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authorDarrick J. Wong <darrick.wong@oracle.com>2016-10-20 15:51:50 +1100
committerDave Chinner <david@fromorbit.com>2016-10-20 15:51:50 +1100
commit0a0af28cad9a43d90f13c2047bd8ee3d4cffb7f3 (patch)
tree998058c14e75c6b7136fb35c7ea3a57bb0d4bd62 /fs
parentd33fd776f992332be110f6ceca6dad60cb5d513f (diff)
xfs: add xfs_trim_extent
This helpers allows to trim an extent to a subset of it's original range while making sure the block numbers in it remain valid, In the future xfs_trim_extent and xfs_bmapi_trim_map should probably be merged in some form. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> [hch: split from a previous patch from Darrick, moved around and added support for "raw" delayed extents"] Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/xfs/libxfs/xfs_bmap.c33
-rw-r--r--fs/xfs/libxfs/xfs_bmap.h2
2 files changed, 35 insertions, 0 deletions
diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 80bdb11ca6bf..381e7659598c 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -3996,6 +3996,39 @@ xfs_bmap_alloc(
return xfs_bmap_btalloc(ap);
}
+/* Trim extent to fit a logical block range. */
+void
+xfs_trim_extent(
+ struct xfs_bmbt_irec *irec,
+ xfs_fileoff_t bno,
+ xfs_filblks_t len)
+{
+ xfs_fileoff_t distance;
+ xfs_fileoff_t end = bno + len;
+
+ if (irec->br_startoff + irec->br_blockcount <= bno ||
+ irec->br_startoff >= end) {
+ irec->br_blockcount = 0;
+ return;
+ }
+
+ if (irec->br_startoff < bno) {
+ distance = bno - irec->br_startoff;
+ if (isnullstartblock(irec->br_startblock))
+ irec->br_startblock = DELAYSTARTBLOCK;
+ if (irec->br_startblock != DELAYSTARTBLOCK &&
+ irec->br_startblock != HOLESTARTBLOCK)
+ irec->br_startblock += distance;
+ irec->br_startoff += distance;
+ irec->br_blockcount -= distance;
+ }
+
+ if (end < irec->br_startoff + irec->br_blockcount) {
+ distance = irec->br_startoff + irec->br_blockcount - end;
+ irec->br_blockcount -= distance;
+ }
+}
+
/*
* Trim the returned map to the required bounds
*/
diff --git a/fs/xfs/libxfs/xfs_bmap.h b/fs/xfs/libxfs/xfs_bmap.h
index f97db7132564..eb86af0c988b 100644
--- a/fs/xfs/libxfs/xfs_bmap.h
+++ b/fs/xfs/libxfs/xfs_bmap.h
@@ -190,6 +190,8 @@ void xfs_bmap_trace_exlist(struct xfs_inode *ip, xfs_extnum_t cnt,
#define XFS_BMAP_TRACE_EXLIST(ip,c,w)
#endif
+void xfs_trim_extent(struct xfs_bmbt_irec *irec, xfs_fileoff_t bno,
+ xfs_filblks_t len);
int xfs_bmap_add_attrfork(struct xfs_inode *ip, int size, int rsvd);
void xfs_bmap_local_to_extents_empty(struct xfs_inode *ip, int whichfork);
void xfs_bmap_add_free(struct xfs_mount *mp, struct xfs_defer_ops *dfops,