diff mbox series

[v3,11/22] btrfs: extent_io: attach private to dummy extent buffer pages

Message ID 20210106010201.37864-12-wqu@suse.com (mailing list archive)
State New, archived
Headers show
Series btrfs: add read-only support for subpage sector size | expand

Commit Message

Qu Wenruo Jan. 6, 2021, 1:01 a.m. UTC
Even for regular btrfs, there are locations where we allocate dummy
extent buffers for temporary usage.

Like tree_mod_log_rewind() and get_old_root().

Those dummy extent buffers will be handled by the same eb accessors, and
if they don't have page::private subpage eb accessors can fail.

To address such problems, make __alloc_dummy_extent_buffer() to attach
page private for dummy extent buffers too.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 fs/btrfs/extent_io.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 3158461ebf4c..3bd4b99897d6 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -5146,9 +5146,14 @@  struct extent_buffer *__alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
 
 	num_pages = num_extent_pages(eb);
 	for (i = 0; i < num_pages; i++) {
+		int ret;
+
 		eb->pages[i] = alloc_page(GFP_NOFS);
 		if (!eb->pages[i])
 			goto err;
+		ret = attach_extent_buffer_page(eb, eb->pages[i]);
+		if (ret < 0)
+			goto err;
 	}
 	set_extent_buffer_uptodate(eb);
 	btrfs_set_header_nritems(eb, 0);
@@ -5156,8 +5161,10 @@  struct extent_buffer *__alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
 
 	return eb;
 err:
-	for (; i > 0; i--)
+	for (; i > 0; i--) {
+		detach_extent_buffer_page(eb, eb->pages[i - 1]);
 		__free_page(eb->pages[i - 1]);
+	}
 	__free_extent_buffer(eb);
 	return NULL;
 }