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| author | Goldwyn Rodrigues <rgoldwyn@suse.de> | 2020-09-15 10:41:40 -0500 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2020-12-08 15:53:37 +0100 |
| commit | 949b32732eab33018283e0517cc528be10a3d085 (patch) | |
| tree | 86a671f0fc5283014f3aab027eff9a0d7a719eef /fs/btrfs/extent_io.c | |
| parent | eefa45f593792827771cfd845ab12fea5a7c7cd9 (diff) | |
| download | lwn-949b32732eab33018283e0517cc528be10a3d085.tar.gz lwn-949b32732eab33018283e0517cc528be10a3d085.zip | |
btrfs: use iosize while reading compressed pages
While using compression, a submitted bio is mapped with a compressed bio
which performs the read from disk, decompresses and returns uncompressed
data to original bio. The original bio must reflect the uncompressed
size (iosize) of the I/O to be performed, or else the page just gets the
decompressed I/O length of data (disk_io_size). The compressed bio
checks the extent map and gets the correct length while performing the
I/O from disk.
This came up in subpage work when only compressed length of the original
bio was filled in the page. This worked correctly for pagesize ==
sectorsize because both compressed and uncompressed data are at pagesize
boundaries, and would end up filling the requested page.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/extent_io.c')
| -rw-r--r-- | fs/btrfs/extent_io.c | 10 |
1 files changed, 3 insertions, 7 deletions
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 60f5f68d892d..14d01b76f5c9 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -3158,7 +3158,6 @@ int btrfs_do_readpage(struct page *page, struct extent_map **em_cached, int nr = 0; size_t pg_offset = 0; size_t iosize; - size_t disk_io_size; size_t blocksize = inode->i_sb->s_blocksize; unsigned long this_bio_flag = 0; struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree; @@ -3224,13 +3223,10 @@ int btrfs_do_readpage(struct page *page, struct extent_map **em_cached, iosize = min(extent_map_end(em) - cur, end - cur + 1); cur_end = min(extent_map_end(em) - 1, end); iosize = ALIGN(iosize, blocksize); - if (this_bio_flag & EXTENT_BIO_COMPRESSED) { - disk_io_size = em->block_len; + if (this_bio_flag & EXTENT_BIO_COMPRESSED) offset = em->block_start; - } else { + else offset = em->block_start + extent_offset; - disk_io_size = iosize; - } block_start = em->block_start; if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) block_start = EXTENT_MAP_HOLE; @@ -3319,7 +3315,7 @@ int btrfs_do_readpage(struct page *page, struct extent_map **em_cached, } ret = submit_extent_page(REQ_OP_READ | read_flags, NULL, - page, offset, disk_io_size, + page, offset, iosize, pg_offset, bio, end_bio_extent_readpage, 0, *bio_flags, |