Commit ea1f0ced authored by Christoph Hellwig's avatar Christoph Hellwig Committed by David Sterba
Browse files

btrfs: handle allocation failure in btrfs_wq_submit_bio gracefully 



btrfs_wq_submit_bio is used for writeback under memory pressure.
Instead of failing the I/O when we can't allocate the async_submit_bio,
just punt back to the synchronous submission path.

Reviewed-by: default avatarNikolay Borisov <nborisov@suse.com>
Tested-by: default avatarNikolay Borisov <nborisov@suse.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 82443fd5

fs/btrfs/disk-io.c

+24 −19
Original line number Diff line number Diff line
@@ -759,8 +759,15 @@ static void run_one_async_free(struct btrfs_work *work) 
	kfree(async);

}



blk_status_t btrfs_wq_submit_bio(struct inode *inode, struct bio *bio,

				 int mirror_num, u64 dio_file_offset,

/*

 * Submit bio to an async queue.

 *

 * Retrun:

 * - true if the work has been succesfuly submitted

 * - false in case of error

 */

bool btrfs_wq_submit_bio(struct inode *inode, struct bio *bio, int mirror_num,

			 u64 dio_file_offset,

			 extent_submit_bio_start_t *submit_bio_start)

{

	struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
@@ -768,7 +775,7 @@ blk_status_t btrfs_wq_submit_bio(struct inode *inode, struct bio *bio, 


	async = kmalloc(sizeof(*async), GFP_NOFS);

	if (!async)

		return BLK_STS_RESOURCE;

		return false;



	async->inode = inode;

	async->bio = bio;
@@ -786,7 +793,7 @@ blk_status_t btrfs_wq_submit_bio(struct inode *inode, struct bio *bio, 
		btrfs_queue_work(fs_info->hipri_workers, &async->work);

	else

		btrfs_queue_work(fs_info->workers, &async->work);

	return 0;

	return true;

}



static blk_status_t btree_csum_one_bio(struct bio *bio)
@@ -840,25 +847,23 @@ void btrfs_submit_metadata_bio(struct inode *inode, struct bio *bio, int mirror_ 
		btrfs_submit_bio(fs_info, bio, mirror_num);

		return;

	}

	if (!should_async_write(fs_info, BTRFS_I(inode))) {

		ret = btree_csum_one_bio(bio);

		if (!ret) {

			btrfs_submit_bio(fs_info, bio, mirror_num);

			return;

		}

	} else {



	/*

		 * kthread helpers are used to submit writes so that

		 * checksumming can happen in parallel across all CPUs

	 * Kthread helpers are used to submit writes so that checksumming can

	 * happen in parallel across all CPUs.

	 */

		ret = btrfs_wq_submit_bio(inode, bio, mirror_num, 0,

					  btree_submit_bio_start);

	}

	if (should_async_write(fs_info, BTRFS_I(inode)) &&

	    btrfs_wq_submit_bio(inode, bio, mirror_num, 0, btree_submit_bio_start))

		return;



	ret = btree_csum_one_bio(bio);

	if (ret) {

		bio->bi_status = ret;

		bio_endio(bio);

		return;

	}



	btrfs_submit_bio(fs_info, bio, mirror_num);

}



#ifdef CONFIG_MIGRATION

fs/btrfs/disk-io.h

+3 −3
Original line number Diff line number Diff line
@@ -114,8 +114,8 @@ int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid, 
			  int atomic);

int btrfs_read_extent_buffer(struct extent_buffer *buf, u64 parent_transid,

			     int level, struct btrfs_key *first_key);

blk_status_t btrfs_wq_submit_bio(struct inode *inode, struct bio *bio,

				 int mirror_num, u64 dio_file_offset,

bool btrfs_wq_submit_bio(struct inode *inode, struct bio *bio, int mirror_num,

			 u64 dio_file_offset,

			 extent_submit_bio_start_t *submit_bio_start);

blk_status_t btrfs_submit_bio_done(void *private_data, struct bio *bio,

			  int mirror_num);

fs/btrfs/inode.c

+9 −8
Original line number Diff line number Diff line
@@ -2674,11 +2674,10 @@ void btrfs_submit_data_write_bio(struct inode *inode, struct bio *bio, int mirro 
	if (!(bi->flags & BTRFS_INODE_NODATASUM) &&

	    !test_bit(BTRFS_FS_STATE_NO_CSUMS, &fs_info->fs_state) &&

	    !btrfs_is_data_reloc_root(bi->root)) {

		if (!atomic_read(&bi->sync_writers)) {

			ret = btrfs_wq_submit_bio(inode, bio, mirror_num, 0,

						  btrfs_submit_bio_start);

			goto out;

		}

		if (!atomic_read(&bi->sync_writers) &&

		    btrfs_wq_submit_bio(inode, bio, mirror_num, 0,

					btrfs_submit_bio_start))

			return;



		ret = btrfs_csum_one_bio(bi, bio, (u64)-1, false);

		if (ret)
@@ -8027,9 +8026,11 @@ static inline blk_status_t btrfs_submit_dio_bio(struct bio *bio, 


	if (btrfs_op(bio) == BTRFS_MAP_WRITE) {

		/* Check btrfs_submit_data_write_bio() for async submit rules */

		if (async_submit && !atomic_read(&BTRFS_I(inode)->sync_writers))

			return btrfs_wq_submit_bio(inode, bio, 0, file_offset,

					btrfs_submit_bio_start_direct_io);

		if (async_submit && !atomic_read(&BTRFS_I(inode)->sync_writers) &&

		    btrfs_wq_submit_bio(inode, bio, 0, file_offset,

					btrfs_submit_bio_start_direct_io))

			return BLK_STS_OK;



		/*

		 * If we aren't doing async submit, calculate the csum of the

		 * bio now.