Btrfs: Integrate metadata reservation with start_transaction
Besides simplify the code, this change makes sure all metadata
reservation for normal metadata operations are released after
committing transaction.
Changes since V1:
Add code that check if unlink and rmdir will free space.
Add ENOSPC handling for clone ioctl.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index f444250..c4b0fd1 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2135,7 +2135,7 @@
* do a destroy_inode
*/
if (is_bad_inode(inode)) {
- trans = btrfs_start_transaction(root, 1);
+ trans = btrfs_start_transaction(root, 0);
btrfs_orphan_del(trans, inode);
btrfs_end_transaction(trans, root);
iput(inode);
@@ -2478,29 +2478,201 @@
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;
+ int ret;
+ u64 refs;
+
+ for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
+ 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, eb->len,
+ &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.
+ */
+static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir,
+ struct dentry *dentry)
+{
+ struct btrfs_trans_handle *trans;
+ struct btrfs_root *root = BTRFS_I(dir)->root;
+ struct btrfs_path *path;
+ struct btrfs_inode_ref *ref;
+ struct btrfs_dir_item *di;
+ struct inode *inode = dentry->d_inode;
+ u64 index;
+ int check_link = 1;
+ int err = -ENOSPC;
+ int ret;
+
+ trans = btrfs_start_transaction(root, 10);
+ if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
+ return trans;
+
+ if (inode->i_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);
+ }
+
+ trans = btrfs_start_transaction(root, 0);
+ 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(root, 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(root, path);
+
+ if (ret == 0 && S_ISREG(inode->i_mode)) {
+ ret = btrfs_lookup_file_extent(trans, root, path,
+ inode->i_ino, (u64)-1, 0);
+ if (ret < 0) {
+ err = ret;
+ goto out;
+ }
+ BUG_ON(ret == 0);
+ if (check_path_shared(root, path))
+ goto out;
+ btrfs_release_path(root, path);
+ }
+
+ if (!check_link) {
+ err = 0;
+ goto out;
+ }
+
+ di = btrfs_lookup_dir_item(trans, root, path, dir->i_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(root, path);
+
+ ref = btrfs_lookup_inode_ref(trans, root, path,
+ dentry->d_name.name, dentry->d_name.len,
+ inode->i_ino, dir->i_ino, 0);
+ if (IS_ERR(ref)) {
+ err = PTR_ERR(ref);
+ goto out;
+ }
+ BUG_ON(!ref);
+ if (check_path_shared(root, path))
+ goto out;
+ index = btrfs_inode_ref_index(path->nodes[0], ref);
+ btrfs_release_path(root, path);
+
+ di = btrfs_lookup_dir_index_item(trans, root, path, dir->i_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);
+ 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 == &root->fs_info->global_block_rsv) {
+ BUG_ON(!root->fs_info->enospc_unlink);
+ root->fs_info->enospc_unlink = 0;
+ }
+ btrfs_end_transaction_throttle(trans, root);
+}
+
static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
{
- struct btrfs_root *root;
+ struct btrfs_root *root = BTRFS_I(dir)->root;
struct btrfs_trans_handle *trans;
struct inode *inode = dentry->d_inode;
int ret;
unsigned long nr = 0;
- root = BTRFS_I(dir)->root;
-
- /*
- * 5 items for unlink inode
- * 1 for orphan
- */
- ret = btrfs_reserve_metadata_space(root, 6);
- if (ret)
- return ret;
-
- trans = btrfs_start_transaction(root, 1);
- if (IS_ERR(trans)) {
- btrfs_unreserve_metadata_space(root, 6);
+ trans = __unlink_start_trans(dir, dentry);
+ if (IS_ERR(trans))
return PTR_ERR(trans);
- }
btrfs_set_trans_block_group(trans, dir);
@@ -2508,14 +2680,15 @@
ret = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
dentry->d_name.name, dentry->d_name.len);
+ BUG_ON(ret);
- if (inode->i_nlink == 0)
+ if (inode->i_nlink == 0) {
ret = btrfs_orphan_add(trans, inode);
+ BUG_ON(ret);
+ }
nr = trans->blocks_used;
-
- btrfs_end_transaction_throttle(trans, root);
- btrfs_unreserve_metadata_space(root, 6);
+ __unlink_end_trans(trans, root);
btrfs_btree_balance_dirty(root, nr);
return ret;
}
@@ -2587,7 +2760,6 @@
{
struct inode *inode = dentry->d_inode;
int err = 0;
- int ret;
struct btrfs_root *root = BTRFS_I(dir)->root;
struct btrfs_trans_handle *trans;
unsigned long nr = 0;
@@ -2596,15 +2768,9 @@
inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
return -ENOTEMPTY;
- ret = btrfs_reserve_metadata_space(root, 5);
- if (ret)
- return ret;
-
- trans = btrfs_start_transaction(root, 1);
- if (IS_ERR(trans)) {
- btrfs_unreserve_metadata_space(root, 5);
+ trans = __unlink_start_trans(dir, dentry);
+ if (IS_ERR(trans))
return PTR_ERR(trans);
- }
btrfs_set_trans_block_group(trans, dir);
@@ -2627,12 +2793,9 @@
btrfs_i_size_write(inode, 0);
out:
nr = trans->blocks_used;
- ret = btrfs_end_transaction_throttle(trans, root);
- btrfs_unreserve_metadata_space(root, 5);
+ __unlink_end_trans(trans, root);
btrfs_btree_balance_dirty(root, nr);
- if (ret && !err)
- err = ret;
return err;
}
@@ -3145,7 +3308,7 @@
struct btrfs_trans_handle *trans;
struct btrfs_root *root = BTRFS_I(inode)->root;
struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
- struct extent_map *em;
+ struct extent_map *em = NULL;
struct extent_state *cached_state = NULL;
u64 mask = root->sectorsize - 1;
u64 hole_start = (inode->i_size + mask) & ~mask;
@@ -3183,11 +3346,11 @@
u64 hint_byte = 0;
hole_size = last_byte - cur_offset;
- err = btrfs_reserve_metadata_space(root, 2);
- if (err)
+ trans = btrfs_start_transaction(root, 2);
+ if (IS_ERR(trans)) {
+ err = PTR_ERR(trans);
break;
-
- trans = btrfs_start_transaction(root, 1);
+ }
btrfs_set_trans_block_group(trans, inode);
err = btrfs_drop_extents(trans, inode, cur_offset,
@@ -3205,14 +3368,15 @@
last_byte - 1, 0);
btrfs_end_transaction(trans, root);
- btrfs_unreserve_metadata_space(root, 2);
}
free_extent_map(em);
+ em = NULL;
cur_offset = last_byte;
if (cur_offset >= block_end)
break;
}
+ free_extent_map(em);
unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state,
GFP_NOFS);
return err;
@@ -3239,10 +3403,6 @@
}
}
- ret = btrfs_reserve_metadata_space(root, 1);
- if (ret)
- return ret;
-
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, inode);
@@ -3251,7 +3411,6 @@
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) {
@@ -4223,26 +4382,21 @@
if (!new_valid_dev(rdev))
return -EINVAL;
+ err = btrfs_find_free_objectid(NULL, root, dir->i_ino, &objectid);
+ if (err)
+ return err;
+
/*
* 2 for inode item and ref
* 2 for dir items
* 1 for xattr if selinux is on
*/
- err = btrfs_reserve_metadata_space(root, 5);
- if (err)
- return err;
+ trans = btrfs_start_transaction(root, 5);
+ if (IS_ERR(trans))
+ return PTR_ERR(trans);
- trans = btrfs_start_transaction(root, 1);
- if (!trans)
- goto fail;
btrfs_set_trans_block_group(trans, dir);
- err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
- if (err) {
- err = -ENOSPC;
- goto out_unlock;
- }
-
inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
dentry->d_name.len,
dentry->d_parent->d_inode->i_ino, objectid,
@@ -4271,13 +4425,11 @@
out_unlock:
nr = trans->blocks_used;
btrfs_end_transaction_throttle(trans, root);
-fail:
- btrfs_unreserve_metadata_space(root, 5);
+ btrfs_btree_balance_dirty(root, nr);
if (drop_inode) {
inode_dec_link_count(inode);
iput(inode);
}
- btrfs_btree_balance_dirty(root, nr);
return err;
}
@@ -4287,32 +4439,26 @@
struct btrfs_trans_handle *trans;
struct btrfs_root *root = BTRFS_I(dir)->root;
struct inode *inode = NULL;
- int err;
int drop_inode = 0;
+ int err;
unsigned long nr = 0;
u64 objectid;
u64 index = 0;
+ err = btrfs_find_free_objectid(NULL, root, dir->i_ino, &objectid);
+ if (err)
+ return err;
/*
* 2 for inode item and ref
* 2 for dir items
* 1 for xattr if selinux is on
*/
- err = btrfs_reserve_metadata_space(root, 5);
- if (err)
- return err;
+ trans = btrfs_start_transaction(root, 5);
+ if (IS_ERR(trans))
+ return PTR_ERR(trans);
- trans = btrfs_start_transaction(root, 1);
- if (!trans)
- goto fail;
btrfs_set_trans_block_group(trans, dir);
- err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
- if (err) {
- err = -ENOSPC;
- goto out_unlock;
- }
-
inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
dentry->d_name.len,
dentry->d_parent->d_inode->i_ino,
@@ -4344,8 +4490,6 @@
out_unlock:
nr = trans->blocks_used;
btrfs_end_transaction_throttle(trans, root);
-fail:
- btrfs_unreserve_metadata_space(root, 5);
if (drop_inode) {
inode_dec_link_count(inode);
iput(inode);
@@ -4372,21 +4516,21 @@
if (root->objectid != BTRFS_I(inode)->root->objectid)
return -EPERM;
- /*
- * 1 item for inode ref
- * 2 items for dir items
- */
- err = btrfs_reserve_metadata_space(root, 3);
- if (err)
- return err;
-
btrfs_inc_nlink(inode);
err = btrfs_set_inode_index(dir, &index);
if (err)
goto fail;
- trans = btrfs_start_transaction(root, 1);
+ /*
+ * 1 item for inode ref
+ * 2 items for dir items
+ */
+ trans = btrfs_start_transaction(root, 3);
+ if (IS_ERR(trans)) {
+ err = PTR_ERR(trans);
+ goto fail;
+ }
btrfs_set_trans_block_group(trans, dir);
atomic_inc(&inode->i_count);
@@ -4405,7 +4549,6 @@
nr = trans->blocks_used;
btrfs_end_transaction_throttle(trans, root);
fail:
- btrfs_unreserve_metadata_space(root, 3);
if (drop_inode) {
inode_dec_link_count(inode);
iput(inode);
@@ -4425,28 +4568,20 @@
u64 index = 0;
unsigned long nr = 1;
+ err = btrfs_find_free_objectid(NULL, root, dir->i_ino, &objectid);
+ if (err)
+ return err;
+
/*
* 2 items for inode and ref
* 2 items for dir items
* 1 for xattr if selinux is on
*/
- err = btrfs_reserve_metadata_space(root, 5);
- if (err)
- return err;
-
- trans = btrfs_start_transaction(root, 1);
- if (!trans) {
- err = -ENOMEM;
- goto out_unlock;
- }
+ trans = btrfs_start_transaction(root, 5);
+ if (IS_ERR(trans))
+ return PTR_ERR(trans);
btrfs_set_trans_block_group(trans, dir);
- err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
- if (err) {
- err = -ENOSPC;
- goto out_fail;
- }
-
inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
dentry->d_name.len,
dentry->d_parent->d_inode->i_ino, objectid,
@@ -4486,9 +4621,6 @@
out_fail:
nr = trans->blocks_used;
btrfs_end_transaction_throttle(trans, root);
-
-out_unlock:
- btrfs_unreserve_metadata_space(root, 5);
if (drop_on_err)
iput(inode);
btrfs_btree_balance_dirty(root, nr);
@@ -5426,19 +5558,6 @@
if (S_ISDIR(old_inode->i_mode) && new_inode &&
new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
return -ENOTEMPTY;
-
- /*
- * We want to reserve the absolute worst case amount of items. So if
- * both inodes are subvols and we need to unlink them then that would
- * require 4 item modifications, but if they are both normal inodes it
- * would require 5 item modifications, so we'll assume their normal
- * inodes. So 5 * 2 is 10, plus 1 for the new link, so 11 total items
- * should cover the worst case number of items we'll modify.
- */
- ret = btrfs_reserve_metadata_space(root, 11);
- if (ret)
- return ret;
-
/*
* we're using rename to replace one file with another.
* and the replacement file is large. Start IO on it now so
@@ -5451,8 +5570,18 @@
/* close the racy window with snapshot create/destroy ioctl */
if (old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
down_read(&root->fs_info->subvol_sem);
+ /*
+ * We want to reserve the absolute worst case amount of items. So if
+ * both inodes are subvols and we need to unlink them then that would
+ * require 4 item modifications, but if they are both normal inodes it
+ * would require 5 item modifications, so we'll assume their normal
+ * inodes. So 5 * 2 is 10, plus 1 for the new link, so 11 total items
+ * should cover the worst case number of items we'll modify.
+ */
+ trans = btrfs_start_transaction(root, 20);
+ if (IS_ERR(trans))
+ return PTR_ERR(trans);
- trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, new_dir);
if (dest != root)
@@ -5551,7 +5680,6 @@
if (old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
up_read(&root->fs_info->subvol_sem);
- btrfs_unreserve_metadata_space(root, 11);
return ret;
}
@@ -5658,26 +5786,20 @@
if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(root))
return -ENAMETOOLONG;
+ err = btrfs_find_free_objectid(NULL, root, dir->i_ino, &objectid);
+ if (err)
+ return err;
/*
* 2 items for inode item and ref
* 2 items for dir items
* 1 item for xattr if selinux is on
*/
- err = btrfs_reserve_metadata_space(root, 5);
- if (err)
- return err;
+ trans = btrfs_start_transaction(root, 5);
+ if (IS_ERR(trans))
+ return PTR_ERR(trans);
- trans = btrfs_start_transaction(root, 1);
- if (!trans)
- goto out_fail;
btrfs_set_trans_block_group(trans, dir);
- err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
- if (err) {
- err = -ENOSPC;
- goto out_unlock;
- }
-
inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
dentry->d_name.len,
dentry->d_parent->d_inode->i_ino, objectid,
@@ -5749,8 +5871,6 @@
out_unlock:
nr = trans->blocks_used;
btrfs_end_transaction_throttle(trans, root);
-out_fail:
- btrfs_unreserve_metadata_space(root, 5);
if (drop_inode) {
inode_dec_link_count(inode);
iput(inode);
@@ -5771,21 +5891,18 @@
u64 i_size;
while (num_bytes > 0) {
- trans = btrfs_start_transaction(root, 1);
+ trans = btrfs_start_transaction(root, 3);
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ break;
+ }
ret = btrfs_reserve_extent(trans, root, num_bytes,
root->sectorsize, 0, alloc_hint,
(u64)-1, &ins, 1);
if (ret) {
- WARN_ON(1);
- goto stop_trans;
- }
-
- ret = btrfs_reserve_metadata_space(root, 3);
- if (ret) {
- btrfs_free_reserved_extent(root, ins.objectid,
- ins.offset);
- goto stop_trans;
+ btrfs_end_transaction(trans, root);
+ break;
}
ret = insert_reserved_file_extent(trans, inode,
@@ -5819,14 +5936,8 @@
BUG_ON(ret);
btrfs_end_transaction(trans, root);
- btrfs_unreserve_metadata_space(root, 3);
}
return ret;
-
-stop_trans:
- btrfs_end_transaction(trans, root);
- return ret;
-
}
static long btrfs_fallocate(struct inode *inode, int mode,