[PATCH v5 05/18] btrfs: make grab_extent_buffer_from_page() handle subpage case
From: Qu Wenruo <hidden>
Date: 2021-01-26 17:24:46
Subsystem:
btrfs file system, filesystems (vfs and infrastructure), the rest · Maintainers:
Chris Mason, David Sterba, Alexander Viro, Christian Brauner, Linus Torvalds
For subpage case, grab_extent_buffer() can't really get an extent buffer just from btrfs_subpage. We have radix tree lock protecting us from inserting the same eb into the tree. Thus we don't really need to do the extra hassle, just let alloc_extent_buffer() handle the existing eb in radix tree. Now if two ebs are being allocated as the same time, one will fail with -EEIXST when inserting into the radix tree. So for grab_extent_buffer(), just always return NULL for subpage case. Signed-off-by: Qu Wenruo <redacted> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> --- fs/btrfs/extent_io.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index ea105cb69e3a..16a29f63cfd1 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c@@ -5282,10 +5282,19 @@ struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info, } #endif -static struct extent_buffer *grab_extent_buffer(struct page *page) +static struct extent_buffer *grab_extent_buffer( + struct btrfs_fs_info *fs_info, struct page *page) { struct extent_buffer *exists; + /* + * For subpage case, we completely rely on radix tree to ensure we + * don't try to insert two ebs for the same bytenr. So here we always + * return NULL and just continue. + */ + if (fs_info->sectorsize < PAGE_SIZE) + return NULL; + /* Page not yet attached to an extent buffer */ if (!PagePrivate(page)) return NULL;
@@ -5371,7 +5380,7 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info, } spin_lock(&mapping->private_lock); - exists = grab_extent_buffer(p); + exists = grab_extent_buffer(fs_info, p); if (exists) { spin_unlock(&mapping->private_lock); unlock_page(p);
--
2.30.0