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| author | Chandan Rajendra <chandan@linux.vnet.ibm.com> | 2016-01-21 15:56:00 +0530 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2016-02-01 19:24:29 +0100 |
| commit | 5f4dc8fc835bbb902f5c2aa3de3978f3f518aa73 (patch) | |
| tree | 8ea4c13c613e02a98a17271197790266ea6286bc /fs/btrfs | |
| parent | 298cfd368364912076fd84fbceb0df864da42a67 (diff) | |
| download | blackbird-op-linux-5f4dc8fc835bbb902f5c2aa3de3978f3f518aa73.tar.gz blackbird-op-linux-5f4dc8fc835bbb902f5c2aa3de3978f3f518aa73.zip | |
Btrfs: btrfs_submit_direct_hook: Handle map_length < bio vector length
In subpagesize-blocksize scenario, map_length can be less than the length of a
bio vector. Such a condition may cause btrfs_submit_direct_hook() to submit a
zero length bio. Fix this by comparing map_length against block size rather
than with bv_len.
Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs')
| -rw-r--r-- | fs/btrfs/inode.c | 25 |
1 files changed, 17 insertions, 8 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 917ab6b6c277..9dd4fb4afce9 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -8244,9 +8244,11 @@ static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip, u64 file_offset = dip->logical_offset; u64 submit_len = 0; u64 map_length; - int nr_pages = 0; - int ret; + u32 blocksize = root->sectorsize; int async_submit = 0; + int nr_sectors; + int ret; + int i; map_length = orig_bio->bi_iter.bi_size; ret = btrfs_map_block(root->fs_info, rw, start_sector << 9, @@ -8276,9 +8278,12 @@ static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip, atomic_inc(&dip->pending_bios); while (bvec <= (orig_bio->bi_io_vec + orig_bio->bi_vcnt - 1)) { - if (map_length < submit_len + bvec->bv_len || - bio_add_page(bio, bvec->bv_page, bvec->bv_len, - bvec->bv_offset) < bvec->bv_len) { + nr_sectors = BTRFS_BYTES_TO_BLKS(root->fs_info, bvec->bv_len); + i = 0; +next_block: + if (unlikely(map_length < submit_len + blocksize || + bio_add_page(bio, bvec->bv_page, blocksize, + bvec->bv_offset + (i * blocksize)) < blocksize)) { /* * inc the count before we submit the bio so * we know the end IO handler won't happen before @@ -8299,7 +8304,6 @@ static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip, file_offset += submit_len; submit_len = 0; - nr_pages = 0; bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev, start_sector, GFP_NOFS); @@ -8317,9 +8321,14 @@ static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip, bio_put(bio); goto out_err; } + + goto next_block; } else { - submit_len += bvec->bv_len; - nr_pages++; + submit_len += blocksize; + if (--nr_sectors) { + i++; + goto next_block; + } bvec++; } } |
