diff options
| author | Omar Sandoval <osandov@fb.com> | 2020-04-16 14:46:16 -0700 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2020-05-25 11:25:25 +0200 |
| commit | fb30f4707d421add0f4bf9a08bb228daac273b9f (patch) | |
| tree | 163e2784f9e69c0032d9f45e11b28fe7a58f27ed /fs/btrfs/file-item.c | |
| parent | f337bd7478178f4c5e2b825fdb8dfaa266c344a2 (diff) | |
btrfs: clarify btrfs_lookup_bio_sums documentation
Fix a couple of issues in the btrfs_lookup_bio_sums documentation:
* The bio doesn't need to be a btrfs_io_bio if dst was provided. Move
the declaration in the code to make that clear, too.
* dst must be large enough to hold nblocks * csum_size, not just
csum_size.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/file-item.c')
| -rw-r--r-- | fs/btrfs/file-item.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c index b618ad5339ba..22cbb4da6d42 100644 --- a/fs/btrfs/file-item.c +++ b/fs/btrfs/file-item.c @@ -242,11 +242,13 @@ int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans, /** * btrfs_lookup_bio_sums - Look up checksums for a bio. * @inode: inode that the bio is for. - * @bio: bio embedded in btrfs_io_bio. + * @bio: bio to look up. * @offset: Unless (u64)-1, look up checksums for this offset in the file. * If (u64)-1, use the page offsets from the bio instead. - * @dst: Buffer of size btrfs_super_csum_size() used to return checksum. If - * NULL, the checksum is returned in btrfs_io_bio(bio)->csum instead. + * @dst: Buffer of size nblocks * btrfs_super_csum_size() used to return + * checksum (nblocks = bio->bi_iter.bi_size / fs_info->sectorsize). If + * NULL, the checksum buffer is allocated and returned in + * btrfs_io_bio(bio)->csum instead. * * Return: BLK_STS_RESOURCE if allocating memory fails, BLK_STS_OK otherwise. */ @@ -256,7 +258,6 @@ blk_status_t btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio, struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); struct bio_vec bvec; struct bvec_iter iter; - struct btrfs_io_bio *btrfs_bio = btrfs_io_bio(bio); struct btrfs_csum_item *item = NULL; struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; struct btrfs_path *path; @@ -277,6 +278,8 @@ blk_status_t btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio, nblocks = bio->bi_iter.bi_size >> inode->i_sb->s_blocksize_bits; if (!dst) { + struct btrfs_io_bio *btrfs_bio = btrfs_io_bio(bio); + if (nblocks * csum_size > BTRFS_BIO_INLINE_CSUM_SIZE) { btrfs_bio->csum = kmalloc_array(nblocks, csum_size, GFP_NOFS); |