filemap: check compound_head(page)->mapping in pagecache_get_page()

Similar to previous patch, pagecache_get_page() avoids race condition with
truncate by checking page->mapping == mapping.  This does not work for
compound pages.  This patch let it check compound_head(page)->mapping
instead.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Song Liu <[email protected]>
Suggested-by: Johannes Weiner <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Cc: Hillf Danton <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Kirill A. Shutemov <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: William Kucharski <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions