xfs: fix potential infinite loop in xfs_iomap_prealloc_size()
If freesp == 0, we could end up in an infinite loop while squashing
the preallocation. Break the loop when we've killed the prealloc
entirely.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
(cherry picked from commit e78c420bfc2608bb5f9a0b9165b1071c1e31166a)
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 912d83d..b0b0f44 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -413,7 +413,7 @@
* have a large file on a small filesystem and the above
* lowspace thresholds are smaller than MAXEXTLEN.
*/
- while (alloc_blocks >= freesp)
+ while (alloc_blocks && alloc_blocks >= freesp)
alloc_blocks >>= 4;
}