We must lock the xattr block in order to avoid spurious checksum failures. https://bugzilla.kernel.org/show_bug.cgi?id=193661 Reported-by: Colin Ian King <colin.king@xxxxxxxxxxxxx> Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> --- fs/ext4/xattr.c | 31 ++++++++++++++----------------- 1 file changed, 14 insertions(+), 17 deletions(-) diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c index 67636acf7624..3247057ef5ff 100644 --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -131,30 +131,27 @@ static __le32 ext4_xattr_block_csum(struct inode *inode, } static int ext4_xattr_block_csum_verify(struct inode *inode, - sector_t block_nr, - struct ext4_xattr_header *hdr) + struct buffer_head *bh) { - if (ext4_has_metadata_csum(inode->i_sb) && - (hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr))) - return 0; - return 1; -} - -static void ext4_xattr_block_csum_set(struct inode *inode, - sector_t block_nr, - struct ext4_xattr_header *hdr) -{ - if (!ext4_has_metadata_csum(inode->i_sb)) - return; + struct ext4_xattr_header *hdr = BHDR(bh); + int ret = 1; - hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr); + if (ext4_has_metadata_csum(inode->i_sb)) { + lock_buffer(bh); + ret = hdr->h_checksum == ext4_xattr_block_csum(inode, + bh->b_blocknr, hdr); + unlock_buffer(bh); + } + return ret; } static inline int ext4_handle_dirty_xattr_block(handle_t *handle, struct inode *inode, struct buffer_head *bh) { - ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh)); + if (ext4_has_metadata_csum(inode->i_sb)) + BHDR(bh)->h_checksum = ext4_xattr_block_csum(inode, + bh->b_blocknr, BHDR(bh)); return ext4_handle_dirty_metadata(handle, inode, bh); } @@ -233,7 +230,7 @@ ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh) if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) || BHDR(bh)->h_blocks != cpu_to_le32(1)) return -EFSCORRUPTED; - if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh))) + if (!ext4_xattr_block_csum_verify(inode, bh)) return -EFSBADCRC; error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size, bh->b_data); -- 2.11.0.rc0.7.gbe5a750
