@@ -66,6 +66,7 @@
#include <trace/events/btrfs.h>
static const struct super_operations btrfs_super_ops;
+static struct file_system_type btrfs_root_fs_type;
static struct file_system_type btrfs_fs_type;
static int btrfs_remount(struct super_block *sb, int *flags, char *data);
@@ -1555,6 +1556,112 @@ static int setup_security_options(struct btrfs_fs_info *fs_info,
return ret;
}
+static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
+ int flags, const char *device_name, void *data)
+{
+ struct block_device *bdev = NULL;
+ struct super_block *s;
+ struct btrfs_fs_devices *fs_devices = NULL;
+ struct btrfs_fs_info *fs_info = NULL;
+ struct security_mnt_opts new_sec_opts;
+ fmode_t mode = FMODE_READ;
+ char *subvol_name = NULL;
+ u64 subvol_objectid = 0;
+ int error = 0;
+
+ if (!(flags & SB_RDONLY))
+ mode |= FMODE_WRITE;
+
+ error = btrfs_parse_early_options(data, mode, fs_type,
+ &subvol_name, &subvol_objectid,
+ &fs_devices);
+ if (error) {
+ kfree(subvol_name);
+ return ERR_PTR(error);
+ }
+
+ security_init_mnt_opts(&new_sec_opts);
+ if (data) {
+ error = parse_security_options(data, &new_sec_opts);
+ if (error)
+ return ERR_PTR(error);
+ }
+
+ error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
+ if (error)
+ goto error_sec_opts;
+
+ /*
+ * Setup a dummy root and fs_info for test/set super. This is because
+ * we don't actually fill this stuff out until open_ctree, but we need
+ * it for searching for existing supers, so this lets us do that and
+ * then open_ctree will properly initialize everything later.
+ */
+ fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
+ if (!fs_info) {
+ error = -ENOMEM;
+ goto error_sec_opts;
+ }
+
+ fs_info->fs_devices = fs_devices;
+
+ fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
+ fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
+ security_init_mnt_opts(&fs_info->security_opts);
+ if (!fs_info->super_copy || !fs_info->super_for_commit) {
+ error = -ENOMEM;
+ goto error_fs_info;
+ }
+
+ error = btrfs_open_devices(fs_devices, mode, fs_type);
+ if (error)
+ goto error_fs_info;
+
+ if (!(flags & SB_RDONLY) && fs_devices->rw_devices == 0) {
+ error = -EACCES;
+ goto error_close_devices;
+ }
+
+ bdev = fs_devices->latest_bdev;
+ s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | SB_NOSEC,
+ fs_info);
+ if (IS_ERR(s)) {
+ error = PTR_ERR(s);
+ goto error_close_devices;
+ }
+
+ if (s->s_root) {
+ btrfs_close_devices(fs_devices);
+ free_fs_info(fs_info);
+ if ((flags ^ s->s_flags) & SB_RDONLY)
+ error = -EBUSY;
+ } else {
+ snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
+ btrfs_sb(s)->bdev_holder = fs_type;
+ error = btrfs_fill_super(s, fs_devices, data);
+ }
+ if (error) {
+ deactivate_locked_super(s);
+ goto error_sec_opts;
+ }
+
+ fs_info = btrfs_sb(s);
+ error = setup_security_options(fs_info, s, &new_sec_opts);
+ if (error) {
+ deactivate_locked_super(s);
+ goto error_sec_opts;
+ }
+
+ return dget(s->s_root);
+
+error_close_devices:
+ btrfs_close_devices(fs_devices);
+error_fs_info:
+ free_fs_info(fs_info);
+error_sec_opts:
+ security_free_mnt_opts(&new_sec_opts);
+ return ERR_PTR(error);
+}
/*
* Find a superblock for the given device / mount point.
*
@@ -2174,6 +2281,15 @@ static struct file_system_type btrfs_fs_type = {
.kill_sb = btrfs_kill_super,
.fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
};
+
+static struct file_system_type btrfs_root_fs_type = {
+ .owner = THIS_MODULE,
+ .name = "btrfs",
+ .mount = btrfs_mount_root,
+ .kill_sb = btrfs_kill_super,
+ .fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
+};
+
MODULE_ALIAS_FS("btrfs");
static int btrfs_control_open(struct inode *inode, struct file *file)
Add btrfs_mount_root() and new file_system_type for preparation of cleanup of btrfs_mount(). Code path is not changed yet. btrfs_mount_root() is almost the same as current btrfs_mount(), but doesn't have subvolume related part. Signed-off-by: Tomohiro Misono <misono.tomohiro@jp.fujitsu.com> --- fs/btrfs/super.c | 116 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 116 insertions(+)