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Commit b4ee1782 authored by Omar Sandoval's avatar Omar Sandoval Committed by Chris Mason
Browse files

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: default avatarOmar Sandoval <osandov@fb.com>
Signed-off-by: default avatarChris Mason <clm@fb.com>
parent 7cb2c420

fs/btrfs/raid56.c

+77 −10
Original line number Diff line number Diff line
@@ -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 @@ 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 {
@@ -1964,6 +1975,8 @@ static void __raid_recover_end_io(struct btrfs_raid_bio *rbio) 
		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 @@ static int __raid56_parity_recover(struct btrfs_raid_bio *rbio) 
	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);

}

fs/btrfs/raid56.h

+8 −2
Original line number Diff line number Diff line
@@ -48,15 +48,21 @@ int raid56_parity_recover(struct btrfs_root *root, struct bio *bio, 
int raid56_parity_write(struct btrfs_root *root, struct bio *bio,

			       struct btrfs_bio *bbio, u64 stripe_len);



void raid56_add_scrub_pages(struct btrfs_raid_bio *rbio, struct page *page,

			    u64 logical);



struct btrfs_raid_bio *

raid56_parity_alloc_scrub_rbio(struct btrfs_root *root, struct bio *bio,

			       struct btrfs_bio *bbio, u64 stripe_len,

			       struct btrfs_device *scrub_dev,

			       unsigned long *dbitmap, int stripe_nsectors);

void raid56_parity_add_scrub_pages(struct btrfs_raid_bio *rbio,

				   struct page *page, u64 logical);

void raid56_parity_submit_scrub_rbio(struct btrfs_raid_bio *rbio);



struct btrfs_raid_bio *

raid56_alloc_missing_rbio(struct btrfs_root *root, struct bio *bio,

			  struct btrfs_bio *bbio, u64 length);

void raid56_submit_missing_rbio(struct btrfs_raid_bio *rbio);



int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info);

void btrfs_free_stripe_hash_table(struct btrfs_fs_info *info);

#endif

fs/btrfs/scrub.c

+1 −2
Original line number Diff line number Diff line
@@ -2720,8 +2720,7 @@ static void scrub_parity_check_and_repair(struct scrub_parity *sparity) 
		goto rbio_out;



	list_for_each_entry(spage, &sparity->spages, list)

		raid56_parity_add_scrub_pages(rbio, spage->page,

					      spage->logical);

		raid56_add_scrub_pages(rbio, spage->page, spage->logical);



	scrub_pending_bio_inc(sctx);

	raid56_parity_submit_scrub_rbio(rbio);