Btrfs: Add support for device scanning and detection ioctls

Signed-off-by: Chris Mason <chris.mason@oracle.com>
git-mirror · Sep 25, 2008 · 8a4b83c · 8a4b83c
1 parent 239b14b
commit 8a4b83c
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Showing 7 changed files with 333 additions and 44 deletions.
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
@@ -37,7 +37,7 @@ extern struct kmem_cache *btrfs_transaction_cachep;
 extern struct kmem_cache *btrfs_bit_radix_cachep;
 extern struct kmem_cache *btrfs_path_cachep;
 
-#define BTRFS_MAGIC "_B4RfS_M"
+#define BTRFS_MAGIC "_B5RfS_M"
 
 #define BTRFS_MAX_LEVEL 8
 
@@ -238,6 +238,7 @@ struct btrfs_super_block {
 	__le64 total_bytes;
 	__le64 bytes_used;
 	__le64 root_dir_objectid;
+	__le64 num_devices;
 	__le32 sectorsize;
 	__le32 nodesize;
 	__le32 leafsize;
@@ -440,6 +441,7 @@ struct btrfs_block_group_cache {
 };
 
 struct btrfs_device;
+struct btrfs_fs_devices;
 struct btrfs_fs_info {
 	u8 fsid[BTRFS_FSID_SIZE];
 	struct btrfs_root *extent_root;
@@ -489,7 +491,7 @@ struct btrfs_fs_info {
 	u64 total_pinned;
 	struct list_head dirty_cowonly_roots;
 
-	struct list_head devices;
+	struct btrfs_fs_devices *fs_devices;
 	struct list_head space_info;
 	spinlock_t delalloc_lock;
 	spinlock_t new_trans_lock;
@@ -677,6 +679,19 @@ BTRFS_SETGET_FUNCS(device_io_width, struct btrfs_dev_item, io_width, 32);
 BTRFS_SETGET_FUNCS(device_sector_size, struct btrfs_dev_item, sector_size, 32);
 BTRFS_SETGET_FUNCS(device_id, struct btrfs_dev_item, devid, 64);
 
+BTRFS_SETGET_STACK_FUNCS(stack_device_type, struct btrfs_dev_item, type, 64);
+BTRFS_SETGET_STACK_FUNCS(stack_device_total_bytes, struct btrfs_dev_item,
+			 total_bytes, 64);
+BTRFS_SETGET_STACK_FUNCS(stack_device_bytes_used, struct btrfs_dev_item,
+			 bytes_used, 64);
+BTRFS_SETGET_STACK_FUNCS(stack_device_io_align, struct btrfs_dev_item,
+			 io_align, 32);
+BTRFS_SETGET_STACK_FUNCS(stack_device_io_width, struct btrfs_dev_item,
+			 io_width, 32);
+BTRFS_SETGET_STACK_FUNCS(stack_device_sector_size, struct btrfs_dev_item,
+			 sector_size, 32);
+BTRFS_SETGET_STACK_FUNCS(stack_device_id, struct btrfs_dev_item, devid, 64);
+
 static inline char *btrfs_device_uuid(struct btrfs_dev_item *d)
 {
 	return (char *)d + offsetof(struct btrfs_dev_item, uuid);
@@ -1106,6 +1121,8 @@ BTRFS_SETGET_STACK_FUNCS(super_stripesize, struct btrfs_super_block,
 			 stripesize, 32);
 BTRFS_SETGET_STACK_FUNCS(super_root_dir, struct btrfs_super_block,
 			 root_dir_objectid, 64);
+BTRFS_SETGET_STACK_FUNCS(super_num_devices, struct btrfs_super_block,
+			 num_devices, 64);
 
 static inline unsigned long btrfs_leaf_data(struct extent_buffer *l)
 {

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
@@ -365,12 +365,12 @@ static int close_all_devices(struct btrfs_fs_info *fs_info)
 	struct list_head *next;
 	struct btrfs_device *device;
 
-	list = &fs_info->devices;
-	while(!list_empty(list)) {
-		next = list->next;
-		list_del(next);
+	list = &fs_info->fs_devices->devices;
+	list_for_each(next, list) {
 		device = list_entry(next, struct btrfs_device, dev_list);
-		kfree(device);
+		if (device->bdev && device->bdev != fs_info->sb->s_bdev)
+			close_bdev_excl(device->bdev);
+		device->bdev = NULL;
 	}
 	return 0;
 }
@@ -655,7 +655,8 @@ static int add_hasher(struct btrfs_fs_info *info, char *type) {
 	return 0;
 }
 #endif
-struct btrfs_root *open_ctree(struct super_block *sb)
+struct btrfs_root *open_ctree(struct super_block *sb,
+			      struct btrfs_fs_devices *fs_devices)
 {
 	u32 sectorsize;
 	u32 nodesize;
@@ -697,8 +698,8 @@ struct btrfs_root *open_ctree(struct super_block *sb)
 	fs_info->extent_root = extent_root;
 	fs_info->chunk_root = chunk_root;
 	fs_info->dev_root = dev_root;
+	fs_info->fs_devices = fs_devices;
 	INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
-	INIT_LIST_HEAD(&fs_info->devices);
 	INIT_LIST_HEAD(&fs_info->space_info);
 	btrfs_mapping_init(&fs_info->mapping_tree);
 	fs_info->sb = sb;
@@ -779,6 +780,12 @@ struct btrfs_root *open_ctree(struct super_block *sb)
 	if (!btrfs_super_root(disk_super))
 		goto fail_sb_buffer;
 
+	if (btrfs_super_num_devices(disk_super) != fs_devices->num_devices) {
+		printk("Btrfs: wanted %llu devices, but found %llu\n",
+		       (unsigned long long)btrfs_super_num_devices(disk_super),
+		       (unsigned long long)fs_devices->num_devices);
+		goto fail_sb_buffer;
+	}
 	nodesize = btrfs_super_nodesize(disk_super);
 	leafsize = btrfs_super_leafsize(disk_super);
 	sectorsize = btrfs_super_sectorsize(disk_super);
@@ -799,8 +806,6 @@ struct btrfs_root *open_ctree(struct super_block *sb)
 	}
 
 	mutex_lock(&fs_info->fs_mutex);
-	ret = btrfs_read_super_device(tree_root, fs_info->sb_buffer);
-	BUG_ON(ret);
 
 	ret = btrfs_read_sys_array(tree_root);
 	BUG_ON(ret);
@@ -859,6 +864,7 @@ struct btrfs_root *open_ctree(struct super_block *sb)
 fail_iput:
 	iput(fs_info->btree_inode);
 fail:
+	close_all_devices(fs_info);
 	kfree(extent_root);
 	kfree(tree_root);
 	kfree(fs_info);

diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
@@ -21,6 +21,7 @@
 
 #define BTRFS_SUPER_INFO_OFFSET (16 * 1024)
 struct btrfs_device;
+struct btrfs_fs_devices;
 
 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
 				      u32 blocksize);
@@ -29,7 +30,8 @@ struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
 						   u64 bytenr, u32 blocksize);
 int clean_tree_block(struct btrfs_trans_handle *trans,
 		     struct btrfs_root *root, struct extent_buffer *buf);
-struct btrfs_root *open_ctree(struct super_block *sb);
+struct btrfs_root *open_ctree(struct super_block *sb,
+			      struct btrfs_fs_devices *fs_devices);
 int close_ctree(struct btrfs_root *root);
 int write_ctree_super(struct btrfs_trans_handle *trans,
 		      struct btrfs_root *root);

diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
@@ -22,8 +22,10 @@
 
 #define BTRFS_IOCTL_MAGIC 0x94
 #define BTRFS_VOL_NAME_MAX 255
+#define BTRFS_PATH_NAME_MAX 4095
+
 struct btrfs_ioctl_vol_args {
-	char name[BTRFS_VOL_NAME_MAX + 1];
+	char name[BTRFS_PATH_NAME_MAX + 1];
 };
 
 #define BTRFS_IOC_SNAP_CREATE _IOW(BTRFS_IOCTL_MAGIC, 1, \
@@ -32,4 +34,6 @@ struct btrfs_ioctl_vol_args {
 				   struct btrfs_ioctl_vol_args)
 #define BTRFS_IOC_RESIZE _IOW(BTRFS_IOCTL_MAGIC, 3, \
 				   struct btrfs_ioctl_vol_args)
+#define BTRFS_IOC_SCAN_DEV _IOW(BTRFS_IOCTL_MAGIC, 4, \
+				   struct btrfs_ioctl_vol_args)
 #endif
diff --git 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)