3 files changed, 50 insertions, 191 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index fd62aa856d1b..a07b8c0a260d 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1495,7 +1495,6 @@ struct btrfs_fs_info {
         int do_barriers;
         int closing;
         int log_root_recovering;
-        int enospc_unlink;
 
         u64 total_pinned;
 
@@ -3183,6 +3182,9 @@ int btrfs_block_rsv_refill(struct btrfs_root *root,
 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
                             struct btrfs_block_rsv *dst_rsv,
                             u64 num_bytes);
+int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
+                             struct btrfs_block_rsv *dest, u64 num_bytes,
+                             int min_factor);
 void btrfs_block_rsv_release(struct btrfs_root *root,
                              struct btrfs_block_rsv *block_rsv,
                              u64 num_bytes);
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 4ec8305fe078..e14f8bd4b310 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4297,6 +4297,31 @@ static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
         spin_unlock(&block_rsv->lock);
 }
 
+int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
+                             struct btrfs_block_rsv *dest, u64 num_bytes,
+                             int min_factor)
+{
+        struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
+        u64 min_bytes;
+
+        if (global_rsv->space_info != dest->space_info)
+                return -ENOSPC;
+
+        spin_lock(&global_rsv->lock);
+        min_bytes = div_factor(global_rsv->size, min_factor);
+        if (global_rsv->reserved < min_bytes + num_bytes) {
+                spin_unlock(&global_rsv->lock);
+                return -ENOSPC;
+        }
+        global_rsv->reserved -= num_bytes;
+        if (global_rsv->reserved < global_rsv->size)
+                global_rsv->full = 0;
+        spin_unlock(&global_rsv->lock);
+
+        block_rsv_add_bytes(dest, num_bytes, 1);
+        return 0;
+}
+
 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
                                     struct btrfs_block_rsv *block_rsv,
                                     struct btrfs_block_rsv *dest, u64 num_bytes)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 51520755f4dc..c0e95b1554a0 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3679,53 +3679,20 @@ int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
         }
         return ret;
 }
-                
-
-/* helper to check if there is any shared block in the path */
-static int check_path_shared(struct btrfs_root *root,
-                             struct btrfs_path *path)
-{
-        struct extent_buffer *eb;
-        int level;
-        u64 refs = 1;
-
-        for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
-                int ret;
-
-                if (!path->nodes[level])
-                        break;
-                eb = path->nodes[level];
-                if (!btrfs_block_can_be_shared(root, eb))
-                        continue;
-                ret = btrfs_lookup_extent_info(NULL, root, eb->start, level, 1,
-                                               &refs, NULL);
-                if (refs > 1)
-                        return 1;
-        }
-        return 0;
-}
 
 /*
  * helper to start transaction for unlink and rmdir.
  *
- * unlink and rmdir are special in btrfs, they do not always free space.
- * so in enospc case, we should make sure they will free space before
- * allowing them to use the global metadata reservation.
+ * unlink and rmdir are special in btrfs, they do not always free space, so
+ * if we cannot make our reservations the normal way try and see if there is
+ * plenty of slack room in the global reserve to migrate, otherwise we cannot
+ * allow the unlink to occur.
  */
-static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir,
-                                                       struct dentry *dentry)
+static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir)
 {
         struct btrfs_trans_handle *trans;
         struct btrfs_root *root = BTRFS_I(dir)->root;
-        struct btrfs_path *path;
-        struct btrfs_dir_item *di;
-        struct inode *inode = dentry->d_inode;
-        u64 index;
-        int check_link = 1;
-        int err = -ENOSPC;
         int ret;
-        u64 ino = btrfs_ino(inode);
-        u64 dir_ino = btrfs_ino(dir);
 
         /*
          * 1 for the possible orphan item
@@ -3738,158 +3705,23 @@ static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir,
         if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
                 return trans;
 
-        if (ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
-                return ERR_PTR(-ENOSPC);
-
-        /* check if there is someone else holds reference */
-        if (S_ISDIR(inode->i_mode) && atomic_read(&inode->i_count) > 1)
-                return ERR_PTR(-ENOSPC);
-
-        if (atomic_read(&inode->i_count) > 2)
-                return ERR_PTR(-ENOSPC);
-
-        if (xchg(&root->fs_info->enospc_unlink, 1))
-                return ERR_PTR(-ENOSPC);
-
-        path = btrfs_alloc_path();
-        if (!path) {
-                root->fs_info->enospc_unlink = 0;
-                return ERR_PTR(-ENOMEM);
-        }
+        if (PTR_ERR(trans) == -ENOSPC) {
+                u64 num_bytes = btrfs_calc_trans_metadata_size(root, 5);
 
-        /* 1 for the orphan item */
-        trans = btrfs_start_transaction(root, 1);
-        if (IS_ERR(trans)) {
-                btrfs_free_path(path);
-                root->fs_info->enospc_unlink = 0;
-                return trans;
-        }
-
-        path->skip_locking = 1;
-        path->search_commit_root = 1;
-
-        ret = btrfs_lookup_inode(trans, root, path,
-                                &BTRFS_I(dir)->location, 0);
-        if (ret < 0) {
-                err = ret;
-                goto out;
-        }
-        if (ret == 0) {
-                if (check_path_shared(root, path))
-                        goto out;
-        } else {
-                check_link = 0;
-        }
-        btrfs_release_path(path);
-
-        ret = btrfs_lookup_inode(trans, root, path,
-                                &BTRFS_I(inode)->location, 0);
-        if (ret < 0) {
-                err = ret;
-                goto out;
-        }
-        if (ret == 0) {
-                if (check_path_shared(root, path))
-                        goto out;
-        } else {
-                check_link = 0;
-        }
-        btrfs_release_path(path);
-
-        if (ret == 0 && S_ISREG(inode->i_mode)) {
-                ret = btrfs_lookup_file_extent(trans, root, path,
-                                               ino, (u64)-1, 0);
-                if (ret < 0) {
-                        err = ret;
-                        goto out;
+                trans = btrfs_start_transaction(root, 0);
+                if (IS_ERR(trans))
+                        return trans;
+                ret = btrfs_cond_migrate_bytes(root->fs_info,
+                                               &root->fs_info->trans_block_rsv,
+                                               num_bytes, 5);
+                if (ret) {
+                        btrfs_end_transaction(trans, root);
+                        return ERR_PTR(ret);
                 }
-                BUG_ON(ret == 0); /* Corruption */
-                if (check_path_shared(root, path))
-                        goto out;
-                btrfs_release_path(path);
-        }
-
-        if (!check_link) {
-                err = 0;
-                goto out;
-        }
-
-        di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
-                                dentry->d_name.name, dentry->d_name.len, 0);
-        if (IS_ERR(di)) {
-                err = PTR_ERR(di);
-                goto out;
-        }
-        if (di) {
-                if (check_path_shared(root, path))
-                        goto out;
-        } else {
-                err = 0;
-                goto out;
-        }
-        btrfs_release_path(path);
-
-        ret = btrfs_get_inode_ref_index(trans, root, path, dentry->d_name.name,
-                                        dentry->d_name.len, ino, dir_ino, 0,
-                                        &index);
-        if (ret) {
-                err = ret;
-                goto out;
-        }
-
-        if (check_path_shared(root, path))
-                goto out;
-
-        btrfs_release_path(path);
-
-        /*
-         * This is a commit root search, if we can lookup inode item and other
-         * relative items in the commit root, it means the transaction of
-         * dir/file creation has been committed, and the dir index item that we
-         * delay to insert has also been inserted into the commit root. So
-         * we needn't worry about the delayed insertion of the dir index item
-         * here.
-         */
-        di = btrfs_lookup_dir_index_item(trans, root, path, dir_ino, index,
-                                dentry->d_name.name, dentry->d_name.len, 0);
-        if (IS_ERR(di)) {
-                err = PTR_ERR(di);
-                goto out;
-        }
-        BUG_ON(ret == -ENOENT);
-        if (check_path_shared(root, path))
-                goto out;
-
-        err = 0;
-out:
-        btrfs_free_path(path);
-        /* Migrate the orphan reservation over */
-        if (!err)
-                err = btrfs_block_rsv_migrate(trans->block_rsv,
-                                &root->fs_info->global_block_rsv,
-                                trans->bytes_reserved);
-
-        if (err) {
-                btrfs_end_transaction(trans, root);
-                root->fs_info->enospc_unlink = 0;
-                return ERR_PTR(err);
-        }
-
-        trans->block_rsv = &root->fs_info->global_block_rsv;
-        return trans;
-}
-
-static void __unlink_end_trans(struct btrfs_trans_handle *trans,
-                               struct btrfs_root *root)
-{
-        if (trans->block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL) {
-                btrfs_block_rsv_release(root, trans->block_rsv,
-                                        trans->bytes_reserved);
                 trans->block_rsv = &root->fs_info->trans_block_rsv;
-                BUG_ON(!root->fs_info->enospc_unlink);
-                root->fs_info->enospc_unlink = 0;
+                trans->bytes_reserved = num_bytes;
         }
-        btrfs_end_transaction(trans, root);
+        return trans;
 }
 
 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
@@ -3899,7 +3731,7 @@ static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
         struct inode *inode = dentry->d_inode;
         int ret;
 
-        trans = __unlink_start_trans(dir, dentry);
+        trans = __unlink_start_trans(dir);
         if (IS_ERR(trans))
                 return PTR_ERR(trans);
 
@@ -3917,7 +3749,7 @@ static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
         }
 
 out:
-        __unlink_end_trans(trans, root);
+        btrfs_end_transaction(trans, root);
         btrfs_btree_balance_dirty(root);
         return ret;
 }
@@ -4014,7 +3846,7 @@ static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
         if (btrfs_ino(inode) == BTRFS_FIRST_FREE_OBJECTID)
                 return -EPERM;
 
-        trans = __unlink_start_trans(dir, dentry);
+        trans = __unlink_start_trans(dir);
         if (IS_ERR(trans))
                 return PTR_ERR(trans);
 
@@ -4036,7 +3868,7 @@ static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
         if (!err)
                 btrfs_i_size_write(inode, 0);
 out:
-        __unlink_end_trans(trans, root);
+        btrfs_end_transaction(trans, root);
         btrfs_btree_balance_dirty(root);
 
         return err;