[PATCH 065/119] xfs: adjust refcount when unmapping file blocks

Darrick J. Wong
2016-06-17T01:24:55Z

When we're unmapping blocks from a reflinked file, decrease the
refcount of the affected blocks and free the extents that are no
longer in use.

v2: Use deferred ops system to avoid deadlocks and running out of
transaction reservation.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/xfs/libxfs/xfs_bmap.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 972dfc2..9044e39 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -48,6 +48,7 @@
#include "xfs_filestream.h"
#include "xfs_rmap_btree.h"
#include "xfs_ag_resv.h"
+#include "xfs_refcount.h"

kmem_zone_t *xfs_bmap_free_item_zone;
@@ -5061,9 +5062,16 @@ xfs_bmap_del_extent(
/*
* If we need to, add to list of extents to delete.
*/
- if (do_fx)
- xfs_bmap_add_free(mp, dfops, del->br_startblock,
- del->br_blockcount, NULL);
+ if (do_fx) {
+ if (xfs_is_reflink_inode(ip) && whichfork == XFS_DATA_FORK) {
+ error = xfs_refcount_decrease_extent(mp, dfops, del);
+ if (error)
+ goto done;
+ } else
+ xfs_bmap_add_free(mp, dfops, del->br_startblock,
+ del->br_blockcount, NULL);
+ }
+
/*
* Adjust inode # blocks in the file.
*/