Bug fixes for 5.7:

- Fix a problem in readahead where we can crash if we can't allocate a
 full bio due to GFP_NORETRY.
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Merge tag 'iomap-5.7-merge-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull iomap fix from Darrick Wong:
 "Fix a problem in readahead where we can crash if we can't allocate a
  full bio due to GFP_NORETRY"

* tag 'iomap-5.7-merge-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  iomap: Handle memory allocation failure in readahead
This commit is contained in:
Linus Torvalds 2020-04-08 21:37:18 -07:00
commit 9744b923d5
1 changed files with 8 additions and 0 deletions

View File

@ -302,6 +302,7 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
if (!ctx->bio || !is_contig || bio_full(ctx->bio, plen)) {
gfp_t gfp = mapping_gfp_constraint(page->mapping, GFP_KERNEL);
gfp_t orig_gfp = gfp;
int nr_vecs = (length + PAGE_SIZE - 1) >> PAGE_SHIFT;
if (ctx->bio)
@ -310,6 +311,13 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
if (ctx->is_readahead) /* same as readahead_gfp_mask */
gfp |= __GFP_NORETRY | __GFP_NOWARN;
ctx->bio = bio_alloc(gfp, min(BIO_MAX_PAGES, nr_vecs));
/*
* If the bio_alloc fails, try it again for a single page to
* avoid having to deal with partial page reads. This emulates
* what do_mpage_readpage does.
*/
if (!ctx->bio)
ctx->bio = bio_alloc(orig_gfp, 1);
ctx->bio->bi_opf = REQ_OP_READ;
if (ctx->is_readahead)
ctx->bio->bi_opf |= REQ_RAHEAD;