diff mbox series

[v15,10/37] xfsprogs: Check for extent overflow when moving extent from cow to data fork

Message ID 20210218164512.4659-11-allison.henderson@oracle.com (mailing list archive)
State Superseded
Headers show
Series xfsprogs: Delayed Attributes | expand

Commit Message

Allison Henderson Feb. 18, 2021, 4:44 p.m. UTC 
From: Chandan Babu R <chandanrlinux@gmail.com>

Source kernel commit: 5f1d5bbfb2e674052a9fe542f53678978af20770

Moving an extent to data fork can cause a sub-interval of an existing
extent to be unmapped. This will increase extent count by 1. Mapping in
the new extent can increase the extent count by 1 again i.e.
| Old extent | New extent | Old extent |
Hence number of extents increases by 2.

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
---
 libxfs/xfs_inode_fork.h | 9 +++++++++
 1 file changed, 9 insertions(+)
diff mbox series

Patch

diff --git a/libxfs/xfs_inode_fork.h b/libxfs/xfs_inode_fork.h
index 917e289..c8f279e 100644
--- a/libxfs/xfs_inode_fork.h
+++ b/libxfs/xfs_inode_fork.h
@@ -80,6 +80,15 @@  struct xfs_ifork {
 
 
 /*
+ * Moving an extent to data fork can cause a sub-interval of an existing extent
+ * to be unmapped. This will increase extent count by 1. Mapping in the new
+ * extent can increase the extent count by 1 again i.e.
+ * | Old extent | New extent | Old extent |
+ * Hence number of extents increases by 2.
+ */
+#define XFS_IEXT_REFLINK_END_COW_CNT	(2)
+
+/*
  * Fork handling.
  */