filemap: check compound_head(page)->mapping in pagecache_get_page()
authorSong Liu <songliubraving@fb.com>
Mon, 23 Sep 2019 22:37:47 +0000 (15:37 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 24 Sep 2019 22:54:11 +0000 (15:54 -0700)
commit31895438e702f48e25b7aa6d88f9c97c795c79c7
tree6d3bf756856dcab897ef9f8cf6d284079711435a
parent585e5a7babd91fd85a5cc97b7324c6c2fc29e1ec
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/20190801184244.3169074-3-songliubraving@fb.com
Signed-off-by: Song Liu <songliubraving@fb.com>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/filemap.c