Introduce new btrfs_mount() using previous setups.
This will do:
(1) parse subvol id related options for later use in mount_subtree()
(2) mount device's root by calling vfs_kern_mount() with
btrfs_root_fs_type. As a result, mount_root() is called
(3) return by calling mount_subtree()
The code of (2) is moved from the first part of mount_subvol().
setup_root_args() is deleted as not needed anymore.
Signed-off-by: Tomohiro Misono <misono.tomoh...@jp.fujitsu.com>
---
fs/btrfs/super.c | 132 ++++++++++++++++++++++++-------------------------------
1 file changed, 58 insertions(+), 74 deletions(-)
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 9498743..47c0692 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1367,85 +1367,13 @@ static inline int is_subvolume_inode(struct inode
*inode)
return 0;
}
-/*
- * This will add subvolid=0 to the argument string while removing any subvol=
- * and subvolid= arguments to make sure we get the top-level root for path
- * walking to the subvol we want.
- */
-static char *setup_root_args(char *args)
-{
- char *buf, *dst, *sep;
-
- if (!args)
- return kstrdup("subvolid=0", GFP_NOFS);
-
- /* The worst case is that we add ",subvolid=0" to the end. */
- buf = dst = kmalloc(strlen(args) + strlen(",subvolid=0") + 1, GFP_NOFS);
- if (!buf)
- return NULL;
-
- while (1) {
- sep = strchrnul(args, ',');
- if (!strstarts(args, "subvol=") &&
- !strstarts(args, "subvolid=")) {
- memcpy(dst, args, sep - args);
- dst += sep - args;
- *dst++ = ',';
- }
- if (*sep)
- args = sep + 1;
- else
- break;
- }
- strcpy(dst, "subvolid=0");
-
- return buf;
-}
-
static struct dentry *mount_subvol(const char *subvol_name, u64
subvol_objectid,
int flags, const char *device_name,
- char *data)
+ char *data, struct vfsmount *mnt)
{
struct dentry *root;
- struct vfsmount *mnt = NULL;
- char *newargs;
int ret;
- newargs = setup_root_args(data);
- if (!newargs) {
- root = ERR_PTR(-ENOMEM);
- goto out;
- }
-
- mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name, newargs);
- if (PTR_ERR_OR_ZERO(mnt) == -EBUSY) {
- if (flags & MS_RDONLY) {
- mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY,
- device_name, newargs);
- } else {
- mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY,
- device_name, newargs);
- if (IS_ERR(mnt)) {
- root = ERR_CAST(mnt);
- mnt = NULL;
- goto out;
- }
-
- down_write(&mnt->mnt_sb->s_umount);
- ret = btrfs_remount(mnt->mnt_sb, &flags, NULL);
- up_write(&mnt->mnt_sb->s_umount);
- if (ret < 0) {
- root = ERR_PTR(ret);
- goto out;
- }
- }
- }
- if (IS_ERR(mnt)) {
- root = ERR_CAST(mnt);
- mnt = NULL;
- goto out;
- }
-
if (!subvol_name) {
if (!subvol_objectid) {
ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
@@ -1501,7 +1429,6 @@ static struct dentry *mount_subvol(const char
*subvol_name, u64 subvol_objectid,
out:
mntput(mnt);
- kfree(newargs);
kfree(subvol_name);
return root;
}
@@ -1665,6 +1592,63 @@ static struct dentry *mount_root(struct file_system_type
*fs_type, int flags,
return ERR_PTR(error);
}
+static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
+ const char *device_name, void *data)
+{
+ struct vfsmount *mnt_root;
+ struct dentry *root;
+ fmode_t mode = FMODE_READ;
+ char *subvol_name = NULL;
+ u64 subvol_objectid = 0;
+ int error = 0;
+
+ if (!(flags & MS_RDONLY))
+ mode |= FMODE_WRITE;
+
+ error = btrfs_parse_subvol_options(data, mode, fs_type,
+ &subvol_name, &subvol_objectid);
+ if (error) {
+ kfree(subvol_name);
+ return ERR_PTR(error);
+ }
+
+ /* mount device's root (/) */
+ mnt_root = vfs_kern_mount(&btrfs_root_fs_type, flags, device_name,
data);
+ if (PTR_ERR_OR_ZERO(mnt_root) == -EBUSY) {
+ if (flags & MS_RDONLY) {
+ mnt_root = vfs_kern_mount(&btrfs_root_fs_type, flags &
~MS_RDONLY,
+ device_name, data);
+ } else {
+ mnt_root = vfs_kern_mount(&btrfs_root_fs_type, flags |
MS_RDONLY,
+ device_name, data);
+ if (IS_ERR(mnt_root)) {
+ root = ERR_CAST(mnt_root);
+ goto out;
+ }
+
+ down_write(&mnt_root->mnt_sb->s_umount);
+ error = btrfs_remount(mnt_root->mnt_sb, &flags, NULL);
+ up_write(&mnt_root->mnt_sb->s_umount);
+ if (error < 0) {
+ root = ERR_PTR(error);
+ mntput(mnt_root);
+ goto out;
+ }
+ }
+ }
+ if (IS_ERR(mnt_root)) {
+ root = ERR_CAST(mnt_root);
+ goto out;
+ }
+
+ /* mount_subvol() will free subvol_name and mnt_root */
+ root = mount_subvol(subvol_name, subvol_objectid, flags,
+ device_name, data, mnt_root);
+
+out:
+ return root;
+}
+
static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
int new_pool_size, int old_pool_size)
{
--
2.9.5
--
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