extent in a single transaction can generate so many EFIs that we overflow the transaction reservation. Therefore, use a heuristic to guess at the number of blocks we can safely unmap from a reflink file's data fork in an single transaction. This should prevent problems such as the log head slamming into the tail and ASSERTs that trigger because we've exceeded the transaction reservation. Note that since bunmapi can fail to unmap the entire range, we must also teach the deferred unmap code to roll into a new transaction whenever we get low on reservation. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> [hch: random edits, all bugs are my fault] Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'fs/xfs/xfs_trans_bmap.c')
-rw-r--r--fs/xfs/xfs_trans_bmap.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/fs/xfs/xfs_trans_bmap.c b/fs/xfs/xfs_trans_bmap.c
index 6408e7d7c08c..14543d93cd4b 100644
--- a/fs/xfs/xfs_trans_bmap.c
+++ b/fs/xfs/xfs_trans_bmap.c
@@ -63,7 +63,7 @@ xfs_trans_log_finish_bmap_update(
int whichfork,
xfs_fileoff_t startoff,
xfs_fsblock_t startblock,
- xfs_filblks_t blockcount,
+ xfs_filblks_t *blockcount,
xfs_exntst_t state)
{
int error;
@@ -196,16 +196,23 @@ xfs_bmap_update_finish_item(
void **state)
{
struct xfs_bmap_intent *bmap;
+ xfs_filblks_t count;
int error;
bmap = container_of(item, struct xfs_bmap_intent, bi_list);
+ count = bmap->bi_bmap.br_blockcount;
error = xfs_trans_log_finish_bmap_update(tp, done_item, dop,
bmap->bi_type,
bmap->bi_owner, bmap->bi_whichfork,
bmap->bi_bmap.br_startoff,
bmap->bi_bmap.br_startblock,
- bmap->bi_bmap.br_blockcount,
+ &count,
bmap->bi_bmap.br_state);
+ if (!error && count > 0) {
+ ASSERT(bmap->bi_type == XFS_BMAP_UNMAP);
+ bmap->bi_bmap.br_blockcount = count;
+ return -EAGAIN;
+ }
kmem_free(bmap);
return error;
}