[PATCH V5 05/12] xfs: Check for extent overflow when adding/removing dir entries

[Chandan Babu R <chandanrlinux@gmail.com>]

Directory entry addition/removal can cause the following,
1. Data block can be added/removed.
   A new extent can cause extent count to increase by 1.
2. Free disk block can be added/removed.
   Same behaviour as described above for Data block.
3. Dabtree blocks.
   XFS_DA_NODE_MAXDEPTH blocks can be added. Each of these
   can be new extents. Hence extent count can increase by
   XFS_DA_NODE_MAXDEPTH.

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
---
 fs/xfs/libxfs/xfs_inode_fork.h | 13 +++++++++++++
 fs/xfs/xfs_inode.c             | 27 +++++++++++++++++++++++++++
 fs/xfs/xfs_symlink.c           |  5 +++++
 3 files changed, 45 insertions(+)

diff --git a/fs/xfs/libxfs/xfs_inode_fork.h b/fs/xfs/libxfs/xfs_inode_fork.h
index 5de2f07d0dd5..fd93fdc67ee4 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.h
+++ b/fs/xfs/libxfs/xfs_inode_fork.h
@@ -57,6 +57,19 @@ struct xfs_ifork {
 #define XFS_IEXT_ATTR_MANIP_CNT(rmt_blks) \
 	(XFS_DA_NODE_MAXDEPTH + max(1, rmt_blks))
 
+/*
+ * Directory entry addition/removal can cause the following,
+ * 1. Data block can be added/removed.
+ *    A new extent can cause extent count to increase by 1.
+ * 2. Free disk block can be added/removed.
+ *    Same behaviour as described above for Data block.
+ * 3. Dabtree blocks.
+ *    XFS_DA_NODE_MAXDEPTH blocks can be added. Each of these can be new
+ *    extents. Hence extent count can increase by XFS_DA_NODE_MAXDEPTH.
+ */
+#define XFS_IEXT_DIR_MANIP_CNT(mp) \
+	((XFS_DA_NODE_MAXDEPTH + 1 + 1) * (mp)->m_dir_geo->fsbcount)
+
 /*
  * Fork handling.
  */
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 49624973eecc..f347b1911d9c 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -1159,6 +1159,11 @@ xfs_create(
 	if (error)
 		goto out_trans_cancel;
 
+	error = xfs_iext_count_may_overflow(dp, XFS_DATA_FORK,
+			XFS_IEXT_DIR_MANIP_CNT(mp));
+	if (error)
+		goto out_trans_cancel;
+
 	/*
 	 * A newly created regular or special file just has one directory
 	 * entry pointing to them, but a directory also the "." entry
@@ -1375,6 +1380,11 @@ xfs_link(
 	xfs_trans_ijoin(tp, sip, XFS_ILOCK_EXCL);
 	xfs_trans_ijoin(tp, tdp, XFS_ILOCK_EXCL);
 
+	error = xfs_iext_count_may_overflow(tdp, XFS_DATA_FORK,
+			XFS_IEXT_DIR_MANIP_CNT(mp));
+	if (error)
+		goto error_return;
+
 	/*
 	 * If we are using project inheritance, we only allow hard link
 	 * creation in our tree when the project IDs are the same; else
@@ -2850,6 +2860,11 @@ xfs_remove(
 	xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL);
 	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
 
+	error = xfs_iext_count_may_overflow(dp, XFS_DATA_FORK,
+			XFS_IEXT_DIR_MANIP_CNT(mp));
+	if (error)
+		goto out_trans_cancel;
+
 	/*
 	 * If we're removing a directory perform some additional validation.
 	 */
@@ -3210,6 +3225,18 @@ xfs_rename(
 	if (wip)
 		xfs_trans_ijoin(tp, wip, XFS_ILOCK_EXCL);
 
+	error = xfs_iext_count_may_overflow(src_dp, XFS_DATA_FORK,
+			XFS_IEXT_DIR_MANIP_CNT(mp));
+	if (error)
+		goto out_trans_cancel;
+
+	if (target_ip == NULL) {
+		error = xfs_iext_count_may_overflow(target_dp, XFS_DATA_FORK,
+				XFS_IEXT_DIR_MANIP_CNT(mp));
+		if (error)
+			goto out_trans_cancel;
+	}
+
 	/*
 	 * If we are using project inheritance, we only allow renames
 	 * into our tree when the project IDs are the same; else the
diff --git a/fs/xfs/xfs_symlink.c b/fs/xfs/xfs_symlink.c
index 8e88a7ca387e..581a4032a817 100644
--- a/fs/xfs/xfs_symlink.c
+++ b/fs/xfs/xfs_symlink.c
@@ -220,6 +220,11 @@ xfs_symlink(
 	if (error)
 		goto out_trans_cancel;
 
+	error = xfs_iext_count_may_overflow(dp, XFS_DATA_FORK,
+			XFS_IEXT_DIR_MANIP_CNT(mp));
+	if (error)
+		goto out_trans_cancel;
+
 	/*
 	 * Allocate an inode for the symlink.
 	 */
-- 
2.28.0