From fd9f8f085a8e22454b2ca5e1a409db8c693fd589 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Tue, 3 Sep 2024 16:13:38 +0930 Subject: [PATCH] btrfs-progs: check/original: detect invalid file extent items for symbolic links [BUG] There is a recent bug that btrfs/012 fails and kernel rejects to read a symbolic link which is backed by a regular extent. Furthremore in that case, "btrfs check" doesn't detect such problem at all. [CAUSE] For symbolic links, we only allow inline file extents, and this means we should only have a symbolic link target which is smaller than 4K. But btrfs check doesn't handle symbolic link inodes any differently, thus it doesn't check if the file extents are inlined or not, nor reporting this problem as an error. [FIX] When processing data extents, if we find the owning inode is a symbolic link, and the file extent is regular/preallocated, mark the inode with I_ERR_FILE_EXTENT_TOO_LARGE error. Signed-off-by: Qu Wenruo --- check/main.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/check/main.c b/check/main.c index 447a03f9..28a1aeca 100644 --- a/check/main.c +++ b/check/main.c @@ -1745,6 +1745,13 @@ static int process_file_extent(struct btrfs_root *root, rec->errors |= I_ERR_BAD_FILE_EXTENT; if (disk_bytenr > 0) rec->found_size += num_bytes; + /* + * Symbolic links should only have inlined extents. + * A regular extent means it's already too large to + * be inlined. + */ + if (S_ISLNK(rec->imode)) + rec->errors |= I_ERR_FILE_EXTENT_TOO_LARGE; } else { rec->errors |= I_ERR_BAD_FILE_EXTENT; }