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 <osandov@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index fa72068..6fe2613 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 @@
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 @@
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 @@
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 @@
* 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 @@
* 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 {
@@ -1965,6 +1976,8 @@
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;
rbio->failb = -1;
@@ -2101,7 +2114,8 @@
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 @@
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 @@
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);
+}
diff --git a/fs/btrfs/raid56.h b/fs/btrfs/raid56.h
index 2b5d797..8b69469 100644
--- a/fs/btrfs/raid56.h
+++ b/fs/btrfs/raid56.h
@@ -48,15 +48,21 @@
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
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index a12c450..0381624 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -2720,8 +2720,7 @@
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);