f2fs: handle failed bio allocation

As the below comment of bio_alloc_bioset, f2fs can allocate multiple bios at the
same time. So, we can't guarantee that bio is allocated all the time.

"
 *   When @bs is not NULL, if %__GFP_WAIT is set then bio_alloc will always be
 *   able to allocate a bio. This is due to the mempool guarantees. To make this
 *   work, callers must never allocate more than 1 bio at a time from this pool.
 *   Callers that need to allocate more than 1 bio must always submit the
 *   previously allocated bio for IO before attempting to allocate a new one.
 *   Failure to do so can cause deadlocks under memory pressure.
"

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 15 insertions, 0 deletions

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 830848836da5..00591f725744 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -19,6 +19,7 @@
 #include <linux/magic.h>
 #include <linux/kobject.h>
 #include <linux/sched.h>
+#include <linux/bio.h>
 
 #ifdef CONFIG_F2FS_CHECK_FS
 #define f2fs_bug_on(sbi, condition)	BUG_ON(condition)
@@ -1253,6 +1254,20 @@ retry:
 	return entry;
 }
 
+static inline struct bio *f2fs_bio_alloc(int npages)
+{
+	struct bio *bio;
+
+	/* No failure on bio allocation */
+retry:
+	bio = bio_alloc(GFP_NOIO, npages);
+	if (!bio) {
+		cond_resched();
+		goto retry;
+	}
+	return bio;
+}
+
 static inline void f2fs_radix_tree_insert(struct radix_tree_root *root,
 				unsigned long index, void *item)
 {