Old btrfs codes do the default subvolume search in get_default_root(),
which makes default subvolume mount will not info vfs that it's a
subtree mount.
Now since btrfs_mount_subvol() will mount all btrfs subvolume throught
mount_subtree() vfs API, merge the default subvolume searching codes
into it, and now btrfs handles all 3 types of subvolume mount in one
place.('subvol=' 'subvolid=' and default subvolume mount).
This is done by reuse the old dir_id->root_objectid search routine and
then reuse the subvolume_object mount routine in previous patch.
Reported-by: Stefan G.Weichinger <li...@xunil.at>
Signed-off-by: Qu Wenruo <quwen...@cn.fujitsu.com>
---
fs/btrfs/super.c | 101 +++++++++++++++++++++++++++++--------------------------
1 file changed, 53 insertions(+), 48 deletions(-)
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 23363a2..7bed7a1 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -842,14 +842,10 @@ out:
return error;
}
-static struct dentry *get_default_root(struct super_block *sb,
- u64 subvol_objectid)
+static struct dentry *get_default_root(struct super_block *sb)
{
struct btrfs_fs_info *fs_info = btrfs_sb(sb);
- struct btrfs_root *root = fs_info->tree_root;
struct btrfs_root *new_root;
- struct btrfs_dir_item *di;
- struct btrfs_path *path;
struct btrfs_key location;
struct inode *inode;
struct dentry *dentry;
@@ -860,51 +856,15 @@ static struct dentry *get_default_root(struct super_block
*sb,
* We have a specific subvol we want to mount, just setup location and
* go look up the root.
*/
- if (subvol_objectid) {
- location.objectid = subvol_objectid;
- location.type = BTRFS_ROOT_ITEM_KEY;
- location.offset = (u64)-1;
- goto find_root;
- }
-
- path = btrfs_alloc_path();
- if (!path)
- return ERR_PTR(-ENOMEM);
- path->leave_spinning = 1;
-
- /*
- * Find the "default" dir item which points to the root item that we
- * will mount by default if we haven't been given a specific subvolume
- * to mount.
- */
- dir_id = btrfs_super_root_dir(fs_info->super_copy);
- di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
- if (IS_ERR(di)) {
- btrfs_free_path(path);
- return ERR_CAST(di);
- }
- if (!di) {
- /*
- * Ok the default dir item isn't there. This is weird since
- * it's always been there, but don't freak out, just try and
- * mount to root most subvolume.
- */
- btrfs_free_path(path);
- dir_id = BTRFS_FIRST_FREE_OBJECTID;
- new_root = fs_info->fs_root;
- goto setup_root;
- }
-
- btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
- btrfs_free_path(path);
+ location.objectid = BTRFS_FS_TREE_OBJECTID;
+ location.type = BTRFS_ROOT_ITEM_KEY;
+ location.offset = (u64)-1;
-find_root:
new_root = btrfs_read_fs_root_no_name(fs_info, &location);
if (IS_ERR(new_root))
return ERR_CAST(new_root);
dir_id = btrfs_root_dirid(&new_root->root_item);
-setup_root:
location.objectid = dir_id;
location.type = BTRFS_INODE_ITEM_KEY;
location.offset = 0;
@@ -1137,7 +1097,7 @@ static int u64_to_strlen(u64 number)
#define CLEAR_SUBVOLID 2
/*
* This will strip out the subvol=%s or subvolid=%s argument for an argumen
- * string and add subvolid=0 to make sure we get the actual tree root for path
+ * string and add subvolid=5 to make sure we get the actual tree root for path
* walking to the subvol we want.
*/
static char *setup_root_args(char *args, int flags, u64 subvol_objectid)
@@ -1198,6 +1158,14 @@ static char *setup_root_args(char *args, int flags, u64
subvol_objectid)
if (!buf)
return NULL;
+ if (!src) {
+ strcpy(dst, args);
+ strcpy(dst, ",");
+ strcpy(dst, subvol_string);
+ return dst;
+ }
+
+
/*
* If the subvol= arg is not at the start of the string,
* copy whatever precedes it into buf.
@@ -1311,6 +1279,37 @@ out:
}
+static int find_default_subvol_objectid(struct btrfs_root *root,
+ u64 *subvol_objectid)
+{
+ struct btrfs_super_block *super = root->fs_info->super_copy;
+ struct btrfs_dir_item *di;
+ struct btrfs_key key;
+ struct btrfs_path *path;
+ u64 dir_id;
+ int ret = 0;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+ path->leave_spinning = 1;
+ dir_id = btrfs_super_root_dir(super);
+ di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "defaults", 7, 0);
+ if (IS_ERR(di)) {
+ ret = PTR_ERR(di);
+ goto out;
+ }
+ if (!di) {
+ *subvol_objectid = BTRFS_FS_TREE_OBJECTID;
+ goto out;
+ }
+ btrfs_dir_item_key_to_cpu(path->nodes[0], di, &key);
+ *subvol_objectid = key.objectid;
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
static struct dentry *mount_subvol(const char *subvol_name, u64
subvol_objectid,
int flags, const char *device_name,
char *data)
@@ -1359,8 +1358,15 @@ static struct dentry *mount_subvol(const char
*subvol_name, u64 subvol_objectid,
if (IS_ERR(mnt))
return ERR_CAST(mnt);
+
tree_root = btrfs_sb(mnt->mnt_sb)->tree_root;
+ if (!subvol_name && !subvol_objectid) {
+ /* default subvolume mount */
+ ret = find_default_subvol_objectid(tree_root, &subvol_objectid);
+ if (ret < 0)
+ goto out;
+ }
if (!subvol_name) {
subvol_ret = find_subvol_by_id(tree_root, subvol_objectid);
if (IS_ERR(subvol_ret)) {
@@ -1421,8 +1427,7 @@ static struct dentry *btrfs_mount(struct file_system_type
*fs_type, int flags,
return ERR_PTR(error);
}
- if (subvol_name || (subvol_objectid != 0 &&
- subvol_objectid != BTRFS_FS_TREE_OBJECTID)) {
+ if (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
root = mount_subvol(subvol_name, subvol_objectid, flags,
device_name, data);
kfree(subvol_name);
@@ -1483,7 +1488,7 @@ static struct dentry *btrfs_mount(struct file_system_type
*fs_type, int flags,
flags & MS_SILENT ? 1 : 0);
}
- root = !error ? get_default_root(s, subvol_objectid) : ERR_PTR(error);
+ root = !error ? get_default_root(s) : ERR_PTR(error);
if (IS_ERR(root))
deactivate_locked_super(s);
--
2.0.1
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