diff options
| -rw-r--r-- | fs/btrfs/extent_io.c | 17 |
1 files changed, 8 insertions, 9 deletions
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index e9c74ce9623f..96039dd56c72 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -5009,8 +5009,11 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info, uptodate = 0; /* - * see below about how we avoid a nasty race with release page - * and why we unlock later + * We can't unlock the pages just yet since the extent buffer + * hasn't been properly inserted in the radix tree, this + * opens a race with btree_releasepage which can free a page + * while we are still filling in all pages for the buffer and + * we could crash. */ } if (uptodate) @@ -5039,13 +5042,9 @@ again: set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags); /* - * there is a race where release page may have - * tried to find this extent buffer in the radix - * but failed. It will tell the VM it is safe to - * reclaim the, and it will clear the page private bit. - * We must make sure to set the page private bit properly - * after the extent buffer is in the radix tree so - * it doesn't get lost + * Now it's safe to unlock the pages because any calls to + * btree_releasepage will correctly detect that a page belongs to a + * live buffer and won't free them prematurely. */ for (i = 0; i < num_pages; i++) unlock_page(eb->pages[i]); |