Btrfs: check size of inode backref before adding hardlink
For every hardlink in btrfs, there is a corresponding inode back
reference. All inode back references for hardlinks in a given
directory are stored in single b-tree item. The size of b-tree item
is limited by the size of b-tree leaf, so we can only create limited
number of hardlinks to a given file in a directory.
The original code lacks of the check, it oops if the number of
hardlinks goes over the limit. This patch fixes the issue by adding
check to btrfs_link and btrfs_rename.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/inode-item.c b/fs/btrfs/inode-item.c
index fc6f4a7..72ce3c1 100644
--- a/fs/btrfs/inode-item.c
+++ b/fs/btrfs/inode-item.c
@@ -149,6 +149,8 @@
ptr = (unsigned long)(ref + 1);
ret = 0;
} else if (ret < 0) {
+ if (ret == -EOVERFLOW)
+ ret = -EMLINK;
goto out;
} else {
ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
