[PATCH v2 11/26] btrfs: introduce alloc_compressed_bio() for compression

Qu Wenruo
2021-08-29T05:25:21Z

Just aggregate the bio allocation code into one helper, so that we can
replace 4 call sites.

There is one special note for zoned write.

Currently btrfs_submit_compressed_write() will only allocate the first
bio using ZONE_APPEND.
If we have to submit current bio due to stripe boundary, the new bio
allocated will not use ZONE_APPEND.

In theory this should be a bug, but considering zoned mode currently
only support SINGLE profile, which doesn't have any stripe boundary
limit, it should never be a problem.

This function will provide a good entrance for any work which needs to be
done at bio allocation time. Like determining the stripe boundary.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
fs/btrfs/compression.c | 85 ++++++++++++++++++++++++++++--------------
1 file changed, 57 insertions(+), 28 deletions(-)

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 033ca1060567..7fdc9c131ac5 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -437,6 +437,35 @@ static blk_status_t submit_compressed_bio(struct btrfs_fs_info *fs_info,
return ret;
}

+/*
+ * To allocate a compressed_bio, which will be used to read/write on-disk data.
+ */
+static struct bio *alloc_compressed_bio(struct compressed_bio *cb, u64 disk_bytenr,
+ unsigned int opf, bio_end_io_t endio_func)
+{
+ struct bio *bio;
+
+ bio = btrfs_bio_alloc(disk_bytenr);
+
+ bio->bi_opf = opf;
+ bio->bi_private = cb;
+ bio->bi_end_io = endio_func;
+
+ if (bio_op(bio) == REQ_OP_ZONE_APPEND) {
+ struct btrfs_fs_info *fs_info = btrfs_sb(cb->inode->i_sb);
+ struct btrfs_device *device;
+
+ device = btrfs_zoned_get_device(fs_info, disk_bytenr,
+ fs_info->sectorsize);
+ if (IS_ERR(device)) {
+ bio_put(bio);
+ return ERR_CAST(device);
+ }
+ bio_set_dev(bio, device->bdev);
+ }
+ return bio;
+}
+
/*
* worker function to build and submit bios for previously compressed pages.
* The corresponding pages in the inode should be marked for writeback
@@ -483,22 +512,11 @@ blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
cb->orig_bio = NULL;
cb->nr_pages = nr_pages;

- bio = btrfs_bio_alloc(first_byte);
- bio->bi_opf = bio_op | write_flags;
- bio->bi_private = cb;
- bio->bi_end_io = end_compressed_bio_write;
-
- if (use_append) {
- struct btrfs_device *device;
-
- device = btrfs_zoned_get_device(fs_info, disk_start, PAGE_SIZE);
- if (IS_ERR(device)) {
- kfree(cb);
- bio_put(bio);
- return BLK_STS_NOTSUPP;
- }
-
- bio_set_dev(bio, device->bdev);
+ bio = alloc_compressed_bio(cb, first_byte, bio_op | write_flags,
+ end_compressed_bio_write);
+ if (IS_ERR(bio)) {
+ kfree(cb);
+ return errno_to_blk_status(PTR_ERR(bio));
}

if (blkcg_css) {
@@ -542,10 +560,14 @@ blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
if (ret)
goto finish_cb;

- bio = btrfs_bio_alloc(first_byte);
- bio->bi_opf = bio_op | write_flags;
- bio->bi_private = cb;
- bio->bi_end_io = end_compressed_bio_write;
+ bio = alloc_compressed_bio(cb, first_byte,
+ bio_op | write_flags,
+ end_compressed_bio_write);
+ if (IS_ERR(bio)) {
+ ret = errno_to_blk_status(PTR_ERR(bio));
+ bio = NULL;
+ goto finish_cb;
+ }
if (blkcg_css)
bio->bi_opf |= REQ_CGROUP_PUNT;
/*
@@ -844,10 +866,13 @@ blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
/* include any pages we added in add_ra-bio_pages */
cb->len = bio->bi_iter.bi_size;

- comp_bio = btrfs_bio_alloc(cur_disk_byte);
- comp_bio->bi_opf = REQ_OP_READ;
- comp_bio->bi_private = cb;
- comp_bio->bi_end_io = end_compressed_bio_read;
+ comp_bio = alloc_compressed_bio(cb, cur_disk_byte, REQ_OP_READ,
+ end_compressed_bio_read);
+ if (IS_ERR(comp_bio)) {
+ ret = errno_to_blk_status(PTR_ERR(comp_bio));
+ comp_bio = NULL;
+ goto fail2;
+ }

for (pg_index = 0; pg_index < nr_pages; pg_index++) {
u32 pg_len = PAGE_SIZE;
@@ -888,10 +913,14 @@ blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
if (ret)
goto finish_cb;

- comp_bio = btrfs_bio_alloc(cur_disk_byte);
- comp_bio->bi_opf = REQ_OP_READ;
- comp_bio->bi_private = cb;
- comp_bio->bi_end_io = end_compressed_bio_read;
+ comp_bio = alloc_compressed_bio(cb, cur_disk_byte,
+ REQ_OP_READ,
+ end_compressed_bio_read);
+ if (IS_ERR(comp_bio)) {
+ ret = errno_to_blk_status(PTR_ERR(comp_bio));
+ comp_bio = NULL;
+ goto finish_cb;
+ }

bio_add_page(comp_bio, page, pg_len, 0);
}
--
2.32.0