From 1bc8779349d6278e2713a1ff94418c2a6746a791 Mon Sep 17 00:00:00 2001 From: Arne Jansen Date: Sat, 28 May 2011 21:57:55 +0200 Subject: btrfs: scrub: don't reuse bios and pages The current scrub implementation reuses bios and pages as often as possible, allocating them only on start and releasing them when finished. This leads to more problems with the block layer than it's worth. The elevator gets confused when there are more pages added to the bio than bi_size suggests. This patch completely rips out the reuse of bios and pages and allocates them freshly for each submit. Signed-off-by: Arne Jansen Signed-off-by: Chris Maosn --- fs/btrfs/scrub.c | 114 +++++++++++++++++++++++++++++++------------------------ 1 file changed, 65 insertions(+), 49 deletions(-) (limited to 'fs/btrfs/scrub.c') diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index 6dfed0c27ac3..2d1f8909a8e1 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -117,33 +117,37 @@ 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; - int j; - struct page *last_page; if (!sdev) return; for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) { struct scrub_bio *sbio = sdev->bios[i]; - struct bio *bio; if (!sbio) break; - bio = sbio->bio; - if (bio) { - last_page = NULL; - for (j = 0; j < bio->bi_vcnt; ++j) { - if (bio->bi_io_vec[j].bv_page == last_page) - continue; - last_page = bio->bi_io_vec[j].bv_page; - __free_page(last_page); - } - bio_put(bio); - } + scrub_free_bio(sbio->bio); kfree(sbio); } @@ -156,8 +160,6 @@ struct scrub_dev *scrub_setup_dev(struct btrfs_device *dev) { struct scrub_dev *sdev; int i; - int j; - int ret; struct btrfs_fs_info *fs_info = dev->dev_root->fs_info; sdev = kzalloc(sizeof(*sdev), GFP_NOFS); @@ -165,7 +167,6 @@ struct scrub_dev *scrub_setup_dev(struct btrfs_device *dev) goto nomem; sdev->dev = dev; for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) { - struct bio *bio; struct scrub_bio *sbio; sbio = kzalloc(sizeof(*sbio), GFP_NOFS); @@ -173,32 +174,10 @@ struct scrub_dev *scrub_setup_dev(struct btrfs_device *dev) goto nomem; sdev->bios[i] = sbio; - bio = bio_kmalloc(GFP_NOFS, SCRUB_PAGES_PER_BIO); - if (!bio) - goto nomem; - sbio->index = i; sbio->sdev = sdev; - sbio->bio = bio; sbio->count = 0; sbio->work.func = scrub_checksum; - bio->bi_private = sdev->bios[i]; - bio->bi_end_io = scrub_bio_end_io; - bio->bi_sector = 0; - bio->bi_bdev = dev->bdev; - bio->bi_size = 0; - - for (j = 0; j < SCRUB_PAGES_PER_BIO; ++j) { - struct page *page; - page = alloc_page(GFP_NOFS); - if (!page) - goto nomem; - - ret = bio_add_page(bio, page, PAGE_SIZE, 0); - if (!ret) - goto nomem; - } - WARN_ON(bio->bi_vcnt != SCRUB_PAGES_PER_BIO); if (i != SCRUB_BIOS_PER_DEV-1) sdev->bios[i]->next_free = i + 1; @@ -394,6 +373,7 @@ static void scrub_bio_end_io(struct bio *bio, int err) 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); } @@ -453,6 +433,8 @@ static void scrub_checksum(struct btrfs_work *work) } 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; @@ -583,25 +565,50 @@ static int scrub_checksum_super(struct scrub_bio *sbio, void *buffer) static int scrub_submit(struct scrub_dev *sdev) { struct scrub_bio *sbio; + struct bio *bio; + int i; 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; + bio = bio_alloc(GFP_NOFS, sbio->count); + if (!bio) + goto nomem; + + bio->bi_private = sbio; + bio->bi_end_io = scrub_bio_end_io; + bio->bi_bdev = sdev->dev->bdev; + bio->bi_sector = sbio->physical >> 9; + + for (i = 0; i < sbio->count; ++i) { + struct page *page; + int ret; + + page = alloc_page(GFP_NOFS); + if (!page) + goto nomem; + + ret = bio_add_page(bio, page, PAGE_SIZE, 0); + if (!ret) { + __free_page(page); + goto nomem; + } + } + sbio->err = 0; sdev->curr = -1; atomic_inc(&sdev->in_flight); - submit_bio(0, sbio->bio); + submit_bio(READ, bio); return 0; + +nomem: + scrub_free_bio(bio); + + return -ENOMEM; } static int scrub_page(struct scrub_dev *sdev, u64 logical, u64 len, @@ -633,7 +640,11 @@ again: sbio->logical = logical; } else if (sbio->physical + sbio->count * PAGE_SIZE != physical || sbio->logical + sbio->count * PAGE_SIZE != logical) { - scrub_submit(sdev); + int ret; + + ret = scrub_submit(sdev); + if (ret) + return ret; goto again; } sbio->spag[sbio->count].flags = flags; @@ -645,8 +656,13 @@ again: memcpy(sbio->spag[sbio->count].csum, csum, sdev->csum_size); } ++sbio->count; - if (sbio->count == SCRUB_PAGES_PER_BIO || force) - scrub_submit(sdev); + if (sbio->count == SCRUB_PAGES_PER_BIO || force) { + int ret; + + ret = scrub_submit(sdev); + if (ret) + return ret; + } return 0; } -- cgit v1.2.2 From e7786c3ae517b2c433edc91714e86be770e9f1ce Mon Sep 17 00:00:00 2001 From: Arne Jansen Date: Sat, 28 May 2011 20:58:38 +0000 Subject: btrfs: scrub: add explicit plugging With the removal of the implicit plugging scrub ends up doing more and smaller I/O than necessary. This patch adds explicit plugging per chunk. Signed-off-by: Arne Jansen Signed-off-by: Chris Mason --- fs/btrfs/scrub.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'fs/btrfs/scrub.c') diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index 2d1f8909a8e1..1204eab94028 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -348,9 +348,6 @@ static int scrub_fixup_io(int rw, struct block_device *bdev, sector_t sector, int ret; DECLARE_COMPLETION_ONSTACK(complete); - /* we are going to wait on this IO */ - rw |= REQ_SYNC; - bio = bio_alloc(GFP_NOFS, 1); bio->bi_bdev = bdev; bio->bi_sector = sector; @@ -359,6 +356,7 @@ static int scrub_fixup_io(int rw, struct block_device *bdev, sector_t sector, bio->bi_private = &complete; submit_bio(rw, bio); + /* this will also unplug the queue */ wait_for_completion(&complete); ret = !test_bit(BIO_UPTODATE, &bio->bi_flags); @@ -743,6 +741,7 @@ static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev, struct btrfs_root *root = fs_info->extent_root; struct btrfs_root *csum_root = fs_info->csum_root; struct btrfs_extent_item *extent; + struct blk_plug plug; u64 flags; int ret; int slot; @@ -847,6 +846,7 @@ static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev, * the scrub. This might currently (crc32) end up to be about 1MB */ start_stripe = 0; + blk_start_plug(&plug); again: logical = base + offset + start_stripe * increment; for (i = start_stripe; i < nstripes; ++i) { @@ -988,6 +988,7 @@ next: scrub_submit(sdev); out: + blk_finish_plug(&plug); btrfs_free_path(path); return ret < 0 ? ret : 0; } -- cgit v1.2.2 From 7841cb2898f66a73062c64d0ef5733dde7279e46 Mon Sep 17 00:00:00 2001 From: David Sterba Date: Tue, 31 May 2011 18:07:27 +0200 Subject: btrfs: add helper for fs_info->closing wrap checking of filesystem 'closing' flag and fix a few missing memory barriers. Signed-off-by: David Sterba --- fs/btrfs/scrub.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/btrfs/scrub.c') diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index 1204eab94028..df50fd1eca8f 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -1183,7 +1183,7 @@ int btrfs_scrub_dev(struct btrfs_root *root, u64 devid, u64 start, u64 end, int ret; struct btrfs_device *dev; - if (root->fs_info->closing) + if (btrfs_fs_closing(root->fs_info)) return -EINVAL; /* -- cgit v1.2.2 From 8c51032f978bac5bec5dae0c5de4f85db97c1cc9 Mon Sep 17 00:00:00 2001 From: Arne Jansen Date: Fri, 3 Jun 2011 10:09:26 +0200 Subject: btrfs: scrub: errors in tree enumeration due to the semantics of btrfs_search_slot the path can point to an invalid slot when ret > 0. This condition went unnoticed, which in turn could have led to an incomplete scrubbing. Signed-off-by: Arne Jansen --- fs/btrfs/scrub.c | 57 +++++++++++++++++++++++++++++++++----------------------- 1 file changed, 34 insertions(+), 23 deletions(-) (limited to 'fs/btrfs/scrub.c') diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index df50fd1eca8f..d5a4108cedaf 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -804,18 +804,12 @@ static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev, 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; - } + goto out_noplug; + /* + * we might miss half an extent here, but that doesn't matter, + * as it's only the prefetch + */ while (1) { l = path->nodes[0]; slot = path->slots[0]; @@ -824,7 +818,7 @@ static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev, if (ret == 0) continue; if (ret < 0) - goto out; + goto out_noplug; break; } @@ -906,15 +900,20 @@ again: 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) { + if (ret > 0) { ret = btrfs_previous_item(root, path, 0, BTRFS_EXTENT_ITEM_KEY); if (ret < 0) goto out; + if (ret > 0) { + /* there's no smaller item, so stick with the + * larger one */ + btrfs_release_path(path); + ret = btrfs_search_slot(NULL, root, &key, + path, 0, 0); + if (ret < 0) + goto out; + } } while (1) { @@ -989,6 +988,7 @@ next: out: blk_finish_plug(&plug); +out_noplug: btrfs_free_path(path); return ret < 0 ? ret : 0; } @@ -1064,8 +1064,15 @@ int scrub_enumerate_chunks(struct scrub_dev *sdev, u64 start, u64 end) while (1) { ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) - goto out; - ret = 0; + break; + if (ret > 0) { + if (path->slots[0] >= + btrfs_header_nritems(path->nodes[0])) { + ret = btrfs_next_leaf(root, path); + if (ret) + break; + } + } l = path->nodes[0]; slot = path->slots[0]; @@ -1075,7 +1082,7 @@ int scrub_enumerate_chunks(struct scrub_dev *sdev, u64 start, u64 end) if (found_key.objectid != sdev->dev->devid) break; - if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY) + if (btrfs_key_type(&found_key) != BTRFS_DEV_EXTENT_KEY) break; if (found_key.offset >= end) @@ -1104,7 +1111,7 @@ int scrub_enumerate_chunks(struct scrub_dev *sdev, u64 start, u64 end) cache = btrfs_lookup_block_group(fs_info, chunk_offset); if (!cache) { ret = -ENOENT; - goto out; + break; } ret = scrub_chunk(sdev, chunk_tree, chunk_objectid, chunk_offset, length); @@ -1116,9 +1123,13 @@ int scrub_enumerate_chunks(struct scrub_dev *sdev, u64 start, u64 end) btrfs_release_path(path); } -out: btrfs_free_path(path); - return ret; + + /* + * ret can still be 1 from search_slot or next_leaf, + * that's not an error + */ + return ret < 0 ? ret : 0; } static noinline_for_stack int scrub_supers(struct scrub_dev *sdev) -- cgit v1.2.2 From 632dd772fcbde2ba37c0e8983bd38ef4a1eac906 Mon Sep 17 00:00:00 2001 From: Arne Jansen Date: Fri, 10 Jun 2011 12:07:07 +0200 Subject: btrfs: reinitialize scrub workers Scrub starts the workers each time a scrub starts and stops them after it finished. This patch adds an initialization for the workers before each start, otherwise the workers behave strangely. Signed-off-by: Arne Jansen --- fs/btrfs/scrub.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'fs/btrfs/scrub.c') diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index d5a4108cedaf..92cac19388ed 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -1166,8 +1166,12 @@ 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) + if (fs_info->scrub_workers_refcnt == 0) { + btrfs_init_workers(&fs_info->scrub_workers, "scrub", + fs_info->thread_pool_size, &fs_info->generic_worker); + fs_info->scrub_workers.idle_thresh = 4; btrfs_start_workers(&fs_info->scrub_workers, 1); + } ++fs_info->scrub_workers_refcnt; mutex_unlock(&fs_info->scrub_lock); -- cgit v1.2.2 From 6eef3125886df260ca0e8758d141308152226f6a Mon Sep 17 00:00:00 2001 From: Arne Jansen Date: Fri, 10 Jun 2011 13:04:58 +0200 Subject: btrfs: remove unneeded includes from scrub.c Signed-off-by: Arne Jansen --- fs/btrfs/scrub.c | 6 ------ 1 file changed, 6 deletions(-) (limited to 'fs/btrfs/scrub.c') diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index 92cac19388ed..a8d03d5efb5d 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -16,13 +16,7 @@ * Boston, MA 021110-1307, USA. */ -#include -#include -#include #include -#include -#include -#include #include "ctree.h" #include "volumes.h" #include "disk-io.h" -- cgit v1.2.2