| From: Vincent Whitchurch <vincent.whitchurch@axis.com> |
| Subject: squashfs: fix page update race |
| Date: Fri, 26 May 2023 15:25:45 +0200 |
| |
| We only put the page into the cache after we've read it, so the |
| PageUptodate() check should not be necessary. In fact, it's actively |
| harmful since the check could fail (since we used find_get_page() and not |
| find_lock_page()) and we could end up submitting a page for I/O after it |
| has been read and while it's actively being used, which could lead to |
| corruption depending on what the block driver does with it. |
| |
| Link: https://lkml.kernel.org/r/20230526-squashfs-cache-fixup-v1-1-d54a7fa23e7b@axis.com |
| Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com> |
| Reviewed-by: Christoph Hellwig <hch@lst.de> |
| Reviewed-by: Phillip Lougher <phillip@squashfs.org.uk> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| --- |
| |
| fs/squashfs/block.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/fs/squashfs/block.c~squashfs-cache-partial-compressed-blocks-fix-2 |
| +++ a/fs/squashfs/block.c |
| @@ -92,7 +92,7 @@ static int squashfs_bio_read_cached(stru |
| bio_for_each_segment_all(bv, fullbio, iter_all) { |
| struct page *page = bv->bv_page; |
| |
| - if (page->mapping == cache_mapping && PageUptodate(page)) { |
| + if (page->mapping == cache_mapping) { |
| idx++; |
| continue; |
| } |
| _ |
