Btrfs: Add support for device scanning and detection ioctls

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 44 insertions, 17 deletions

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 67ed216df475..9624923a33dc 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -44,6 +44,7 @@
 #include "ioctl.h"
 #include "print-tree.h"
 #include "xattr.h"
+#include "volumes.h"
 
 #define BTRFS_SUPER_MAGIC 0x9123683E
 
@@ -216,7 +217,9 @@ static int parse_options (char * options,
         return 1;
 }
 
-static int btrfs_fill_super(struct super_block * sb, void * data, int silent)
+static int btrfs_fill_super(struct super_block * sb,
+                            struct btrfs_fs_devices *fs_devices,
+                            void * data, int silent)
 {
         struct inode * inode;
         struct dentry * root_dentry;
@@ -231,7 +234,7 @@ static int btrfs_fill_super(struct super_block * sb, void * data, int silent)
         sb->s_xattr = btrfs_xattr_handlers;
         sb->s_time_gran = 1;
 
-        tree_root = open_ctree(sb);
+        tree_root = open_ctree(sb, fs_devices);
 
         if (!tree_root || IS_ERR(tree_root)) {
                 printk("btrfs: open_ctree failed\n");
@@ -334,18 +337,23 @@ static int test_bdev_super(struct super_block *s, void *data)
 
 int btrfs_get_sb_bdev(struct file_system_type *fs_type,
         int flags, const char *dev_name, void *data,
-        int (*fill_super)(struct super_block *, void *, int),
         struct vfsmount *mnt, const char *subvol)
 {
         struct block_device *bdev = NULL;
         struct super_block *s;
         struct dentry *root;
+        struct btrfs_fs_devices *fs_devices = NULL;
         int error = 0;
 
-        bdev = open_bdev_excl(dev_name, flags, fs_type);
-        if (IS_ERR(bdev))
-                return PTR_ERR(bdev);
+        error = btrfs_scan_one_device(dev_name, flags, fs_type, &fs_devices);
+        if (error)
+                return error;
 
+        error = btrfs_open_devices(fs_devices, flags, fs_type);
+        if (error)
+                return error;
+
+        bdev = fs_devices->lowest_bdev;
         /*
          * once the super is inserted into the list by sget, s_umount
          * will protect the lockfs code from trying to start a snapshot
@@ -372,7 +380,8 @@ int btrfs_get_sb_bdev(struct file_system_type *fs_type,
                 s->s_flags = flags;
                 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
                 sb_set_blocksize(s, block_size(bdev));
-                error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
+                error = btrfs_fill_super(s, fs_devices, data,
+                                         flags & MS_SILENT ? 1 : 0);
                 if (error) {
                         up_write(&s->s_umount);
                         deactivate_super(s);
@@ -408,7 +417,7 @@ int btrfs_get_sb_bdev(struct file_system_type *fs_type,
 error_s:
         error = PTR_ERR(s);
 error_bdev:
-        close_bdev_excl(bdev);
+        btrfs_close_devices(fs_devices);
 error:
         return error;
 }
@@ -421,8 +430,7 @@ static int btrfs_get_sb(struct file_system_type *fs_type,
         char *subvol_name = NULL;
 
         parse_options((char *)data, NULL, &subvol_name);
-        ret = btrfs_get_sb_bdev(fs_type, flags, dev_name, data,
-                        btrfs_fill_super, mnt,
+        ret = btrfs_get_sb_bdev(fs_type, flags, dev_name, data, mnt,
                         subvol_name ? subvol_name : "default");
         if (subvol_name)
                 kfree(subvol_name);
@@ -445,13 +453,6 @@ static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
         return 0;
 }
 
-static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
-                                unsigned long arg)
-{
-        printk("btrfs control ioctl %d\n", cmd);
-        return 0;
-}
-
 static struct file_system_type btrfs_fs_type = {
         .owner          = THIS_MODULE,
         .name           = "btrfs",
@@ -460,6 +461,31 @@ static struct file_system_type btrfs_fs_type = {
         .fs_flags       = FS_REQUIRES_DEV,
 };
 
+static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
+                                unsigned long arg)
+{
+        struct btrfs_ioctl_vol_args *vol;
+        struct btrfs_fs_devices *fs_devices;
+        int ret;
+        int len;
+
+        vol = kmalloc(sizeof(*vol), GFP_KERNEL);
+        if (copy_from_user(vol, (void __user *)arg, sizeof(*vol))) {
+                ret = -EFAULT;
+                goto out;
+        }
+        len = strnlen(vol->name, BTRFS_PATH_NAME_MAX);
+        switch (cmd) {
+        case BTRFS_IOC_SCAN_DEV:
+                ret = btrfs_scan_one_device(vol->name, MS_RDONLY,
+                                            &btrfs_fs_type, &fs_devices);
+                break;
+        }
+out:
+        kfree(vol);
+        return 0;
+}
+
 static void btrfs_write_super_lockfs(struct super_block *sb)
 {
         struct btrfs_root *root = btrfs_sb(sb);
@@ -567,6 +593,7 @@ static void __exit exit_btrfs_fs(void)
         btrfs_interface_exit();
         unregister_filesystem(&btrfs_fs_type);
         btrfs_exit_sysfs();
+        btrfs_cleanup_fs_uuids();
 }
 
 module_init(init_btrfs_fs)