[PATCH 2/3] btrfs-progs: lowmem: check symlinks with append/immutable flags

[Su Yue <suy.fnst@cn.fujitsu.com>]

Symlinks should never have append/immutable flags.
While checking inodes, if found a symlink with append/immutable
flags, report and record the fatal error.

This is for lowmem mode.

Signed-off-by: Su Yue <suy.fnst@cn.fujitsu.com>
---
 check/mode-lowmem.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/check/mode-lowmem.c b/check/mode-lowmem.c
index 9890180d1d3c..61c4e7f23d47 100644
--- a/check/mode-lowmem.c
+++ b/check/mode-lowmem.c
@@ -2274,6 +2274,7 @@ static int check_inode_item(struct btrfs_root *root, struct btrfs_path *path)
 	struct btrfs_key last_key;
 	u64 inode_id;
 	u32 mode;
+	u64 flags;
 	u64 nlink;
 	u64 nbytes;
 	u64 isize;
@@ -2307,10 +2308,19 @@ static int check_inode_item(struct btrfs_root *root, struct btrfs_path *path)
 	isize = btrfs_inode_size(node, ii);
 	nbytes = btrfs_inode_nbytes(node, ii);
 	mode = btrfs_inode_mode(node, ii);
+	flags = btrfs_inode_flags(node, ii);
 	dir = imode_to_type(mode) == BTRFS_FT_DIR;
 	nlink = btrfs_inode_nlink(node, ii);
 	nodatasum = btrfs_inode_flags(node, ii) & BTRFS_INODE_NODATASUM;
 
+	if (mode & BTRFS_FT_SYMLINK &&
+	    (flags & (BTRFS_INODE_IMMUTABLE | BTRFS_INODE_APPEND))) {
+		err = FATAL_ERROR;
+		error(
+"symlinks shall never be with immutable/append, root %llu inode item [%llu] flags %llu may be corrupted",
+		      root->objectid, inode_id, flags);
+	}
+
 	while (1) {
 		btrfs_item_key_to_cpu(path->nodes[0], &last_key, path->slots[0]);
 		ret = btrfs_next_item(root, path);
-- 
2.17.0