[PATCH 6.1 010/197] btrfs: reject encoded write if inode has nodatasum flag set

Greg Kroah-Hartman
2024-02-20T20:59:57Z

From: Filipe Manana <fdmanana@suse.com>

commit 1bd96c92c6a0a4d43815eb685c15aa4b78879dc9 upstream.

Currently we allow an encoded write against inodes that have the NODATASUM
flag set, either because they are NOCOW files or they were created while
the filesystem was mounted with "-o nodatasum". This results in having
compressed extents without corresponding checksums, which is a filesystem
inconsistency reported by 'btrfs check'.

For example, running btrfs/281 with MOUNT_OPTIONS="-o nodatacow" triggers
this and 'btrfs check' errors out with:

[1/7] checking root items
[2/7] checking extents
[3/7] checking free space tree
[4/7] checking fs roots
root 256 inode 257 errors 1040, bad file extent, some csum missing
root 256 inode 258 errors 1040, bad file extent, some csum missing
ERROR: errors found in fs roots
(...)

So reject encoded writes if the target inode has NODATASUM set.

CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/btrfs/inode.c | 7 +++++++
1 file changed, 7 insertions(+)

--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -10774,6 +10774,13 @@ ssize_t btrfs_do_encoded_write(struct ki
if (encoded->encryption != BTRFS_ENCODED_IO_ENCRYPTION_NONE)
return -EINVAL;

+ /*
+ * Compressed extents should always have checksums, so error out if we
+ * have a NOCOW file or inode was created while mounted with NODATASUM.
+ */
+ if (inode->flags & BTRFS_INODE_NODATASUM)
+ return -EINVAL;
+
orig_count = iov_iter_count(from);

/* The extent size must be sane. */