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Commit bc77789a authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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
parents 47a43f2f 3cc31fa6

fs/iomap.c

+15 −2
Original line number Diff line number Diff line
@@ -492,16 +492,29 @@ iomap_readpages(struct address_space *mapping, struct list_head *pages, 
}

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))