Signed-off-by: Ming Lei <tom.leiming@xxxxxxxxx> --- fs/btrfs/compression.c | 4 ++++ fs/btrfs/inode.c | 17 +++++++++++++++++ 2 files changed, 21 insertions(+) diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c index 485a60923bba..54306dee392a 100644 --- a/fs/btrfs/compression.c +++ b/fs/btrfs/compression.c @@ -601,6 +601,10 @@ int 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 fa77cb210907..d0714208495f 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -7914,6 +7914,11 @@ static int dio_read_error(struct inode *inode, struct bio *failed_bio, return -EIO; } + /* + * In this case it is still correct to retrieve length + * of the 1st bvec of the bio in this way after supporting + * multipage bvec. + */ if ((bio_segments_all(failed_bio) > 1) || (failed_bio->bi_io_vec->bv_len > btrfs_inode_sectorsize(inode))) @@ -7960,6 +7965,12 @@ static void btrfs_retry_endio_nocsum(struct bio *bio) if (bio->bi_error) 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); inode = bio->bi_io_vec->bv_page->mapping->host; ASSERT(bio->bi_io_vec->bv_len == btrfs_inode_sectorsize(inode)); @@ -8045,6 +8056,12 @@ static void btrfs_retry_endio(struct bio *bio) start = done->start; + /* + * 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); inode = bio->bi_io_vec->bv_page->mapping->host; ASSERT(bio->bi_io_vec->bv_len == btrfs_inode_sectorsize(inode)); -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
