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btrfs: raid56: migrate recovery and scrub recovery path to use error_bitmap
Since we have rbio::error_bitmap to indicate exactly where the errors
are (including read error and csum mismatch error), we can make recovery
path more accurate.
For example:
0 32K 64K
Data 1 |XXXXXXXX| |
Data 2 | |XXXXXXXXX|
Parity | | |
1) Get csum mismatch when reading data 1 [0, 32K)
2) Mark corresponding range error
The old code will mark the whole data 1 stripe as error.
While the new code will only mark data 1 [0, 32K) as error.
3) Recovery path
The old code will recover data 1 [0, 64K), all using Data 2 and
parity.
This means, Data 1 [32K, 64K) will be corrupted data, as data 2
[32K, 64K) is already corrupted.
While the new code will only recover data 1 [0, 32K), as only
that range has error so far.
This new behavior can avoid populating rbio cache with incorrect data.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Qu Wenruo
David Sterba
parent
2942a50dea
commit
75b4703329
@ -1013,6 +1013,36 @@ static int alloc_rbio_parity_pages(struct btrfs_raid_bio *rbio)
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return 0;
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}
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/*
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* Return the total numer of errors found in the vertical stripe of @sector_nr.
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*
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* @faila and @failb will also be updated to the first and second stripe
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* number of the errors.
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*/
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static int get_rbio_veritical_errors(struct btrfs_raid_bio *rbio, int sector_nr,
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int *faila, int *failb)
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{
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int stripe_nr;
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int found_errors = 0;
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ASSERT(faila && failb);
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*faila = -1;
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*failb = -1;
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for (stripe_nr = 0; stripe_nr < rbio->real_stripes; stripe_nr++) {
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int total_sector_nr = stripe_nr * rbio->stripe_nsectors + sector_nr;
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if (test_bit(total_sector_nr, rbio->error_bitmap)) {
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found_errors++;
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if (*faila < 0)
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*faila = stripe_nr;
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else if (*failb < 0)
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*failb = stripe_nr;
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}
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}
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return found_errors;
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}
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/*
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* Add a single sector @sector into our list of bios for IO.
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*
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@ -1740,14 +1770,15 @@ fail:
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* @*pointers are the pre-allocated pointers by the caller, so we don't
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* need to allocate/free the pointers again and again.
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*/
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static void recover_vertical(struct btrfs_raid_bio *rbio, int sector_nr,
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void **pointers, void **unmap_array)
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static int recover_vertical(struct btrfs_raid_bio *rbio, int sector_nr,
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void **pointers, void **unmap_array)
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{
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struct btrfs_fs_info *fs_info = rbio->bioc->fs_info;
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struct sector_ptr *sector;
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const u32 sectorsize = fs_info->sectorsize;
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const int faila = rbio->faila;
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const int failb = rbio->failb;
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int found_errors;
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int faila;
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int failb;
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int stripe_nr;
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/*
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@ -1756,7 +1787,19 @@ static void recover_vertical(struct btrfs_raid_bio *rbio, int sector_nr,
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*/
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if (rbio->operation == BTRFS_RBIO_PARITY_SCRUB &&
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!test_bit(sector_nr, &rbio->dbitmap))
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return;
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return 0;
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found_errors = get_rbio_veritical_errors(rbio, sector_nr, &faila,
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&failb);
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/*
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* No errors in the veritical stripe, skip it. Can happen for recovery
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* which only part of a stripe failed csum check.
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*/
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if (!found_errors)
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return 0;
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if (found_errors > rbio->bioc->max_errors)
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return -EIO;
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/*
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* Setup our array of pointers with sectors from each stripe
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@ -1766,12 +1809,11 @@ static void recover_vertical(struct btrfs_raid_bio *rbio, int sector_nr,
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*/
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for (stripe_nr = 0; stripe_nr < rbio->real_stripes; stripe_nr++) {
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/*
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* If we're rebuilding a read, we have to use
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* pages from the bio list
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* If we're rebuilding a read, we have to use pages from the
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* bio list if possible.
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*/
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if ((rbio->operation == BTRFS_RBIO_READ_REBUILD ||
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rbio->operation == BTRFS_RBIO_REBUILD_MISSING) &&
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(stripe_nr == faila || stripe_nr == failb)) {
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rbio->operation == BTRFS_RBIO_REBUILD_MISSING)) {
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sector = sector_in_rbio(rbio, stripe_nr, sector_nr, 0);
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} else {
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sector = rbio_stripe_sector(rbio, stripe_nr, sector_nr);
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@ -1859,18 +1901,19 @@ pstripe:
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* Especially if we determine to cache the rbio, we need to
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* have at least all data sectors uptodate.
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*/
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if (rbio->faila >= 0) {
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sector = rbio_stripe_sector(rbio, rbio->faila, sector_nr);
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if (faila >= 0) {
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sector = rbio_stripe_sector(rbio, faila, sector_nr);
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sector->uptodate = 1;
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}
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if (rbio->failb >= 0) {
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sector = rbio_stripe_sector(rbio, rbio->failb, sector_nr);
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if (failb >= 0) {
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sector = rbio_stripe_sector(rbio, failb, sector_nr);
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sector->uptodate = 1;
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}
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cleanup:
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for (stripe_nr = rbio->real_stripes - 1; stripe_nr >= 0; stripe_nr--)
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kunmap_local(unmap_array[stripe_nr]);
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return 0;
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}
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static int recover_sectors(struct btrfs_raid_bio *rbio)
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@ -1893,10 +1936,6 @@ static int recover_sectors(struct btrfs_raid_bio *rbio)
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goto out;
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}
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/* Make sure faila and fail b are in order. */
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if (rbio->faila >= 0 && rbio->failb >= 0 && rbio->faila > rbio->failb)
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swap(rbio->faila, rbio->failb);
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if (rbio->operation == BTRFS_RBIO_READ_REBUILD ||
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rbio->operation == BTRFS_RBIO_REBUILD_MISSING) {
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spin_lock_irq(&rbio->bio_list_lock);
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@ -1906,8 +1945,11 @@ static int recover_sectors(struct btrfs_raid_bio *rbio)
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index_rbio_pages(rbio);
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for (sectornr = 0; sectornr < rbio->stripe_nsectors; sectornr++)
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recover_vertical(rbio, sectornr, pointers, unmap_array);
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for (sectornr = 0; sectornr < rbio->stripe_nsectors; sectornr++) {
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ret = recover_vertical(rbio, sectornr, pointers, unmap_array);
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if (ret < 0)
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break;
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}
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out:
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kfree(pointers);
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@ -1937,13 +1979,21 @@ static int recover_assemble_read_bios(struct btrfs_raid_bio *rbio,
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int sectornr = total_sector_nr % rbio->stripe_nsectors;
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struct sector_ptr *sector;
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if (rbio->faila == stripe || rbio->failb == stripe) {
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/* Skip the current stripe. */
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ASSERT(sectornr == 0);
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total_sector_nr += rbio->stripe_nsectors - 1;
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atomic_inc(&rbio->error);
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/*
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* Skip the range which has error. It can be a range which is
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* marked error (for csum mismatch), or it can be a missing
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* device.
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*/
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if (!rbio->bioc->stripes[stripe].dev->bdev ||
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test_bit(total_sector_nr, rbio->error_bitmap)) {
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/*
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* Also set the error bit for missing device, which
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* may not yet have its error bit set.
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*/
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set_bit(total_sector_nr, rbio->error_bitmap);
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continue;
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}
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sector = rbio_stripe_sector(rbio, stripe, sectornr);
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ret = rbio_add_io_sector(rbio, bio_list, sector, stripe,
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sectornr, REQ_OP_READ);
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@ -1966,9 +2016,8 @@ static int recover_rbio(struct btrfs_raid_bio *rbio)
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/*
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* Either we're doing recover for a read failure or degraded write,
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* caller should have set faila/b and error bitmap correctly.
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* caller should have set error bitmap correctly.
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*/
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ASSERT(rbio->faila >= 0 || rbio->failb >= 0);
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ASSERT(bitmap_weight(rbio->error_bitmap, rbio->nr_sectors));
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bio_list_init(&bio_list);
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@ -1992,12 +2041,6 @@ static int recover_rbio(struct btrfs_raid_bio *rbio)
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submit_read_bios(rbio, &bio_list);
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wait_event(rbio->io_wait, atomic_read(&rbio->stripes_pending) == 0);
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/* We have more errors than our tolerance during the read. */
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if (atomic_read(&rbio->error) > rbio->bioc->max_errors) {
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ret = -EIO;
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goto out;
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}
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ret = recover_sectors(rbio);
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out:
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@ -2032,6 +2075,51 @@ static void recover_rbio_work_locked(struct work_struct *work)
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rbio_orig_end_io(rbio, errno_to_blk_status(ret));
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}
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static void set_rbio_raid6_extra_error(struct btrfs_raid_bio *rbio, int mirror_num)
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{
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bool found = false;
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int sector_nr;
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/*
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* This is for RAID6 extra recovery tries, thus mirror number should
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* be large than 2.
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* Mirror 1 means read from data stripes. Mirror 2 means rebuild using
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* RAID5 methods.
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*/
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ASSERT(mirror_num > 2);
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for (sector_nr = 0; sector_nr < rbio->stripe_nsectors; sector_nr++) {
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int found_errors;
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int faila;
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int failb;
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found_errors = get_rbio_veritical_errors(rbio, sector_nr,
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&faila, &failb);
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/* This vertical stripe doesn't have errors. */
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if (!found_errors)
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continue;
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/*
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* If we found errors, there should be only one error marked
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* by previous set_rbio_range_error().
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*/
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ASSERT(found_errors == 1);
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found = true;
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/* Now select another stripe to mark as error. */
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failb = rbio->real_stripes - (mirror_num - 1);
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if (failb <= faila)
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failb--;
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/* Set the extra bit in error bitmap. */
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if (failb >= 0)
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set_bit(failb * rbio->stripe_nsectors + sector_nr,
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rbio->error_bitmap);
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}
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/* We should found at least one vertical stripe with error.*/
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ASSERT(found);
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}
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/*
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* the main entry point for reads from the higher layers. This
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* is really only called when the normal read path had a failure,
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@ -2074,11 +2162,7 @@ void raid56_parity_recover(struct bio *bio, struct btrfs_io_context *bioc,
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* for 'mirror_num > 2', select a stripe to fail on every retry.
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*/
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if (mirror_num > 2) {
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/*
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* 'mirror == 3' is to fail the p stripe and
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* reconstruct from the q stripe. 'mirror > 3' is to
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* fail a data stripe and reconstruct from p+q stripe.
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*/
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set_rbio_raid6_extra_error(rbio, mirror_num);
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rbio->failb = rbio->real_stripes - (mirror_num - 1);
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ASSERT(rbio->failb > 0);
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if (rbio->failb <= rbio->faila)
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@ -2507,48 +2591,85 @@ static inline int is_data_stripe(struct btrfs_raid_bio *rbio, int stripe)
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static int recover_scrub_rbio(struct btrfs_raid_bio *rbio)
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{
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int dfail = 0, failp = -1;
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void **pointers = NULL;
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void **unmap_array = NULL;
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int sector_nr;
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int ret;
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/* No error case should be already handled by the caller. */
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ASSERT(rbio->faila >= 0 || rbio->failb >= 0);
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if (is_data_stripe(rbio, rbio->faila))
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dfail++;
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else if (is_parity_stripe(rbio->faila))
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failp = rbio->faila;
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if (is_data_stripe(rbio, rbio->failb))
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dfail++;
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else if (is_parity_stripe(rbio->failb))
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failp = rbio->failb;
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/*
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* Because we can not use a scrubbing parity to repair
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* the data, so the capability of the repair is declined.
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* (In the case of RAID5, we can not repair anything)
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* @pointers array stores the pointer for each sector.
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*
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* @unmap_array stores copy of pointers that does not get reordered
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* during reconstruction so that kunmap_local works.
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*/
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if (dfail > rbio->bioc->max_errors - 1)
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return -EIO;
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pointers = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
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unmap_array = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
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if (!pointers || !unmap_array) {
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ret = -ENOMEM;
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goto out;
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}
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/*
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* If all data is good, only parity is correctly, just
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* repair the parity.
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*/
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if (dfail == 0)
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return 0;
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for (sector_nr = 0; sector_nr < rbio->stripe_nsectors; sector_nr++) {
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int dfail = 0, failp = -1;
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int faila;
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int failb;
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int found_errors;
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/*
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* Here means we got one corrupted data stripe and one
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* corrupted parity on RAID6, if the corrupted parity
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* is scrubbing parity, luckily, use the other one to repair
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* the data, or we can not repair the data stripe.
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*/
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if (failp != rbio->scrubp)
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return -EIO;
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found_errors = get_rbio_veritical_errors(rbio, sector_nr,
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&faila, &failb);
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if (found_errors > rbio->bioc->max_errors) {
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ret = -EIO;
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goto out;
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}
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if (found_errors == 0)
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continue;
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/* We have some corrupted sectors, need to repair them. */
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ret = recover_sectors(rbio);
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/* We should have at least one error here. */
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ASSERT(faila >= 0 || failb >= 0);
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if (is_data_stripe(rbio, faila))
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dfail++;
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else if (is_parity_stripe(faila))
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failp = faila;
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if (is_data_stripe(rbio, failb))
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dfail++;
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else if (is_parity_stripe(failb))
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failp = failb;
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/*
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* Because we can not use a scrubbing parity to repair the
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* data, so the capability of the repair is declined. (In the
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* case of RAID5, we can not repair anything.)
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*/
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if (dfail > rbio->bioc->max_errors - 1) {
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ret = -EIO;
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goto out;
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}
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/*
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* If all data is good, only parity is correctly, just repair
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* the parity, no need to recover data stripes.
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*/
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if (dfail == 0)
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continue;
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/*
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* Here means we got one corrupted data stripe and one
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* corrupted parity on RAID6, if the corrupted parity is
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* scrubbing parity, luckily, use the other one to repair the
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* data, or we can not repair the data stripe.
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*/
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if (failp != rbio->scrubp) {
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ret = -EIO;
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goto out;
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}
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ret = recover_vertical(rbio, sector_nr, pointers, unmap_array);
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if (ret < 0)
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goto out;
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}
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out:
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kfree(pointers);
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kfree(unmap_array);
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return ret;
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}
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@ -2624,25 +2745,11 @@ static int scrub_rbio(struct btrfs_raid_bio *rbio)
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submit_read_bios(rbio, &bio_list);
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wait_event(rbio->io_wait, atomic_read(&rbio->stripes_pending) == 0);
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if (atomic_read(&rbio->error) > rbio->bioc->max_errors) {
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ret = -EIO;
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goto cleanup;
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}
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/*
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* No error during read, can finish the scrub and need to verify the
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* P/Q sectors;
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*/
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if (atomic_read(&rbio->error) == 0) {
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need_check = true;
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goto finish;
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}
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/* We have some failures, need to recover the failed sectors first. */
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/* We may have some failures, recover the failed sectors first. */
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ret = recover_scrub_rbio(rbio);
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if (ret < 0)
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goto cleanup;
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finish:
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/*
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* We have every sector properly prepared. Can finish the scrub
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* and writeback the good content.
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