Btrfs: Make truncate(2) more ENOSPC friendly

truncating and deleting regular files are unbound operations,
so it's not good to do them in a single transaction. This
patch makes btrfs_truncate and btrfs_delete_inode start a
new transaction after all items in a tree leaf are deleted.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 192 insertions, 124 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 8d8baaa61504..dcec42ee8cf2 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2848,37 +2848,40 @@ out:
  * min_type is the minimum key type to truncate down to.  If set to 0, this
  * will kill all the items on this inode, including the INODE_ITEM_KEY.
  */
-noinline int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
-                                        struct btrfs_root *root,
-                                        struct inode *inode,
-                                        u64 new_size, u32 min_type)
+int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
+                               struct btrfs_root *root,
+                               struct inode *inode,
+                               u64 new_size, u32 min_type)
 {
-        int ret;
         struct btrfs_path *path;
-        struct btrfs_key key;
-        struct btrfs_key found_key;
-        u32 found_type = (u8)-1;
         struct extent_buffer *leaf;
         struct btrfs_file_extent_item *fi;
+        struct btrfs_key key;
+        struct btrfs_key found_key;
         u64 extent_start = 0;
         u64 extent_num_bytes = 0;
         u64 extent_offset = 0;
         u64 item_end = 0;
+        u64 mask = root->sectorsize - 1;
+        u32 found_type = (u8)-1;
         int found_extent;
         int del_item;
         int pending_del_nr = 0;
         int pending_del_slot = 0;
         int extent_type = -1;
         int encoding;
-        u64 mask = root->sectorsize - 1;
+        int ret;
+        int err = 0;
+
+        BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
 
         if (root->ref_cows)
                 btrfs_drop_extent_cache(inode, new_size & (~mask), (u64)-1, 0);
+
         path = btrfs_alloc_path();
         BUG_ON(!path);
         path->reada = -1;
 
-        /* FIXME, add redo link to tree so we don't leak on crash */
         key.objectid = inode->i_ino;
         key.offset = (u64)-1;
         key.type = (u8)-1;
@@ -2886,17 +2889,17 @@ noinline int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
 search_again:
         path->leave_spinning = 1;
         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
-        if (ret < 0)
-                goto error;
+        if (ret < 0) {
+                err = ret;
+                goto out;
+        }
 
         if (ret > 0) {
                 /* there are no items in the tree for us to truncate, we're
                  * done
                  */
-                if (path->slots[0] == 0) {
-                        ret = 0;
-                        goto error;
-                }
+                if (path->slots[0] == 0)
+                        goto out;
                 path->slots[0]--;
         }
 
@@ -2931,28 +2934,17 @@ search_again:
                         }
                         item_end--;
                 }
-                if (item_end < new_size) {
-                        if (found_type == BTRFS_DIR_ITEM_KEY)
-                                found_type = BTRFS_INODE_ITEM_KEY;
-                        else if (found_type == BTRFS_EXTENT_ITEM_KEY)
-                                found_type = BTRFS_EXTENT_DATA_KEY;
-                        else if (found_type == BTRFS_EXTENT_DATA_KEY)
-                                found_type = BTRFS_XATTR_ITEM_KEY;
-                        else if (found_type == BTRFS_XATTR_ITEM_KEY)
-                                found_type = BTRFS_INODE_REF_KEY;
-                        else if (found_type)
-                                found_type--;
-                        else
+                if (found_type > min_type) {
+                        del_item = 1;
+                } else {
+                        if (item_end < new_size)
                                 break;
-                        btrfs_set_key_type(&key, found_type);
-                        goto next;
+                        if (found_key.offset >= new_size)
+                                del_item = 1;
+                        else
+                                del_item = 0;
                 }
-                if (found_key.offset >= new_size)
-                        del_item = 1;
-                else
-                        del_item = 0;
                 found_extent = 0;
-
                 /* FIXME, shrink the extent if the ref count is only 1 */
                 if (found_type != BTRFS_EXTENT_DATA_KEY)
                         goto delete;
@@ -3039,42 +3031,36 @@ delete:
                                                 inode->i_ino, extent_offset);
                         BUG_ON(ret);
                 }
-next:
-                if (path->slots[0] == 0) {
-                        if (pending_del_nr)
-                                goto del_pending;
-                        btrfs_release_path(root, path);
-                        if (found_type == BTRFS_INODE_ITEM_KEY)
-                                break;
-                        goto search_again;
-                }
 
-                path->slots[0]--;
-                if (pending_del_nr &&
-                    path->slots[0] + 1 != pending_del_slot) {
-                        struct btrfs_key debug;
-del_pending:
-                        btrfs_item_key_to_cpu(path->nodes[0], &debug,
-                                              pending_del_slot);
-                        ret = btrfs_del_items(trans, root, path,
-                                              pending_del_slot,
-                                              pending_del_nr);
-                        BUG_ON(ret);
-                        pending_del_nr = 0;
+                if (found_type == BTRFS_INODE_ITEM_KEY)
+                        break;
+
+                if (path->slots[0] == 0 ||
+                    path->slots[0] != pending_del_slot) {
+                        if (root->ref_cows) {
+                                err = -EAGAIN;
+                                goto out;
+                        }
+                        if (pending_del_nr) {
+                                ret = btrfs_del_items(trans, root, path,
+                                                pending_del_slot,
+                                                pending_del_nr);
+                                BUG_ON(ret);
+                                pending_del_nr = 0;
+                        }
                         btrfs_release_path(root, path);
-                        if (found_type == BTRFS_INODE_ITEM_KEY)
-                                break;
                         goto search_again;
+                } else {
+                        path->slots[0]--;
                 }
         }
-        ret = 0;
-error:
+out:
         if (pending_del_nr) {
                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
                                       pending_del_nr);
         }
         btrfs_free_path(path);
-        return ret;
+        return err;
 }
 
 /*
@@ -3194,10 +3180,6 @@ int btrfs_cont_expand(struct inode *inode, loff_t size)
         if (size <= hole_start)
                 return 0;
 
-        err = btrfs_truncate_page(inode->i_mapping, inode->i_size);
-        if (err)
-                return err;
-
         while (1) {
                 struct btrfs_ordered_extent *ordered;
                 btrfs_wait_ordered_range(inode, hole_start,
@@ -3210,9 +3192,6 @@ int btrfs_cont_expand(struct inode *inode, loff_t size)
                 btrfs_put_ordered_extent(ordered);
         }
 
-        trans = btrfs_start_transaction(root, 1);
-        btrfs_set_trans_block_group(trans, inode);
-
         cur_offset = hole_start;
         while (1) {
                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
@@ -3220,38 +3199,120 @@ int btrfs_cont_expand(struct inode *inode, loff_t size)
                 BUG_ON(IS_ERR(em) || !em);
                 last_byte = min(extent_map_end(em), block_end);
                 last_byte = (last_byte + mask) & ~mask;
-                if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
+                if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
                         u64 hint_byte = 0;
                         hole_size = last_byte - cur_offset;
-                        err = btrfs_drop_extents(trans, inode, cur_offset,
-                                                 cur_offset + hole_size,
-                                                 &hint_byte, 1);
-                        if (err)
-                                break;
 
-                        err = btrfs_reserve_metadata_space(root, 1);
+                        err = btrfs_reserve_metadata_space(root, 2);
                         if (err)
                                 break;
 
+                        trans = btrfs_start_transaction(root, 1);
+                        btrfs_set_trans_block_group(trans, inode);
+
+                        err = btrfs_drop_extents(trans, inode, cur_offset,
+                                                 cur_offset + hole_size,
+                                                 &hint_byte, 1);
+                        BUG_ON(err);
+
                         err = btrfs_insert_file_extent(trans, root,
                                         inode->i_ino, cur_offset, 0,
                                         0, hole_size, 0, hole_size,
                                         0, 0, 0);
+                        BUG_ON(err);
+
                         btrfs_drop_extent_cache(inode, hole_start,
                                         last_byte - 1, 0);
-                        btrfs_unreserve_metadata_space(root, 1);
+
+                        btrfs_end_transaction(trans, root);
+                        btrfs_unreserve_metadata_space(root, 2);
                 }
                 free_extent_map(em);
                 cur_offset = last_byte;
-                if (err || cur_offset >= block_end)
+                if (cur_offset >= block_end)
                         break;
         }
 
-        btrfs_end_transaction(trans, root);
         unlock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
         return err;
 }
 
+static int btrfs_setattr_size(struct inode *inode, struct iattr *attr)
+{
+        struct btrfs_root *root = BTRFS_I(inode)->root;
+        struct btrfs_trans_handle *trans;
+        unsigned long nr;
+        int ret;
+
+        if (attr->ia_size == inode->i_size)
+                return 0;
+
+        if (attr->ia_size > inode->i_size) {
+                unsigned long limit;
+                limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
+                if (attr->ia_size > inode->i_sb->s_maxbytes)
+                        return -EFBIG;
+                if (limit != RLIM_INFINITY && attr->ia_size > limit) {
+                        send_sig(SIGXFSZ, current, 0);
+                        return -EFBIG;
+                }
+        }
+
+        ret = btrfs_reserve_metadata_space(root, 1);
+        if (ret)
+                return ret;
+
+        trans = btrfs_start_transaction(root, 1);
+        btrfs_set_trans_block_group(trans, inode);
+
+        ret = btrfs_orphan_add(trans, inode);
+        BUG_ON(ret);
+
+        nr = trans->blocks_used;
+        btrfs_end_transaction(trans, root);
+        btrfs_unreserve_metadata_space(root, 1);
+        btrfs_btree_balance_dirty(root, nr);
+
+        if (attr->ia_size > inode->i_size) {
+                ret = btrfs_cont_expand(inode, attr->ia_size);
+                if (ret) {
+                        btrfs_truncate(inode);
+                        return ret;
+                }
+
+                i_size_write(inode, attr->ia_size);
+                btrfs_ordered_update_i_size(inode, inode->i_size, NULL);
+
+                trans = btrfs_start_transaction(root, 1);
+                btrfs_set_trans_block_group(trans, inode);
+
+                ret = btrfs_update_inode(trans, root, inode);
+                BUG_ON(ret);
+                if (inode->i_nlink > 0) {
+                        ret = btrfs_orphan_del(trans, inode);
+                        BUG_ON(ret);
+                }
+                nr = trans->blocks_used;
+                btrfs_end_transaction(trans, root);
+                btrfs_btree_balance_dirty(root, nr);
+                return 0;
+        }
+
+        /*
+         * We're truncating a file that used to have good data down to
+         * zero. Make sure it gets into the ordered flush list so that
+         * any new writes get down to disk quickly.
+         */
+        if (attr->ia_size == 0)
+                BTRFS_I(inode)->ordered_data_close = 1;
+
+        /* we don't support swapfiles, so vmtruncate shouldn't fail */
+        ret = vmtruncate(inode, attr->ia_size);
+        BUG_ON(ret);
+
+        return 0;
+}
+
 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
 {
         struct inode *inode = dentry->d_inode;
@@ -3262,23 +3323,14 @@ static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
                 return err;
 
         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
-                if (attr->ia_size > inode->i_size) {
-                        err = btrfs_cont_expand(inode, attr->ia_size);
-                        if (err)
-                                return err;
-                } else if (inode->i_size > 0 &&
-                           attr->ia_size == 0) {
-
-                        /* we're truncating a file that used to have good
-                         * data down to zero.  Make sure it gets into
-                         * the ordered flush list so that any new writes
-                         * get down to disk quickly.
-                         */
-                        BTRFS_I(inode)->ordered_data_close = 1;
-                }
+                err = btrfs_setattr_size(inode, attr);
+                if (err)
+                        return err;
         }
+        attr->ia_valid &= ~ATTR_SIZE;
 
-        err = inode_setattr(inode, attr);
+        if (attr->ia_valid)
+                err = inode_setattr(inode, attr);
 
         if (!err && ((attr->ia_valid & ATTR_MODE)))
                 err = btrfs_acl_chmod(inode);
@@ -3310,30 +3362,32 @@ void btrfs_delete_inode(struct inode *inode)
         }
 
         btrfs_i_size_write(inode, 0);
-        trans = btrfs_join_transaction(root, 1);
 
-        btrfs_set_trans_block_group(trans, inode);
-        ret = btrfs_truncate_inode_items(trans, root, inode, inode->i_size, 0);
-        if (ret) {
-                btrfs_orphan_del(NULL, inode);
-                goto no_delete_lock;
-        }
+        while (1) {
+                trans = btrfs_start_transaction(root, 1);
+                btrfs_set_trans_block_group(trans, inode);
+                ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
 
-        btrfs_orphan_del(trans, inode);
+                if (ret != -EAGAIN)
+                        break;
 
-        nr = trans->blocks_used;
-        clear_inode(inode);
+                nr = trans->blocks_used;
+                btrfs_end_transaction(trans, root);
+                trans = NULL;
+                btrfs_btree_balance_dirty(root, nr);
+        }
 
-        btrfs_end_transaction(trans, root);
-        btrfs_btree_balance_dirty(root, nr);
-        return;
+        if (ret == 0) {
+                ret = btrfs_orphan_del(trans, inode);
+                BUG_ON(ret);
+        }
 
-no_delete_lock:
         nr = trans->blocks_used;
         btrfs_end_transaction(trans, root);
         btrfs_btree_balance_dirty(root, nr);
 no_delete:
         clear_inode(inode);
+        return;
 }
 
 /*
@@ -5097,17 +5151,20 @@ static void btrfs_truncate(struct inode *inode)
         unsigned long nr;
         u64 mask = root->sectorsize - 1;
 
-        if (!S_ISREG(inode->i_mode))
-                return;
-        if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
+        if (!S_ISREG(inode->i_mode)) {
+                WARN_ON(1);
                 return;
+        }
 
         ret = btrfs_truncate_page(inode->i_mapping, inode->i_size);
         if (ret)
                 return;
+
         btrfs_wait_ordered_range(inode, inode->i_size & (~mask), (u64)-1);
+        btrfs_ordered_update_i_size(inode, inode->i_size, NULL);
 
         trans = btrfs_start_transaction(root, 1);
+        btrfs_set_trans_block_group(trans, inode);
 
         /*
          * setattr is responsible for setting the ordered_data_close flag,
@@ -5129,21 +5186,32 @@ static void btrfs_truncate(struct inode *inode)
         if (inode->i_size == 0 && BTRFS_I(inode)->ordered_data_close)
                 btrfs_add_ordered_operation(trans, root, inode);
 
-        btrfs_set_trans_block_group(trans, inode);
-        btrfs_i_size_write(inode, inode->i_size);
+        while (1) {
+                ret = btrfs_truncate_inode_items(trans, root, inode,
+                                                 inode->i_size,
+                                                 BTRFS_EXTENT_DATA_KEY);
+                if (ret != -EAGAIN)
+                        break;
 
-        ret = btrfs_orphan_add(trans, inode);
-        if (ret)
-                goto out;
-        /* FIXME, add redo link to tree so we don't leak on crash */
-        ret = btrfs_truncate_inode_items(trans, root, inode, inode->i_size,
-                                      BTRFS_EXTENT_DATA_KEY);
-        btrfs_update_inode(trans, root, inode);
+                ret = btrfs_update_inode(trans, root, inode);
+                BUG_ON(ret);
+
+                nr = trans->blocks_used;
+                btrfs_end_transaction(trans, root);
+                btrfs_btree_balance_dirty(root, nr);
+
+                trans = btrfs_start_transaction(root, 1);
+                btrfs_set_trans_block_group(trans, inode);
+        }
 
-        ret = btrfs_orphan_del(trans, inode);
+        if (ret == 0 && inode->i_nlink > 0) {
+                ret = btrfs_orphan_del(trans, inode);
+                BUG_ON(ret);
+        }
+
+        ret = btrfs_update_inode(trans, root, inode);
         BUG_ON(ret);
 
-out:
         nr = trans->blocks_used;
         ret = btrfs_end_transaction_throttle(trans, root);
         BUG_ON(ret);
@@ -5240,9 +5308,9 @@ void btrfs_destroy_inode(struct inode *inode)
 
         spin_lock(&root->list_lock);
         if (!list_empty(&BTRFS_I(inode)->i_orphan)) {
-                printk(KERN_ERR "BTRFS: inode %lu: inode still on the orphan"
-                       " list\n", inode->i_ino);
-                dump_stack();
+                printk(KERN_INFO "BTRFS: inode %lu still on the orphan list\n",
+                       inode->i_ino);
+                list_del_init(&BTRFS_I(inode)->i_orphan);
         }
         spin_unlock(&root->list_lock);