diff options
| author | David Sterba <dsterba@suse.com> | 2019-08-30 15:42:07 +0200 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2019-11-18 12:47:01 +0100 |
| commit | 8530c37a70df71ea8a04fbafabba0b92f4475c6c (patch) | |
| tree | 2de5f4dc87ba63a5f586dec62ca53fd84b9f4df7 | |
| parent | c3e14909d3b399d49d8dfcf3edbcd5463a7eed6f (diff) | |
btrfs: get bdev from latest_dev for dio bh_result
To remove use of extent_map::bdev we need to find a replacement, and the
latest_bdev is the only one we can use here, because inode::i_bdev and
superblock::s_bdev are NULL.
The DIO code uses bdev in two places:
* to read blocksize to perform alignment checks in
do_blockdev_direct_IO, but we do them in btrfs code before any call to
DIO
* in the following call chain:
do_direct_IO
get_more_blocks
sdio->get_block() <-- this is btrfs_get_blocks_direct
subsequently the map_bh->b_dev member is used in clean_bdev_aliases
and dio_new_bio to set the bio's bdev to that of the buffer_head.
However, because we have provided a submit function dio_bio_submit
calls our submission function and ignores the bdev.
So it's safe to pass any valid bdev that's used within the filesystem.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
| -rw-r--r-- | fs/btrfs/inode.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index b943c9770533..5edc6a27ea4a 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -7662,6 +7662,8 @@ static int btrfs_get_blocks_direct_read(struct extent_map *em, struct inode *inode, u64 start, u64 len) { + struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); + if (em->block_start == EXTENT_MAP_HOLE || test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) return -ENOENT; @@ -7671,7 +7673,7 @@ static int btrfs_get_blocks_direct_read(struct extent_map *em, bh_result->b_blocknr = (em->block_start + (start - em->start)) >> inode->i_blkbits; bh_result->b_size = len; - bh_result->b_bdev = em->bdev; + bh_result->b_bdev = fs_info->fs_devices->latest_bdev; set_buffer_mapped(bh_result); return 0; @@ -7754,7 +7756,7 @@ skip_cow: bh_result->b_blocknr = (em->block_start + (start - em->start)) >> inode->i_blkbits; bh_result->b_size = len; - bh_result->b_bdev = em->bdev; + bh_result->b_bdev = fs_info->fs_devices->latest_bdev; set_buffer_mapped(bh_result); if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) |