btrfs: introduce alloc_compressed_bio() for compression

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 and we have assertions in place.

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>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 60b4da6..1381473 100644 (file)
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -435,6 +435,36 @@ static blk_status_t submit_compressed_bio(struct btrfs_fs_info *fs_info,
 }
 
 /*
+ * 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(BIO_MAX_VECS);
+
+       bio->bi_iter.bi_sector = disk_bytenr >> SECTOR_SHIFT;
+       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
  * and the compressed pages should have a reference on them for dropping
@@ -479,23 +509,11 @@ 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(BIO_MAX_VECS);
-       bio->bi_iter.bi_sector = first_byte >> SECTOR_SHIFT;
-       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) {
@@ -539,11 +557,14 @@ blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
                        if (ret)
                                goto finish_cb;
 
-                       bio = btrfs_bio_alloc(BIO_MAX_VECS);
-                       bio->bi_iter.bi_sector = first_byte >> SECTOR_SHIFT;
-                       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;
                        /*
@@ -839,11 +860,13 @@ 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(BIO_MAX_VECS);
-       comp_bio->bi_iter.bi_sector = cur_disk_byte >> SECTOR_SHIFT;
-       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;
@@ -884,11 +907,14 @@ blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
                        if (ret)
                                goto finish_cb;
 
-                       comp_bio = btrfs_bio_alloc(BIO_MAX_VECS);
-                       comp_bio->bi_iter.bi_sector = cur_disk_byte >> SECTOR_SHIFT;
-                       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);
                }