For subpage metadata validation check, there are some differences:
- Read must finish in one bvec
Since we're just reading one subpage range in one page, it should
never be split into two bios nor two bvecs.
- How to grab the existing eb
Instead of grabbing eb using page->private, we have to go search radix
tree as we don't have any direct pointer at hand.
Signed-off-by: Qu Wenruo <w...@suse.com>
Reviewed-by: David Sterba <dste...@suse.com>
Signed-off-by: David Sterba <dste...@suse.com>
---
fs/btrfs/disk-io.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 57 insertions(+)
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 5473bed6a7e8..0b10577ad2bd 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -591,6 +591,59 @@ static int validate_extent_buffer(struct extent_buffer *eb)
return ret;
}
+static int validate_subpage_buffer(struct page *page, u64 start, u64 end,
+ int mirror)
+{
+ struct btrfs_fs_info *fs_info = btrfs_sb(page->mapping->host->i_sb);
+ struct extent_buffer *eb;
+ bool reads_done;
+ int ret = 0;
+
+ /*
+ * We don't allow bio merge for subpage metadata read, so we should
+ * only get one eb for each endio hook.
+ */
+ ASSERT(end == start + fs_info->nodesize - 1);
+ ASSERT(PagePrivate(page));
+
+ eb = find_extent_buffer(fs_info, start);
+ /*
+ * When we are reading one tree block, eb must have been inserted into
+ * the radix tree. If not, something is wrong.
+ */
+ ASSERT(eb);
+
+ reads_done = atomic_dec_and_test(&eb->io_pages);
+ /* Subpage read must finish in page read */
+ ASSERT(reads_done);
+
+ eb->read_mirror = mirror;
+ if (test_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags)) {
+ ret = -EIO;
+ goto err;
+ }
+ ret = validate_extent_buffer(eb);
+ if (ret < 0)
+ goto err;
+
+ if (test_and_clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags))
+ btree_readahead_hook(eb, ret);
+
+ set_extent_buffer_uptodate(eb);
+
+ free_extent_buffer(eb);
+ return ret;
+err:
+ /*
+ * end_bio_extent_readpage decrements io_pages in case of error,
+ * make sure it has something to decrement.
+ */
+ atomic_inc(&eb->io_pages);
+ clear_extent_buffer_uptodate(eb);
+ free_extent_buffer(eb);
+ return ret;
+}
+
int btrfs_validate_metadata_buffer(struct btrfs_io_bio *io_bio,
struct page *page, u64 start, u64 end,
int mirror)
@@ -600,6 +653,10 @@ int btrfs_validate_metadata_buffer(struct btrfs_io_bio
*io_bio,
int reads_done;
ASSERT(page->private);
+
+ if (btrfs_sb(page->mapping->host->i_sb)->sectorsize < PAGE_SIZE)
+ return validate_subpage_buffer(page, start, end, mirror);
+
eb = (struct extent_buffer *)page->private;
/*
--
2.30.0
