Current submit_extent_page() just if the current page range can fit into
the current bio, and if not, submit then re-add.
But this behavior has a problem, it can't handle subpage cases.
For subpage case, the problem is in the page size, 64K, which is also
the same size as stripe size.
This means, if we can't fit a full 64K into a bio, due to stripe limit,
then it won't fit into next bio without crossing stripe either.
The proper way to handle it is:
- Check how many bytes we can put into current bio
- Put as many bytes as possible into current bio first
- Submit current bio
- Create new bio
- Add the remaining bytes into the new bio
Refactor submit_extent_page() so that it does the above iteration.
The main loop inside submit_extent_page() will look like this:
cur = pg_offset;
while (cur < pg_offset + size) {
u32 offset = cur - pg_offset;
int added;
if (!bio_ctrl->bio) {
/* Allocate new bio if needed */
}
/* Add as many bytes into the bio */
if (added < size - offset) {
/* The current bio is full, submit it */
}
cur += added;
}
Also, since we're doing new bio allocation deep inside the main loop,
extra that code into a new function, alloc_new_bio().
Signed-off-by: Qu Wenruo <w...@suse.com>
---
fs/btrfs/extent_io.c | 183 ++++++++++++++++++++++++++++---------------
1 file changed, 122 insertions(+), 61 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 4afc3949e6e6..692cc9e693db 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -172,6 +172,7 @@ int __must_check submit_one_bio(struct bio *bio, int
mirror_num,
bio->bi_private = NULL;
+ ASSERT(bio->bi_iter.bi_size);
if (is_data_inode(tree->private_data))
ret = btrfs_submit_data_bio(tree->private_data, bio, mirror_num,
bio_flags);
@@ -3201,13 +3202,13 @@ struct bio *btrfs_bio_clone_partial(struct bio *orig,
int offset, int size)
* @size: portion of page that we want to write
* @prev_bio_flags: flags of previous bio to see if we can merge the current
one
* @bio_flags: flags of the current bio to see if we can merge them
- * @return: true if page was added, false otherwise
*
* Attempt to add a page to bio considering stripe alignment etc.
*
- * Return true if successfully page added. Otherwise, return false.
+ * Return >= 0 for the number of bytes added to the bio.
+ * Return <0 for error.
*/
-static bool btrfs_bio_add_page(struct btrfs_bio_ctrl *bio_ctrl,
+static int btrfs_bio_add_page(struct btrfs_bio_ctrl *bio_ctrl,
struct page *page,
u64 disk_bytenr, unsigned int size,
unsigned int pg_offset,
@@ -3215,6 +3216,7 @@ static bool btrfs_bio_add_page(struct btrfs_bio_ctrl
*bio_ctrl,
{
struct bio *bio = bio_ctrl->bio;
u32 bio_size = bio->bi_iter.bi_size;
+ u32 real_size;
const sector_t sector = disk_bytenr >> SECTOR_SHIFT;
bool contig;
int ret;
@@ -3223,26 +3225,33 @@ static bool btrfs_bio_add_page(struct btrfs_bio_ctrl
*bio_ctrl,
/* The limit should be calculated when bio_ctrl->bio is allocated */
ASSERT(bio_ctrl->len_to_oe_boundary &&
bio_ctrl->len_to_stripe_boundary);
+
if (bio_ctrl->bio_flags != bio_flags)
- return false;
+ return 0;
if (bio_ctrl->bio_flags & EXTENT_BIO_COMPRESSED)
contig = bio->bi_iter.bi_sector == sector;
else
contig = bio_end_sector(bio) == sector;
if (!contig)
- return false;
+ return 0;
- if (bio_size + size > bio_ctrl->len_to_oe_boundary ||
- bio_size + size > bio_ctrl->len_to_stripe_boundary)
- return false;
+ real_size = min(bio_ctrl->len_to_oe_boundary,
+ bio_ctrl->len_to_stripe_boundary) - bio_size;
+ real_size = min(real_size, size);
+ /*
+ * If real_size is 0, never call bio_add_*_page(), as even size is 0,
+ * bio will still execute its endio function on the page!
+ */
+ if (real_size == 0)
+ return 0;
if (bio_op(bio) == REQ_OP_ZONE_APPEND)
- ret = bio_add_zone_append_page(bio, page, size, pg_offset);
+ ret = bio_add_zone_append_page(bio, page, real_size, pg_offset);
else
- ret = bio_add_page(bio, page, size, pg_offset);
+ ret = bio_add_page(bio, page, real_size, pg_offset);
- return ret == size;
+ return ret;
}
static int calc_bio_boundaries(struct btrfs_bio_ctrl *bio_ctrl,
@@ -3301,6 +3310,61 @@ static int calc_bio_boundaries(struct btrfs_bio_ctrl
*bio_ctrl,
return 0;
}
+static int alloc_new_bio(struct btrfs_inode *inode,
+ struct btrfs_bio_ctrl *bio_ctrl,
+ unsigned int opf,
+ bio_end_io_t end_io_func,
+ u64 disk_bytenr, u32 offset,
+ unsigned long bio_flags)
+{
+ struct btrfs_fs_info *fs_info = inode->root->fs_info;
+ struct bio *bio;
+ int ret;
+
+ /*
+ * For compressed page range, its disk_bytenr is always
+ * @disk_bytenr passed in, no matter if we have added
+ * any range into previous bio.
+ */
+ if (bio_flags & EXTENT_BIO_COMPRESSED)
+ bio = btrfs_bio_alloc(disk_bytenr);
+ else
+ bio = btrfs_bio_alloc(disk_bytenr + offset);
+ bio_ctrl->bio = bio;
+ bio_ctrl->bio_flags = bio_flags;
+ ret = calc_bio_boundaries(bio_ctrl, inode);
+ if (ret < 0) {
+ bio_ctrl->bio = NULL;
+ bio->bi_status = errno_to_blk_status(ret);
+ bio_endio(bio);
+ return ret;
+ }
+ bio->bi_end_io = end_io_func;
+ bio->bi_private = &inode->io_tree;
+ bio->bi_write_hint = inode->vfs_inode.i_write_hint;
+ bio->bi_opf = opf;
+ if (btrfs_is_zoned(fs_info) && bio_op(bio) == REQ_OP_ZONE_APPEND) {
+ struct extent_map *em;
+ struct map_lookup *map;
+
+ em = btrfs_get_chunk_map(fs_info, disk_bytenr,
+ fs_info->sectorsize);
+ if (IS_ERR(em)) {
+ bio_ctrl->bio = NULL;
+ bio->bi_status = errno_to_blk_status(ret);
+ bio_endio(bio);
+ return ret;
+ }
+
+ map = em->map_lookup;
+ /* We only support single profile for now */
+ ASSERT(map->num_stripes == 1);
+ btrfs_io_bio(bio)->device = map->stripes[0].dev;
+
+ free_extent_map(em);
+ }
+ return 0;
+}
/*
* @opf: bio REQ_OP_* and REQ_* flags as one value
* @wbc: optional writeback control for io accounting
@@ -3326,67 +3390,64 @@ static int submit_extent_page(unsigned int opf,
bool force_bio_submit)
{
int ret = 0;
- struct bio *bio;
- size_t io_size = min_t(size_t, size, PAGE_SIZE);
struct btrfs_inode *inode = BTRFS_I(page->mapping->host);
- struct extent_io_tree *tree = &inode->io_tree;
- struct btrfs_fs_info *fs_info = inode->root->fs_info;
+ unsigned int cur = pg_offset;
ASSERT(bio_ctrl);
ASSERT(pg_offset < PAGE_SIZE && size <= PAGE_SIZE &&
pg_offset + size <= PAGE_SIZE);
- if (bio_ctrl->bio) {
- bio = bio_ctrl->bio;
- if (force_bio_submit ||
- !btrfs_bio_add_page(bio_ctrl, page, disk_bytenr, io_size,
- pg_offset, bio_flags)) {
- ret = submit_one_bio(bio, mirror_num,
bio_ctrl->bio_flags);
+ if (force_bio_submit && bio_ctrl->bio) {
+ ret = submit_one_bio(bio_ctrl->bio, mirror_num,
+ bio_ctrl->bio_flags);
+ bio_ctrl->bio = NULL;
+ if (ret < 0)
+ return ret;
+ }
+ while (cur < pg_offset + size) {
+ u32 offset = cur - pg_offset;
+ int added;
+ /* Allocate new bio if needed */
+ if (!bio_ctrl->bio) {
+ ret = alloc_new_bio(inode, bio_ctrl, opf, end_io_func,
+ disk_bytenr, offset, bio_flags);
+ if (ret < 0)
+ return ret;
+ }
+ /*
+ * We must go through btrfs_bio_add_page() to ensure each
+ * page range won't cross various boundaries.
+ */
+ if (bio_flags & EXTENT_BIO_COMPRESSED)
+ added = btrfs_bio_add_page(bio_ctrl, page, disk_bytenr,
+ size - offset, pg_offset + offset,
+ bio_flags);
+ else
+ added = btrfs_bio_add_page(bio_ctrl, page,
+ disk_bytenr + offset, size - offset,
+ pg_offset + offset, bio_flags);
+
+ /* Metadata page range should never be split */
+ if (!is_data_inode(&inode->vfs_inode))
+ ASSERT(added == 0 || added == size);
+
+ /* At least we added some page, update the account */
+ if (wbc && added)
+ wbc_account_cgroup_owner(wbc, page, added);
+
+ /* We have reached boundary, submit right now */
+ if (added < size - offset) {
+ /* The bio should contain some page(s) */
+ ASSERT(bio_ctrl->bio->bi_iter.bi_size);
+ ret = submit_one_bio(bio_ctrl->bio, mirror_num,
+ bio_ctrl->bio_flags);
bio_ctrl->bio = NULL;
if (ret < 0)
return ret;
- } else {
- if (wbc)
- wbc_account_cgroup_owner(wbc, page, io_size);
- return 0;
}
+ cur += added;
}
-
- bio = btrfs_bio_alloc(disk_bytenr);
- bio_add_page(bio, page, io_size, pg_offset);
- bio->bi_end_io = end_io_func;
- bio->bi_private = tree;
- bio->bi_write_hint = page->mapping->host->i_write_hint;
- bio->bi_opf = opf;
- if (wbc) {
- struct block_device *bdev;
-
- bdev = fs_info->fs_devices->latest_bdev;
- bio_set_dev(bio, bdev);
- wbc_init_bio(wbc, bio);
- wbc_account_cgroup_owner(wbc, page, io_size);
- }
- if (btrfs_is_zoned(fs_info) && bio_op(bio) == REQ_OP_ZONE_APPEND) {
- struct extent_map *em;
- struct map_lookup *map;
-
- em = btrfs_get_chunk_map(fs_info, disk_bytenr, io_size);
- if (IS_ERR(em))
- return PTR_ERR(em);
-
- map = em->map_lookup;
- /* We only support single profile for now */
- ASSERT(map->num_stripes == 1);
- btrfs_io_bio(bio)->device = map->stripes[0].dev;
-
- free_extent_map(em);
- }
-
- bio_ctrl->bio = bio;
- bio_ctrl->bio_flags = bio_flags;
- ret = calc_bio_boundaries(bio_ctrl, inode);
-
- return ret;
+ return 0;
}
static int attach_extent_buffer_page(struct extent_buffer *eb,
--
2.31.1
