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btrfs: zoned: fix parallel compressed writes 

When multiple processes write data to the same block group on a
compressed zoned filesystem, the underlying device could report I/O
errors and data corruption is possible.

This happens because on a zoned file system, compressed data writes
where sent to the device via a REQ_OP_WRITE instead of a
REQ_OP_ZONE_APPEND operation. But with REQ_OP_WRITE and parallel
submission it cannot be guaranteed that the data is always submitted
aligned to the underlying zone's write pointer.

The change to using REQ_OP_ZONE_APPEND instead of REQ_OP_WRITE on a
zoned filesystem is non intrusive on a regular file system or when
submitting to a conventional zone on a zoned filesystem, as it is
guarded by btrfs_use_zone_append.

Reported-by: David Sterba <dsterba@suse.com>
Fixes: 9d294a685f ("btrfs: zoned: enable to mount ZONED incompat flag")
CC: stable@vger.kernel.org # 5.12.x: e380adfc213a13: btrfs: zoned: pass start block to btrfs_use_zone_append
CC: stable@vger.kernel.org # 5.12.x
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Johannes Thumshirn 2021-05-19 00:40:28 +09:00 committed by David Sterba
parent e380adfc21
commit 764c7c9a46
1 changed files with 38 additions and 4 deletions
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42
fs/btrfs/compression.c
View File

@ -28,6 +28,7 @@
#include "compression.h"
#include "extent_io.h"
#include "extent_map.h"
#include "zoned.h"
static const char* const btrfs_compress_types[] = { "", "zlib", "lzo", "zstd" };
@ -349,6 +350,7 @@ static void end_compressed_bio_write(struct bio *bio)
*/
inode = cb->inode;
cb->compressed_pages[0]->mapping = cb->inode->i_mapping;
btrfs_record_physical_zoned(inode, cb->start, bio);
btrfs_writepage_endio_finish_ordered(cb->compressed_pages[0],
cb->start, cb->start + cb->len - 1,
bio->bi_status == BLK_STS_OK);
@ -401,6 +403,8 @@ blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
u64 first_byte = disk_start;
blk_status_t ret;
int skip_sum = inode->flags & BTRFS_INODE_NODATASUM;
const bool use_append = btrfs_use_zone_append(inode, disk_start);
const unsigned int bio_op = use_append ? REQ_OP_ZONE_APPEND : REQ_OP_WRITE;
WARN_ON(!PAGE_ALIGNED(start));
cb = kmalloc(compressed_bio_size(fs_info, compressed_len), GFP_NOFS);
@ -418,10 +422,31 @@ blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
cb->nr_pages = nr_pages;
bio = btrfs_bio_alloc(first_byte);
bio->bi_opf = REQ_OP_WRITE | write_flags;
bio->bi_opf = bio_op | write_flags;
bio->bi_private = cb;
bio->bi_end_io = end_compressed_bio_write;
if (use_append) {
struct extent_map *em;
struct map_lookup *map;
struct block_device *bdev;
em = btrfs_get_chunk_map(fs_info, disk_start, PAGE_SIZE);
if (IS_ERR(em)) {
kfree(cb);
bio_put(bio);
return BLK_STS_NOTSUPP;
}
map = em->map_lookup;
/* We only support single profile for now */
ASSERT(map->num_stripes == 1);
bdev = map->stripes[0].dev->bdev;
bio_set_dev(bio, bdev);
free_extent_map(em);
}
if (blkcg_css) {
bio->bi_opf |= REQ_CGROUP_PUNT;
kthread_associate_blkcg(blkcg_css);
@ -432,6 +457,7 @@ blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
bytes_left = compressed_len;
for (pg_index = 0; pg_index < cb->nr_pages; pg_index++) {
int submit = 0;
int len;
page = compressed_pages[pg_index];
page->mapping = inode->vfs_inode.i_mapping;
@ -439,9 +465,13 @@ blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
submit = btrfs_bio_fits_in_stripe(page, PAGE_SIZE, bio,
0);
if (pg_index == 0 && use_append)
len = bio_add_zone_append_page(bio, page, PAGE_SIZE, 0);
else
len = bio_add_page(bio, page, PAGE_SIZE, 0);
page->mapping = NULL;
if (submit || bio_add_page(bio, page, PAGE_SIZE, 0) <
PAGE_SIZE) {
if (submit || len < PAGE_SIZE) {
/*
* inc the count before we submit the bio so
* we know the end IO handler won't happen before
@ -465,11 +495,15 @@ blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
}
bio = btrfs_bio_alloc(first_byte);
bio->bi_opf = REQ_OP_WRITE | write_flags;
bio->bi_opf = bio_op | write_flags;
bio->bi_private = cb;
bio->bi_end_io = end_compressed_bio_write;
if (blkcg_css)
bio->bi_opf |= REQ_CGROUP_PUNT;
/*
* Use bio_add_page() to ensure the bio has at least one
* page.
*/
bio_add_page(bio, page, PAGE_SIZE, 0);
}
if (bytes_left < PAGE_SIZE) {