From a2de733c78fa7af51ba9670482fa7d392aa67c57 Mon Sep 17 00:00:00 2001 From: Arne Jansen Date: Tue, 8 Mar 2011 14:14:00 +0100 Subject: btrfs: scrub This adds an initial implementation for scrub. It works quite straightforward. The usermode issues an ioctl for each device in the fs. For each device, it enumerates the allocated device chunks. For each chunk, the contained extents are enumerated and the data checksums fetched. The extents are read sequentially and the checksums verified. If an error occurs (checksum or EIO), a good copy is searched for. If one is found, the bad copy will be rewritten. All enumerations happen from the commit roots. During a transaction commit, the scrubs get paused and afterwards continue from the new roots. This commit is based on the series originally posted to linux-btrfs with some improvements that resulted from comments from David Sterba, Ilya Dryomov and Jan Schmidt. Signed-off-by: Arne Jansen --- fs/btrfs/scrub.c | 1492 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 1492 insertions(+) create mode 100644 fs/btrfs/scrub.c (limited to 'fs/btrfs/scrub.c') 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 +#include +#include +#include +#include +#include +#include +#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; +} -- cgit v1.2.2 From 96e369208e65a7d017a52361fd572df41fde8472 Mon Sep 17 00:00:00 2001 From: Ilya Dryomov Date: Sat, 9 Apr 2011 14:27:01 +0300 Subject: btrfs scrub: make fixups sync btrfs scrub - make fixups sync, don't reuse fixup bios Fixups are already sync for csum failures, this patch makes them sync for EIO case as well. Fixups are now sharing pages with the parent sbio - instead of allocating a separate page to do a fixup we grab the page from the sbio buffer. Fixup bios are no longer reused. struct fixup is no longer needed, instead pass [sbio pointer, index]. Originally this was added to look at the possibility of sharing the code between drive swap and scrub, but it actually fixes a serious bug in scrub code where errors that could be corrected were ignored and reported as uncorrectable. btrfs scrub - restore bios properly after media errors The current code reallocates a bio after a media error. This is a temporary measure introduced in v3 after a serious problem related to bio reuse was found in v2 of scrub patchset. Basically we did not reset bv_offset and bv_len fields of the bio_vec structure. They are changed in case I/O error happens, for example, at offset 512 or 1024 into the page. Also bi_flags field wasn't properly setup before reusing the bio. Signed-off-by: Arne Jansen --- fs/btrfs/scrub.c | 287 ++++++++++++++++--------------------------------------- 1 file changed, 80 insertions(+), 207 deletions(-) (limited to 'fs/btrfs/scrub.c') diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index 70f9fa772ee9..6a50801ecfa0 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -50,7 +50,6 @@ 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, @@ -59,9 +58,11 @@ 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); +static int scrub_fixup_check(struct scrub_bio *sbio, int ix); +static void scrub_fixup_end_io(struct bio *bio, int err); +static int scrub_fixup_io(int rw, struct block_device *bdev, sector_t sector, + struct page *page); +static void scrub_fixup(struct scrub_bio *sbio, int ix); #define SCRUB_PAGES_PER_BIO 16 /* 64k per bio */ #define SCRUB_BIOS_PER_DEV 16 /* 1 MB per device in flight */ @@ -105,17 +106,6 @@ struct scrub_dev { 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)) { @@ -240,107 +230,34 @@ nomem: */ 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; + if (sbio->err) { + if (scrub_fixup_io(READ, sbio->sdev->dev->bdev, + (sbio->physical + ix * PAGE_SIZE) >> 9, + sbio->bio->bi_io_vec[ix].bv_page) == 0) { + if (scrub_fixup_check(sbio, ix) == 0) + 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); + scrub_fixup(sbio, ix); } -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) +static int scrub_fixup_check(struct scrub_bio *sbio, int ix) { int ret = 1; struct page *page; void *buffer; - u64 flags = fixup->spag.flags; + u64 flags = sbio->spag[ix].flags; - page = fixup->bio->bi_io_vec[0].bv_page; + page = sbio->bio->bi_io_vec[ix].bv_page; buffer = kmap_atomic(page, KM_USER0); if (flags & BTRFS_EXTENT_FLAG_DATA) { - ret = scrub_checksum_data(fixup->sdev, - &fixup->spag, buffer); + ret = scrub_checksum_data(sbio->sdev, + sbio->spag + ix, buffer); } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { - ret = scrub_checksum_tree_block(fixup->sdev, - &fixup->spag, - fixup->logical, + ret = scrub_checksum_tree_block(sbio->sdev, + sbio->spag + ix, + sbio->logical + ix * PAGE_SIZE, buffer); } else { WARN_ON(1); @@ -350,51 +267,25 @@ static int scrub_fixup_check(struct scrub_fixup *fixup) 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) +static void scrub_fixup(struct scrub_bio *sbio, int ix) { - struct scrub_dev *sdev = fixup->sdev; + struct scrub_dev *sdev = sbio->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 logical = sbio->logical + ix * PAGE_SIZE; u64 length; int i; int ret; DECLARE_COMPLETION_ONSTACK(complete); - if ((fixup->spag.flags & BTRFS_EXTENT_FLAG_DATA) && - (fixup->spag.have_csum == 0)) { + if ((sbio->spag[ix].flags & BTRFS_EXTENT_FLAG_DATA) && + (sbio->spag[ix].have_csum == 0)) { /* * nodatasum, don't try to fix anything * FIXME: we can do better, open the inode and trigger a @@ -404,71 +295,49 @@ static void scrub_fixup(struct scrub_fixup *fixup) } length = PAGE_SIZE; - ret = btrfs_map_block(map_tree, REQ_WRITE, fixup->logical, &length, + ret = btrfs_map_block(map_tree, REQ_WRITE, 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); + (unsigned long long)logical); WARN_ON(1); return; } - if (multi->num_stripes == 1) { + 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) + if (i == sbio->spag[ix].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)) + if (scrub_fixup_io(READ, multi->stripes[i].dev->bdev, + multi->stripes[i].physical >> 9, + sbio->bio->bi_io_vec[ix].bv_page)) { /* I/O-error, this is not a good copy */ continue; + } - ret = scrub_fixup_check(fixup); - if (ret == 0) + if (scrub_fixup_check(sbio, ix) == 0) break; } if (i == multi->num_stripes) goto uncorrectable; /* - * the bio now contains good data, write it back + * bi_io_vec[ix].bv_page 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)) + if (scrub_fixup_io(WRITE, sdev->dev->bdev, + (sbio->physical + ix * PAGE_SIZE) >> 9, + sbio->bio->bi_io_vec[ix].bv_page)) { /* I/O-error, writeback failed, give up */ goto uncorrectable; + } kfree(multi); spin_lock(&sdev->stat_lock); @@ -477,7 +346,7 @@ static void scrub_fixup(struct scrub_fixup *fixup) if (printk_ratelimit()) printk(KERN_ERR "btrfs: fixed up at %llu\n", - (unsigned long long)fixup->logical); + (unsigned long long)logical); return; uncorrectable: @@ -488,7 +357,32 @@ uncorrectable: if (printk_ratelimit()) printk(KERN_ERR "btrfs: unable to fixup at %llu\n", - (unsigned long long)fixup->logical); + (unsigned long long)logical); +} + +static int scrub_fixup_io(int rw, struct block_device *bdev, sector_t sector, + struct page *page) +{ + struct bio *bio = NULL; + int ret; + DECLARE_COMPLETION_ONSTACK(complete); + + /* we are going to wait on this IO */ + rw |= REQ_SYNC | REQ_UNPLUG; + + bio = bio_alloc(GFP_NOFS, 1); + bio->bi_bdev = bdev; + bio->bi_sector = sector; + bio_add_page(bio, page, PAGE_SIZE, 0); + bio->bi_end_io = scrub_fixup_end_io; + bio->bi_private = &complete; + submit_bio(rw, bio); + + wait_for_completion(&complete); + + ret = !test_bit(BIO_UPTODATE, &bio->bi_flags); + bio_put(bio); + return ret; } static void scrub_bio_end_io(struct bio *bio, int err) @@ -514,44 +408,24 @@ static void scrub_checksum(struct btrfs_work *work) int ret; if (sbio->err) { - struct bio *bio; - struct bio *old_bio; - for (i = 0; i < sbio->count; ++i) scrub_recheck_error(sbio, i); + + sbio->bio->bi_flags &= ~(BIO_POOL_MASK - 1); + sbio->bio->bi_flags |= 1 << BIO_UPTODATE; + sbio->bio->bi_phys_segments = 0; + sbio->bio->bi_idx = 0; + + for (i = 0; i < sbio->count; i++) { + struct bio_vec *bi; + bi = &sbio->bio->bi_io_vec[i]; + bi->bv_offset = 0; + bi->bv_len = PAGE_SIZE; + } + 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) { @@ -581,7 +455,6 @@ out: 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); } -- cgit v1.2.2 From 8628764e1a5e1998a42b9713e9edea7753653d01 Mon Sep 17 00:00:00 2001 From: Arne Jansen Date: Wed, 23 Mar 2011 16:34:19 +0100 Subject: btrfs: add readonly flag setting the readonly flag prevents writes in case an error is detected Signed-off-by: Arne Jansen --- fs/btrfs/scrub.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) (limited to 'fs/btrfs/scrub.c') diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index 6a50801ecfa0..a31f2a9bd2e2 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -42,7 +42,6 @@ * - 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 */ @@ -99,6 +98,7 @@ struct scrub_dev { u16 csum_size; struct list_head csum_list; atomic_t cancel_req; + int readonly; /* * statistics */ @@ -329,14 +329,16 @@ static void scrub_fixup(struct scrub_bio *sbio, int ix) if (i == multi->num_stripes) goto uncorrectable; - /* - * bi_io_vec[ix].bv_page now contains good data, write it back - */ - if (scrub_fixup_io(WRITE, sdev->dev->bdev, - (sbio->physical + ix * PAGE_SIZE) >> 9, - sbio->bio->bi_io_vec[ix].bv_page)) { - /* I/O-error, writeback failed, give up */ - goto uncorrectable; + if (!sdev->readonly) { + /* + * bi_io_vec[ix].bv_page now contains good data, write it back + */ + if (scrub_fixup_io(WRITE, sdev->dev->bdev, + (sbio->physical + ix * PAGE_SIZE) >> 9, + sbio->bio->bi_io_vec[ix].bv_page)) { + /* I/O-error, writeback failed, give up */ + goto uncorrectable; + } } kfree(multi); @@ -1156,7 +1158,7 @@ static noinline_for_stack void scrub_workers_put(struct btrfs_root *root) int btrfs_scrub_dev(struct btrfs_root *root, u64 devid, u64 start, u64 end, - struct btrfs_scrub_progress *progress) + struct btrfs_scrub_progress *progress, int readonly) { struct scrub_dev *sdev; struct btrfs_fs_info *fs_info = root->fs_info; @@ -1209,6 +1211,7 @@ int btrfs_scrub_dev(struct btrfs_root *root, u64 devid, u64 start, u64 end, scrub_workers_put(root); return PTR_ERR(sdev); } + sdev->readonly = readonly; dev->scrub_device = sdev; atomic_inc(&fs_info->scrubs_running); -- cgit v1.2.2