| From | Jiri Slaby <> | Subject | [PATCH 3.12 028/100] tmpfs: don't undo fallocate past its last page | Date | Fri, 19 Aug 2016 09:10:27 +0200 |
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From: Anthony Romano <anthony.romano@coreos.com>
3.12-stable review patch. If anyone has any objections, please let me know.
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commit b9b4bb26af017dbe930cd4df7f9b2fc3a0497bfe upstream.
When fallocate is interrupted it will undo a range that extends one byte past its range of allocated pages. This can corrupt an in-use page by zeroing out its first byte. Instead, undo using the inclusive byte range.
Fixes: 1635f6a74152f1d ("tmpfs: undo fallocation on failure") Link: http://lkml.kernel.org/r/1462713387-16724-1-git-send-email-anthony.romano@coreos.com Signed-off-by: Anthony Romano <anthony.romano@coreos.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Brandon Philips <brandon@ifup.co> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Jiri Slaby <jslaby@suse.cz> --- mm/shmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/shmem.c b/mm/shmem.c index e9502a67e300..ff42f161fc32 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1897,7 +1897,7 @@ static long shmem_fallocate(struct file *file, int mode, loff_t offset, /* Remove the !PageUptodate pages we added */ shmem_undo_range(inode, (loff_t)start << PAGE_CACHE_SHIFT, - (loff_t)index << PAGE_CACHE_SHIFT, true); + ((loff_t)index << PAGE_CACHE_SHIFT) - 1, true); goto undone; } -- 2.9.3
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