On Tue, Jan 26, 2021 at 11:25:07AM +0900, Naohiro Aota wrote:
If more than one IO is issued for one file extent, these IO can be written
to separate regions on a device. Since we cannot map one file extent to
such a separate area, we need to follow the "one IO == one ordered extent"
rule.
The Normal buffered, uncompressed, not pre-allocated write path (used by
cow_file_range()) sometimes does not follow this rule. It can write a part
of an ordered extent when specified a region to write e.g., when its
called from fdatasync().
Introduces a dedicated (uncompressed buffered) data write path for ZONED
mode. This write path will CoW the region and write it at once.
Reviewed-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
Signed-off-by: Naohiro Aota <naohiro.aota@xxxxxxx>
---
fs/btrfs/inode.c | 34 ++++++++++++++++++++++++++++++++--
1 file changed, 32 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index a9bf78eaed42..6d43aaa1f537 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1400,6 +1400,29 @@ static int cow_file_range_async(struct btrfs_inode *inode,
return 0;
}
+static noinline int run_delalloc_zoned(struct btrfs_inode *inode,
+ struct page *locked_page, u64 start,
+ u64 end, int *page_started,
+ unsigned long *nr_written)
+{
+ int ret;
+
+ ret = cow_file_range(inode, locked_page, start, end,
+ page_started, nr_written, 0);
+ if (ret)
+ return ret;
+
+ if (*page_started)
+ return 0;
+
+ __set_page_dirty_nobuffers(locked_page);
+ account_page_redirty(locked_page);
+ extent_write_locked_range(&inode->vfs_inode, start, end, WB_SYNC_ALL);
+ *page_started = 1;
+
+ return 0;
+}
+
static noinline int csum_exist_in_range(struct btrfs_fs_info *fs_info,
u64 bytenr, u64 num_bytes)
{
@@ -1879,17 +1902,24 @@ int btrfs_run_delalloc_range(struct btrfs_inode *inode, struct page *locked_page
{
int ret;
int force_cow = need_force_cow(inode, start, end);
+ const bool do_compress = inode_can_compress(inode) &&
+ inode_need_compress(inode, start, end);
This would make sense to cache the values, but inode_need_compress is
quite heavy as it runs the compression heuristic. This would affect all
cases and drop some perf.
+ const bool zoned = btrfs_is_zoned(inode->root->fs_info);
if (inode->flags & BTRFS_INODE_NODATACOW && !force_cow) {
+ ASSERT(!zoned);
ret = run_delalloc_nocow(inode, locked_page, start, end,
page_started, 1, nr_written);
} else if (inode->flags & BTRFS_INODE_PREALLOC && !force_cow) {
+ ASSERT(!zoned);
ret = run_delalloc_nocow(inode, locked_page, start, end,
page_started, 0, nr_written);
- } else if (!inode_can_compress(inode) ||
- !inode_need_compress(inode, start, end)) {
+ } else if (!do_compress && !zoned) {
ret = cow_file_range(inode, locked_page, start, end,
page_started, nr_written, 1);
+ } else if (!do_compress && zoned) {
+ ret = run_delalloc_zoned(inode, locked_page, start, end,
+ page_started, nr_written);
The part of the condition is shared so it should be structured lik
} else if (!<the compression checks>) {
if (zoned)
run_delalloc_zoned
else
cow_file_range
} ...
