[PATCH 09/10] btrfs: avoid access to .bi_vcnt directly

Ming Lei
2017-12-08T13:16:12Z

BTRFS uses bio->bi_vcnt to figure out page numbers, this way becomes not
correct once we start to enable multipage bvec.

So use bio_nr_pages() to do that instead.

Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <jbacik@fb.com>
Cc: David Sterba <dsterba@suse.com>
Cc: linux-btrfs@vger.kernel.org
Acked-by: David Sterba <dsterba@suse.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
fs/btrfs/extent_io.c | 9 +++++----
fs/btrfs/extent_io.h | 2 +-
2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 6f6669f93beb..27795bf2507c 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2257,7 +2257,7 @@ int btrfs_get_io_failure_record(struct inode *inode, u64 start, u64 end,
return 0;
}

-bool btrfs_check_repairable(struct inode *inode, struct bio *failed_bio,
+bool btrfs_check_repairable(struct inode *inode, unsigned failed_bio_pages,
struct io_failure_record *failrec, int failed_mirror)
{
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
@@ -2281,7 +2281,7 @@ bool btrfs_check_repairable(struct inode *inode, struct bio *failed_bio,
* a) deliver good data to the caller
* b) correct the bad sectors on disk
*/
- if (failed_bio->bi_vcnt > 1) {
+ if (failed_bio_pages > 1) {
/*
* to fulfill b), we need to know the exact failing sectors, as
* we don't want to rewrite any more than the failed ones. thus,
@@ -2374,6 +2374,7 @@ static int bio_readpage_error(struct bio *failed_bio, u64 phy_offset,
int read_mode = 0;
blk_status_t status;
int ret;
+ unsigned failed_bio_pages = bio_nr_pages(failed_bio);

BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);

@@ -2381,13 +2382,13 @@ static int bio_readpage_error(struct bio *failed_bio, u64 phy_offset,
if (ret)
return ret;

- if (!btrfs_check_repairable(inode, failed_bio, failrec,
+ if (!btrfs_check_repairable(inode, failed_bio_pages, failrec,
failed_mirror)) {
free_io_failure(failure_tree, tree, failrec);
return -EIO;
}

- if (failed_bio->bi_vcnt > 1)
+ if (failed_bio_pages > 1)
read_mode |= REQ_FAILFAST_DEV;

phy_offset >>= inode->i_sb->s_blocksize_bits;
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 93dcae0c3183..20854d63c75b 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -540,7 +540,7 @@ void btrfs_free_io_failure_record(struct btrfs_inode *inode, u64 start,
u64 end);
int btrfs_get_io_failure_record(struct inode *inode, u64 start, u64 end,
struct io_failure_record **failrec_ret);
-bool btrfs_check_repairable(struct inode *inode, struct bio *failed_bio,
+bool btrfs_check_repairable(struct inode *inode, unsigned failed_bio_pages,
struct io_failure_record *failrec, int fail_mirror);
struct bio *btrfs_create_repair_bio(struct inode *inode, struct bio *failed_bio,
struct io_failure_record *failrec,
--
2.9.5