btrfs: limit write bios to a single ordered extent

Currently buffered writeback bios are allowed to span multiple
ordered_extents, although that basically never actually happens since
commit 4a445b7b6178 ("btrfs: don't merge pages into bio if their page
offset is not contiguous").

Supporting bios than span ordered_extents complicates the file
checksumming code, and prevents us from adding an ordered_extent pointer
to the btrfs_bio structure.  Use the existing code to limit a bio to
single ordered_extent for zoned device writes for all writes.

This allows to remove the REQ_BTRFS_ONE_ORDERED flags, and the
handling of multiple ordered_extents in btrfs_csum_one_bio.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/bio.c b/fs/btrfs/bio.c
index 846deed..4a75efd 100644 (file)
--- a/fs/btrfs/bio.c
+++ b/fs/btrfs/bio.c
@@ -457,9 +457,6 @@ static void btrfs_submit_mirrored_bio(struct btrfs_io_context *bioc, int dev_nr)
 static void __btrfs_submit_bio(struct bio *bio, struct btrfs_io_context *bioc,
                               struct btrfs_io_stripe *smap, int mirror_num)
 {
-       /* Do not leak our private flag into the block layer. */
-       bio->bi_opf &= ~REQ_BTRFS_ONE_ORDERED;
-
        if (!bioc) {
                /* Single mirror read/write fast path. */
                btrfs_bio(bio)->mirror_num = mirror_num;

diff --git a/fs/btrfs/bio.h b/fs/btrfs/bio.h
index 8a29980..52e7962 100644 (file)
--- a/fs/btrfs/bio.h
+++ b/fs/btrfs/bio.h
@@ -102,9 +102,6 @@ static inline void btrfs_bio_end_io(struct btrfs_bio *bbio, blk_status_t status)
        bbio->end_io(bbio);
 }
 
-/* Bio only refers to one ordered extent. */
-#define REQ_BTRFS_ONE_ORDERED                  REQ_DRV
-
 /* Submit using blkcg_punt_bio_submit. */
 #define REQ_BTRFS_CGROUP_PUNT                  REQ_FS_PRIVATE
 

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index bb2d1a4..617b957 100644 (file)
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -293,8 +293,6 @@ void btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
        ASSERT(IS_ALIGNED(start, fs_info->sectorsize) &&
               IS_ALIGNED(len, fs_info->sectorsize));
 
-       write_flags |= REQ_BTRFS_ONE_ORDERED;
-
        cb = alloc_compressed_bio(inode, start, REQ_OP_WRITE | write_flags,
                                  end_compressed_bio_write);
        cb->start = start;

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index f4d3c56..35141a2 100644 (file)
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -826,13 +826,8 @@ static void alloc_new_bio(struct btrfs_inode *inode,
        bio_ctrl->bbio = bbio;
        bio_ctrl->len_to_oe_boundary = U32_MAX;
 
-       /*
-        * Limit the extent to the ordered boundary for Zone Append.
-        * Compressed bios aren't submitted directly, so it doesn't apply to
-        * them.
-        */
-       if (bio_ctrl->compress_type == BTRFS_COMPRESS_NONE &&
-           btrfs_use_zone_append(bbio)) {
+       /* Limit data write bios to the ordered boundary. */
+       if (bio_ctrl->wbc) {
                struct btrfs_ordered_extent *ordered;
 
                ordered = btrfs_lookup_ordered_extent(inode, file_offset);
@@ -842,9 +837,7 @@ static void alloc_new_bio(struct btrfs_inode *inode,
                                        ordered->disk_num_bytes - file_offset);
                        btrfs_put_ordered_extent(ordered);
                }
-       }
 
-       if (bio_ctrl->wbc) {
                /*
                 * Pick the last added device to support cgroup writeback.  For
                 * multi-device file systems this means blk-cgroup policies have

diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 0cb4a99..782bbf0 100644 (file)
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -733,8 +733,6 @@ blk_status_t btrfs_csum_one_bio(struct btrfs_bio *bbio)
        struct bio_vec bvec;
        int index;
        unsigned int blockcount;
-       unsigned long total_bytes = 0;
-       unsigned long this_sum_bytes = 0;
        int i;
        unsigned nofs_flag;
 
@@ -776,34 +774,6 @@ blk_status_t btrfs_csum_one_bio(struct btrfs_bio *bbio)
                                                 - 1);
 
                for (i = 0; i < blockcount; i++) {
-                       if (!(bio->bi_opf & REQ_BTRFS_ONE_ORDERED) &&
-                           !in_range(offset, ordered->file_offset,
-                                     ordered->num_bytes)) {
-                               unsigned long bytes_left;
-
-                               sums->len = this_sum_bytes;
-                               this_sum_bytes = 0;
-                               btrfs_add_ordered_sum(ordered, sums);
-                               btrfs_put_ordered_extent(ordered);
-
-                               bytes_left = bio->bi_iter.bi_size - total_bytes;
-
-                               nofs_flag = memalloc_nofs_save();
-                               sums = kvzalloc(btrfs_ordered_sum_size(fs_info,
-                                                     bytes_left), GFP_KERNEL);
-                               memalloc_nofs_restore(nofs_flag);
-                               if (!sums)
-                                       return BLK_STS_RESOURCE;
-
-                               sums->len = bytes_left;
-                               ordered = btrfs_lookup_ordered_extent(inode,
-                                                               offset);
-                               ASSERT(ordered); /* Logic error */
-                               sums->logical = (bio->bi_iter.bi_sector << SECTOR_SHIFT)
-                                       + total_bytes;
-                               index = 0;
-                       }
-
                        data = bvec_kmap_local(&bvec);
                        crypto_shash_digest(shash,
                                            data + (i * fs_info->sectorsize),
@@ -812,18 +782,10 @@ blk_status_t btrfs_csum_one_bio(struct btrfs_bio *bbio)
                        kunmap_local(data);
                        index += fs_info->csum_size;
                        offset += fs_info->sectorsize;
-                       this_sum_bytes += fs_info->sectorsize;
-                       total_bytes += fs_info->sectorsize;
                }
 
        }
-       this_sum_bytes = 0;
 
-       /*
-        * The ->sums assignment is for zoned writes, where a bio never spans
-        * ordered extents and is only done unconditionally because that's cheaper
-        * than a branch.
-        */
        bbio->sums = sums;
        btrfs_add_ordered_sum(ordered, sums);
        btrfs_put_ordered_extent(ordered);