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>

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index cad9ebe45692626210ca57f56a35913c79fca35b..726e58b762959f5f5c603090056ae257339be863 100644 (file)
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -90,8 +90,7 @@ static struct bio *__bio_alloc(struct f2fs_sb_info *sbi, block_t blk_addr,
 {
        struct bio *bio;
 
-       /* No failure on bio allocation */
-       bio = bio_alloc(GFP_NOIO, npages);
+       bio = f2fs_bio_alloc(npages);
 
        bio->bi_bdev = sbi->sb->s_bdev;
        bio->bi_iter.bi_sector = SECTOR_FROM_BLOCK(blk_addr);

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 830848836da5a0c8ed3c619de9e2ed38787dcb55..00591f7257444609d69005afca1b12f633344231 100644 (file)
--- 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)
 {

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 1b4265639f07ec88dc207a1ff64bd6d60bc9a0ad..6273e2cde93e751330c0aa29be3ffcbd80e9a8cb 100644 (file)
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -330,10 +330,12 @@ repeat:
                return 0;
 
        if (!llist_empty(&fcc->issue_list)) {
-               struct bio *bio = bio_alloc(GFP_NOIO, 0);
+               struct bio *bio;
                struct flush_cmd *cmd, *next;
                int ret;
 
+               bio = f2fs_bio_alloc(0);
+
                fcc->dispatch_list = llist_del_all(&fcc->issue_list);
                fcc->dispatch_list = llist_reverse_order(fcc->dispatch_list);
 
@@ -365,8 +367,15 @@ int f2fs_issue_flush(struct f2fs_sb_info *sbi)
        if (test_opt(sbi, NOBARRIER))
                return 0;
 
-       if (!test_opt(sbi, FLUSH_MERGE))
-               return blkdev_issue_flush(sbi->sb->s_bdev, GFP_KERNEL, NULL);
+       if (!test_opt(sbi, FLUSH_MERGE)) {
+               struct bio *bio = f2fs_bio_alloc(0);
+               int ret;
+
+               bio->bi_bdev = sbi->sb->s_bdev;
+               ret = submit_bio_wait(WRITE_FLUSH, bio);
+               bio_put(bio);
+               return ret;
+       }
 
        init_completion(&cmd.wait);