On Fri, Mar 11, 2011 at 03:49:40PM +0100, Arne Jansen wrote:
> This is the main scrub code.
>
> Signed-off-by: Arne Jansen <sensille@xxxxxxx>
> ---
> fs/btrfs/Makefile | 2 +-
> fs/btrfs/ctree.h | 14 +
> fs/btrfs/scrub.c | 1463 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 1478 insertions(+), 1 deletions(-)
>
> diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
> index 31610ea..8fda313 100644
> --- a/fs/btrfs/Makefile
> +++ b/fs/btrfs/Makefile
> @@ -7,4 +7,4 @@ btrfs-y += super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \
> extent_map.o sysfs.o struct-funcs.o xattr.o ordered-data.o \
> extent_io.o volumes.o async-thread.o ioctl.o locking.o orphan.o \
> export.o tree-log.o acl.o free-space-cache.o zlib.o lzo.o \
> - compression.o delayed-ref.o relocation.o
> + compression.o delayed-ref.o relocation.o scrub.o
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index 4c99834..030c321 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -2610,4 +2610,18 @@ void btrfs_reloc_pre_snapshot(struct btrfs_trans_handle *trans,
> u64 *bytes_to_reserve);
> void btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
> struct btrfs_pending_snapshot *pending);
> +
> +/* scrub.c */
> +int btrfs_scrub_dev(struct btrfs_root *root, u64 devid, u64 start, u64 end,
> + struct btrfs_scrub_progress *progress);
> +int btrfs_scrub_pause(struct btrfs_root *root);
> +int btrfs_scrub_pause_super(struct btrfs_root *root);
> +int btrfs_scrub_continue(struct btrfs_root *root);
> +int btrfs_scrub_continue_super(struct btrfs_root *root);
> +int btrfs_scrub_cancel(struct btrfs_root *root);
> +int btrfs_scrub_cancel_dev(struct btrfs_root *root, struct btrfs_device *dev);
> +int btrfs_scrub_cancel_devid(struct btrfs_root *root, u64 devid);
> +int btrfs_scrub_progress(struct btrfs_root *root, u64 devid,
> + struct btrfs_scrub_progress *progress);
> +
> #endif
> diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
> new file mode 100644
> index 0000000..d606f4d
> --- /dev/null
> +++ b/fs/btrfs/scrub.c
> @@ -0,0 +1,1463 @@
> +/*
> + * 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
> + */
> +
> +#ifdef SCRUB_BTRFS_WORKER
> +typedef struct btrfs_work scrub_work_t;
> +#define SCRUB_INIT_WORK(work, fn) do { (work)->func = (fn); } while (0)
> +#define SCRUB_QUEUE_WORK(wq, w) do { btrfs_queue_worker(&(wq), w); } while (0)
> +#else
> +typedef struct work_struct scrub_work_t;
> +#define SCRUB_INIT_WORK INIT_WORK
> +#define SCRUB_QUEUE_WORK queue_work
> +#endif
> +
> +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(scrub_work_t *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(scrub_work_t *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;
> + scrub_work_t work;
> +};
> +
> +struct scrub_dev {
> + struct scrub_bio bios[SCRUB_BIOS_PER_DEV];
sizeof(struct scrub_bio) == 1160
SCRUB_BIOS_PER_DEV == 16
> + 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;
> +};
sizeof(struct scrub_dev) == 18760 on an x86_64, an order 3 allocation in
scrub_setup_dev()
> +
> +struct scrub_fixup {
> + struct scrub_dev *sdev;
> + struct bio *bio;
> + u64 logical;
> + u64 physical;
> + struct scrub_page spag;
> + scrub_work_t 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 bio *bio = sdev->bios[i].bio;
> + if (bio)
^^^^^
stop when we found something to free?
> + break;
> +
> + last_page = NULL;
> + for (j = 0; j < bio->bi_vcnt; ++j) {
^^^
and dereference it.
> + if (bio->bi_io_vec[i].bv_page == last_page)
> + continue;
> + last_page = bio->bi_io_vec[i].bv_page;
> + __free_page(last_page);
> + }
> + bio_put(sdev->bios[i].bio);
> + }
> +
> + 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;
(coding style expects a newline here)
> + 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;
> +
> + bio = bio_alloc(GFP_NOFS, SCRUB_PAGES_PER_BIO);
> + if (!bio)
> + goto nomem;
> +
> + sdev->bios[i].index = i;
> + sdev->bios[i].sdev = sdev;
> + sdev->bios[i].bio = bio;
> + sdev->bios[i].count = 0;
> + SCRUB_INIT_WORK(&sdev->bios[i].work, 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);
When taking the 'goto nomem' path, either all bios are leaked, or the
check in scrub_free_dev is buggy ...
> + 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
> + */
> + mutex_lock(&fs_info->scrub_lock);
> + atomic_inc(&fs_info->scrubs_running);
> + mutex_unlock(&fs_info->scrub_lock);
> +
> + 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; /* FIXME: temporary for add_page */
> + 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
> + */
> + SCRUB_INIT_WORK(&fixup->work, 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);
> + if (fixup)
> + kfree(fixup);
> + spin_lock(&sdev->stat_lock);
> + ++sdev->stat.malloc_errors;
> + spin_unlock(&sdev->stat_lock);
> + mutex_lock(&fs_info->scrub_lock);
> + atomic_dec(&fs_info->scrubs_running);
> + mutex_unlock(&fs_info->scrub_lock);
> + 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;
> + SCRUB_QUEUE_WORK(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(scrub_work_t *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);
> +
> + mutex_lock(&fs_info->scrub_lock);
> + atomic_dec(&fs_info->scrubs_running);
> + mutex_unlock(&fs_info->scrub_lock);
> + 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 %lld\n",
> + 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 (~bio->bi_flags & BIO_UPTODATE)
> + /* 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 (~bio->bi_flags & BIO_UPTODATE)
> + /* 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 %lld\n", 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 %lld\n",
> + 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;
> +
> + SCRUB_QUEUE_WORK(fs_info->scrub_workers, &sbio->work);
> +}
> +
> +static void scrub_checksum(scrub_work_t *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);
> + }
> + 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;
> + 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) {
> + unsigned long flags;
> + spin_lock_irqsave(&sdev->list_lock, flags);
Is this called from an interrupt or why is the _irqsave variant used?
> + 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_irqrestore(&sdev->list_lock, flags);
> + } else {
> + spin_unlock_irqrestore(&sdev->list_lock, flags);
> + 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;
> + int 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 + key.offset <= logical)
> + goto next1;
> +
> + if (key.objectid >= logical + map->stripe_len)
> + break;
> +next1:
> + 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 * map->stripe_len;
> + physical = map->stripes[num].physical + start_stripe * map->stripe_len;
> + 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 * map->stripe_len;
> + 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);
> + 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 %lld spanning "
> + "stripes, ignored. logical=%lld\n",
> + key.objectid, 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;
> +
> + 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)
> + return -EINVAL;
> +
> + if (em->len < length)
> + return -EINVAL;
> +
> + 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)
> + return ret;
> + }
> + }
> + return 0;
> +}
> +
> +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) {
> +#ifdef SCRUB_BTRFS_WORKER
> + btrfs_start_workers(&fs_info->scrub_workers, 1);
> +#else
> + fs_info->scrub_workers = create_workqueue("scrub");
> + if (!fs_info->scrub_workers) {
> + mutex_unlock(&fs_info->scrub_lock);
> + return -ENOMEM;
> + }
> +#endif
> + }
> + ++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)
This func is always called immediately after a mutex_unlock(scrub_lock),
and then takes the lock again. I suggest to drop locking here and adjust
all callsites.
Same applies for scrub_workers_get()
> +{
> + struct btrfs_fs_info *fs_info = root->fs_info;
> +
> + mutex_lock(&fs_info->scrub_lock);
> + if (--fs_info->scrub_workers_refcnt == 0) {
> +#ifdef SCRUB_BTRFS_WORKER
> + btrfs_stop_workers(&fs_info->scrub_workers);
> +#else
> + destroy_workqueue(fs_info->scrub_workers);
> + fs_info->scrub_workers = NULL;
> +#endif
> +
> + }
> + 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->scrub_device) {
> + mutex_unlock(&fs_info->scrub_lock);
> + scrub_workers_put(root);
> + return -EINPROGRESS;
> + }
> + sdev = scrub_setup_dev(dev);
> + if (IS_ERR(sdev)) {
> + mutex_unlock(&fs_info->scrub_lock);
> + 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);
> +
> + mutex_lock(&fs_info->scrub_lock);
> + atomic_dec(&fs_info->scrubs_running);
> + mutex_unlock(&fs_info->scrub_lock);
> + 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;
> +}
> --
> 1.7.3.4
>
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