[V2,07/10] xfs: Check for extent overflow when inserting a hole
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Message ID 20200814080833.84760-8-chandanrlinux@gmail.com
State Superseded
Headers show
Series
  • Bail out if transaction can cause extent count to overflow
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Commit Message

Chandan Babu R Aug. 14, 2020, 8:08 a.m. UTC
The extent mapping the file offset at which a hole has to be
inserted will be split into two extents causing extent count to
increase by 1.

Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
---
 fs/xfs/libxfs/xfs_inode_fork.h | 6 ++++++
 fs/xfs/xfs_bmap_util.c         | 9 +++++++++
 2 files changed, 15 insertions(+)

Patch
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diff --git a/fs/xfs/libxfs/xfs_inode_fork.h b/fs/xfs/libxfs/xfs_inode_fork.h
index a929fa094cf6..63f83a13e0a8 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.h
+++ b/fs/xfs/libxfs/xfs_inode_fork.h
@@ -70,6 +70,12 @@  struct xfs_ifork {
  * Hence extent count can increase by 2.
  */
 #define XFS_IEXT_WRITE_UNWRITTEN_CNT 2
+/*
+ * The extent mapping the file offset at which a hole has to be
+ * inserted will be split into two extents causing extent count to
+ * increase by 1.
+ */
+#define XFS_IEXT_INSERT_HOLE_CNT 1
 
 /*
  * Fork handling.
diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index 94abdb547c7f..f6352b5e5552 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -1165,6 +1165,15 @@  xfs_insert_file_space(
 	xfs_ilock(ip, XFS_ILOCK_EXCL);
 	xfs_trans_ijoin(tp, ip, 0);
 
+	/*
+	 * Splitting the extent mapping containing stop_fsb will cause
+	 * extent count to increase by 1.
+	 */
+	error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
+			XFS_IEXT_INSERT_HOLE_CNT);
+	if (error)
+		goto out_trans_cancel;
+
 	/*
 	 * The extent shifting code works on extent granularity. So, if stop_fsb
 	 * is not the starting block of extent, we need to split the extent at