From 819822107d8837fc3363ceaeb172b981c8600a2b Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Tue, 26 Jan 2021 16:33:49 +0800 Subject: btrfs: make grab_extent_buffer_from_page() handle subpage case 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. Reviewed-by: Josef Bacik Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/extent_io.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'fs/btrfs/extent_io.c') diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index e498d496560b..133ff4531472 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -5284,10 +5284,19 @@ free_eb: } #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; @@ -5373,7 +5382,7 @@ 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); -- cgit v1.2.3