* [PATCH 3/3] Btrfs: change scrub to support big blocks
2012-03-23 14:59 [PATCH 0/3] Btrfs: change scrub to support big blocks Stefan Behrens
2012-03-23 14:59 ` [PATCH 1/3] Btrfs: introduce common define for max number of mirrors Stefan Behrens
2012-03-23 14:59 ` [PATCH 2/3] Btrfs: minor cleanup in scrub Stefan Behrens
@ 2012-03-23 14:59 ` Stefan Behrens
2 siblings, 0 replies; 4+ messages in thread
From: Stefan Behrens @ 2012-03-23 14:59 UTC (permalink / raw)
To: linux-btrfs
Scrub used to be coded for nodesize == leafsize == sectorsize == PAGE_SIZE.
This is now changed to support sizes for nodesize and leafsize which are
N * PAGE_SIZE.
Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
---
fs/btrfs/scrub.c | 1353 ++++++++++++++++++++++++++++++++++++++++--------------
1 files changed, 1013 insertions(+), 340 deletions(-)
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index e68bab4..5221e07 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -40,16 +40,26 @@
* - add a mode to also read unallocated space
*/
+struct scrub_block;
struct scrub_dev;
#define SCRUB_PAGES_PER_BIO 16 /* 64k per bio */
#define SCRUB_BIOS_PER_DEV 16 /* 1 MB per device in flight */
+#define SCRUB_MAX_PAGES_PER_BLOCK 16 /* 64k per node/leaf/sector */
struct scrub_page {
+ struct scrub_block *sblock;
+ struct page *page;
+ struct block_device *bdev;
u64 flags; /* extent flags */
u64 generation;
- int mirror_num;
- int have_csum;
+ u64 logical;
+ u64 physical;
+ struct {
+ unsigned int mirror_num:8;
+ unsigned int have_csum:1;
+ unsigned int io_error:1;
+ };
u8 csum[BTRFS_CSUM_SIZE];
};
@@ -60,12 +70,25 @@ struct scrub_bio {
int err;
u64 logical;
u64 physical;
- struct scrub_page spag[SCRUB_PAGES_PER_BIO];
- u64 count;
+ struct scrub_page *pagev[SCRUB_PAGES_PER_BIO];
+ int page_count;
int next_free;
struct btrfs_work work;
};
+struct scrub_block {
+ struct scrub_page pagev[SCRUB_MAX_PAGES_PER_BLOCK];
+ int page_count;
+ atomic_t outstanding_pages;
+ atomic_t ref_count; /* free mem on transition to zero */
+ struct scrub_dev *sdev;
+ struct {
+ unsigned int header_error:1;
+ unsigned int checksum_error:1;
+ unsigned int no_io_error_seen:1;
+ };
+};
+
struct scrub_dev {
struct scrub_bio *bios[SCRUB_BIOS_PER_DEV];
struct btrfs_device *dev;
@@ -79,6 +102,10 @@ struct scrub_dev {
struct list_head csum_list;
atomic_t cancel_req;
int readonly;
+ int pages_per_bio; /* <= SCRUB_PAGES_PER_BIO */
+ u32 sectorsize;
+ u32 nodesize;
+ u32 leafsize;
/*
* statistics
*/
@@ -107,19 +134,41 @@ struct scrub_warning {
int scratch_bufsize;
};
+
+static int scrub_handle_errored_block(struct scrub_block *sblock_to_check);
+static int scrub_setup_recheck_block(struct scrub_dev *sdev,
+ struct btrfs_mapping_tree *map_tree,
+ u64 length, u64 logical,
+ struct scrub_block *sblock);
+static int scrub_recheck_block(struct btrfs_fs_info *fs_info,
+ struct scrub_block *sblock, int is_metadata,
+ int have_csum, u8 *csum, u64 generation,
+ u16 csum_size);
+static void scrub_recheck_block_checksum(struct btrfs_fs_info *fs_info,
+ struct scrub_block *sblock,
+ int is_metadata, int have_csum,
+ const u8 *csum, u64 generation,
+ u16 csum_size);
+static void scrub_complete_bio_end_io(struct bio *bio, int err);
+static int scrub_repair_block_from_good_copy(struct scrub_block *sblock_bad,
+ struct scrub_block *sblock_good,
+ int force_write);
+static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
+ struct scrub_block *sblock_good,
+ int page_num, int force_write);
+static int scrub_checksum_data(struct scrub_block *sblock);
+static int scrub_checksum_tree_block(struct scrub_block *sblock);
+static int scrub_checksum_super(struct scrub_block *sblock);
+static void scrub_block_get(struct scrub_block *sblock);
+static void scrub_block_put(struct scrub_block *sblock);
+static int scrub_add_page_to_bio(struct scrub_dev *sdev,
+ struct scrub_page *spage);
+static int scrub_pages(struct scrub_dev *sdev, u64 logical, u64 len,
+ u64 physical, u64 flags, u64 gen, int mirror_num,
+ u8 *csum, int force);
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);
+static void scrub_bio_end_io_worker(struct btrfs_work *work);
+static void scrub_block_complete(struct scrub_block *sblock);
static void scrub_free_csums(struct scrub_dev *sdev)
@@ -133,23 +182,6 @@ static void scrub_free_csums(struct scrub_dev *sdev)
}
}
-static void scrub_free_bio(struct bio *bio)
-{
- int i;
- struct page *last_page = NULL;
-
- if (!bio)
- return;
-
- for (i = 0; i < bio->bi_vcnt; ++i) {
- 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(bio);
-}
-
static noinline_for_stack void scrub_free_dev(struct scrub_dev *sdev)
{
int i;
@@ -157,13 +189,23 @@ static noinline_for_stack void scrub_free_dev(struct scrub_dev *sdev)
if (!sdev)
return;
+ /* this can happen when scrub is cancelled */
+ if (sdev->curr != -1) {
+ struct scrub_bio *sbio = sdev->bios[sdev->curr];
+
+ for (i = 0; i < sbio->page_count; i++) {
+ BUG_ON(!sbio->pagev[i]);
+ BUG_ON(!sbio->pagev[i]->page);
+ scrub_block_put(sbio->pagev[i]->sblock);
+ }
+ bio_put(sbio->bio);
+ }
+
for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) {
struct scrub_bio *sbio = sdev->bios[i];
if (!sbio)
break;
-
- scrub_free_bio(sbio->bio);
kfree(sbio);
}
@@ -177,11 +219,16 @@ struct scrub_dev *scrub_setup_dev(struct btrfs_device *dev)
struct scrub_dev *sdev;
int i;
struct btrfs_fs_info *fs_info = dev->dev_root->fs_info;
+ int pages_per_bio;
+ pages_per_bio = min_t(int, SCRUB_PAGES_PER_BIO,
+ bio_get_nr_vecs(dev->bdev));
sdev = kzalloc(sizeof(*sdev), GFP_NOFS);
if (!sdev)
goto nomem;
sdev->dev = dev;
+ sdev->pages_per_bio = pages_per_bio;
+ sdev->curr = -1;
for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) {
struct scrub_bio *sbio;
@@ -192,8 +239,8 @@ struct scrub_dev *scrub_setup_dev(struct btrfs_device *dev)
sbio->index = i;
sbio->sdev = sdev;
- sbio->count = 0;
- sbio->work.func = scrub_checksum;
+ sbio->page_count = 0;
+ sbio->work.func = scrub_bio_end_io_worker;
if (i != SCRUB_BIOS_PER_DEV-1)
sdev->bios[i]->next_free = i + 1;
@@ -201,7 +248,9 @@ struct scrub_dev *scrub_setup_dev(struct btrfs_device *dev)
sdev->bios[i]->next_free = -1;
}
sdev->first_free = 0;
- sdev->curr = -1;
+ sdev->nodesize = dev->dev_root->nodesize;
+ sdev->leafsize = dev->dev_root->leafsize;
+ sdev->sectorsize = dev->dev_root->sectorsize;
atomic_set(&sdev->in_flight, 0);
atomic_set(&sdev->fixup_cnt, 0);
atomic_set(&sdev->cancel_req, 0);
@@ -292,10 +341,9 @@ err:
return 0;
}
-static void scrub_print_warning(const char *errstr, struct scrub_bio *sbio,
- int ix)
+static void scrub_print_warning(const char *errstr, struct scrub_block *sblock)
{
- struct btrfs_device *dev = sbio->sdev->dev;
+ struct btrfs_device *dev = sblock->sdev->dev;
struct btrfs_fs_info *fs_info = dev->dev_root->fs_info;
struct btrfs_path *path;
struct btrfs_key found_key;
@@ -314,8 +362,9 @@ static void scrub_print_warning(const char *errstr, struct scrub_bio *sbio,
swarn.scratch_buf = kmalloc(bufsize, GFP_NOFS);
swarn.msg_buf = kmalloc(bufsize, GFP_NOFS);
- swarn.sector = (sbio->physical + ix * PAGE_SIZE) >> 9;
- swarn.logical = sbio->logical + ix * PAGE_SIZE;
+ BUG_ON(sblock->page_count < 1);
+ swarn.sector = (sblock->pagev[0].physical) >> 9;
+ swarn.logical = sblock->pagev[0].logical;
swarn.errstr = errstr;
swarn.dev = dev;
swarn.msg_bufsize = bufsize;
@@ -530,9 +579,9 @@ out:
spin_lock(&sdev->stat_lock);
++sdev->stat.uncorrectable_errors;
spin_unlock(&sdev->stat_lock);
- printk_ratelimited(KERN_ERR "btrfs: unable to fixup "
- "(nodatasum) error at logical %llu\n",
- fixup->logical);
+ printk_ratelimited(KERN_ERR
+ "btrfs: unable to fixup (nodatasum) error at logical %llu on dev %s\n",
+ (unsigned long long)fixup->logical, sdev->dev->name);
}
btrfs_free_path(path);
@@ -549,91 +598,168 @@ out:
}
/*
- * 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
+ * scrub_handle_errored_block gets called when either verification of the
+ * pages failed or the bio failed to read, e.g. with EIO. In the latter
+ * case, this function handles all pages in the bio, even though only one
+ * may be bad.
+ * The goal of this function is to repair the errored block by using the
+ * contents of one of the mirrors.
*/
-static int scrub_recheck_error(struct scrub_bio *sbio, int ix)
+static int scrub_handle_errored_block(struct scrub_block *sblock_to_check)
{
- struct scrub_dev *sdev = sbio->sdev;
- u64 sector = (sbio->physical + ix * PAGE_SIZE) >> 9;
+ struct scrub_dev *sdev = sblock_to_check->sdev;
+ struct btrfs_fs_info *fs_info;
+ u64 length;
+ u64 logical;
+ u64 generation;
+ unsigned int failed_mirror_index;
+ unsigned int is_metadata;
+ unsigned int have_csum;
+ u8 *csum;
+ struct scrub_block *sblocks_for_recheck; /* holds one for each mirror */
+ struct scrub_block *sblock_bad;
+ int ret;
+ int mirror_index;
+ int page_num;
+ int success;
static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
- DEFAULT_RATELIMIT_BURST);
+ DEFAULT_RATELIMIT_BURST);
+
+ BUG_ON(sblock_to_check->page_count < 1);
+ fs_info = sdev->dev->dev_root->fs_info;
+ length = sblock_to_check->page_count * PAGE_SIZE;
+ logical = sblock_to_check->pagev[0].logical;
+ generation = sblock_to_check->pagev[0].generation;
+ BUG_ON(sblock_to_check->pagev[0].mirror_num < 1);
+ failed_mirror_index = sblock_to_check->pagev[0].mirror_num - 1;
+ is_metadata = !(sblock_to_check->pagev[0].flags &
+ BTRFS_EXTENT_FLAG_DATA);
+ have_csum = sblock_to_check->pagev[0].have_csum;
+ csum = sblock_to_check->pagev[0].csum;
- if (sbio->err) {
- if (scrub_fixup_io(READ, sbio->sdev->dev->bdev, sector,
- sbio->bio->bi_io_vec[ix].bv_page) == 0) {
- if (scrub_fixup_check(sbio, ix) == 0)
- return 0;
- }
- if (__ratelimit(&_rs))
- scrub_print_warning("i/o error", sbio, ix);
- } else {
- if (__ratelimit(&_rs))
- scrub_print_warning("checksum error", sbio, ix);
+ /*
+ * read all mirrors one after the other. This includes to
+ * re-read the extent or metadata block that failed (that was
+ * the cause that this fixup code is called) another time,
+ * page by page this time in order to know which pages
+ * caused I/O errors and which ones are good (for all mirrors).
+ * It is the goal to handle the situation when more than one
+ * mirror contains I/O errors, but the errors do not
+ * overlap, i.e. the data can be repaired by selecting the
+ * pages from those mirrors without I/O error on the
+ * particular pages. One example (with blocks >= 2 * PAGE_SIZE)
+ * would be that mirror #1 has an I/O error on the first page,
+ * the second page is good, and mirror #2 has an I/O error on
+ * the second page, but the first page is good.
+ * Then the first page of the first mirror can be repaired by
+ * taking the first page of the second mirror, and the
+ * second page of the second mirror can be repaired by
+ * copying the contents of the 2nd page of the 1st mirror.
+ * One more note: if the pages of one mirror contain I/O
+ * errors, the checksum cannot be verified. In order to get
+ * the best data for repairing, the first attempt is to find
+ * a mirror without I/O errors and with a validated checksum.
+ * Only if this is not possible, the pages are picked from
+ * mirrors with I/O errors without considering the checksum.
+ * If the latter is the case, at the end, the checksum of the
+ * repaired area is verified in order to correctly maintain
+ * the statistics.
+ */
+
+ sblocks_for_recheck = kzalloc(BTRFS_MAX_MIRRORS *
+ sizeof(*sblocks_for_recheck),
+ GFP_NOFS);
+ if (!sblocks_for_recheck) {
+ spin_lock(&sdev->stat_lock);
+ sdev->stat.malloc_errors++;
+ sdev->stat.read_errors++;
+ sdev->stat.uncorrectable_errors++;
+ spin_unlock(&sdev->stat_lock);
+ goto out;
}
- spin_lock(&sdev->stat_lock);
- ++sdev->stat.read_errors;
- spin_unlock(&sdev->stat_lock);
+ /* setup the context, map the logical blocks and alloc the pages */
+ ret = scrub_setup_recheck_block(sdev, &fs_info->mapping_tree, length,
+ logical, sblocks_for_recheck);
+ if (ret) {
+ spin_lock(&sdev->stat_lock);
+ sdev->stat.read_errors++;
+ sdev->stat.uncorrectable_errors++;
+ spin_unlock(&sdev->stat_lock);
+ goto out;
+ }
+ BUG_ON(failed_mirror_index >= BTRFS_MAX_MIRRORS);
+ sblock_bad = sblocks_for_recheck + failed_mirror_index;
- scrub_fixup(sbio, ix);
- return 1;
-}
+ /* build and submit the bios for the failed mirror, check checksums */
+ ret = scrub_recheck_block(fs_info, sblock_bad, is_metadata, have_csum,
+ csum, generation, sdev->csum_size);
+ if (ret) {
+ spin_lock(&sdev->stat_lock);
+ sdev->stat.read_errors++;
+ sdev->stat.uncorrectable_errors++;
+ spin_unlock(&sdev->stat_lock);
+ goto out;
+ }
-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;
+ if (!sblock_bad->header_error && !sblock_bad->checksum_error &&
+ sblock_bad->no_io_error_seen) {
+ /*
+ * the error disappeared after reading page by page, or
+ * the area was part of a huge bio and other parts of the
+ * bio caused I/O errors, or the block layer merged several
+ * read requests into one and the error is caused by a
+ * different bio (usually one of the two latter cases is
+ * the cause)
+ */
+ spin_lock(&sdev->stat_lock);
+ sdev->stat.unverified_errors++;
+ spin_unlock(&sdev->stat_lock);
- 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);
+ goto out;
}
- kunmap_atomic(buffer, KM_USER0);
- return ret;
-}
+ if (!sblock_bad->no_io_error_seen) {
+ spin_lock(&sdev->stat_lock);
+ sdev->stat.read_errors++;
+ spin_unlock(&sdev->stat_lock);
+ if (__ratelimit(&_rs))
+ scrub_print_warning("i/o error", sblock_to_check);
+ } else if (sblock_bad->checksum_error) {
+ spin_lock(&sdev->stat_lock);
+ sdev->stat.csum_errors++;
+ spin_unlock(&sdev->stat_lock);
+ if (__ratelimit(&_rs))
+ scrub_print_warning("checksum error", sblock_to_check);
+ } else if (sblock_bad->header_error) {
+ spin_lock(&sdev->stat_lock);
+ sdev->stat.verify_errors++;
+ spin_unlock(&sdev->stat_lock);
+ if (__ratelimit(&_rs))
+ scrub_print_warning("checksum/header error",
+ sblock_to_check);
+ }
-static void scrub_fixup_end_io(struct bio *bio, int err)
-{
- complete((struct completion *)bio->bi_private);
-}
+ if (sdev->readonly)
+ goto did_not_correct_error;
+
+ if (!is_metadata && !have_csum) {
+ struct scrub_fixup_nodatasum *fixup_nodatasum;
-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_bio *bbio = NULL;
- struct scrub_fixup_nodatasum *fixup;
- 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)) {
- fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
- if (!fixup)
- goto uncorrectable;
- fixup->sdev = sdev;
- fixup->logical = logical;
- fixup->root = fs_info->extent_root;
- fixup->mirror_num = sbio->spag[ix].mirror_num;
+ /*
+ * !is_metadata and !have_csum, this means that the data
+ * might not be COW'ed, that it might be modified
+ * concurrently. The general strategy to work on the
+ * commit root does not help in the case when COW is not
+ * used.
+ */
+ fixup_nodatasum = kzalloc(sizeof(*fixup_nodatasum), GFP_NOFS);
+ if (!fixup_nodatasum)
+ goto did_not_correct_error;
+ fixup_nodatasum->sdev = sdev;
+ fixup_nodatasum->logical = logical;
+ fixup_nodatasum->root = fs_info->extent_root;
+ fixup_nodatasum->mirror_num = failed_mirror_index + 1;
/*
* increment scrubs_running to prevent cancel requests from
* completing as long as a fixup worker is running. we must also
@@ -648,235 +774,529 @@ static void scrub_fixup(struct scrub_bio *sbio, int ix)
atomic_inc(&fs_info->scrubs_paused);
mutex_unlock(&fs_info->scrub_lock);
atomic_inc(&sdev->fixup_cnt);
- fixup->work.func = scrub_fixup_nodatasum;
- btrfs_queue_worker(&fs_info->scrub_workers, &fixup->work);
- return;
+ fixup_nodatasum->work.func = scrub_fixup_nodatasum;
+ btrfs_queue_worker(&fs_info->scrub_workers,
+ &fixup_nodatasum->work);
+ goto out;
}
- length = PAGE_SIZE;
- ret = btrfs_map_block(map_tree, REQ_WRITE, logical, &length,
- &bbio, 0);
- if (ret || !bbio || length < PAGE_SIZE) {
- printk(KERN_ERR
- "scrub_fixup: btrfs_map_block failed us for %llu\n",
- (unsigned long long)logical);
- WARN_ON(1);
- kfree(bbio);
- return;
+ /*
+ * now build and submit the bios for the other mirrors, check
+ * checksums
+ */
+ for (mirror_index = 0;
+ mirror_index < BTRFS_MAX_MIRRORS &&
+ sblocks_for_recheck[mirror_index].page_count > 0;
+ mirror_index++) {
+ if (mirror_index == failed_mirror_index)
+ continue;
+
+ /* build and submit the bios, check checksums */
+ ret = scrub_recheck_block(fs_info,
+ sblocks_for_recheck + mirror_index,
+ is_metadata, have_csum, csum,
+ generation, sdev->csum_size);
+ if (ret)
+ goto did_not_correct_error;
}
- if (bbio->num_stripes == 1)
- /* there aren't any replicas */
- goto uncorrectable;
+ /*
+ * first try to pick the mirror which is completely without I/O
+ * errors and also does not have a checksum error.
+ * If one is found, and if a checksum is present, the full block
+ * that is known to contain an error is rewritten. Afterwards
+ * the block is known to be corrected.
+ * If a mirror is found which is completely correct, and no
+ * checksum is present, only those pages are rewritten that had
+ * an I/O error in the block to be repaired, since it cannot be
+ * determined, which copy of the other pages is better (and it
+ * could happen otherwise that a correct page would be
+ * overwritten by a bad one).
+ */
+ for (mirror_index = 0;
+ mirror_index < BTRFS_MAX_MIRRORS &&
+ sblocks_for_recheck[mirror_index].page_count > 0;
+ mirror_index++) {
+ struct scrub_block *sblock_other = sblocks_for_recheck +
+ mirror_index;
+
+ if (!sblock_other->header_error &&
+ !sblock_other->checksum_error &&
+ sblock_other->no_io_error_seen) {
+ int force_write = is_metadata || have_csum;
+
+ ret = scrub_repair_block_from_good_copy(sblock_bad,
+ sblock_other,
+ force_write);
+ if (0 == ret)
+ goto corrected_error;
+ }
+ }
/*
- * first find a good copy
+ * in case of I/O errors in the area that is supposed to be
+ * repaired, continue by picking good copies of those pages.
+ * Select the good pages from mirrors to rewrite bad pages from
+ * the area to fix. Afterwards verify the checksum of the block
+ * that is supposed to be repaired. This verification step is
+ * only done for the purpose of statistic counting and for the
+ * final scrub report, whether errors remain.
+ * A perfect algorithm could make use of the checksum and try
+ * all possible combinations of pages from the different mirrors
+ * until the checksum verification succeeds. For example, when
+ * the 2nd page of mirror #1 faces I/O errors, and the 2nd page
+ * of mirror #2 is readable but the final checksum test fails,
+ * then the 2nd page of mirror #3 could be tried, whether now
+ * the final checksum succeedes. But this would be a rare
+ * exception and is therefore not implemented. At least it is
+ * avoided that the good copy is overwritten.
+ * A more useful improvement would be to pick the sectors
+ * without I/O error based on sector sizes (512 bytes on legacy
+ * disks) instead of on PAGE_SIZE. Then maybe 512 byte of one
+ * mirror could be repaired by taking 512 byte of a different
+ * mirror, even if other 512 byte sectors in the same PAGE_SIZE
+ * area are unreadable.
*/
- for (i = 0; i < bbio->num_stripes; ++i) {
- if (i + 1 == sbio->spag[ix].mirror_num)
- continue;
- if (scrub_fixup_io(READ, bbio->stripes[i].dev->bdev,
- bbio->stripes[i].physical >> 9,
- sbio->bio->bi_io_vec[ix].bv_page)) {
- /* I/O-error, this is not a good copy */
+ /* can only fix I/O errors from here on */
+ if (sblock_bad->no_io_error_seen)
+ goto did_not_correct_error;
+
+ success = 1;
+ for (page_num = 0; page_num < sblock_bad->page_count; page_num++) {
+ struct scrub_page *page_bad = sblock_bad->pagev + page_num;
+
+ if (!page_bad->io_error)
continue;
+
+ for (mirror_index = 0;
+ mirror_index < BTRFS_MAX_MIRRORS &&
+ sblocks_for_recheck[mirror_index].page_count > 0;
+ mirror_index++) {
+ struct scrub_block *sblock_other = sblocks_for_recheck +
+ mirror_index;
+ struct scrub_page *page_other = sblock_other->pagev +
+ page_num;
+
+ if (!page_other->io_error) {
+ ret = scrub_repair_page_from_good_copy(
+ sblock_bad, sblock_other, page_num, 0);
+ if (0 == ret) {
+ page_bad->io_error = 0;
+ break; /* succeeded for this page */
+ }
+ }
}
- if (scrub_fixup_check(sbio, ix) == 0)
- break;
+ if (page_bad->io_error) {
+ /* did not find a mirror to copy the page from */
+ success = 0;
+ }
}
- if (i == bbio->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;
+ if (success) {
+ if (is_metadata || have_csum) {
+ /*
+ * need to verify the checksum now that all
+ * sectors on disk are repaired (the write
+ * request for data to be repaired is on its way).
+ * Just be lazy and use scrub_recheck_block()
+ * which re-reads the data before the checksum
+ * is verified, but most likely the data comes out
+ * of the page cache.
+ */
+ ret = scrub_recheck_block(fs_info, sblock_bad,
+ is_metadata, have_csum, csum,
+ generation, sdev->csum_size);
+ if (!ret && !sblock_bad->header_error &&
+ !sblock_bad->checksum_error &&
+ sblock_bad->no_io_error_seen)
+ goto corrected_error;
+ else
+ goto did_not_correct_error;
+ } else {
+corrected_error:
+ spin_lock(&sdev->stat_lock);
+ sdev->stat.corrected_errors++;
+ spin_unlock(&sdev->stat_lock);
+ printk_ratelimited(KERN_ERR
+ "btrfs: fixed up error at logical %llu on dev %s\n",
+ (unsigned long long)logical, sdev->dev->name);
}
+ } else {
+did_not_correct_error:
+ spin_lock(&sdev->stat_lock);
+ sdev->stat.uncorrectable_errors++;
+ spin_unlock(&sdev->stat_lock);
+ printk_ratelimited(KERN_ERR
+ "btrfs: unable to fixup (regular) error at logical %llu on dev %s\n",
+ (unsigned long long)logical, sdev->dev->name);
}
- kfree(bbio);
- spin_lock(&sdev->stat_lock);
- ++sdev->stat.corrected_errors;
- spin_unlock(&sdev->stat_lock);
+out:
+ if (sblocks_for_recheck) {
+ for (mirror_index = 0; mirror_index < BTRFS_MAX_MIRRORS;
+ mirror_index++) {
+ struct scrub_block *sblock = sblocks_for_recheck +
+ mirror_index;
+ int page_index;
+
+ for (page_index = 0; page_index < SCRUB_PAGES_PER_BIO;
+ page_index++)
+ if (sblock->pagev[page_index].page)
+ __free_page(
+ sblock->pagev[page_index].page);
+ }
+ kfree(sblocks_for_recheck);
+ }
- printk_ratelimited(KERN_ERR "btrfs: fixed up error at logical %llu\n",
- (unsigned long long)logical);
- return;
+ return 0;
+}
-uncorrectable:
- kfree(bbio);
- spin_lock(&sdev->stat_lock);
- ++sdev->stat.uncorrectable_errors;
- spin_unlock(&sdev->stat_lock);
+static int scrub_setup_recheck_block(struct scrub_dev *sdev,
+ struct btrfs_mapping_tree *map_tree,
+ u64 length, u64 logical,
+ struct scrub_block *sblocks_for_recheck)
+{
+ int page_index;
+ int mirror_index;
+ int ret;
+
+ /*
+ * note: the three members sdev, ref_count and outstanding_pages
+ * are not used (and not set) in the blocks that are used for
+ * the recheck procedure
+ */
+
+ page_index = 0;
+ while (length > 0) {
+ u64 sublen = min_t(u64, length, PAGE_SIZE);
+ u64 mapped_length = sublen;
+ struct btrfs_bio *bbio = NULL;
- printk_ratelimited(KERN_ERR "btrfs: unable to fixup (regular) error at "
- "logical %llu\n", (unsigned long long)logical);
+ /*
+ * with a length of PAGE_SIZE, each returned stripe
+ * represents one mirror
+ */
+ ret = btrfs_map_block(map_tree, WRITE, logical, &mapped_length,
+ &bbio, 0);
+ if (ret || !bbio || mapped_length < sublen) {
+ kfree(bbio);
+ return -EIO;
+ }
+
+ BUG_ON(page_index >= SCRUB_PAGES_PER_BIO);
+ for (mirror_index = 0; mirror_index < (int)bbio->num_stripes;
+ mirror_index++) {
+ struct scrub_block *sblock;
+ struct scrub_page *page;
+
+ if (mirror_index >= BTRFS_MAX_MIRRORS)
+ continue;
+
+ sblock = sblocks_for_recheck + mirror_index;
+ page = sblock->pagev + page_index;
+ page->logical = logical;
+ page->physical = bbio->stripes[mirror_index].physical;
+ page->bdev = bbio->stripes[mirror_index].dev->bdev;
+ page->mirror_num = mirror_index + 1;
+ page->page = alloc_page(GFP_NOFS);
+ if (!page->page) {
+ spin_lock(&sdev->stat_lock);
+ sdev->stat.malloc_errors++;
+ spin_unlock(&sdev->stat_lock);
+ return -ENOMEM;
+ }
+ sblock->page_count++;
+ }
+ kfree(bbio);
+ length -= sublen;
+ logical += sublen;
+ page_index++;
+ }
+
+ return 0;
}
-static int scrub_fixup_io(int rw, struct block_device *bdev, sector_t sector,
- struct page *page)
+/*
+ * this function will check the on disk data for checksum errors, header
+ * errors and read I/O errors. If any I/O errors happen, the exact pages
+ * which are errored are marked as being bad. The goal is to enable scrub
+ * to take those pages that are not errored from all the mirrors so that
+ * the pages that are errored in the just handled mirror can be repaired.
+ */
+static int scrub_recheck_block(struct btrfs_fs_info *fs_info,
+ struct scrub_block *sblock, int is_metadata,
+ int have_csum, u8 *csum, u64 generation,
+ u16 csum_size)
{
- struct bio *bio = NULL;
- int ret;
- DECLARE_COMPLETION_ONSTACK(complete);
+ int page_num;
- 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;
- btrfsic_submit_bio(rw, bio);
+ sblock->no_io_error_seen = 1;
+ sblock->header_error = 0;
+ sblock->checksum_error = 0;
- /* this will also unplug the queue */
- wait_for_completion(&complete);
+ for (page_num = 0; page_num < sblock->page_count; page_num++) {
+ struct bio *bio;
+ int ret;
+ struct scrub_page *page = sblock->pagev + page_num;
+ DECLARE_COMPLETION_ONSTACK(complete);
+
+ BUG_ON(!page->page);
+ bio = bio_alloc(GFP_NOFS, 1);
+ bio->bi_bdev = page->bdev;
+ bio->bi_sector = page->physical >> 9;
+ bio->bi_end_io = scrub_complete_bio_end_io;
+ bio->bi_private = &complete;
+
+ ret = bio_add_page(bio, page->page, PAGE_SIZE, 0);
+ if (PAGE_SIZE != ret) {
+ bio_put(bio);
+ return -EIO;
+ }
+ btrfsic_submit_bio(READ, bio);
- ret = !test_bit(BIO_UPTODATE, &bio->bi_flags);
- bio_put(bio);
- return ret;
+ /* this will also unplug the queue */
+ wait_for_completion(&complete);
+
+ page->io_error = !test_bit(BIO_UPTODATE, &bio->bi_flags);
+ if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
+ sblock->no_io_error_seen = 0;
+ bio_put(bio);
+ }
+
+ if (sblock->no_io_error_seen)
+ scrub_recheck_block_checksum(fs_info, sblock, is_metadata,
+ have_csum, csum, generation,
+ csum_size);
+
+ return 0;
}
-static void scrub_bio_end_io(struct bio *bio, int err)
+static void scrub_recheck_block_checksum(struct btrfs_fs_info *fs_info,
+ struct scrub_block *sblock,
+ int is_metadata, int have_csum,
+ const u8 *csum, u64 generation,
+ u16 csum_size)
{
- 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;
+ int page_num;
+ u8 calculated_csum[BTRFS_CSUM_SIZE];
+ u32 crc = ~(u32)0;
+ struct btrfs_root *root = fs_info->extent_root;
+ void *mapped_buffer;
+
+ BUG_ON(!sblock->pagev[0].page);
+ if (is_metadata) {
+ struct btrfs_header *h;
+
+ mapped_buffer = kmap_atomic(sblock->pagev[0].page, KM_USER0);
+ h = (struct btrfs_header *)mapped_buffer;
+
+ if (sblock->pagev[0].logical != le64_to_cpu(h->bytenr) ||
+ generation != le64_to_cpu(h->generation) ||
+ memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE) ||
+ memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
+ BTRFS_UUID_SIZE))
+ sblock->header_error = 1;
+ csum = h->csum;
+ } else {
+ if (!have_csum)
+ return;
- sbio->err = err;
- sbio->bio = bio;
+ mapped_buffer = kmap_atomic(sblock->pagev[0].page, KM_USER0);
+ }
- btrfs_queue_worker(&fs_info->scrub_workers, &sbio->work);
+ for (page_num = 0;;) {
+ if (page_num == 0 && is_metadata)
+ crc = btrfs_csum_data(root,
+ ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE,
+ crc, PAGE_SIZE - BTRFS_CSUM_SIZE);
+ else
+ crc = btrfs_csum_data(root, mapped_buffer, crc,
+ PAGE_SIZE);
+
+ kunmap_atomic(mapped_buffer, KM_USER0);
+ page_num++;
+ if (page_num >= sblock->page_count)
+ break;
+ BUG_ON(!sblock->pagev[page_num].page);
+
+ mapped_buffer = kmap_atomic(sblock->pagev[page_num].page,
+ KM_USER0);
+ }
+
+ btrfs_csum_final(crc, calculated_csum);
+ if (memcmp(calculated_csum, csum, csum_size))
+ sblock->checksum_error = 1;
}
-static void scrub_checksum(struct btrfs_work *work)
+static void scrub_complete_bio_end_io(struct bio *bio, int err)
{
- 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;
+ complete((struct completion *)bio->bi_private);
+}
- if (sbio->err) {
- ret = 0;
- for (i = 0; i < sbio->count; ++i)
- ret |= scrub_recheck_error(sbio, i);
- if (!ret) {
- spin_lock(&sdev->stat_lock);
- ++sdev->stat.unverified_errors;
- spin_unlock(&sdev->stat_lock);
- }
+static int scrub_repair_block_from_good_copy(struct scrub_block *sblock_bad,
+ struct scrub_block *sblock_good,
+ int force_write)
+{
+ int page_num;
+ int ret = 0;
- 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 (page_num = 0; page_num < sblock_bad->page_count; page_num++) {
+ int ret_sub;
- 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;
- }
- goto out;
+ ret_sub = scrub_repair_page_from_good_copy(sblock_bad,
+ sblock_good,
+ page_num,
+ force_write);
+ if (ret_sub)
+ ret = ret_sub;
}
- 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) {
- ret = scrub_recheck_error(sbio, i);
- if (!ret) {
- spin_lock(&sdev->stat_lock);
- ++sdev->stat.unverified_errors;
- spin_unlock(&sdev->stat_lock);
- }
+
+ return ret;
+}
+
+static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
+ struct scrub_block *sblock_good,
+ int page_num, int force_write)
+{
+ struct scrub_page *page_bad = sblock_bad->pagev + page_num;
+ struct scrub_page *page_good = sblock_good->pagev + page_num;
+
+ BUG_ON(sblock_bad->pagev[page_num].page == NULL);
+ BUG_ON(sblock_good->pagev[page_num].page == NULL);
+ if (force_write || sblock_bad->header_error ||
+ sblock_bad->checksum_error || page_bad->io_error) {
+ struct bio *bio;
+ int ret;
+ DECLARE_COMPLETION_ONSTACK(complete);
+
+ bio = bio_alloc(GFP_NOFS, 1);
+ bio->bi_bdev = page_bad->bdev;
+ bio->bi_sector = page_bad->physical >> 9;
+ bio->bi_end_io = scrub_complete_bio_end_io;
+ bio->bi_private = &complete;
+
+ ret = bio_add_page(bio, page_good->page, PAGE_SIZE, 0);
+ if (PAGE_SIZE != ret) {
+ bio_put(bio);
+ return -EIO;
}
+ btrfsic_submit_bio(WRITE, bio);
+
+ /* this will also unplug the queue */
+ wait_for_completion(&complete);
+ bio_put(bio);
}
-out:
- scrub_free_bio(sbio->bio);
- sbio->bio = NULL;
- 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);
+ return 0;
+}
+
+static void scrub_checksum(struct scrub_block *sblock)
+{
+ u64 flags;
+ int ret;
+
+ BUG_ON(sblock->page_count < 1);
+ flags = sblock->pagev[0].flags;
+ ret = 0;
+ if (flags & BTRFS_EXTENT_FLAG_DATA)
+ ret = scrub_checksum_data(sblock);
+ else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
+ ret = scrub_checksum_tree_block(sblock);
+ else if (flags & BTRFS_EXTENT_FLAG_SUPER)
+ (void)scrub_checksum_super(sblock);
+ else
+ WARN_ON(1);
+ if (ret)
+ scrub_handle_errored_block(sblock);
}
-static int scrub_checksum_data(struct scrub_dev *sdev,
- struct scrub_page *spag, void *buffer)
+static int scrub_checksum_data(struct scrub_block *sblock)
{
+ struct scrub_dev *sdev = sblock->sdev;
u8 csum[BTRFS_CSUM_SIZE];
+ u8 *on_disk_csum;
+ struct page *page;
+ void *buffer;
u32 crc = ~(u32)0;
int fail = 0;
struct btrfs_root *root = sdev->dev->dev_root;
+ u64 len;
+ int index;
- if (!spag->have_csum)
+ BUG_ON(sblock->page_count < 1);
+ if (!sblock->pagev[0].have_csum)
return 0;
- crc = btrfs_csum_data(root, buffer, crc, PAGE_SIZE);
+ on_disk_csum = sblock->pagev[0].csum;
+ page = sblock->pagev[0].page;
+ buffer = kmap_atomic(page, KM_USER0);
+
+ len = sdev->sectorsize;
+ index = 0;
+ for (;;) {
+ u64 l = min_t(u64, len, PAGE_SIZE);
+
+ crc = btrfs_csum_data(root, buffer, crc, l);
+ kunmap_atomic(buffer, KM_USER0);
+ len -= l;
+ if (len == 0)
+ break;
+ index++;
+ BUG_ON(index >= sblock->page_count);
+ BUG_ON(!sblock->pagev[index].page);
+ page = sblock->pagev[index].page;
+ buffer = kmap_atomic(page, KM_USER0);
+ }
+
btrfs_csum_final(crc, csum);
- if (memcmp(csum, spag->csum, sdev->csum_size))
+ if (memcmp(csum, on_disk_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)
+ if (fail) {
+ spin_lock(&sdev->stat_lock);
++sdev->stat.csum_errors;
- spin_unlock(&sdev->stat_lock);
+ 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)
+static int scrub_checksum_tree_block(struct scrub_block *sblock)
{
+ struct scrub_dev *sdev = sblock->sdev;
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];
+ u8 calculated_csum[BTRFS_CSUM_SIZE];
+ u8 on_disk_csum[BTRFS_CSUM_SIZE];
+ struct page *page;
+ void *mapped_buffer;
+ u64 mapped_size;
+ void *p;
u32 crc = ~(u32)0;
int fail = 0;
int crc_fail = 0;
+ u64 len;
+ int index;
+
+ BUG_ON(sblock->page_count < 1);
+ page = sblock->pagev[0].page;
+ mapped_buffer = kmap_atomic(page, KM_USER0);
+ h = (struct btrfs_header *)mapped_buffer;
+ memcpy(on_disk_csum, h->csum, sdev->csum_size);
/*
* 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))
+ if (sblock->pagev[0].logical != le64_to_cpu(h->bytenr))
++fail;
- if (spag->generation != le64_to_cpu(h->generation))
+ if (sblock->pagev[0].generation != le64_to_cpu(h->generation))
++fail;
if (memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
@@ -886,51 +1306,99 @@ static int scrub_checksum_tree_block(struct scrub_dev *sdev,
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))
+ BUG_ON(sdev->nodesize != sdev->leafsize);
+ len = sdev->nodesize - BTRFS_CSUM_SIZE;
+ mapped_size = PAGE_SIZE - BTRFS_CSUM_SIZE;
+ p = ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE;
+ index = 0;
+ for (;;) {
+ u64 l = min_t(u64, len, mapped_size);
+
+ crc = btrfs_csum_data(root, p, crc, l);
+ kunmap_atomic(mapped_buffer, KM_USER0);
+ len -= l;
+ if (len == 0)
+ break;
+ index++;
+ BUG_ON(index >= sblock->page_count);
+ BUG_ON(!sblock->pagev[index].page);
+ page = sblock->pagev[index].page;
+ mapped_buffer = kmap_atomic(page, KM_USER0);
+ mapped_size = PAGE_SIZE;
+ p = mapped_buffer;
+ }
+
+ btrfs_csum_final(crc, calculated_csum);
+ if (memcmp(calculated_csum, on_disk_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);
+ if (crc_fail || fail) {
+ spin_lock(&sdev->stat_lock);
+ 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)
+static int scrub_checksum_super(struct scrub_block *sblock)
{
struct btrfs_super_block *s;
- u64 logical;
- struct scrub_dev *sdev = sbio->sdev;
+ struct scrub_dev *sdev = sblock->sdev;
struct btrfs_root *root = sdev->dev->dev_root;
struct btrfs_fs_info *fs_info = root->fs_info;
- u8 csum[BTRFS_CSUM_SIZE];
+ u8 calculated_csum[BTRFS_CSUM_SIZE];
+ u8 on_disk_csum[BTRFS_CSUM_SIZE];
+ struct page *page;
+ void *mapped_buffer;
+ u64 mapped_size;
+ void *p;
u32 crc = ~(u32)0;
int fail = 0;
+ u64 len;
+ int index;
- s = (struct btrfs_super_block *)buffer;
- logical = sbio->logical;
+ BUG_ON(sblock->page_count < 1);
+ page = sblock->pagev[0].page;
+ mapped_buffer = kmap_atomic(page, KM_USER0);
+ s = (struct btrfs_super_block *)mapped_buffer;
+ memcpy(on_disk_csum, s->csum, sdev->csum_size);
- if (logical != le64_to_cpu(s->bytenr))
+ if (sblock->pagev[0].logical != le64_to_cpu(s->bytenr))
++fail;
- if (sbio->spag[0].generation != le64_to_cpu(s->generation))
+ if (sblock->pagev[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))
+ len = BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE;
+ mapped_size = PAGE_SIZE - BTRFS_CSUM_SIZE;
+ p = ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE;
+ index = 0;
+ for (;;) {
+ u64 l = min_t(u64, len, mapped_size);
+
+ crc = btrfs_csum_data(root, p, crc, l);
+ kunmap_atomic(mapped_buffer, KM_USER0);
+ len -= l;
+ if (len == 0)
+ break;
+ index++;
+ BUG_ON(index >= sblock->page_count);
+ BUG_ON(!sblock->pagev[index].page);
+ page = sblock->pagev[index].page;
+ mapped_buffer = kmap_atomic(page, KM_USER0);
+ mapped_size = PAGE_SIZE;
+ p = mapped_buffer;
+ }
+
+ btrfs_csum_final(crc, calculated_csum);
+ if (memcmp(calculated_csum, on_disk_csum, sdev->csum_size))
++fail;
if (fail) {
@@ -947,6 +1415,23 @@ static int scrub_checksum_super(struct scrub_bio *sbio, void *buffer)
return fail;
}
+static void scrub_block_get(struct scrub_block *sblock)
+{
+ atomic_inc(&sblock->ref_count);
+}
+
+static void scrub_block_put(struct scrub_block *sblock)
+{
+ if (atomic_dec_and_test(&sblock->ref_count)) {
+ int i;
+
+ for (i = 0; i < sblock->page_count; i++)
+ if (sblock->pagev[i].page)
+ __free_page(sblock->pagev[i].page);
+ kfree(sblock);
+ }
+}
+
static void scrub_submit(struct scrub_dev *sdev)
{
struct scrub_bio *sbio;
@@ -955,19 +1440,17 @@ static void scrub_submit(struct scrub_dev *sdev)
return;
sbio = sdev->bios[sdev->curr];
- sbio->err = 0;
sdev->curr = -1;
atomic_inc(&sdev->in_flight);
btrfsic_submit_bio(READ, sbio->bio);
}
-static int scrub_page(struct scrub_dev *sdev, u64 logical, u64 len,
- u64 physical, u64 flags, u64 gen, int mirror_num,
- u8 *csum, int force)
+static int scrub_add_page_to_bio(struct scrub_dev *sdev,
+ struct scrub_page *spage)
{
+ struct scrub_block *sblock = spage->sblock;
struct scrub_bio *sbio;
- struct page *page;
int ret;
again:
@@ -980,7 +1463,7 @@ again:
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;
+ sdev->bios[sdev->curr]->page_count = 0;
spin_unlock(&sdev->list_lock);
} else {
spin_unlock(&sdev->list_lock);
@@ -988,53 +1471,200 @@ again:
}
}
sbio = sdev->bios[sdev->curr];
- if (sbio->count == 0) {
+ if (sbio->page_count == 0) {
struct bio *bio;
- sbio->physical = physical;
- sbio->logical = logical;
- bio = bio_alloc(GFP_NOFS, SCRUB_PAGES_PER_BIO);
- if (!bio)
- return -ENOMEM;
+ sbio->physical = spage->physical;
+ sbio->logical = spage->logical;
+ bio = sbio->bio;
+ if (!bio) {
+ bio = bio_alloc(GFP_NOFS, sdev->pages_per_bio);
+ if (!bio)
+ return -ENOMEM;
+ sbio->bio = bio;
+ }
bio->bi_private = sbio;
bio->bi_end_io = scrub_bio_end_io;
bio->bi_bdev = sdev->dev->bdev;
- bio->bi_sector = sbio->physical >> 9;
+ bio->bi_sector = spage->physical >> 9;
sbio->err = 0;
- sbio->bio = bio;
- } else if (sbio->physical + sbio->count * PAGE_SIZE != physical ||
- sbio->logical + sbio->count * PAGE_SIZE != logical) {
+ } else if (sbio->physical + sbio->page_count * PAGE_SIZE !=
+ spage->physical ||
+ sbio->logical + sbio->page_count * PAGE_SIZE !=
+ spage->logical) {
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;
-
- page = alloc_page(GFP_NOFS);
- if (!page)
- return -ENOMEM;
- ret = bio_add_page(sbio->bio, page, PAGE_SIZE, 0);
- if (!ret) {
- __free_page(page);
+ sbio->pagev[sbio->page_count] = spage;
+ ret = bio_add_page(sbio->bio, spage->page, PAGE_SIZE, 0);
+ if (ret != PAGE_SIZE) {
+ if (sbio->page_count < 1) {
+ bio_put(sbio->bio);
+ sbio->bio = NULL;
+ return -EIO;
+ }
scrub_submit(sdev);
goto again;
}
- if (csum) {
- sbio->spag[sbio->count].have_csum = 1;
- memcpy(sbio->spag[sbio->count].csum, csum, sdev->csum_size);
+ scrub_block_get(sblock); /* one for the added page */
+ atomic_inc(&sblock->outstanding_pages);
+ sbio->page_count++;
+ if (sbio->page_count == sdev->pages_per_bio)
+ scrub_submit(sdev);
+
+ return 0;
+}
+
+static int scrub_pages(struct scrub_dev *sdev, u64 logical, u64 len,
+ u64 physical, u64 flags, u64 gen, int mirror_num,
+ u8 *csum, int force)
+{
+ struct scrub_block *sblock;
+ int index;
+
+ sblock = kzalloc(sizeof(*sblock), GFP_NOFS);
+ if (!sblock) {
+ spin_lock(&sdev->stat_lock);
+ sdev->stat.malloc_errors++;
+ spin_unlock(&sdev->stat_lock);
+ return -ENOMEM;
+ }
+
+ /* one ref inside this function, plus one for each page later on */
+ atomic_set(&sblock->ref_count, 1);
+ sblock->sdev = sdev;
+ sblock->no_io_error_seen = 1;
+
+ for (index = 0; len > 0; index++) {
+ struct scrub_page *spage = sblock->pagev + index;
+ u64 l = min_t(u64, len, PAGE_SIZE);
+
+ BUG_ON(index >= SCRUB_MAX_PAGES_PER_BLOCK);
+ spage->page = alloc_page(GFP_NOFS);
+ if (!spage->page) {
+ spin_lock(&sdev->stat_lock);
+ sdev->stat.malloc_errors++;
+ spin_unlock(&sdev->stat_lock);
+ while (index > 0) {
+ index--;
+ __free_page(sblock->pagev[index].page);
+ }
+ kfree(sblock);
+ return -ENOMEM;
+ }
+ spage->sblock = sblock;
+ spage->bdev = sdev->dev->bdev;
+ spage->flags = flags;
+ spage->generation = gen;
+ spage->logical = logical;
+ spage->physical = physical;
+ spage->mirror_num = mirror_num;
+ if (csum) {
+ spage->have_csum = 1;
+ memcpy(spage->csum, csum, sdev->csum_size);
+ } else {
+ spage->have_csum = 0;
+ }
+ sblock->page_count++;
+ len -= l;
+ logical += l;
+ physical += l;
+ }
+
+ BUG_ON(sblock->page_count == 0);
+ for (index = 0; index < sblock->page_count; index++) {
+ struct scrub_page *spage = sblock->pagev + index;
+ int ret;
+
+ ret = scrub_add_page_to_bio(sdev, spage);
+ if (ret) {
+ scrub_block_put(sblock);
+ return ret;
+ }
}
- ++sbio->count;
- if (sbio->count == SCRUB_PAGES_PER_BIO || force)
+
+ if (force)
scrub_submit(sdev);
+ /* last one frees, either here or in bio completion for last page */
+ scrub_block_put(sblock);
return 0;
}
+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;
+ sbio->bio = bio;
+
+ btrfs_queue_worker(&fs_info->scrub_workers, &sbio->work);
+}
+
+static void scrub_bio_end_io_worker(struct btrfs_work *work)
+{
+ struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
+ struct scrub_dev *sdev = sbio->sdev;
+ int i;
+
+ BUG_ON(sbio->page_count > SCRUB_PAGES_PER_BIO);
+ if (sbio->err) {
+ for (i = 0; i < sbio->page_count; i++) {
+ struct scrub_page *spage = sbio->pagev[i];
+
+ spage->io_error = 1;
+ spage->sblock->no_io_error_seen = 0;
+ }
+ }
+
+ /* now complete the scrub_block items that have all pages completed */
+ for (i = 0; i < sbio->page_count; i++) {
+ struct scrub_page *spage = sbio->pagev[i];
+ struct scrub_block *sblock = spage->sblock;
+
+ if (atomic_dec_and_test(&sblock->outstanding_pages))
+ scrub_block_complete(sblock);
+ scrub_block_put(sblock);
+ }
+
+ if (sbio->err) {
+ /* what is this good for??? */
+ 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->page_count; i++) {
+ struct bio_vec *bi;
+ bi = &sbio->bio->bi_io_vec[i];
+ bi->bv_offset = 0;
+ bi->bv_len = PAGE_SIZE;
+ }
+ }
+
+ bio_put(sbio->bio);
+ sbio->bio = NULL;
+ 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 void scrub_block_complete(struct scrub_block *sblock)
+{
+ if (!sblock->no_io_error_seen)
+ scrub_handle_errored_block(sblock);
+ else
+ scrub_checksum(sblock);
+}
+
static int scrub_find_csum(struct scrub_dev *sdev, u64 logical, u64 len,
u8 *csum)
{
@@ -1042,7 +1672,6 @@ static int scrub_find_csum(struct scrub_dev *sdev, u64 logical, u64 len,
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,
@@ -1060,7 +1689,7 @@ static int scrub_find_csum(struct scrub_dev *sdev, u64 logical, u64 len,
if (!sum)
return 0;
- num_sectors = sum->len / sectorsize;
+ num_sectors = sum->len / sdev->sectorsize;
for (i = 0; i < num_sectors; ++i) {
if (sum->sums[i].bytenr == logical) {
memcpy(csum, &sum->sums[i].sum, sdev->csum_size);
@@ -1081,9 +1710,28 @@ static int scrub_extent(struct scrub_dev *sdev, u64 logical, u64 len,
{
int ret;
u8 csum[BTRFS_CSUM_SIZE];
+ u32 blocksize;
+
+ if (flags & BTRFS_EXTENT_FLAG_DATA) {
+ blocksize = sdev->sectorsize;
+ spin_lock(&sdev->stat_lock);
+ sdev->stat.data_extents_scrubbed++;
+ sdev->stat.data_bytes_scrubbed += len;
+ spin_unlock(&sdev->stat_lock);
+ } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
+ BUG_ON(sdev->nodesize != sdev->leafsize);
+ blocksize = sdev->nodesize;
+ spin_lock(&sdev->stat_lock);
+ sdev->stat.tree_extents_scrubbed++;
+ sdev->stat.tree_bytes_scrubbed += len;
+ spin_unlock(&sdev->stat_lock);
+ } else {
+ blocksize = sdev->sectorsize;
+ BUG_ON(1);
+ }
while (len) {
- u64 l = min_t(u64, len, PAGE_SIZE);
+ u64 l = min_t(u64, len, blocksize);
int have_csum = 0;
if (flags & BTRFS_EXTENT_FLAG_DATA) {
@@ -1092,8 +1740,8 @@ static int scrub_extent(struct scrub_dev *sdev, u64 logical, u64 len,
if (have_csum == 0)
++sdev->stat.no_csum;
}
- ret = scrub_page(sdev, logical, l, physical, flags, gen,
- mirror_num, have_csum ? csum : NULL, 0);
+ ret = scrub_pages(sdev, logical, l, physical, flags, gen,
+ mirror_num, have_csum ? csum : NULL, 0);
if (ret)
return ret;
len -= l;
@@ -1158,6 +1806,11 @@ static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev,
if (!path)
return -ENOMEM;
+ /*
+ * work on commit root. The related disk blocks are static as
+ * long as COW is applied. This means, it is save to rewrite
+ * them to repair disk errors without any race conditions
+ */
path->search_commit_root = 1;
path->skip_locking = 1;
@@ -1511,8 +2164,8 @@ static noinline_for_stack int scrub_supers(struct scrub_dev *sdev)
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);
+ ret = scrub_pages(sdev, bytenr, BTRFS_SUPER_INFO_SIZE, bytenr,
+ BTRFS_EXTENT_FLAG_SUPER, gen, i, NULL, 1);
if (ret)
return ret;
}
@@ -1571,10 +2224,30 @@ int btrfs_scrub_dev(struct btrfs_root *root, u64 devid, u64 start, u64 end,
/*
* 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");
+ if (root->nodesize != root->leafsize) {
+ printk(KERN_ERR
+ "btrfs_scrub: size assumption nodesize == leafsize (%d == %d) fails\n",
+ root->nodesize, root->leafsize);
+ return -EINVAL;
+ }
+
+ if (root->nodesize > BTRFS_STRIPE_LEN) {
+ /*
+ * in this case scrub is unable to calculate the checksum
+ * the way scrub is implemented. Do not handle this
+ * situation at all because it won't ever happen.
+ */
+ printk(KERN_ERR
+ "btrfs_scrub: size assumption nodesize <= BTRFS_STRIPE_LEN (%d <= %d) fails\n",
+ root->nodesize, BTRFS_STRIPE_LEN);
+ return -EINVAL;
+ }
+
+ if (root->sectorsize != PAGE_SIZE) {
+ /* not supported for data w/o checksums */
+ printk(KERN_ERR
+ "btrfs_scrub: size assumption sectorsize != PAGE_SIZE (%d != %lld) fails\n",
+ root->sectorsize, (unsigned long long)PAGE_SIZE);
return -EINVAL;
}
--
1.7.3.4
^ permalink raw reply related [flat|nested] 4+ messages in thread