btrfs: remove stripe boundary calculation for buffered I/O

Remove btrfs_bio_ctrl::len_to_stripe_boundary, so that buffer
I/O will no longer limit its bio size according to stripe length
now that btrfs_submit_bio can split bios at stripe boundaries.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
[hch: simplify calc_bio_boundaries a little more]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 2983fe2..03dac03 100644 (file)
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -99,7 +99,6 @@ struct btrfs_bio_ctrl {
        struct bio *bio;
        int mirror_num;
        enum btrfs_compression_type compress_type;
-       u32 len_to_stripe_boundary;
        u32 len_to_oe_boundary;
        btrfs_bio_end_io_t end_io_func;
 
@@ -900,7 +899,7 @@ static int btrfs_bio_add_page(struct btrfs_bio_ctrl *bio_ctrl,
 
        ASSERT(bio);
        /* The limit should be calculated when bio_ctrl->bio is allocated */
-       ASSERT(bio_ctrl->len_to_oe_boundary && bio_ctrl->len_to_stripe_boundary);
+       ASSERT(bio_ctrl->len_to_oe_boundary);
        if (bio_ctrl->compress_type != compress_type)
                return 0;
 
@@ -936,9 +935,7 @@ static int btrfs_bio_add_page(struct btrfs_bio_ctrl *bio_ctrl,
        if (!contig)
                return 0;
 
-       real_size = min(bio_ctrl->len_to_oe_boundary,
-                       bio_ctrl->len_to_stripe_boundary) - bio_size;
-       real_size = min(real_size, size);
+       real_size = min(bio_ctrl->len_to_oe_boundary - bio_size, size);
 
        /*
         * If real_size is 0, never call bio_add_*_page(), as even size is 0,
@@ -955,58 +952,30 @@ static int btrfs_bio_add_page(struct btrfs_bio_ctrl *bio_ctrl,
        return ret;
 }
 
-static int calc_bio_boundaries(struct btrfs_bio_ctrl *bio_ctrl,
-                              struct btrfs_inode *inode, u64 file_offset)
+static void calc_bio_boundaries(struct btrfs_bio_ctrl *bio_ctrl,
+                               struct btrfs_inode *inode, u64 file_offset)
 {
-       struct btrfs_fs_info *fs_info = inode->root->fs_info;
-       struct btrfs_io_geometry geom;
        struct btrfs_ordered_extent *ordered;
-       struct extent_map *em;
        u64 logical = (bio_ctrl->bio->bi_iter.bi_sector << SECTOR_SHIFT);
-       int ret;
 
        /*
-        * Pages for compressed extent are never submitted to disk directly,
-        * thus it has no real boundary, just set them to U32_MAX.
-        *
-        * The split happens for real compressed bio, which happens in
-        * btrfs_submit_compressed_read/write().
+        * 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) {
-               bio_ctrl->len_to_oe_boundary = U32_MAX;
-               bio_ctrl->len_to_stripe_boundary = U32_MAX;
-               return 0;
-       }
-       em = btrfs_get_chunk_map(fs_info, logical, fs_info->sectorsize);
-       if (IS_ERR(em))
-               return PTR_ERR(em);
-       ret = btrfs_get_io_geometry(fs_info, em, btrfs_op(bio_ctrl->bio),
-                                   logical, &geom);
-       free_extent_map(em);
-       if (ret < 0) {
-               return ret;
-       }
-       if (geom.len > U32_MAX)
-               bio_ctrl->len_to_stripe_boundary = U32_MAX;
-       else
-               bio_ctrl->len_to_stripe_boundary = (u32)geom.len;
-
-       if (bio_op(bio_ctrl->bio) != REQ_OP_ZONE_APPEND) {
-               bio_ctrl->len_to_oe_boundary = U32_MAX;
-               return 0;
-       }
-
-       /* Ordered extent not yet created, so we're good */
-       ordered = btrfs_lookup_ordered_extent(inode, file_offset);
-       if (!ordered) {
-               bio_ctrl->len_to_oe_boundary = U32_MAX;
-               return 0;
+       if (bio_ctrl->compress_type == BTRFS_COMPRESS_NONE &&
+           bio_op(bio_ctrl->bio) == REQ_OP_ZONE_APPEND) {
+               ordered = btrfs_lookup_ordered_extent(inode, file_offset);
+               if (ordered) {
+                       bio_ctrl->len_to_oe_boundary = min_t(u32, U32_MAX,
+                                       ordered->disk_bytenr +
+                                       ordered->disk_num_bytes - logical);
+                       btrfs_put_ordered_extent(ordered);
+                       return;
+               }
        }
 
-       bio_ctrl->len_to_oe_boundary = min_t(u32, U32_MAX,
-               ordered->disk_bytenr + ordered->disk_num_bytes - logical);
-       btrfs_put_ordered_extent(ordered);
-       return 0;
+       bio_ctrl->len_to_oe_boundary = U32_MAX;
 }
 
 static int alloc_new_bio(struct btrfs_inode *inode,
@@ -1032,9 +1001,7 @@ static int alloc_new_bio(struct btrfs_inode *inode,
                bio->bi_iter.bi_sector = (disk_bytenr + offset) >> SECTOR_SHIFT;
        bio_ctrl->bio = bio;
        bio_ctrl->compress_type = compress_type;
-       ret = calc_bio_boundaries(bio_ctrl, inode, file_offset);
-       if (ret < 0)
-               goto error;
+       calc_bio_boundaries(bio_ctrl, inode, file_offset);
 
        if (wbc) {
                /*