Cc: Chris Mason <clm@xxxxxx> Cc: Josef Bacik <jbacik@xxxxxx> Cc: David Sterba <dsterba@xxxxxxxx> Cc: linux-btrfs@xxxxxxxxxxxxxxx Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> --- fs/btrfs/compression.c | 4 ++++ fs/btrfs/inode.c | 12 ++++++++++++ 2 files changed, 16 insertions(+) diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c index 2c0b7b57fcd5..5972f74354ca 100644 --- a/fs/btrfs/compression.c +++ b/fs/btrfs/compression.c @@ -541,6 +541,10 @@ blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, /* we need the actual starting offset of this extent in the file */ read_lock(&em_tree->lock); + /* + * It is still safe to retrieve the 1st page of the bio + * in this way after supporting multipage bvec. + */ em = lookup_extent_mapping(em_tree, page_offset(bio->bi_io_vec->bv_page), PAGE_SIZE); diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 4ab02b34f029..7e725d84917b 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -8055,6 +8055,12 @@ static void btrfs_retry_endio_nocsum(struct bio *bio) if (bio->bi_status) goto end; + /* + * WARNING: + * + * With multipage bvec, the following way of direct access to + * bvec table is only safe if the bio includes single page. + */ ASSERT(bio->bi_vcnt == 1); io_tree = &BTRFS_I(inode)->io_tree; failure_tree = &BTRFS_I(inode)->io_failure_tree; @@ -8146,6 +8152,12 @@ static void btrfs_retry_endio(struct bio *bio) uptodate = 1; + /* + * WARNING: + * + * With multipage bvec, the following way of direct access to + * bvec table is only safe if the bio includes single page. + */ ASSERT(bio->bi_vcnt == 1); ASSERT(bio->bi_io_vec->bv_len == btrfs_inode_sectorsize(done->inode)); -- 2.9.4
