From abbb3b8ebfec577390873d33076d56bc6e758939 Mon Sep 17 00:00:00 2001 From: David Sterba Date: Fri, 16 Jun 2017 00:50:33 +0200 Subject: [PATCH] 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: David Sterba --- fs/btrfs/disk-io.c | 129 +++++++++++++++++++++++++-------------------- 1 file changed, 73 insertions(+), 56 deletions(-) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index a42ae7676759..b72711ad7121 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -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; @@ -3403,57 +3401,33 @@ 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++; + btrfs_set_super_bytenr(sb, bytenr); - /* drop our reference */ - brelse(bh); + crc = ~(u32)0; + crc = btrfs_csum_data((const char *)sb + BTRFS_CSUM_SIZE, crc, + BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE); + btrfs_csum_final(crc, sb->csum); - /* drop the reference from the wait == 0 run */ - brelse(bh); + /* One reference for us, and we leave it for the caller */ + bh = __getblk(device->bdev, bytenr / 4096, + BTRFS_SUPER_INFO_SIZE); + if (!bh) { + btrfs_err(device->fs_info, + "couldn't get super buffer head for bytenr %llu", + bytenr); + errors++; 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); - btrfs_csum_final(crc, sb->csum); - - /* - * one reference for us, and we leave it for the - * caller - */ - bh = __getblk(device->bdev, bytenr / 4096, - BTRFS_SUPER_INFO_SIZE); - if (!bh) { - btrfs_err(device->fs_info, - "couldn't get super buffer head for bytenr %llu", - bytenr); - errors++; - continue; - } + } - memcpy(bh->b_data, sb, BTRFS_SUPER_INFO_SIZE); + memcpy(bh->b_data, sb, BTRFS_SUPER_INFO_SIZE); - /* one reference for submit_bh */ - get_bh(bh); + /* one reference for submit_bh */ + get_bh(bh); - set_buffer_uptodate(bh); - lock_buffer(bh); - bh->b_end_io = btrfs_end_buffer_write_sync; - bh->b_private = device; - } + set_buffer_uptodate(bh); + 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++; } -- 2.20.1