1 files changed, 207 insertions, 129 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 9879bd474632..f5fbe576d2ba 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -467,13 +467,59 @@ static int cache_block_group(struct btrfs_block_group_cache *cache,
                              struct btrfs_root *root,
                              int load_cache_only)
 {
+        DEFINE_WAIT(wait);
         struct btrfs_fs_info *fs_info = cache->fs_info;
         struct btrfs_caching_control *caching_ctl;
         int ret = 0;
 
-        smp_mb();
-        if (cache->cached != BTRFS_CACHE_NO)
+        caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
+        BUG_ON(!caching_ctl);
+
+        INIT_LIST_HEAD(&caching_ctl->list);
+        mutex_init(&caching_ctl->mutex);
+        init_waitqueue_head(&caching_ctl->wait);
+        caching_ctl->block_group = cache;
+        caching_ctl->progress = cache->key.objectid;
+        atomic_set(&caching_ctl->count, 1);
+        caching_ctl->work.func = caching_thread;
+
+        spin_lock(&cache->lock);
+        /*
+         * This should be a rare occasion, but this could happen I think in the
+         * case where one thread starts to load the space cache info, and then
+         * some other thread starts a transaction commit which tries to do an
+         * allocation while the other thread is still loading the space cache
+         * info.  The previous loop should have kept us from choosing this block
+         * group, but if we've moved to the state where we will wait on caching
+         * block groups we need to first check if we're doing a fast load here,
+         * so we can wait for it to finish, otherwise we could end up allocating
+         * from a block group who's cache gets evicted for one reason or
+         * another.
+         */
+        while (cache->cached == BTRFS_CACHE_FAST) {
+                struct btrfs_caching_control *ctl;
+
+                ctl = cache->caching_ctl;
+                atomic_inc(&ctl->count);
+                prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
+                spin_unlock(&cache->lock);
+
+                schedule();
+
+                finish_wait(&ctl->wait, &wait);
+                put_caching_control(ctl);
+                spin_lock(&cache->lock);
+        }
+
+        if (cache->cached != BTRFS_CACHE_NO) {
+                spin_unlock(&cache->lock);
+                kfree(caching_ctl);
                 return 0;
+        }
+        WARN_ON(cache->caching_ctl);
+        cache->caching_ctl = caching_ctl;
+        cache->cached = BTRFS_CACHE_FAST;
+        spin_unlock(&cache->lock);
 
         /*
          * We can't do the read from on-disk cache during a commit since we need
@@ -484,56 +530,51 @@ static int cache_block_group(struct btrfs_block_group_cache *cache,
         if (trans && (!trans->transaction->in_commit) &&
             (root && root != root->fs_info->tree_root) &&
             btrfs_test_opt(root, SPACE_CACHE)) {
-                spin_lock(&cache->lock);
-                if (cache->cached != BTRFS_CACHE_NO) {
-                        spin_unlock(&cache->lock);
-                        return 0;
-                }
-                cache->cached = BTRFS_CACHE_STARTED;
-                spin_unlock(&cache->lock);
-
                 ret = load_free_space_cache(fs_info, cache);
 
                 spin_lock(&cache->lock);
                 if (ret == 1) {
+                        cache->caching_ctl = NULL;
                         cache->cached = BTRFS_CACHE_FINISHED;
                         cache->last_byte_to_unpin = (u64)-1;
                 } else {
-                        cache->cached = BTRFS_CACHE_NO;
+                        if (load_cache_only) {
+                                cache->caching_ctl = NULL;
+                                cache->cached = BTRFS_CACHE_NO;
+                        } else {
+                                cache->cached = BTRFS_CACHE_STARTED;
+                        }
                 }
                 spin_unlock(&cache->lock);
+                wake_up(&caching_ctl->wait);
                 if (ret == 1) {
+                        put_caching_control(caching_ctl);
                         free_excluded_extents(fs_info->extent_root, cache);
                         return 0;
                 }
+        } else {
+                /*
+                 * We are not going to do the fast caching, set cached to the
+                 * appropriate value and wakeup any waiters.
+                 */
+                spin_lock(&cache->lock);
+                if (load_cache_only) {
+                        cache->caching_ctl = NULL;
+                        cache->cached = BTRFS_CACHE_NO;
+                } else {
+                        cache->cached = BTRFS_CACHE_STARTED;
+                }
+                spin_unlock(&cache->lock);
+                wake_up(&caching_ctl->wait);
         }
 
-        if (load_cache_only)
-                return 0;
-
-        caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
-        BUG_ON(!caching_ctl);
-
-        INIT_LIST_HEAD(&caching_ctl->list);
-        mutex_init(&caching_ctl->mutex);
-        init_waitqueue_head(&caching_ctl->wait);
-        caching_ctl->block_group = cache;
-        caching_ctl->progress = cache->key.objectid;
-        /* one for caching kthread, one for caching block group list */
-        atomic_set(&caching_ctl->count, 2);
-        caching_ctl->work.func = caching_thread;
-
-        spin_lock(&cache->lock);
-        if (cache->cached != BTRFS_CACHE_NO) {
-                spin_unlock(&cache->lock);
-                kfree(caching_ctl);
+        if (load_cache_only) {
+                put_caching_control(caching_ctl);
                 return 0;
         }
-        cache->caching_ctl = caching_ctl;
-        cache->cached = BTRFS_CACHE_STARTED;
-        spin_unlock(&cache->lock);
 
         down_write(&fs_info->extent_commit_sem);
+        atomic_inc(&caching_ctl->count);
         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
         up_write(&fs_info->extent_commit_sem);
 
@@ -2781,7 +2822,7 @@ out_free:
         btrfs_release_path(path);
 out:
         spin_lock(&block_group->lock);
-        if (!ret)
+        if (!ret && dcs == BTRFS_DC_SETUP)
                 block_group->cache_generation = trans->transid;
         block_group->disk_cache_state = dcs;
         spin_unlock(&block_group->lock);
@@ -3797,16 +3838,16 @@ void btrfs_free_block_rsv(struct btrfs_root *root,
         kfree(rsv);
 }
 
-int btrfs_block_rsv_add(struct btrfs_root *root,
-                        struct btrfs_block_rsv *block_rsv,
-                        u64 num_bytes)
+static inline int __block_rsv_add(struct btrfs_root *root,
+                                  struct btrfs_block_rsv *block_rsv,
+                                  u64 num_bytes, int flush)
 {
         int ret;
 
         if (num_bytes == 0)
                 return 0;
 
-        ret = reserve_metadata_bytes(root, block_rsv, num_bytes, 1);
+        ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
         if (!ret) {
                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
                 return 0;
@@ -3815,22 +3856,18 @@ int btrfs_block_rsv_add(struct btrfs_root *root,
         return ret;
 }
 
+int btrfs_block_rsv_add(struct btrfs_root *root,
+                        struct btrfs_block_rsv *block_rsv,
+                        u64 num_bytes)
+{
+        return __block_rsv_add(root, block_rsv, num_bytes, 1);
+}
+
 int btrfs_block_rsv_add_noflush(struct btrfs_root *root,
                                 struct btrfs_block_rsv *block_rsv,
                                 u64 num_bytes)
 {
-        int ret;
-
-        if (num_bytes == 0)
-                return 0;
-
-        ret = reserve_metadata_bytes(root, block_rsv, num_bytes, 0);
-        if (!ret) {
-                block_rsv_add_bytes(block_rsv, num_bytes, 1);
-                return 0;
-        }
-
-        return ret;
+        return __block_rsv_add(root, block_rsv, num_bytes, 0);
 }
 
 int btrfs_block_rsv_check(struct btrfs_root *root,
@@ -3851,9 +3888,9 @@ int btrfs_block_rsv_check(struct btrfs_root *root,
         return ret;
 }
 
-int btrfs_block_rsv_refill(struct btrfs_root *root,
-                          struct btrfs_block_rsv *block_rsv,
-                          u64 min_reserved)
+static inline int __btrfs_block_rsv_refill(struct btrfs_root *root,
+                                           struct btrfs_block_rsv *block_rsv,
+                                           u64 min_reserved, int flush)
 {
         u64 num_bytes = 0;
         int ret = -ENOSPC;
@@ -3872,7 +3909,7 @@ int btrfs_block_rsv_refill(struct btrfs_root *root,
         if (!ret)
                 return 0;
 
-        ret = reserve_metadata_bytes(root, block_rsv, num_bytes, 1);
+        ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
         if (!ret) {
                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
                 return 0;
@@ -3881,6 +3918,20 @@ int btrfs_block_rsv_refill(struct btrfs_root *root,
         return ret;
 }
 
+int btrfs_block_rsv_refill(struct btrfs_root *root,
+                           struct btrfs_block_rsv *block_rsv,
+                           u64 min_reserved)
+{
+        return __btrfs_block_rsv_refill(root, block_rsv, min_reserved, 1);
+}
+
+int btrfs_block_rsv_refill_noflush(struct btrfs_root *root,
+                                   struct btrfs_block_rsv *block_rsv,
+                                   u64 min_reserved)
+{
+        return __btrfs_block_rsv_refill(root, block_rsv, min_reserved, 0);
+}
+
 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
                             struct btrfs_block_rsv *dst_rsv,
                             u64 num_bytes)
@@ -4064,23 +4115,30 @@ int btrfs_snap_reserve_metadata(struct btrfs_trans_handle *trans,
  */
 static unsigned drop_outstanding_extent(struct inode *inode)
 {
+        unsigned drop_inode_space = 0;
         unsigned dropped_extents = 0;
 
         BUG_ON(!BTRFS_I(inode)->outstanding_extents);
         BTRFS_I(inode)->outstanding_extents--;
 
+        if (BTRFS_I(inode)->outstanding_extents == 0 &&
+            BTRFS_I(inode)->delalloc_meta_reserved) {
+                drop_inode_space = 1;
+                BTRFS_I(inode)->delalloc_meta_reserved = 0;
+        }
+
         /*
          * If we have more or the same amount of outsanding extents than we have
          * reserved then we need to leave the reserved extents count alone.
          */
         if (BTRFS_I(inode)->outstanding_extents >=
             BTRFS_I(inode)->reserved_extents)
-                return 0;
+                return drop_inode_space;
 
         dropped_extents = BTRFS_I(inode)->reserved_extents -
                 BTRFS_I(inode)->outstanding_extents;
         BTRFS_I(inode)->reserved_extents -= dropped_extents;
-        return dropped_extents;
+        return dropped_extents + drop_inode_space;
 }
 
 /**
@@ -4146,12 +4204,17 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
         struct btrfs_root *root = BTRFS_I(inode)->root;
         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
         u64 to_reserve = 0;
+        u64 csum_bytes;
         unsigned nr_extents = 0;
+        int extra_reserve = 0;
         int flush = 1;
         int ret;
 
+        /* Need to be holding the i_mutex here if we aren't free space cache */
         if (btrfs_is_free_space_inode(root, inode))
                 flush = 0;
+        else
+                WARN_ON(!mutex_is_locked(&inode->i_mutex));
 
         if (flush && btrfs_transaction_in_commit(root->fs_info))
                 schedule_timeout(1);
@@ -4162,14 +4225,22 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
         BTRFS_I(inode)->outstanding_extents++;
 
         if (BTRFS_I(inode)->outstanding_extents >
-            BTRFS_I(inode)->reserved_extents) {
+            BTRFS_I(inode)->reserved_extents)
                 nr_extents = BTRFS_I(inode)->outstanding_extents -
                         BTRFS_I(inode)->reserved_extents;
-                BTRFS_I(inode)->reserved_extents += nr_extents;
 
-                to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
+        /*
+         * Add an item to reserve for updating the inode when we complete the
+         * delalloc io.
+         */
+        if (!BTRFS_I(inode)->delalloc_meta_reserved) {
+                nr_extents++;
+                extra_reserve = 1;
         }
+
+        to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
+        csum_bytes = BTRFS_I(inode)->csum_bytes;
         spin_unlock(&BTRFS_I(inode)->lock);
 
         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
@@ -4179,22 +4250,35 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
 
                 spin_lock(&BTRFS_I(inode)->lock);
                 dropped = drop_outstanding_extent(inode);
-                to_free = calc_csum_metadata_size(inode, num_bytes, 0);
-                spin_unlock(&BTRFS_I(inode)->lock);
-                to_free += btrfs_calc_trans_metadata_size(root, dropped);
-
                 /*
-                 * Somebody could have come in and twiddled with the
-                 * reservation, so if we have to free more than we would have
-                 * reserved from this reservation go ahead and release those
-                 * bytes.
+                 * If the inodes csum_bytes is the same as the original
+                 * csum_bytes then we know we haven't raced with any free()ers
+                 * so we can just reduce our inodes csum bytes and carry on.
+                 * Otherwise we have to do the normal free thing to account for
+                 * the case that the free side didn't free up its reserve
+                 * because of this outstanding reservation.
                  */
-                to_free -= to_reserve;
+                if (BTRFS_I(inode)->csum_bytes == csum_bytes)
+                        calc_csum_metadata_size(inode, num_bytes, 0);
+                else
+                        to_free = calc_csum_metadata_size(inode, num_bytes, 0);
+                spin_unlock(&BTRFS_I(inode)->lock);
+                if (dropped)
+                        to_free += btrfs_calc_trans_metadata_size(root, dropped);
+
                 if (to_free)
                         btrfs_block_rsv_release(root, block_rsv, to_free);
                 return ret;
         }
 
+        spin_lock(&BTRFS_I(inode)->lock);
+        if (extra_reserve) {
+                BTRFS_I(inode)->delalloc_meta_reserved = 1;
+                nr_extents--;
+        }
+        BTRFS_I(inode)->reserved_extents += nr_extents;
+        spin_unlock(&BTRFS_I(inode)->lock);
+
         block_rsv_add_bytes(block_rsv, to_reserve, 1);
 
         return 0;
@@ -5040,11 +5124,11 @@ static noinline int find_free_extent(struct btrfs_trans_handle *trans,
         struct btrfs_root *root = orig_root->fs_info->extent_root;
         struct btrfs_free_cluster *last_ptr = NULL;
         struct btrfs_block_group_cache *block_group = NULL;
+        struct btrfs_block_group_cache *used_block_group;
         int empty_cluster = 2 * 1024 * 1024;
         int allowed_chunk_alloc = 0;
         int done_chunk_alloc = 0;
         struct btrfs_space_info *space_info;
-        int last_ptr_loop = 0;
         int loop = 0;
         int index = 0;
         int alloc_type = (data & BTRFS_BLOCK_GROUP_DATA) ?
@@ -5106,6 +5190,7 @@ static noinline int find_free_extent(struct btrfs_trans_handle *trans,
 ideal_cache:
                 block_group = btrfs_lookup_block_group(root->fs_info,
                                                        search_start);
+                used_block_group = block_group;
                 /*
                  * we don't want to use the block group if it doesn't match our
                  * allocation bits, or if its not cached.
@@ -5143,6 +5228,7 @@ search:
                 u64 offset;
                 int cached;
 
+                used_block_group = block_group;
                 btrfs_get_block_group(block_group);
                 search_start = block_group->key.objectid;
 
@@ -5166,13 +5252,15 @@ search:
                 }
 
 have_block_group:
-                if (unlikely(block_group->cached == BTRFS_CACHE_NO)) {
+                cached = block_group_cache_done(block_group);
+                if (unlikely(!cached)) {
                         u64 free_percent;
 
+                        found_uncached_bg = true;
                         ret = cache_block_group(block_group, trans,
                                                 orig_root, 1);
                         if (block_group->cached == BTRFS_CACHE_FINISHED)
-                                goto have_block_group;
+                                goto alloc;
 
                         free_percent = btrfs_block_group_used(&block_group->item);
                         free_percent *= 100;
@@ -5194,7 +5282,6 @@ have_block_group:
                                                         orig_root, 0);
                                 BUG_ON(ret);
                         }
-                        found_uncached_bg = true;
 
                         /*
                          * If loop is set for cached only, try the next block
@@ -5204,94 +5291,80 @@ have_block_group:
                                 goto loop;
                 }
 
-                cached = block_group_cache_done(block_group);
-                if (unlikely(!cached))
-                        found_uncached_bg = true;
-
+alloc:
                 if (unlikely(block_group->ro))
                         goto loop;
 
                 spin_lock(&block_group->free_space_ctl->tree_lock);
                 if (cached &&
                     block_group->free_space_ctl->free_space <
-                    num_bytes + empty_size) {
+                    num_bytes + empty_cluster + empty_size) {
                         spin_unlock(&block_group->free_space_ctl->tree_lock);
                         goto loop;
                 }
                 spin_unlock(&block_group->free_space_ctl->tree_lock);
 
                 /*
-                 * Ok we want to try and use the cluster allocator, so lets look
-                 * there, unless we are on LOOP_NO_EMPTY_SIZE, since we will
-                 * have tried the cluster allocator plenty of times at this
-                 * point and not have found anything, so we are likely way too
-                 * fragmented for the clustering stuff to find anything, so lets
-                 * just skip it and let the allocator find whatever block it can
-                 * find
+                 * Ok we want to try and use the cluster allocator, so
+                 * lets look there
                  */
-                if (last_ptr && loop < LOOP_NO_EMPTY_SIZE) {
+                if (last_ptr) {
                         /*
                          * the refill lock keeps out other
                          * people trying to start a new cluster
                          */
                         spin_lock(&last_ptr->refill_lock);
-                        if (last_ptr->block_group &&
-                            (last_ptr->block_group->ro ||
-                            !block_group_bits(last_ptr->block_group, data))) {
-                                offset = 0;
+                        used_block_group = last_ptr->block_group;
+                        if (used_block_group != block_group &&
+                            (!used_block_group ||
+                             used_block_group->ro ||
+                             !block_group_bits(used_block_group, data))) {
+                                used_block_group = block_group;
                                 goto refill_cluster;
                         }
 
-                        offset = btrfs_alloc_from_cluster(block_group, last_ptr,
-                                                 num_bytes, search_start);
+                        if (used_block_group != block_group)
+                                btrfs_get_block_group(used_block_group);
+
+                        offset = btrfs_alloc_from_cluster(used_block_group,
+                          last_ptr, num_bytes, used_block_group->key.objectid);
                         if (offset) {
                                 /* we have a block, we're done */
                                 spin_unlock(&last_ptr->refill_lock);
                                 goto checks;
                         }
 
-                        spin_lock(&last_ptr->lock);
-                        /*
-                         * whoops, this cluster doesn't actually point to
-                         * this block group.  Get a ref on the block
-                         * group is does point to and try again
-                         */
-                        if (!last_ptr_loop && last_ptr->block_group &&
-                            last_ptr->block_group != block_group &&
-                            index <=
-                                 get_block_group_index(last_ptr->block_group)) {
-
-                                btrfs_put_block_group(block_group);
-                                block_group = last_ptr->block_group;
-                                btrfs_get_block_group(block_group);
-                                spin_unlock(&last_ptr->lock);
-                                spin_unlock(&last_ptr->refill_lock);
-
-                                last_ptr_loop = 1;
-                                search_start = block_group->key.objectid;
-                                /*
-                                 * we know this block group is properly
-                                 * in the list because
-                                 * btrfs_remove_block_group, drops the
-                                 * cluster before it removes the block
-                                 * group from the list
-                                 */
-                                goto have_block_group;
+                        WARN_ON(last_ptr->block_group != used_block_group);
+                        if (used_block_group != block_group) {
+                                btrfs_put_block_group(used_block_group);
+                                used_block_group = block_group;
                         }
-                        spin_unlock(&last_ptr->lock);
 refill_cluster:
+                        BUG_ON(used_block_group != block_group);
+                        /* If we are on LOOP_NO_EMPTY_SIZE, we can't
+                         * set up a new clusters, so lets just skip it
+                         * and let the allocator find whatever block
+                         * it can find.  If we reach this point, we
+                         * will have tried the cluster allocator
+                         * plenty of times and not have found
+                         * anything, so we are likely way too
+                         * fragmented for the clustering stuff to find
+                         * anything.  */
+                        if (loop >= LOOP_NO_EMPTY_SIZE) {
+                                spin_unlock(&last_ptr->refill_lock);
+                                goto unclustered_alloc;
+                        }
+
                         /*
                          * this cluster didn't work out, free it and
                          * start over
                          */
                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
 
-                        last_ptr_loop = 0;
-
                         /* allocate a cluster in this block group */
                         ret = btrfs_find_space_cluster(trans, root,
                                                block_group, last_ptr,
-                                               offset, num_bytes,
+                                               search_start, num_bytes,
                                                empty_cluster + empty_size);
                         if (ret == 0) {
                                 /*
@@ -5327,6 +5400,7 @@ refill_cluster:
                         goto loop;
                 }
 
+unclustered_alloc:
                 offset = btrfs_find_space_for_alloc(block_group, search_start,
                                                     num_bytes, empty_size);
                 /*
@@ -5353,14 +5427,14 @@ checks:
                 search_start = stripe_align(root, offset);
                 /* move on to the next group */
                 if (search_start + num_bytes >= search_end) {
-                        btrfs_add_free_space(block_group, offset, num_bytes);
+                        btrfs_add_free_space(used_block_group, offset, num_bytes);
                         goto loop;
                 }
 
                 /* move on to the next group */
                 if (search_start + num_bytes >
-                    block_group->key.objectid + block_group->key.offset) {
-                        btrfs_add_free_space(block_group, offset, num_bytes);
+                    used_block_group->key.objectid + used_block_group->key.offset) {
+                        btrfs_add_free_space(used_block_group, offset, num_bytes);
                         goto loop;
                 }
 
@@ -5368,14 +5442,14 @@ checks:
                 ins->offset = num_bytes;
 
                 if (offset < search_start)
-                        btrfs_add_free_space(block_group, offset,
+                        btrfs_add_free_space(used_block_group, offset,
                                              search_start - offset);
                 BUG_ON(offset > search_start);
 
-                ret = btrfs_update_reserved_bytes(block_group, num_bytes,
+                ret = btrfs_update_reserved_bytes(used_block_group, num_bytes,
                                                   alloc_type);
                 if (ret == -EAGAIN) {
-                        btrfs_add_free_space(block_group, offset, num_bytes);
+                        btrfs_add_free_space(used_block_group, offset, num_bytes);
                         goto loop;
                 }
 
@@ -5384,15 +5458,19 @@ checks:
                 ins->offset = num_bytes;
 
                 if (offset < search_start)
-                        btrfs_add_free_space(block_group, offset,
+                        btrfs_add_free_space(used_block_group, offset,
                                              search_start - offset);
                 BUG_ON(offset > search_start);
+                if (used_block_group != block_group)
+                        btrfs_put_block_group(used_block_group);
                 btrfs_put_block_group(block_group);
                 break;
 loop:
                 failed_cluster_refill = false;
                 failed_alloc = false;
                 BUG_ON(index != get_block_group_index(block_group));
+                if (used_block_group != block_group)
+                        btrfs_put_block_group(used_block_group);
                 btrfs_put_block_group(block_group);
         }
         up_read(&space_info->groups_sem);