[PATCH 40/44] btrfs: push btrfs_grab_fs_root into btrfs_get_fs_root

Josef Bacik
2019-12-06T14:46:53Z

Now that all callers of btrfs_get_fs_root are subsequently calling
btrfs_grab_fs_root and handling dropping the ref when they are done
appropriately, go ahead and push btrfs_grab_fs_root up into
btrfs_get_fs_root.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
fs/btrfs/backref.c | 6 ------
fs/btrfs/disk-io.c | 48 +++++++++++++++++++++++++-----------------
fs/btrfs/export.c | 4 ----
fs/btrfs/file.c | 4 ----
fs/btrfs/inode.c | 9 --------
fs/btrfs/ioctl.c | 26 -----------------------
fs/btrfs/relocation.c | 8 +------
fs/btrfs/root-tree.c | 2 --
fs/btrfs/scrub.c | 4 ----
fs/btrfs/send.c | 11 ----------
fs/btrfs/super.c | 4 ----
fs/btrfs/transaction.c | 6 ------
fs/btrfs/tree-log.c | 4 ----
fs/btrfs/volumes.c | 4 ----
14 files changed, 30 insertions(+), 110 deletions(-)

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 193747b6e1f9..b69154d72529 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -527,12 +527,6 @@ static int resolve_indirect_ref(struct btrfs_fs_info *fs_info,
goto out_free;
}

- if (!btrfs_grab_fs_root(root)) {
- srcu_read_unlock(&fs_info->subvol_srcu, index);
- ret = -ENOENT;
- goto out_free;
- }
-
if (btrfs_is_testing(fs_info)) {
srcu_read_unlock(&fs_info->subvol_srcu, index);
ret = -ENOENT;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index b7a2c570c438..adcabd6d3a92 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1498,6 +1498,8 @@ static struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
spin_lock(&fs_info->fs_roots_radix_lock);
root = radix_tree_lookup(&fs_info->fs_roots_radix,
(unsigned long)root_id);
+ if (root)
+ root = btrfs_grab_fs_root(root);
spin_unlock(&fs_info->fs_roots_radix_lock);
return root;
}
@@ -1554,29 +1556,34 @@ struct btrfs_root *btrfs_get_fs_root(struct btrfs_fs_info *fs_info,
int ret;

if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
- return fs_info->tree_root;
+ return btrfs_grab_fs_root(fs_info->tree_root);
if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
- return fs_info->extent_root;
+ return btrfs_grab_fs_root(fs_info->extent_root);
if (location->objectid == BTRFS_CHUNK_TREE_OBJECTID)
- return fs_info->chunk_root;
+ return btrfs_grab_fs_root(fs_info->chunk_root);
if (location->objectid == BTRFS_DEV_TREE_OBJECTID)
- return fs_info->dev_root;
+ return btrfs_grab_fs_root(fs_info->dev_root);
if (location->objectid == BTRFS_CSUM_TREE_OBJECTID)
- return fs_info->csum_root;
+ return btrfs_grab_fs_root(fs_info->csum_root);
if (location->objectid == BTRFS_QUOTA_TREE_OBJECTID)
- return fs_info->quota_root ? fs_info->quota_root :
- ERR_PTR(-ENOENT);
+ return fs_info->quota_root ?
+ btrfs_grab_fs_root(fs_info->quota_root) :
+ ERR_PTR(-ENOENT);
if (location->objectid == BTRFS_UUID_TREE_OBJECTID)
- return fs_info->uuid_root ? fs_info->uuid_root :
- ERR_PTR(-ENOENT);
+ return fs_info->uuid_root ?
+ btrfs_grab_fs_root(fs_info->uuid_root) :
+ ERR_PTR(-ENOENT);
if (location->objectid == BTRFS_FREE_SPACE_TREE_OBJECTID)
- return fs_info->free_space_root ? fs_info->free_space_root :
- ERR_PTR(-ENOENT);
+ return fs_info->free_space_root ?
+ btrfs_grab_fs_root(fs_info->free_space_root) :
+ ERR_PTR(-ENOENT);
again:
root = btrfs_lookup_fs_root(fs_info, location->objectid);
if (root) {
- if (check_ref && btrfs_root_refs(&root->root_item) == 0)
+ if (check_ref && btrfs_root_refs(&root->root_item) == 0) {
+ btrfs_put_fs_root(root);
return ERR_PTR(-ENOENT);
+ }
return root;
}

@@ -1609,8 +1616,18 @@ struct btrfs_root *btrfs_get_fs_root(struct btrfs_fs_info *fs_info,
if (ret == 0)
set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state);

+ /*
+ * All roots have two refs on them at all times, one for the mounted fs,
+ * and one for being in the radix tree. This way we only free the root
+ * when we are unmounting or deleting the subvolume. We get one ref
+ * from __setup_root, one for inserting it into the radix tree, and then
+ * we have the third for returning it, and the caller will put it when
+ * it's done with the root.
+ */
+ btrfs_grab_fs_root(root);
ret = btrfs_insert_fs_root(fs_info, root);
if (ret) {
+ btrfs_put_fs_root(root);
if (ret == -EEXIST) {
btrfs_free_fs_root(root);
goto again;
@@ -3207,13 +3224,6 @@ int __cold open_ctree(struct super_block *sb,
goto fail_qgroup;
}

- if (!btrfs_grab_fs_root(fs_info->fs_root)) {
- fs_info->fs_root = NULL;
- err = -ENOENT;
- btrfs_warn(fs_info, "failed to grab a ref on the fs tree");
- goto fail_qgroup;
- }
-
if (sb_rdonly(sb))
return 0;

diff --git a/fs/btrfs/export.c b/fs/btrfs/export.c
index eba6c6d27bad..f07c2300ade2 100644
--- a/fs/btrfs/export.c
+++ b/fs/btrfs/export.c
@@ -82,10 +82,6 @@ static struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
err = PTR_ERR(root);
goto fail;
}
- if (!btrfs_grab_fs_root(root)) {
- err = -ENOENT;
- goto fail;
- }

key.objectid = objectid;
key.type = BTRFS_INODE_ITEM_KEY;
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index f8e16f44a970..062580a1721f 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -292,10 +292,6 @@ static int __btrfs_run_defrag_inode(struct btrfs_fs_info *fs_info,
ret = PTR_ERR(inode_root);
goto cleanup;
}
- if (!btrfs_grab_fs_root(inode_root)) {
- ret = -ENOENT;
- goto cleanup;
- }

key.objectid = defrag->ino;
key.type = BTRFS_INODE_ITEM_KEY;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 5fa39ac23472..bc961ca6995f 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2523,8 +2523,6 @@ static noinline int record_one_backref(u64 inum, u64 offset, u64 root_id,
inum, offset, root_id);
return PTR_ERR(root);
}
- if (!btrfs_grab_fs_root(root))
- return 0;

key.objectid = inum;
key.type = BTRFS_EXTENT_DATA_KEY;
@@ -2711,9 +2709,6 @@ static noinline int relink_extent_backref(struct btrfs_path *path,
return PTR_ERR(root);
}

- if (!btrfs_grab_fs_root(root))
- return 0;
-
if (btrfs_root_readonly(root)) {
srcu_read_unlock(&fs_info->subvol_srcu, index);
return 0;
@@ -5689,10 +5684,6 @@ static int fixup_tree_root_location(struct btrfs_fs_info *fs_info,
err = PTR_ERR(new_root);
goto out;
}
- if (!btrfs_grab_fs_root(new_root)) {
- err = -ENOENT;
- goto out;
- }

*sub_root = new_root;
location->objectid = btrfs_root_dirid(&new_root->root_item);
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index d5a994ab9602..7df2576aa2e3 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -672,11 +672,6 @@ static noinline int create_subvol(struct inode *dir,
btrfs_abort_transaction(trans, ret);
goto fail;
}
- if (!btrfs_grab_fs_root(new_root)) {
- ret = -ENOENT;
- btrfs_abort_transaction(trans, ret);
- goto fail;
- }

btrfs_record_root_in_trans(trans, new_root);

@@ -2191,10 +2186,6 @@ static noinline int search_ioctl(struct inode *inode,
btrfs_free_path(path);
return PTR_ERR(root);
}
- if (!btrfs_grab_fs_root(root)) {
- btrfs_free_path(path);
- return -ENOENT;
- }
}

key.objectid = sk->min_objectid;
@@ -2332,11 +2323,6 @@ static noinline int btrfs_search_path_in_tree(struct btrfs_fs_info *info,
root = NULL;
goto out;
}
- if (!btrfs_grab_fs_root(root)) {
- ret = -ENOENT;
- root = NULL;
- goto out;
- }

key.objectid = dirid;
key.type = BTRFS_INODE_REF_KEY;
@@ -2433,10 +2419,6 @@ static int btrfs_search_path_in_tree_user(struct inode *inode,
ret = PTR_ERR(root);
goto out;
}
- if (!btrfs_grab_fs_root(root)) {
- ret = -ENOENT;
- goto out;
- }

key.objectid = dirid;
key.type = BTRFS_INODE_REF_KEY;
@@ -2686,10 +2668,6 @@ static int btrfs_ioctl_get_subvol_info(struct file *file, void __user *argp)
ret = PTR_ERR(root);
goto out_free;
}
- if (!btrfs_grab_fs_root(root)) {
- ret = -ENOENT;
- goto out;
- }
root_item = &root->root_item;

subvol_info->treeid = key.objectid;
@@ -4025,10 +4003,6 @@ static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
ret = PTR_ERR(new_root);
goto out;
}
- if (!btrfs_grab_fs_root(root)) {
- ret = -ENOENT;
- goto out;
- }
if (!is_fstree(new_root->root_key.objectid)) {
ret = -ENOENT;
goto out_free;
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 086c8126ebf2..f6d63d6cf22d 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -581,7 +581,6 @@ static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
u64 root_objectid)
{
struct btrfs_key key;
- struct btrfs_root *root;

key.objectid = root_objectid;
key.type = BTRFS_ROOT_ITEM_KEY;
@@ -590,12 +589,7 @@ static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
else
key.offset = (u64)-1;

- root = btrfs_get_fs_root(fs_info, &key, false);
- if (IS_ERR(root))
- return root;
- if (!btrfs_grab_fs_root(root))
- return ERR_PTR(-ENOENT);
- return root;
+ return btrfs_get_fs_root(fs_info, &key, false);
}

static noinline_for_stack
diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index cac2407cc003..2c94b5318b40 100644
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -257,8 +257,6 @@ int btrfs_find_orphan_roots(struct btrfs_fs_info *fs_info)

root = btrfs_get_fs_root(fs_info, &root_key, false);
err = PTR_ERR_OR_ZERO(root);
- if (!err && !btrfs_grab_fs_root(root))
- err = -ENOENT;
if (err && err != -ENOENT) {
break;
} else if (err == -ENOENT) {
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 904e860c509c..0c8b60055c2e 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -657,10 +657,6 @@ static int scrub_print_warning_inode(u64 inum, u64 offset, u64 root,
ret = PTR_ERR(local_root);
goto err;
}
- if (!btrfs_grab_fs_root(local_root)) {
- ret = -ENOENT;
- goto err;
- }

/*
* this makes the path point to (inum INODE_ITEM ioff)
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index a82201e6979e..6520ad8f4e81 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -7206,11 +7206,6 @@ long btrfs_ioctl_send(struct file *mnt_file, struct btrfs_ioctl_send_args *arg)
ret = PTR_ERR(clone_root);
goto out;
}
- if (!btrfs_grab_fs_root(clone_root)) {
- srcu_read_unlock(&fs_info->subvol_srcu, index);
- ret = -ENOENT;
- goto out;
- }
spin_lock(&clone_root->root_item_lock);
if (!btrfs_root_readonly(clone_root) ||
btrfs_root_dead(clone_root)) {
@@ -7252,12 +7247,6 @@ long btrfs_ioctl_send(struct file *mnt_file, struct btrfs_ioctl_send_args *arg)
ret = PTR_ERR(sctx->parent_root);
goto out;
}
- if (!btrfs_grab_fs_root(sctx->parent_root)) {
- srcu_read_unlock(&fs_info->subvol_srcu, index);
- ret = -ENOENT;
- sctx->parent_root = ERR_PTR(ret);
- goto out;
- }

spin_lock(&sctx->parent_root->root_item_lock);
sctx->parent_root->send_in_progress++;
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index cc411304e2c9..80fea16cf34c 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1082,10 +1082,6 @@ static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
ret = PTR_ERR(fs_root);
goto err;
}
- if (!btrfs_grab_fs_root(fs_root)) {
- ret = -ENOENT;
- goto err;
- }

/*
* Walk up the filesystem tree by inode refs until we hit the
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 7008def3391b..e194d3e4e3a9 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -1637,12 +1637,6 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
btrfs_abort_transaction(trans, ret);
goto fail;
}
- if (!btrfs_grab_fs_root(pending->snap)) {
- ret = -ENOENT;
- pending->snap = NULL;
- btrfs_abort_transaction(trans, ret);
- goto fail;
- }

ret = btrfs_reloc_post_snapshot(trans, pending);
if (ret) {
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index f2c26e07eedb..32ee8698a87f 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -6292,10 +6292,6 @@ int btrfs_recover_log_trees(struct btrfs_root *log_root_tree)
tmp_key.offset = (u64)-1;

wc.replay_dest = btrfs_get_fs_root(fs_info, &tmp_key, true);
- if (!IS_ERR(wc.replay_dest)) {
- if (!btrfs_grab_fs_root(wc.replay_dest))
- wc.replay_dest = ERR_PTR(-ENOENT);
- }
if (IS_ERR(wc.replay_dest)) {
ret = PTR_ERR(wc.replay_dest);

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 47ac3277ee08..d261a39b7aa6 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -4379,10 +4379,6 @@ static int btrfs_check_uuid_tree_entry(struct btrfs_fs_info *fs_info,
ret = 1;
goto out;
}
- if (!btrfs_grab_fs_root(subvol_root)) {
- ret = 1;
- goto out;
- }

switch (type) {
case BTRFS_UUID_KEY_SUBVOL:
--
2.23.0