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Commit abbb3b8e authored by David Sterba's avatar David Sterba
Browse files

btrfs: split write_dev_supers to two functions 



There are two independent parts, one that writes the superblocks and
another that waits for completion. No functional changes, but cleanups,
reformatting and comment updates.

Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 35c70103

fs/btrfs/disk-io.c

+73 −56
Original line number Diff line number Diff line
@@ -3373,19 +3373,17 @@ struct buffer_head *btrfs_read_dev_super(struct block_device *bdev) 
}



/*

 * this should be called twice, once with wait == 0 and

 * once with wait == 1.  When wait == 0 is done, all the buffer heads

 * we write are pinned.

 * Write superblock @sb to the @device. Do not wait for completion, all the

 * buffer heads we write are pinned.

 *

 * They are released when wait == 1 is done.

 * max_mirrors must be the same for both runs, and it indicates how

 * many supers on this one device should be written.

 * Write @max_mirrors copies of the superblock, where 0 means default that fit

 * the expected device size at commit time. Note that max_mirrors must be

 * same for write and wait phases.

 *

 * max_mirrors == 0 means to write them all.

 * Return number of errors when buffer head is not found or submission fails.

 */

static int write_dev_supers(struct btrfs_device *device,

			    struct btrfs_super_block *sb,

			    int wait, int max_mirrors)

			    struct btrfs_super_block *sb, int max_mirrors)

{

	struct buffer_head *bh;

	int i;
@@ -3403,37 +3401,14 @@ static int write_dev_supers(struct btrfs_device *device, 
		    device->commit_total_bytes)

			break;



		if (wait) {

			bh = __find_get_block(device->bdev, bytenr / 4096,

					      BTRFS_SUPER_INFO_SIZE);

			if (!bh) {

				errors++;

				continue;

			}

			wait_on_buffer(bh);

			if (!buffer_uptodate(bh))

				errors++;



			/* drop our reference */

			brelse(bh);



			/* drop the reference from the wait == 0 run */

			brelse(bh);

			continue;

		} else {

		btrfs_set_super_bytenr(sb, bytenr);



		crc = ~(u32)0;

			crc = btrfs_csum_data((const char *)sb +

					      BTRFS_CSUM_SIZE, crc,

					      BTRFS_SUPER_INFO_SIZE -

					      BTRFS_CSUM_SIZE);

		crc = btrfs_csum_data((const char *)sb + BTRFS_CSUM_SIZE, crc,

				      BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);

		btrfs_csum_final(crc, sb->csum);



			/*

			 * one reference for us, and we leave it for the

			 * caller

			 */

		/* One reference for us, and we leave it for the caller */

		bh = __getblk(device->bdev, bytenr / 4096,

			      BTRFS_SUPER_INFO_SIZE);

		if (!bh) {
@@ -3453,7 +3428,6 @@ static int write_dev_supers(struct btrfs_device *device, 
		lock_buffer(bh);

		bh->b_end_io = btrfs_end_buffer_write_sync;

		bh->b_private = device;

		}



		/*

		 * we fua the first super.  The others we allow
@@ -3471,6 +3445,49 @@ static int write_dev_supers(struct btrfs_device *device, 
	return errors < i ? 0 : -1;

}



/*

 * Wait for write completion of superblocks done by write_dev_supers,

 * @max_mirrors same for write and wait phases.

 *

 * Return number of errors when buffer head is not found or not marked up to

 * date.

 */

static int wait_dev_supers(struct btrfs_device *device, int max_mirrors)

{

	struct buffer_head *bh;

	int i;

	int errors = 0;

	u64 bytenr;



	if (max_mirrors == 0)

		max_mirrors = BTRFS_SUPER_MIRROR_MAX;



	for (i = 0; i < max_mirrors; i++) {

		bytenr = btrfs_sb_offset(i);

		if (bytenr + BTRFS_SUPER_INFO_SIZE >=

		    device->commit_total_bytes)

			break;



		bh = __find_get_block(device->bdev, bytenr / 4096,

				      BTRFS_SUPER_INFO_SIZE);

		if (!bh) {

			errors++;

			continue;

		}

		wait_on_buffer(bh);

		if (!buffer_uptodate(bh))

			errors++;



		/* drop our reference */

		brelse(bh);



		/* drop the reference from the writing run */

		brelse(bh);

	}



	return errors < i ? 0 : -1;

}



/*

 * endio for the write_dev_flush, this will wake anyone waiting

 * for the barrier when it is done
@@ -3668,7 +3685,7 @@ int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors) 
		flags = btrfs_super_flags(sb);

		btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);



		ret = write_dev_supers(dev, sb, 0, max_mirrors);

		ret = write_dev_supers(dev, sb, max_mirrors);

		if (ret)

			total_errors++;

	}
@@ -3691,7 +3708,7 @@ int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors) 
		if (!dev->in_fs_metadata || !dev->writeable)

			continue;



		ret = write_dev_supers(dev, sb, 1, max_mirrors);

		ret = wait_dev_supers(dev, max_mirrors);

		if (ret)

			total_errors++;

	}