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authorLinus Torvalds <torvalds@linux-foundation.org>2018-12-28 04:07:35 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-12-28 04:07:35 +0300
commitbc77789a491cdc6f47e5bbd1d04ddd283d64658b (patch)
tree7ee181b42c600a6456be1d337f47ff60f1c955c2 /fs/iomap.c
parent47a43f2f0ce24bb75e3e4500118000585a3b496a (diff)
parent3cc31fa65d85610574c0f6a474e89f4c419923d5 (diff)
downloadlinux-bc77789a491cdc6f47e5bbd1d04ddd283d64658b.tar.xz
Merge tag 'iomap-4.21-merge-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
Pull iomap update from Darrick Wong: "Fix a memory overflow bug for blocksize < pagesize" * tag 'iomap-4.21-merge-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: iomap: don't search past page end in iomap_is_partially_uptodate
Diffstat (limited to 'fs/iomap.c')
-rw-r--r--fs/iomap.c17
1 files changed, 15 insertions, 2 deletions
diff --git a/fs/iomap.c b/fs/iomap.c
index d6bc98ae8d35..ce837d962d47 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -492,16 +492,29 @@ done:
}
EXPORT_SYMBOL_GPL(iomap_readpages);
+/*
+ * iomap_is_partially_uptodate checks whether blocks within a page are
+ * uptodate or not.
+ *
+ * Returns true if all blocks which correspond to a file portion
+ * we want to read within the page are uptodate.
+ */
int
iomap_is_partially_uptodate(struct page *page, unsigned long from,
unsigned long count)
{
struct iomap_page *iop = to_iomap_page(page);
struct inode *inode = page->mapping->host;
- unsigned first = from >> inode->i_blkbits;
- unsigned last = (from + count - 1) >> inode->i_blkbits;
+ unsigned len, first, last;
unsigned i;
+ /* Limit range to one page */
+ len = min_t(unsigned, PAGE_SIZE - from, count);
+
+ /* First and last blocks in range within page */
+ first = from >> inode->i_blkbits;
+ last = (from + len - 1) >> inode->i_blkbits;
+
if (iop) {
for (i = first; i <= last; i++)
if (!test_bit(i, iop->uptodate))