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authorChris Mason <chris.mason@oracle.com>2011-05-23 06:30:52 -0400
committerChris Mason <chris.mason@oracle.com>2011-05-23 06:30:52 -0400
commit712673339a0d085358fd1cd3a6477cc7979bb69f (patch)
treeb2e268685e3cbba19a4adb2a47d853e4e461fcfc /fs/btrfs/scrub.c
parentaa2dfb372a2a647beedac163ce6f8b0fcbefac29 (diff)
parent8628764e1a5e1998a42b9713e9edea7753653d01 (diff)
downloadlinux-stericsson-712673339a0d085358fd1cd3a6477cc7979bb69f.tar.gz
Merge branch 'for-chris' of git://git.kernel.org/pub/scm/linux/kernel/git/arne/btrfs-unstable-arne into inode_numbers
Conflicts: fs/btrfs/Makefile fs/btrfs/ctree.h fs/btrfs/volumes.h Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/scrub.c')
-rw-r--r--fs/btrfs/scrub.c1368
1 files changed, 1368 insertions, 0 deletions
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
new file mode 100644
index 000000000000..87a2f1273136
--- /dev/null
+++ b/fs/btrfs/scrub.c
@@ -0,0 +1,1368 @@
+/*
+ * 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 mode to also read unallocated space
+ * - make the prefetch cancellable
+ */
+
+struct scrub_bio;
+struct scrub_page;
+struct scrub_dev;
+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 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 */
+
+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;
+ int readonly;
+ /*
+ * statistics
+ */
+ struct btrfs_scrub_progress stat;
+ spinlock_t stat_lock;
+};
+
+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)
+{
+ 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;
+ }
+ }
+
+ scrub_fixup(sbio, ix);
+}
+
+static int scrub_fixup_check(struct scrub_bio *sbio, int ix)
+{
+ int ret = 1;
+ struct page *page;
+ void *buffer;
+ u64 flags = sbio->spag[ix].flags;
+
+ 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(sbio->sdev,
+ sbio->spag + ix, buffer);
+ } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
+ ret = scrub_checksum_tree_block(sbio->sdev,
+ sbio->spag + ix,
+ sbio->logical + ix * PAGE_SIZE,
+ buffer);
+ } else {
+ WARN_ON(1);
+ }
+ kunmap_atomic(buffer, KM_USER0);
+
+ return ret;
+}
+
+static void scrub_fixup_end_io(struct bio *bio, int err)
+{
+ complete((struct completion *)bio->bi_private);
+}
+
+static void scrub_fixup(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 btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
+ struct btrfs_multi_bio *multi = NULL;
+ u64 logical = sbio->logical + ix * PAGE_SIZE;
+ u64 length;
+ int i;
+ int ret;
+ DECLARE_COMPLETION_ONSTACK(complete);
+
+ 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
+ * writeback
+ */
+ goto uncorrectable;
+ }
+
+ length = PAGE_SIZE;
+ 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)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 == sbio->spag[ix].mirror_num)
+ continue;
+
+ 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;
+ }
+
+ if (scrub_fixup_check(sbio, ix) == 0)
+ break;
+ }
+ if (i == multi->num_stripes)
+ 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);
+ 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)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)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;
+
+ 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)
+{
+ 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) {
+ 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);
+ 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);
+ 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(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(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(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(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, int readonly)
+{
+ 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);
+ }
+ sdev->readonly = readonly;
+ 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;
+}