From b4ee1782686d5b7a97826d67fdeaefaedbca23ce Mon Sep 17 00:00:00 2001 From: Omar Sandoval Date: Fri, 19 Jun 2015 11:52:50 -0700 Subject: Btrfs: add RAID 5/6 BTRFS_RBIO_REBUILD_MISSING operation The current RAID 5/6 recovery code isn't quite prepared to handle missing devices. In particular, it expects a bio that we previously attempted to use in the read path, meaning that it has valid pages allocated. However, missing devices have a NULL blkdev, and we can't call bio_add_page() on a bio with a NULL blkdev. We could do manual manipulation of bio->bi_io_vec, but that's pretty gross. So instead, add a separate path that allows us to manually add pages to the rbio. Signed-off-by: Omar Sandoval Signed-off-by: Chris Mason --- fs/btrfs/raid56.c | 87 ++++++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 77 insertions(+), 10 deletions(-) (limited to 'fs/btrfs/raid56.c') diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c index fa72068bd256..6fe2613ef288 100644 --- a/fs/btrfs/raid56.c +++ b/fs/btrfs/raid56.c @@ -61,9 +61,10 @@ #define RBIO_CACHE_SIZE 1024 enum btrfs_rbio_ops { - BTRFS_RBIO_WRITE = 0, - BTRFS_RBIO_READ_REBUILD = 1, - BTRFS_RBIO_PARITY_SCRUB = 2, + BTRFS_RBIO_WRITE, + BTRFS_RBIO_READ_REBUILD, + BTRFS_RBIO_PARITY_SCRUB, + BTRFS_RBIO_REBUILD_MISSING, }; struct btrfs_raid_bio { @@ -602,6 +603,10 @@ static int rbio_can_merge(struct btrfs_raid_bio *last, cur->operation == BTRFS_RBIO_PARITY_SCRUB) return 0; + if (last->operation == BTRFS_RBIO_REBUILD_MISSING || + cur->operation == BTRFS_RBIO_REBUILD_MISSING) + return 0; + return 1; } @@ -793,7 +798,10 @@ static noinline void unlock_stripe(struct btrfs_raid_bio *rbio) if (next->operation == BTRFS_RBIO_READ_REBUILD) async_read_rebuild(next); - else if (next->operation == BTRFS_RBIO_WRITE) { + else if (next->operation == BTRFS_RBIO_REBUILD_MISSING) { + steal_rbio(rbio, next); + async_read_rebuild(next); + } else if (next->operation == BTRFS_RBIO_WRITE) { steal_rbio(rbio, next); async_rmw_stripe(next); } else if (next->operation == BTRFS_RBIO_PARITY_SCRUB) { @@ -1809,7 +1817,8 @@ static void __raid_recover_end_io(struct btrfs_raid_bio *rbio) faila = rbio->faila; failb = rbio->failb; - if (rbio->operation == BTRFS_RBIO_READ_REBUILD) { + if (rbio->operation == BTRFS_RBIO_READ_REBUILD || + rbio->operation == BTRFS_RBIO_REBUILD_MISSING) { spin_lock_irq(&rbio->bio_list_lock); set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags); spin_unlock_irq(&rbio->bio_list_lock); @@ -1834,7 +1843,8 @@ static void __raid_recover_end_io(struct btrfs_raid_bio *rbio) * if we're rebuilding a read, we have to use * pages from the bio list */ - if (rbio->operation == BTRFS_RBIO_READ_REBUILD && + if ((rbio->operation == BTRFS_RBIO_READ_REBUILD || + rbio->operation == BTRFS_RBIO_REBUILD_MISSING) && (stripe == faila || stripe == failb)) { page = page_in_rbio(rbio, stripe, pagenr, 0); } else { @@ -1943,7 +1953,8 @@ pstripe: * if we're rebuilding a read, we have to use * pages from the bio list */ - if (rbio->operation == BTRFS_RBIO_READ_REBUILD && + if ((rbio->operation == BTRFS_RBIO_READ_REBUILD || + rbio->operation == BTRFS_RBIO_REBUILD_MISSING) && (stripe == faila || stripe == failb)) { page = page_in_rbio(rbio, stripe, pagenr, 0); } else { @@ -1964,6 +1975,8 @@ cleanup_io: else clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags); + rbio_orig_end_io(rbio, err, err == 0); + } else if (rbio->operation == BTRFS_RBIO_REBUILD_MISSING) { rbio_orig_end_io(rbio, err, err == 0); } else if (err == 0) { rbio->faila = -1; @@ -2101,7 +2114,8 @@ out: return 0; cleanup: - if (rbio->operation == BTRFS_RBIO_READ_REBUILD) + if (rbio->operation == BTRFS_RBIO_READ_REBUILD || + rbio->operation == BTRFS_RBIO_REBUILD_MISSING) rbio_orig_end_io(rbio, -EIO, 0); return -EIO; } @@ -2232,8 +2246,9 @@ raid56_parity_alloc_scrub_rbio(struct btrfs_root *root, struct bio *bio, return rbio; } -void raid56_parity_add_scrub_pages(struct btrfs_raid_bio *rbio, - struct page *page, u64 logical) +/* Used for both parity scrub and missing. */ +void raid56_add_scrub_pages(struct btrfs_raid_bio *rbio, struct page *page, + u64 logical) { int stripe_offset; int index; @@ -2668,3 +2683,55 @@ void raid56_parity_submit_scrub_rbio(struct btrfs_raid_bio *rbio) if (!lock_stripe_add(rbio)) async_scrub_parity(rbio); } + +/* The following code is used for dev replace of a missing RAID 5/6 device. */ + +struct btrfs_raid_bio * +raid56_alloc_missing_rbio(struct btrfs_root *root, struct bio *bio, + struct btrfs_bio *bbio, u64 length) +{ + struct btrfs_raid_bio *rbio; + + rbio = alloc_rbio(root, bbio, length); + if (IS_ERR(rbio)) + return NULL; + + rbio->operation = BTRFS_RBIO_REBUILD_MISSING; + bio_list_add(&rbio->bio_list, bio); + /* + * This is a special bio which is used to hold the completion handler + * and make the scrub rbio is similar to the other types + */ + ASSERT(!bio->bi_iter.bi_size); + + rbio->faila = find_logical_bio_stripe(rbio, bio); + if (rbio->faila == -1) { + BUG(); + kfree(rbio); + return NULL; + } + + return rbio; +} + +static void missing_raid56_work(struct btrfs_work *work) +{ + struct btrfs_raid_bio *rbio; + + rbio = container_of(work, struct btrfs_raid_bio, work); + __raid56_parity_recover(rbio); +} + +static void async_missing_raid56(struct btrfs_raid_bio *rbio) +{ + btrfs_init_work(&rbio->work, btrfs_rmw_helper, + missing_raid56_work, NULL, NULL); + + btrfs_queue_work(rbio->fs_info->rmw_workers, &rbio->work); +} + +void raid56_submit_missing_rbio(struct btrfs_raid_bio *rbio) +{ + if (!lock_stripe_add(rbio)) + async_missing_raid56(rbio); +} -- cgit v1.2.3