[RFC PATCH 3/6] btrfs: don't set ->private on swapcache pages

[Omar Sandoval]

Swapcache pages use ->private to store the swp_entry_t; overwriting it is sure
to cause insanity.

Signed-off-by: Omar Sandoval <osan...@osandov.com>
---
 fs/btrfs/extent_io.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 9b67b37..54b2d00 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2824,6 +2824,7 @@ static int submit_extent_page(int rw, struct 
extent_io_tree *tree,
 static void attach_extent_buffer_page(struct extent_buffer *eb,
                                      struct page *page)
 {
+       BUG_ON(PageSwapCache(page));
        if (!PagePrivate(page)) {
                SetPagePrivate(page);
                page_cache_get(page);
@@ -2835,6 +2836,7 @@ static void attach_extent_buffer_page(struct 
extent_buffer *eb,
 
 void set_page_extent_mapped(struct page *page)
 {
+       BUG_ON(PageSwapCache(page));
        if (!PagePrivate(page)) {
                SetPagePrivate(page);
                page_cache_get(page);
@@ -2903,7 +2905,8 @@ static int __do_readpage(struct extent_io_tree *tree,
        size_t blocksize = inode->i_sb->s_blocksize;
        unsigned long this_bio_flag = *bio_flags & EXTENT_BIO_PARENT_LOCKED;
 
-       set_page_extent_mapped(page);
+       if (likely(!PageSwapCache(page)))
+               set_page_extent_mapped(page);
 
        end = page_end;
        if (!PageUptodate(page)) {
-- 
2.1.3

--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html