diff options
Diffstat (limited to 'fs/btrfs/scrub.c')
| -rw-r--r-- | fs/btrfs/scrub.c | 1492 |
1 files changed, 1492 insertions, 0 deletions
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c new file mode 100644 index 000000000000..70f9fa772ee9 --- /dev/null +++ b/fs/btrfs/scrub.c @@ -0,0 +1,1492 @@ +/* + * Copyright (C) 2011 STRATO. All rights reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public + * License v2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public + * License along with this program; if not, write to the + * Free Software Foundation, Inc., 59 Temple Place - Suite 330, + * Boston, MA 021110-1307, USA. + */ + +#include <linux/sched.h> +#include <linux/pagemap.h> +#include <linux/writeback.h> +#include <linux/blkdev.h> +#include <linux/rbtree.h> +#include <linux/slab.h> +#include <linux/workqueue.h> +#include "ctree.h" +#include "volumes.h" +#include "disk-io.h" +#include "ordered-data.h" + +/* + * This is only the first step towards a full-features scrub. It reads all + * extent and super block and verifies the checksums. In case a bad checksum + * is found or the extent cannot be read, good data will be written back if + * any can be found. + * + * Future enhancements: + * - To enhance the performance, better read-ahead strategies for the + * extent-tree can be employed. + * - In case an unrepairable extent is encountered, track which files are + * affected and report them + * - In case of a read error on files with nodatasum, map the file and read + * the extent to trigger a writeback of the good copy + * - track and record media errors, throw out bad devices + * - add a readonly mode + * - add a mode to also read unallocated space + * - make the prefetch cancellable + */ + +struct scrub_bio; +struct scrub_page; +struct scrub_dev; +struct scrub_fixup; +static void scrub_bio_end_io(struct bio *bio, int err); +static void scrub_checksum(struct btrfs_work *work); +static int scrub_checksum_data(struct scrub_dev *sdev, + struct scrub_page *spag, void *buffer); +static int scrub_checksum_tree_block(struct scrub_dev *sdev, + struct scrub_page *spag, u64 logical, + void *buffer); +static int scrub_checksum_super(struct scrub_bio *sbio, void *buffer); +static void scrub_recheck_end_io(struct bio *bio, int err); +static void scrub_fixup_worker(struct btrfs_work *work); +static void scrub_fixup(struct scrub_fixup *fixup); + +#define SCRUB_PAGES_PER_BIO 16 /* 64k per bio */ +#define SCRUB_BIOS_PER_DEV 16 /* 1 MB per device in flight */ + +struct scrub_page { + u64 flags; /* extent flags */ + u64 generation; + u64 mirror_num; + int have_csum; + u8 csum[BTRFS_CSUM_SIZE]; +}; + +struct scrub_bio { + int index; + struct scrub_dev *sdev; + struct bio *bio; + int err; + u64 logical; + u64 physical; + struct scrub_page spag[SCRUB_PAGES_PER_BIO]; + u64 count; + int next_free; + struct btrfs_work work; +}; + +struct scrub_dev { + struct scrub_bio *bios[SCRUB_BIOS_PER_DEV]; + struct btrfs_device *dev; + int first_free; + int curr; + atomic_t in_flight; + spinlock_t list_lock; + wait_queue_head_t list_wait; + u16 csum_size; + struct list_head csum_list; + atomic_t cancel_req; + /* + * statistics + */ + struct btrfs_scrub_progress stat; + spinlock_t stat_lock; +}; + +struct scrub_fixup { + struct scrub_dev *sdev; + struct bio *bio; + u64 logical; + u64 physical; + struct scrub_page spag; + struct btrfs_work work; + int err; + int recheck; +}; + +static void scrub_free_csums(struct scrub_dev *sdev) +{ + while (!list_empty(&sdev->csum_list)) { + struct btrfs_ordered_sum *sum; + sum = list_first_entry(&sdev->csum_list, + struct btrfs_ordered_sum, list); + list_del(&sum->list); + kfree(sum); + } +} + +static noinline_for_stack void scrub_free_dev(struct scrub_dev *sdev) +{ + int i; + int j; + struct page *last_page; + + if (!sdev) + return; + + for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) { + struct scrub_bio *sbio = sdev->bios[i]; + struct bio *bio; + + if (!sbio) + break; + + bio = sbio->bio; + if (bio) { + last_page = NULL; + for (j = 0; j < bio->bi_vcnt; ++j) { + if (bio->bi_io_vec[j].bv_page == last_page) + continue; + last_page = bio->bi_io_vec[j].bv_page; + __free_page(last_page); + } + bio_put(bio); + } + kfree(sbio); + } + + scrub_free_csums(sdev); + kfree(sdev); +} + +static noinline_for_stack +struct scrub_dev *scrub_setup_dev(struct btrfs_device *dev) +{ + struct scrub_dev *sdev; + int i; + int j; + int ret; + struct btrfs_fs_info *fs_info = dev->dev_root->fs_info; + + sdev = kzalloc(sizeof(*sdev), GFP_NOFS); + if (!sdev) + goto nomem; + sdev->dev = dev; + for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) { + struct bio *bio; + struct scrub_bio *sbio; + + sbio = kzalloc(sizeof(*sbio), GFP_NOFS); + if (!sbio) + goto nomem; + sdev->bios[i] = sbio; + + bio = bio_kmalloc(GFP_NOFS, SCRUB_PAGES_PER_BIO); + if (!bio) + goto nomem; + + sbio->index = i; + sbio->sdev = sdev; + sbio->bio = bio; + sbio->count = 0; + sbio->work.func = scrub_checksum; + bio->bi_private = sdev->bios[i]; + bio->bi_end_io = scrub_bio_end_io; + bio->bi_sector = 0; + bio->bi_bdev = dev->bdev; + bio->bi_size = 0; + + for (j = 0; j < SCRUB_PAGES_PER_BIO; ++j) { + struct page *page; + page = alloc_page(GFP_NOFS); + if (!page) + goto nomem; + + ret = bio_add_page(bio, page, PAGE_SIZE, 0); + if (!ret) + goto nomem; + } + WARN_ON(bio->bi_vcnt != SCRUB_PAGES_PER_BIO); + + if (i != SCRUB_BIOS_PER_DEV-1) + sdev->bios[i]->next_free = i + 1; + else + sdev->bios[i]->next_free = -1; + } + sdev->first_free = 0; + sdev->curr = -1; + atomic_set(&sdev->in_flight, 0); + atomic_set(&sdev->cancel_req, 0); + sdev->csum_size = btrfs_super_csum_size(&fs_info->super_copy); + INIT_LIST_HEAD(&sdev->csum_list); + + spin_lock_init(&sdev->list_lock); + spin_lock_init(&sdev->stat_lock); + init_waitqueue_head(&sdev->list_wait); + return sdev; + +nomem: + scrub_free_dev(sdev); + return ERR_PTR(-ENOMEM); +} + +/* + * scrub_recheck_error gets called when either verification of the page + * failed or the bio failed to read, e.g. with EIO. In the latter case, + * recheck_error gets called for every page in the bio, even though only + * one may be bad + */ +static void scrub_recheck_error(struct scrub_bio *sbio, int ix) +{ + struct scrub_dev *sdev = sbio->sdev; + struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info; + struct bio *bio = NULL; + struct page *page = NULL; + struct scrub_fixup *fixup = NULL; + int ret; + + /* + * while we're in here we do not want the transaction to commit. + * To prevent it, we increment scrubs_running. scrub_pause will + * have to wait until we're finished + * we can safely increment scrubs_running here, because we're + * in the context of the original bio which is still marked in_flight + */ + atomic_inc(&fs_info->scrubs_running); + + fixup = kzalloc(sizeof(*fixup), GFP_NOFS); + if (!fixup) + goto malloc_error; + + fixup->logical = sbio->logical + ix * PAGE_SIZE; + fixup->physical = sbio->physical + ix * PAGE_SIZE; + fixup->spag = sbio->spag[ix]; + fixup->sdev = sdev; + + bio = bio_alloc(GFP_NOFS, 1); + if (!bio) + goto malloc_error; + bio->bi_private = fixup; + bio->bi_size = 0; + bio->bi_bdev = sdev->dev->bdev; + fixup->bio = bio; + fixup->recheck = 0; + + page = alloc_page(GFP_NOFS); + if (!page) + goto malloc_error; + + ret = bio_add_page(bio, page, PAGE_SIZE, 0); + if (!ret) + goto malloc_error; + + if (!sbio->err) { + /* + * shorter path: just a checksum error, go ahead and correct it + */ + scrub_fixup_worker(&fixup->work); + return; + } + + /* + * an I/O-error occured for one of the blocks in the bio, not + * necessarily for this one, so first try to read it separately + */ + fixup->work.func = scrub_fixup_worker; + fixup->recheck = 1; + bio->bi_end_io = scrub_recheck_end_io; + bio->bi_sector = fixup->physical >> 9; + bio->bi_bdev = sdev->dev->bdev; + submit_bio(0, bio); + + return; + +malloc_error: + if (bio) + bio_put(bio); + if (page) + __free_page(page); + kfree(fixup); + spin_lock(&sdev->stat_lock); + ++sdev->stat.malloc_errors; + spin_unlock(&sdev->stat_lock); + atomic_dec(&fs_info->scrubs_running); + wake_up(&fs_info->scrub_pause_wait); +} + +static void scrub_recheck_end_io(struct bio *bio, int err) +{ + struct scrub_fixup *fixup = bio->bi_private; + struct btrfs_fs_info *fs_info = fixup->sdev->dev->dev_root->fs_info; + + fixup->err = err; + btrfs_queue_worker(&fs_info->scrub_workers, &fixup->work); +} + +static int scrub_fixup_check(struct scrub_fixup *fixup) +{ + int ret = 1; + struct page *page; + void *buffer; + u64 flags = fixup->spag.flags; + + page = fixup->bio->bi_io_vec[0].bv_page; + buffer = kmap_atomic(page, KM_USER0); + if (flags & BTRFS_EXTENT_FLAG_DATA) { + ret = scrub_checksum_data(fixup->sdev, + &fixup->spag, buffer); + } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { + ret = scrub_checksum_tree_block(fixup->sdev, + &fixup->spag, + fixup->logical, + buffer); + } else { + WARN_ON(1); + } + kunmap_atomic(buffer, KM_USER0); + + return ret; +} + +static void scrub_fixup_worker(struct btrfs_work *work) +{ + struct scrub_fixup *fixup; + struct btrfs_fs_info *fs_info; + u64 flags; + int ret = 1; + + fixup = container_of(work, struct scrub_fixup, work); + fs_info = fixup->sdev->dev->dev_root->fs_info; + flags = fixup->spag.flags; + + if (fixup->recheck && fixup->err == 0) + ret = scrub_fixup_check(fixup); + + if (ret || fixup->err) + scrub_fixup(fixup); + + __free_page(fixup->bio->bi_io_vec[0].bv_page); + bio_put(fixup->bio); + + atomic_dec(&fs_info->scrubs_running); + wake_up(&fs_info->scrub_pause_wait); + + kfree(fixup); +} + +static void scrub_fixup_end_io(struct bio *bio, int err) +{ + complete((struct completion *)bio->bi_private); +} + +static void scrub_fixup(struct scrub_fixup *fixup) +{ + struct scrub_dev *sdev = fixup->sdev; + struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info; + struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree; + struct btrfs_multi_bio *multi = NULL; + struct bio *bio = fixup->bio; + u64 length; + int i; + int ret; + DECLARE_COMPLETION_ONSTACK(complete); + + if ((fixup->spag.flags & BTRFS_EXTENT_FLAG_DATA) && + (fixup->spag.have_csum == 0)) { + /* + * nodatasum, don't try to fix anything + * FIXME: we can do better, open the inode and trigger a + * writeback + */ + goto uncorrectable; + } + + length = PAGE_SIZE; + ret = btrfs_map_block(map_tree, REQ_WRITE, fixup->logical, &length, + &multi, 0); + if (ret || !multi || length < PAGE_SIZE) { + printk(KERN_ERR + "scrub_fixup: btrfs_map_block failed us for %llu\n", + (unsigned long long)fixup->logical); + WARN_ON(1); + return; + } + + if (multi->num_stripes == 1) { + /* there aren't any replicas */ + goto uncorrectable; + } + + /* + * first find a good copy + */ + for (i = 0; i < multi->num_stripes; ++i) { + if (i == fixup->spag.mirror_num) + continue; + + bio->bi_sector = multi->stripes[i].physical >> 9; + bio->bi_bdev = multi->stripes[i].dev->bdev; + bio->bi_size = PAGE_SIZE; + bio->bi_next = NULL; + bio->bi_flags |= 1 << BIO_UPTODATE; + bio->bi_comp_cpu = -1; + bio->bi_end_io = scrub_fixup_end_io; + bio->bi_private = &complete; + + submit_bio(0, bio); + + wait_for_completion(&complete); + + if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) + /* I/O-error, this is not a good copy */ + continue; + + ret = scrub_fixup_check(fixup); + if (ret == 0) + break; + } + if (i == multi->num_stripes) + goto uncorrectable; + + /* + * the bio now contains good data, write it back + */ + bio->bi_sector = fixup->physical >> 9; + bio->bi_bdev = sdev->dev->bdev; + bio->bi_size = PAGE_SIZE; + bio->bi_next = NULL; + bio->bi_flags |= 1 << BIO_UPTODATE; + bio->bi_comp_cpu = -1; + bio->bi_end_io = scrub_fixup_end_io; + bio->bi_private = &complete; + + submit_bio(REQ_WRITE, bio); + + wait_for_completion(&complete); + + if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) + /* I/O-error, writeback failed, give up */ + goto uncorrectable; + + kfree(multi); + spin_lock(&sdev->stat_lock); + ++sdev->stat.corrected_errors; + spin_unlock(&sdev->stat_lock); + + if (printk_ratelimit()) + printk(KERN_ERR "btrfs: fixed up at %llu\n", + (unsigned long long)fixup->logical); + return; + +uncorrectable: + kfree(multi); + spin_lock(&sdev->stat_lock); + ++sdev->stat.uncorrectable_errors; + spin_unlock(&sdev->stat_lock); + + if (printk_ratelimit()) + printk(KERN_ERR "btrfs: unable to fixup at %llu\n", + (unsigned long long)fixup->logical); +} + +static void scrub_bio_end_io(struct bio *bio, int err) +{ + struct scrub_bio *sbio = bio->bi_private; + struct scrub_dev *sdev = sbio->sdev; + struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info; + + sbio->err = err; + + btrfs_queue_worker(&fs_info->scrub_workers, &sbio->work); +} + +static void scrub_checksum(struct btrfs_work *work) +{ + struct scrub_bio *sbio = container_of(work, struct scrub_bio, work); + struct scrub_dev *sdev = sbio->sdev; + struct page *page; + void *buffer; + int i; + u64 flags; + u64 logical; + int ret; + + if (sbio->err) { + struct bio *bio; + struct bio *old_bio; + + for (i = 0; i < sbio->count; ++i) + scrub_recheck_error(sbio, i); + spin_lock(&sdev->stat_lock); + ++sdev->stat.read_errors; + spin_unlock(&sdev->stat_lock); + + /* + * FIXME: allocate a new bio after a media error. I haven't + * figured out how to reuse this one + */ + old_bio = sbio->bio; + bio = bio_kmalloc(GFP_NOFS, SCRUB_PAGES_PER_BIO); + if (!bio) { + /* + * alloc failed. cancel the scrub and don't requeue + * this sbio + */ + printk(KERN_ERR "btrfs scrub: allocation failure, " + "cancelling scrub\n"); + atomic_inc(&sdev->dev->dev_root->fs_info-> + scrub_cancel_req); + goto out_no_enqueue; + } + sbio->bio = bio; + bio->bi_private = sbio; + bio->bi_end_io = scrub_bio_end_io; + bio->bi_sector = 0; + bio->bi_bdev = sbio->sdev->dev->bdev; + bio->bi_size = 0; + for (i = 0; i < SCRUB_PAGES_PER_BIO; ++i) { + struct page *page; + page = old_bio->bi_io_vec[i].bv_page; + bio_add_page(bio, page, PAGE_SIZE, 0); + } + bio_put(old_bio); + goto out; + } + for (i = 0; i < sbio->count; ++i) { + page = sbio->bio->bi_io_vec[i].bv_page; + buffer = kmap_atomic(page, KM_USER0); + flags = sbio->spag[i].flags; + logical = sbio->logical + i * PAGE_SIZE; + ret = 0; + if (flags & BTRFS_EXTENT_FLAG_DATA) { + ret = scrub_checksum_data(sdev, sbio->spag + i, buffer); + } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { + ret = scrub_checksum_tree_block(sdev, sbio->spag + i, + logical, buffer); + } else if (flags & BTRFS_EXTENT_FLAG_SUPER) { + BUG_ON(i); + (void)scrub_checksum_super(sbio, buffer); + } else { + WARN_ON(1); + } + kunmap_atomic(buffer, KM_USER0); + if (ret) + scrub_recheck_error(sbio, i); + } + +out: + spin_lock(&sdev->list_lock); + sbio->next_free = sdev->first_free; + sdev->first_free = sbio->index; + spin_unlock(&sdev->list_lock); +out_no_enqueue: + atomic_dec(&sdev->in_flight); + wake_up(&sdev->list_wait); +} + +static int scrub_checksum_data(struct scrub_dev *sdev, + struct scrub_page *spag, void *buffer) +{ + u8 csum[BTRFS_CSUM_SIZE]; + u32 crc = ~(u32)0; + int fail = 0; + struct btrfs_root *root = sdev->dev->dev_root; + + if (!spag->have_csum) + return 0; + + crc = btrfs_csum_data(root, buffer, crc, PAGE_SIZE); + btrfs_csum_final(crc, csum); + if (memcmp(csum, spag->csum, sdev->csum_size)) + fail = 1; + + spin_lock(&sdev->stat_lock); + ++sdev->stat.data_extents_scrubbed; + sdev->stat.data_bytes_scrubbed += PAGE_SIZE; + if (fail) + ++sdev->stat.csum_errors; + spin_unlock(&sdev->stat_lock); + + return fail; +} + +static int scrub_checksum_tree_block(struct scrub_dev *sdev, + struct scrub_page *spag, u64 logical, + void *buffer) +{ + struct btrfs_header *h; + struct btrfs_root *root = sdev->dev->dev_root; + struct btrfs_fs_info *fs_info = root->fs_info; + u8 csum[BTRFS_CSUM_SIZE]; + u32 crc = ~(u32)0; + int fail = 0; + int crc_fail = 0; + + /* + * we don't use the getter functions here, as we + * a) don't have an extent buffer and + * b) the page is already kmapped + */ + h = (struct btrfs_header *)buffer; + + if (logical != le64_to_cpu(h->bytenr)) + ++fail; + + if (spag->generation != le64_to_cpu(h->generation)) + ++fail; + + if (memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE)) + ++fail; + + if (memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid, + BTRFS_UUID_SIZE)) + ++fail; + + crc = btrfs_csum_data(root, buffer + BTRFS_CSUM_SIZE, crc, + PAGE_SIZE - BTRFS_CSUM_SIZE); + btrfs_csum_final(crc, csum); + if (memcmp(csum, h->csum, sdev->csum_size)) + ++crc_fail; + + spin_lock(&sdev->stat_lock); + ++sdev->stat.tree_extents_scrubbed; + sdev->stat.tree_bytes_scrubbed += PAGE_SIZE; + if (crc_fail) + ++sdev->stat.csum_errors; + if (fail) + ++sdev->stat.verify_errors; + spin_unlock(&sdev->stat_lock); + + return fail || crc_fail; +} + +static int scrub_checksum_super(struct scrub_bio *sbio, void *buffer) +{ + struct btrfs_super_block *s; + u64 logical; + struct scrub_dev *sdev = sbio->sdev; + struct btrfs_root *root = sdev->dev->dev_root; + struct btrfs_fs_info *fs_info = root->fs_info; + u8 csum[BTRFS_CSUM_SIZE]; + u32 crc = ~(u32)0; + int fail = 0; + + s = (struct btrfs_super_block *)buffer; + logical = sbio->logical; + + if (logical != le64_to_cpu(s->bytenr)) + ++fail; + + if (sbio->spag[0].generation != le64_to_cpu(s->generation)) + ++fail; + + if (memcmp(s->fsid, fs_info->fsid, BTRFS_UUID_SIZE)) + ++fail; + + crc = btrfs_csum_data(root, buffer + BTRFS_CSUM_SIZE, crc, + PAGE_SIZE - BTRFS_CSUM_SIZE); + btrfs_csum_final(crc, csum); + if (memcmp(csum, s->csum, sbio->sdev->csum_size)) + ++fail; + + if (fail) { + /* + * if we find an error in a super block, we just report it. + * They will get written with the next transaction commit + * anyway + */ + spin_lock(&sdev->stat_lock); + ++sdev->stat.super_errors; + spin_unlock(&sdev->stat_lock); + } + + return fail; +} + +static int scrub_submit(struct scrub_dev *sdev) +{ + struct scrub_bio *sbio; + + if (sdev->curr == -1) + return 0; + + sbio = sdev->bios[sdev->curr]; + + sbio->bio->bi_sector = sbio->physical >> 9; + sbio->bio->bi_size = sbio->count * PAGE_SIZE; + sbio->bio->bi_next = NULL; + sbio->bio->bi_flags |= 1 << BIO_UPTODATE; + sbio->bio->bi_comp_cpu = -1; + sbio->bio->bi_bdev = sdev->dev->bdev; + sbio->err = 0; + sdev->curr = -1; + atomic_inc(&sdev->in_flight); + + submit_bio(0, sbio->bio); + + return 0; +} + +static int scrub_page(struct scrub_dev *sdev, u64 logical, u64 len, + u64 physical, u64 flags, u64 gen, u64 mirror_num, + u8 *csum, int force) +{ + struct scrub_bio *sbio; + +again: + /* + * grab a fresh bio or wait for one to become available + */ + while (sdev->curr == -1) { + spin_lock(&sdev->list_lock); + sdev->curr = sdev->first_free; + if (sdev->curr != -1) { + sdev->first_free = sdev->bios[sdev->curr]->next_free; + sdev->bios[sdev->curr]->next_free = -1; + sdev->bios[sdev->curr]->count = 0; + spin_unlock(&sdev->list_lock); + } else { + spin_unlock(&sdev->list_lock); + wait_event(sdev->list_wait, sdev->first_free != -1); + } + } + sbio = sdev->bios[sdev->curr]; + if (sbio->count == 0) { + sbio->physical = physical; + sbio->logical = logical; + } else if (sbio->physical + sbio->count * PAGE_SIZE != physical) { + scrub_submit(sdev); + goto again; + } + sbio->spag[sbio->count].flags = flags; + sbio->spag[sbio->count].generation = gen; + sbio->spag[sbio->count].have_csum = 0; + sbio->spag[sbio->count].mirror_num = mirror_num; + if (csum) { + sbio->spag[sbio->count].have_csum = 1; + memcpy(sbio->spag[sbio->count].csum, csum, sdev->csum_size); + } + ++sbio->count; + if (sbio->count == SCRUB_PAGES_PER_BIO || force) + scrub_submit(sdev); + + return 0; +} + +static int scrub_find_csum(struct scrub_dev *sdev, u64 logical, u64 len, + u8 *csum) +{ + struct btrfs_ordered_sum *sum = NULL; + int ret = 0; + unsigned long i; + unsigned long num_sectors; + u32 sectorsize = sdev->dev->dev_root->sectorsize; + + while (!list_empty(&sdev->csum_list)) { + sum = list_first_entry(&sdev->csum_list, + struct btrfs_ordered_sum, list); + if (sum->bytenr > logical) + return 0; + if (sum->bytenr + sum->len > logical) + break; + + ++sdev->stat.csum_discards; + list_del(&sum->list); + kfree(sum); + sum = NULL; + } + if (!sum) + return 0; + + num_sectors = sum->len / sectorsize; + for (i = 0; i < num_sectors; ++i) { + if (sum->sums[i].bytenr == logical) { + memcpy(csum, &sum->sums[i].sum, sdev->csum_size); + ret = 1; + break; + } + } + if (ret && i == num_sectors - 1) { + list_del(&sum->list); + kfree(sum); + } + return ret; +} + +/* scrub extent tries to collect up to 64 kB for each bio */ +static int scrub_extent(struct scrub_dev *sdev, u64 logical, u64 len, + u64 physical, u64 flags, u64 gen, u64 mirror_num) +{ + int ret; + u8 csum[BTRFS_CSUM_SIZE]; + + while (len) { + u64 l = min_t(u64, len, PAGE_SIZE); + int have_csum = 0; + + if (flags & BTRFS_EXTENT_FLAG_DATA) { + /* push csums to sbio */ + have_csum = scrub_find_csum(sdev, logical, l, csum); + if (have_csum == 0) + ++sdev->stat.no_csum; + } + ret = scrub_page(sdev, logical, l, physical, flags, gen, + mirror_num, have_csum ? csum : NULL, 0); + if (ret) + return ret; + len -= l; + logical += l; + physical += l; + } + return 0; +} + +static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev, + struct map_lookup *map, int num, u64 base, u64 length) +{ + struct btrfs_path *path; + struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info; + struct btrfs_root *root = fs_info->extent_root; + struct btrfs_root *csum_root = fs_info->csum_root; + struct btrfs_extent_item *extent; + u64 flags; + int ret; + int slot; + int i; + u64 nstripes; + int start_stripe; + struct extent_buffer *l; + struct btrfs_key key; + u64 physical; + u64 logical; + u64 generation; + u64 mirror_num; + + u64 increment = map->stripe_len; + u64 offset; + + nstripes = length; + offset = 0; + do_div(nstripes, map->stripe_len); + if (map->type & BTRFS_BLOCK_GROUP_RAID0) { + offset = map->stripe_len * num; + increment = map->stripe_len * map->num_stripes; + mirror_num = 0; + } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) { + int factor = map->num_stripes / map->sub_stripes; + offset = map->stripe_len * (num / map->sub_stripes); + increment = map->stripe_len * factor; + mirror_num = num % map->sub_stripes; + } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) { + increment = map->stripe_len; + mirror_num = num % map->num_stripes; + } else if (map->type & BTRFS_BLOCK_GROUP_DUP) { + increment = map->stripe_len; + mirror_num = num % map->num_stripes; + } else { + increment = map->stripe_len; + mirror_num = 0; + } + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + path->reada = 2; + path->search_commit_root = 1; + path->skip_locking = 1; + + /* + * find all extents for each stripe and just read them to get + * them into the page cache + * FIXME: we can do better. build a more intelligent prefetching + */ + logical = base + offset; + physical = map->stripes[num].physical; + ret = 0; + for (i = 0; i < nstripes; ++i) { + key.objectid = logical; + key.type = BTRFS_EXTENT_ITEM_KEY; + key.offset = (u64)0; + + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); + if (ret < 0) + goto out; + + l = path->nodes[0]; + slot = path->slots[0]; + btrfs_item_key_to_cpu(l, &key, slot); + if (key.objectid != logical) { + ret = btrfs_previous_item(root, path, 0, + BTRFS_EXTENT_ITEM_KEY); + if (ret < 0) + goto out; + } + + while (1) { + l = path->nodes[0]; + slot = path->slots[0]; + if (slot >= btrfs_header_nritems(l)) { + ret = btrfs_next_leaf(root, path); + if (ret == 0) + continue; + if (ret < 0) + goto out; + + break; + } + btrfs_item_key_to_cpu(l, &key, slot); + + if (key.objectid >= logical + map->stripe_len) + break; + + path->slots[0]++; + } + btrfs_release_path(root, path); + logical += increment; + physical += map->stripe_len; + cond_resched(); + } + + /* + * collect all data csums for the stripe to avoid seeking during + * the scrub. This might currently (crc32) end up to be about 1MB + */ + start_stripe = 0; +again: + logical = base + offset + start_stripe * increment; + for (i = start_stripe; i < nstripes; ++i) { + ret = btrfs_lookup_csums_range(csum_root, logical, + logical + map->stripe_len - 1, + &sdev->csum_list, 1); + if (ret) + goto out; + + logical += increment; + cond_resched(); + } + /* + * now find all extents for each stripe and scrub them + */ + logical = base + offset + start_stripe * increment; + physical = map->stripes[num].physical + start_stripe * map->stripe_len; + ret = 0; + for (i = start_stripe; i < nstripes; ++i) { + /* + * canceled? + */ + if (atomic_read(&fs_info->scrub_cancel_req) || + atomic_read(&sdev->cancel_req)) { + ret = -ECANCELED; + goto out; + } + /* + * check to see if we have to pause + */ + if (atomic_read(&fs_info->scrub_pause_req)) { + /* push queued extents */ + scrub_submit(sdev); + wait_event(sdev->list_wait, + atomic_read(&sdev->in_flight) == 0); + atomic_inc(&fs_info->scrubs_paused); + wake_up(&fs_info->scrub_pause_wait); + mutex_lock(&fs_info->scrub_lock); + while (atomic_read(&fs_info->scrub_pause_req)) { + mutex_unlock(&fs_info->scrub_lock); + wait_event(fs_info->scrub_pause_wait, + atomic_read(&fs_info->scrub_pause_req) == 0); + mutex_lock(&fs_info->scrub_lock); + } + atomic_dec(&fs_info->scrubs_paused); + mutex_unlock(&fs_info->scrub_lock); + wake_up(&fs_info->scrub_pause_wait); + scrub_free_csums(sdev); + start_stripe = i; + goto again; + } + + key.objectid = logical; + key.type = BTRFS_EXTENT_ITEM_KEY; + key.offset = (u64)0; + + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); + if (ret < 0) + goto out; + + l = path->nodes[0]; + slot = path->slots[0]; + btrfs_item_key_to_cpu(l, &key, slot); + if (key.objectid != logical) { + ret = btrfs_previous_item(root, path, 0, + BTRFS_EXTENT_ITEM_KEY); + if (ret < 0) + goto out; + } + + while (1) { + l = path->nodes[0]; + slot = path->slots[0]; + if (slot >= btrfs_header_nritems(l)) { + ret = btrfs_next_leaf(root, path); + if (ret == 0) + continue; + if (ret < 0) + goto out; + + break; + } + btrfs_item_key_to_cpu(l, &key, slot); + + if (key.objectid + key.offset <= logical) + goto next; + + if (key.objectid >= logical + map->stripe_len) + break; + + if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY) + goto next; + + extent = btrfs_item_ptr(l, slot, + struct btrfs_extent_item); + flags = btrfs_extent_flags(l, extent); + generation = btrfs_extent_generation(l, extent); + + if (key.objectid < logical && + (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) { + printk(KERN_ERR + "btrfs scrub: tree block %llu spanning " + "stripes, ignored. logical=%llu\n", + (unsigned long long)key.objectid, + (unsigned long long)logical); + goto next; + } + + /* + * trim extent to this stripe + */ + if (key.objectid < logical) { + key.offset -= logical - key.objectid; + key.objectid = logical; + } + if (key.objectid + key.offset > + logical + map->stripe_len) { + key.offset = logical + map->stripe_len - + key.objectid; + } + + ret = scrub_extent(sdev, key.objectid, key.offset, + key.objectid - logical + physical, + flags, generation, mirror_num); + if (ret) + goto out; + +next: + path->slots[0]++; + } + btrfs_release_path(root, path); + logical += increment; + physical += map->stripe_len; + spin_lock(&sdev->stat_lock); + sdev->stat.last_physical = physical; + spin_unlock(&sdev->stat_lock); + } + /* push queued extents */ + scrub_submit(sdev); + +out: + btrfs_free_path(path); + return ret < 0 ? ret : 0; +} + +static noinline_for_stack int scrub_chunk(struct scrub_dev *sdev, + u64 chunk_tree, u64 chunk_objectid, u64 chunk_offset, u64 length) +{ + struct btrfs_mapping_tree *map_tree = + &sdev->dev->dev_root->fs_info->mapping_tree; + struct map_lookup *map; + struct extent_map *em; + int i; + int ret = -EINVAL; + + read_lock(&map_tree->map_tree.lock); + em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1); + read_unlock(&map_tree->map_tree.lock); + + if (!em) + return -EINVAL; + + map = (struct map_lookup *)em->bdev; + if (em->start != chunk_offset) + goto out; + + if (em->len < length) + goto out; + + for (i = 0; i < map->num_stripes; ++i) { + if (map->stripes[i].dev == sdev->dev) { + ret = scrub_stripe(sdev, map, i, chunk_offset, length); + if (ret) + goto out; + } + } +out: + free_extent_map(em); + + return ret; +} + +static noinline_for_stack +int scrub_enumerate_chunks(struct scrub_dev *sdev, u64 start, u64 end) +{ + struct btrfs_dev_extent *dev_extent = NULL; + struct btrfs_path *path; + struct btrfs_root *root = sdev->dev->dev_root; + struct btrfs_fs_info *fs_info = root->fs_info; + u64 length; + u64 chunk_tree; + u64 chunk_objectid; + u64 chunk_offset; + int ret; + int slot; + struct extent_buffer *l; + struct btrfs_key key; + struct btrfs_key found_key; + struct btrfs_block_group_cache *cache; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + path->reada = 2; + path->search_commit_root = 1; + path->skip_locking = 1; + + key.objectid = sdev->dev->devid; + key.offset = 0ull; + key.type = BTRFS_DEV_EXTENT_KEY; + + + while (1) { + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); + if (ret < 0) + goto out; + ret = 0; + + l = path->nodes[0]; + slot = path->slots[0]; + + btrfs_item_key_to_cpu(l, &found_key, slot); + + if (found_key.objectid != sdev->dev->devid) + break; + + if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY) + break; + + if (found_key.offset >= end) + break; + + if (found_key.offset < key.offset) + break; + + dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent); + length = btrfs_dev_extent_length(l, dev_extent); + + if (found_key.offset + length <= start) { + key.offset = found_key.offset + length; + btrfs_release_path(root, path); + continue; + } + + chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent); + chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent); + chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent); + + /* + * get a reference on the corresponding block group to prevent + * the chunk from going away while we scrub it + */ + cache = btrfs_lookup_block_group(fs_info, chunk_offset); + if (!cache) { + ret = -ENOENT; + goto out; + } + ret = scrub_chunk(sdev, chunk_tree, chunk_objectid, + chunk_offset, length); + btrfs_put_block_group(cache); + if (ret) + break; + + key.offset = found_key.offset + length; + btrfs_release_path(root, path); + } + +out: + btrfs_free_path(path); + return ret; +} + +static noinline_for_stack int scrub_supers(struct scrub_dev *sdev) +{ + int i; + u64 bytenr; + u64 gen; + int ret; + struct btrfs_device *device = sdev->dev; + struct btrfs_root *root = device->dev_root; + + gen = root->fs_info->last_trans_committed; + + for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) { + bytenr = btrfs_sb_offset(i); + if (bytenr + BTRFS_SUPER_INFO_SIZE >= device->total_bytes) + break; + + ret = scrub_page(sdev, bytenr, PAGE_SIZE, bytenr, + BTRFS_EXTENT_FLAG_SUPER, gen, i, NULL, 1); + if (ret) + return ret; + } + wait_event(sdev->list_wait, atomic_read(&sdev->in_flight) == 0); + + return 0; +} + +/* + * get a reference count on fs_info->scrub_workers. start worker if necessary + */ +static noinline_for_stack int scrub_workers_get(struct btrfs_root *root) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + + mutex_lock(&fs_info->scrub_lock); + if (fs_info->scrub_workers_refcnt == 0) + btrfs_start_workers(&fs_info->scrub_workers, 1); + ++fs_info->scrub_workers_refcnt; + mutex_unlock(&fs_info->scrub_lock); + + return 0; +} + +static noinline_for_stack void scrub_workers_put(struct btrfs_root *root) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + + mutex_lock(&fs_info->scrub_lock); + if (--fs_info->scrub_workers_refcnt == 0) + btrfs_stop_workers(&fs_info->scrub_workers); + WARN_ON(fs_info->scrub_workers_refcnt < 0); + mutex_unlock(&fs_info->scrub_lock); +} + + +int btrfs_scrub_dev(struct btrfs_root *root, u64 devid, u64 start, u64 end, + struct btrfs_scrub_progress *progress) +{ + struct scrub_dev *sdev; + struct btrfs_fs_info *fs_info = root->fs_info; + int ret; + struct btrfs_device *dev; + + if (root->fs_info->closing) + return -EINVAL; + + /* + * check some assumptions + */ + if (root->sectorsize != PAGE_SIZE || + root->sectorsize != root->leafsize || + root->sectorsize != root->nodesize) { + printk(KERN_ERR "btrfs_scrub: size assumptions fail\n"); + return -EINVAL; + } + + ret = scrub_workers_get(root); + if (ret) + return ret; + + mutex_lock(&root->fs_info->fs_devices->device_list_mutex); + dev = btrfs_find_device(root, devid, NULL, NULL); + if (!dev || dev->missing) { + mutex_unlock(&root->fs_info->fs_devices->device_list_mutex); + scrub_workers_put(root); + return -ENODEV; + } + mutex_lock(&fs_info->scrub_lock); + + if (!dev->in_fs_metadata) { + mutex_unlock(&fs_info->scrub_lock); + mutex_unlock(&root->fs_info->fs_devices->device_list_mutex); + scrub_workers_put(root); + return -ENODEV; + } + + if (dev->scrub_device) { + mutex_unlock(&fs_info->scrub_lock); + mutex_unlock(&root->fs_info->fs_devices->device_list_mutex); + scrub_workers_put(root); + return -EINPROGRESS; + } + sdev = scrub_setup_dev(dev); + if (IS_ERR(sdev)) { + mutex_unlock(&fs_info->scrub_lock); + mutex_unlock(&root->fs_info->fs_devices->device_list_mutex); + scrub_workers_put(root); + return PTR_ERR(sdev); + } + dev->scrub_device = sdev; + + atomic_inc(&fs_info->scrubs_running); + mutex_unlock(&fs_info->scrub_lock); + mutex_unlock(&root->fs_info->fs_devices->device_list_mutex); + + down_read(&fs_info->scrub_super_lock); + ret = scrub_supers(sdev); + up_read(&fs_info->scrub_super_lock); + + if (!ret) + ret = scrub_enumerate_chunks(sdev, start, end); + + wait_event(sdev->list_wait, atomic_read(&sdev->in_flight) == 0); + + atomic_dec(&fs_info->scrubs_running); + wake_up(&fs_info->scrub_pause_wait); + + if (progress) + memcpy(progress, &sdev->stat, sizeof(*progress)); + + mutex_lock(&fs_info->scrub_lock); + dev->scrub_device = NULL; + mutex_unlock(&fs_info->scrub_lock); + + scrub_free_dev(sdev); + scrub_workers_put(root); + + return ret; +} + +int btrfs_scrub_pause(struct btrfs_root *root) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + + mutex_lock(&fs_info->scrub_lock); + atomic_inc(&fs_info->scrub_pause_req); + while (atomic_read(&fs_info->scrubs_paused) != + atomic_read(&fs_info->scrubs_running)) { + mutex_unlock(&fs_info->scrub_lock); + wait_event(fs_info->scrub_pause_wait, + atomic_read(&fs_info->scrubs_paused) == + atomic_read(&fs_info->scrubs_running)); + mutex_lock(&fs_info->scrub_lock); + } + mutex_unlock(&fs_info->scrub_lock); + + return 0; +} + +int btrfs_scrub_continue(struct btrfs_root *root) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + + atomic_dec(&fs_info->scrub_pause_req); + wake_up(&fs_info->scrub_pause_wait); + return 0; +} + +int btrfs_scrub_pause_super(struct btrfs_root *root) +{ + down_write(&root->fs_info->scrub_super_lock); + return 0; +} + +int btrfs_scrub_continue_super(struct btrfs_root *root) +{ + up_write(&root->fs_info->scrub_super_lock); + return 0; +} + +int btrfs_scrub_cancel(struct btrfs_root *root) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + + mutex_lock(&fs_info->scrub_lock); + if (!atomic_read(&fs_info->scrubs_running)) { + mutex_unlock(&fs_info->scrub_lock); + return -ENOTCONN; + } + + atomic_inc(&fs_info->scrub_cancel_req); + while (atomic_read(&fs_info->scrubs_running)) { + mutex_unlock(&fs_info->scrub_lock); + wait_event(fs_info->scrub_pause_wait, + atomic_read(&fs_info->scrubs_running) == 0); + mutex_lock(&fs_info->scrub_lock); + } + atomic_dec(&fs_info->scrub_cancel_req); + mutex_unlock(&fs_info->scrub_lock); + + return 0; +} + +int btrfs_scrub_cancel_dev(struct btrfs_root *root, struct btrfs_device *dev) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + struct scrub_dev *sdev; + + mutex_lock(&fs_info->scrub_lock); + sdev = dev->scrub_device; + if (!sdev) { + mutex_unlock(&fs_info->scrub_lock); + return -ENOTCONN; + } + atomic_inc(&sdev->cancel_req); + while (dev->scrub_device) { + mutex_unlock(&fs_info->scrub_lock); + wait_event(fs_info->scrub_pause_wait, + dev->scrub_device == NULL); + mutex_lock(&fs_info->scrub_lock); + } + mutex_unlock(&fs_info->scrub_lock); + + return 0; +} +int btrfs_scrub_cancel_devid(struct btrfs_root *root, u64 devid) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + struct btrfs_device *dev; + int ret; + + /* + * we have to hold the device_list_mutex here so the device + * does not go away in cancel_dev. FIXME: find a better solution + */ + mutex_lock(&fs_info->fs_devices->device_list_mutex); + dev = btrfs_find_device(root, devid, NULL, NULL); + if (!dev) { + mutex_unlock(&fs_info->fs_devices->device_list_mutex); + return -ENODEV; + } + ret = btrfs_scrub_cancel_dev(root, dev); + mutex_unlock(&fs_info->fs_devices->device_list_mutex); + + return ret; +} + +int btrfs_scrub_progress(struct btrfs_root *root, u64 devid, + struct btrfs_scrub_progress *progress) +{ + struct btrfs_device *dev; + struct scrub_dev *sdev = NULL; + + mutex_lock(&root->fs_info->fs_devices->device_list_mutex); + dev = btrfs_find_device(root, devid, NULL, NULL); + if (dev) + sdev = dev->scrub_device; + if (sdev) + memcpy(progress, &sdev->stat, sizeof(*progress)); + mutex_unlock(&root->fs_info->fs_devices->device_list_mutex); + + return dev ? (sdev ? 0 : -ENOTCONN) : -ENODEV; +} |