Remapping an extent involves unmapping the existing extent and mapping
in the new extent. When unmapping, an extent containing the entire unmap
range can be split into two extents,
i.e. | Old extent | hole | Old extent |
Hence extent count increases by 1.
Mapping in the new extent into the destination file can increase the
extent count by 1.
Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Signed-off-by: Chandan Babu R <chandanrlinux@xxxxxxxxx>
---
fs/xfs/libxfs/xfs_inode_fork.h | 15 +++++++++++++++
fs/xfs/xfs_reflink.c | 5 +++++
2 files changed, 20 insertions(+)
diff --git a/fs/xfs/libxfs/xfs_inode_fork.h b/fs/xfs/libxfs/xfs_inode_fork.h
index b99e67e7b59b..ded3c1b56c94 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.h
+++ b/fs/xfs/libxfs/xfs_inode_fork.h
@@ -87,6 +87,21 @@ struct xfs_ifork {
*/
#define XFS_IEXT_REFLINK_END_COW_CNT (2)
+/*
+ * Remapping an extent involves unmapping the existing extent and mapping in the
+ * new extent.
+ *
+ * When unmapping, an extent containing the entire unmap range can be split into
+ * two extents,
+ * i.e. | Old extent | hole | Old extent |
+ * Hence extent count increases by 1.
+ *
+ * Mapping in the new extent into the destination file can increase the extent
+ * count by 1.
+ */
+#define XFS_IEXT_REFLINK_REMAP_CNT(smap_real, dmap_written) \
+ (((smap_real) ? 1 : 0) + ((dmap_written) ? 1 : 0))
+
/*
* Fork handling.
*/
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 4f0198f636ad..c9f9ff68b5bb 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -1099,6 +1099,11 @@ xfs_reflink_remap_extent(
goto out_cancel;
}
+ error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
+ XFS_IEXT_REFLINK_REMAP_CNT(smap_real, dmap_written));
+ if (error)
+ goto out_cancel;
+
if (smap_real) {
/*
* If the extent we're unmapping is backed by storage (written
--
2.28.0
