1 files changed, 39 insertions, 77 deletions

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 51dcec86757..e24b7964a15 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -216,17 +216,11 @@ static void wait_current_trans(struct btrfs_root *root)
         spin_lock(&root->fs_info->trans_lock);
         cur_trans = root->fs_info->running_transaction;
         if (cur_trans && cur_trans->blocked) {
-                DEFINE_WAIT(wait);
                 atomic_inc(&cur_trans->use_count);
                 spin_unlock(&root->fs_info->trans_lock);
-                while (1) {
-                        prepare_to_wait(&root->fs_info->transaction_wait, &wait,
-                                        TASK_UNINTERRUPTIBLE);
-                        if (!cur_trans->blocked)
-                                break;
-                        schedule();
-                }
-                finish_wait(&root->fs_info->transaction_wait, &wait);
+
+                wait_event(root->fs_info->transaction_wait,
+                           !cur_trans->blocked);
                 put_transaction(cur_trans);
         } else {
                 spin_unlock(&root->fs_info->trans_lock);
@@ -260,7 +254,7 @@ static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
 {
         struct btrfs_trans_handle *h;
         struct btrfs_transaction *cur_trans;
-        int retries = 0;
+        u64 num_bytes = 0;
         int ret;
 
         if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)
@@ -274,6 +268,19 @@ static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
                 h->block_rsv = NULL;
                 goto got_it;
         }
+
+        /*
+         * Do the reservation before we join the transaction so we can do all
+         * the appropriate flushing if need be.
+         */
+        if (num_items > 0 && root != root->fs_info->chunk_root) {
+                num_bytes = btrfs_calc_trans_metadata_size(root, num_items);
+                ret = btrfs_block_rsv_add(NULL, root,
+                                          &root->fs_info->trans_block_rsv,
+                                          num_bytes);
+                if (ret)
+                        return ERR_PTR(ret);
+        }
 again:
         h = kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
         if (!h)
@@ -310,24 +317,9 @@ again:
                 goto again;
         }
 
-        if (num_items > 0) {
-                ret = btrfs_trans_reserve_metadata(h, root, num_items);
-                if (ret == -EAGAIN && !retries) {
-                        retries++;
-                        btrfs_commit_transaction(h, root);
-                        goto again;
-                } else if (ret == -EAGAIN) {
-                        /*
-                         * We have already retried and got EAGAIN, so really we
-                         * don't have space, so set ret to -ENOSPC.
-                         */
-                        ret = -ENOSPC;
-                }
-
-                if (ret < 0) {
-                        btrfs_end_transaction(h, root);
-                        return ERR_PTR(ret);
-                }
+        if (num_bytes) {
+                h->block_rsv = &root->fs_info->trans_block_rsv;
+                h->bytes_reserved = num_bytes;
         }
 
 got_it:
@@ -359,19 +351,10 @@ struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *root
 }
 
 /* wait for a transaction commit to be fully complete */
-static noinline int wait_for_commit(struct btrfs_root *root,
+static noinline void wait_for_commit(struct btrfs_root *root,
                                     struct btrfs_transaction *commit)
 {
-        DEFINE_WAIT(wait);
-        while (!commit->commit_done) {
-                prepare_to_wait(&commit->commit_wait, &wait,
-                                TASK_UNINTERRUPTIBLE);
-                if (commit->commit_done)
-                        break;
-                schedule();
-        }
-        finish_wait(&commit->commit_wait, &wait);
-        return 0;
+        wait_event(commit->commit_wait, commit->commit_done);
 }
 
 int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid)
@@ -499,10 +482,17 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
         }
 
         if (lock && cur_trans->blocked && !cur_trans->in_commit) {
-                if (throttle)
+                if (throttle) {
+                        /*
+                         * We may race with somebody else here so end up having
+                         * to call end_transaction on ourselves again, so inc
+                         * our use_count.
+                         */
+                        trans->use_count++;
                         return btrfs_commit_transaction(trans, root);
-                else
+                } else {
                         wake_up_process(info->transaction_kthread);
+                }
         }
 
         WARN_ON(cur_trans != info->running_transaction);
@@ -894,6 +884,7 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
         struct btrfs_root *tree_root = fs_info->tree_root;
         struct btrfs_root *root = pending->root;
         struct btrfs_root *parent_root;
+        struct btrfs_block_rsv *rsv;
         struct inode *parent_inode;
         struct dentry *parent;
         struct dentry *dentry;
@@ -905,6 +896,8 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
         u64 objectid;
         u64 root_flags;
 
+        rsv = trans->block_rsv;
+
         new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
         if (!new_root_item) {
                 pending->error = -ENOMEM;
@@ -1012,6 +1005,7 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
         btrfs_orphan_post_snapshot(trans, pending);
 fail:
         kfree(new_root_item);
+        trans->block_rsv = rsv;
         btrfs_block_rsv_release(root, &pending->block_rsv, (u64)-1);
         return 0;
 }
@@ -1080,22 +1074,7 @@ int btrfs_transaction_blocked(struct btrfs_fs_info *info)
 static void wait_current_trans_commit_start(struct btrfs_root *root,
                                             struct btrfs_transaction *trans)
 {
-        DEFINE_WAIT(wait);
-
-        if (trans->in_commit)
-                return;
-
-        while (1) {
-                prepare_to_wait(&root->fs_info->transaction_blocked_wait, &wait,
-                                TASK_UNINTERRUPTIBLE);
-                if (trans->in_commit) {
-                        finish_wait(&root->fs_info->transaction_blocked_wait,
-                                    &wait);
-                        break;
-                }
-                schedule();
-                finish_wait(&root->fs_info->transaction_blocked_wait, &wait);
-        }
+        wait_event(root->fs_info->transaction_blocked_wait, trans->in_commit);
 }
 
 /*
@@ -1105,24 +1084,8 @@ static void wait_current_trans_commit_start(struct btrfs_root *root,
 static void wait_current_trans_commit_start_and_unblock(struct btrfs_root *root,
                                          struct btrfs_transaction *trans)
 {
-        DEFINE_WAIT(wait);
-
-        if (trans->commit_done || (trans->in_commit && !trans->blocked))
-                return;
-
-        while (1) {
-                prepare_to_wait(&root->fs_info->transaction_wait, &wait,
-                                TASK_UNINTERRUPTIBLE);
-                if (trans->commit_done ||
-                    (trans->in_commit && !trans->blocked)) {
-                        finish_wait(&root->fs_info->transaction_wait,
-                                    &wait);
-                        break;
-                }
-                schedule();
-                finish_wait(&root->fs_info->transaction_wait,
-                            &wait);
-        }
+        wait_event(root->fs_info->transaction_wait,
+                   trans->commit_done || (trans->in_commit && !trans->blocked));
 }
 
 /*
@@ -1229,8 +1192,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
                 atomic_inc(&cur_trans->use_count);
                 btrfs_end_transaction(trans, root);
 
-                ret = wait_for_commit(root, cur_trans);
-                BUG_ON(ret);
+                wait_for_commit(root, cur_trans);
 
                 put_transaction(cur_trans);