On Tue, Feb 28, 2017 at 08:56:50AM -0500, Theodore Ts'o wrote: > 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> Looks good, Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> --D > --- > 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 >
