Updates for 4.21:

- Fix a memory overflow bug for blocksize < pagesize
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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
This commit is contained in:
Linus Torvalds 2018-12-27 17:07:35 -08:00
commit bc77789a49
1 changed files with 15 additions and 2 deletions

View File

@ -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))