Commit 42d23732 authored by Kent Overstreet's avatar Kent Overstreet Committed by Kent Overstreet
Browse files

bcachefs: Snapshot creation, deletion 



This is the final patch in the patch series implementing snapshots.
This patch implements two new ioctls that work like creation and
deletion of directories, but fancier.

 - BCH_IOCTL_SUBVOLUME_CREATE, for creating new subvolumes and snaphots
 - BCH_IOCTL_SUBVOLUME_DESTROY, for deleting subvolumes and snapshots

Signed-off-by: default avatarKent Overstreet <kent.overstreet@gmail.com>
parent a861c722

fs/bcachefs/dirent.c

+0 −8
Original line number Diff line number Diff line
@@ -383,14 +383,6 @@ int bch2_dirent_rename(struct btree_trans *trans, 
	return ret;

}



int bch2_dirent_delete_at(struct btree_trans *trans,

			  const struct bch_hash_info *hash_info,

			  struct btree_iter *iter)

{

	return bch2_hash_delete_at(trans, bch2_dirent_hash_desc,

				   hash_info, iter);

}



int __bch2_dirent_lookup_trans(struct btree_trans *trans,

			       struct btree_iter *iter,

			       subvol_inum dir,

fs/bcachefs/dirent.h

+0 −4
Original line number Diff line number Diff line
@@ -33,10 +33,6 @@ int bch2_dirent_create(struct btree_trans *, subvol_inum, 
		       const struct bch_hash_info *, u8,

		       const struct qstr *, u64, u64 *, int);



int bch2_dirent_delete_at(struct btree_trans *,

			  const struct bch_hash_info *,

			  struct btree_iter *);



int __bch2_dirent_read_target(struct btree_trans *, struct bkey_s_c_dirent,

			      u32 *, u32 *, u64 *, bool);

fs/bcachefs/fs-common.c

+148 −34
Original line number Diff line number Diff line
@@ -11,6 +11,11 @@ 


#include <linux/posix_acl.h>



static inline int is_subdir_for_nlink(struct bch_inode_unpacked *inode)

{

	return S_ISDIR(inode->bi_mode) && !inode->bi_subvol;

}



int bch2_create_trans(struct btree_trans *trans,

		      subvol_inum dir,

		      struct bch_inode_unpacked *dir_u,
@@ -19,6 +24,7 @@ int bch2_create_trans(struct btree_trans *trans, 
		      uid_t uid, gid_t gid, umode_t mode, dev_t rdev,

		      struct posix_acl *default_acl,

		      struct posix_acl *acl,

		      subvol_inum snapshot_src,

		      unsigned flags)

{

	struct bch_fs *c = trans->c;
@@ -27,10 +33,9 @@ int bch2_create_trans(struct btree_trans *trans, 
	subvol_inum new_inum = dir;

	u64 now = bch2_current_time(c);

	u64 cpu = raw_smp_processor_id();

	u64 dir_offset = 0;

	u64 dir_target;

	u32 snapshot;

	unsigned dir_type;

	unsigned dir_type = mode_to_type(mode);

	int ret;



	ret = bch2_subvolume_get_snapshot(trans, dir.subvol, &snapshot);
@@ -41,19 +46,102 @@ int bch2_create_trans(struct btree_trans *trans, 
	if (ret)

		goto err;



	if (!(flags & BCH_CREATE_SNAPSHOT)) {

		/* Normal create path - allocate a new inode: */

		bch2_inode_init_late(new_inode, now, uid, gid, mode, rdev, dir_u);



	if (!name)

		if (flags & BCH_CREATE_TMPFILE)

			new_inode->bi_flags |= BCH_INODE_UNLINKED;



		ret = bch2_inode_create(trans, &inode_iter, new_inode, snapshot, cpu);

		if (ret)

			goto err;



		snapshot_src = (subvol_inum) { 0 };

	} else {

		/*

		 * Creating a snapshot - we're not allocating a new inode, but

		 * we do have to lookup the root inode of the subvolume we're

		 * snapshotting and update it (in the new snapshot):

		 */



		if (!snapshot_src.inum) {

			/* Inode wasn't specified, just snapshot: */

			struct btree_iter subvol_iter;

			struct bkey_s_c k;



			bch2_trans_iter_init(trans, &subvol_iter, BTREE_ID_subvolumes,

					     POS(0, snapshot_src.subvol), 0);

			k = bch2_btree_iter_peek_slot(&subvol_iter);



			ret = bkey_err(k);

			if (!ret && k.k->type != KEY_TYPE_subvolume) {

				bch_err(c, "subvolume %u not found",

					snapshot_src.subvol);

				ret = -ENOENT;

			}



			if (!ret)

				snapshot_src.inum = le64_to_cpu(bkey_s_c_to_subvolume(k).v->inode);

			bch2_trans_iter_exit(trans, &subvol_iter);



			if (ret)

				goto err;

		}



		ret = bch2_inode_peek(trans, &inode_iter, new_inode, snapshot_src,

				      BTREE_ITER_INTENT);

		if (ret)

			goto err;



		if (new_inode->bi_subvol != snapshot_src.subvol) {

			/* Not a subvolume root: */

			ret = -EINVAL;

			goto err;

		}



		/*

		 * If we're not root, we have to own the subvolume being

		 * snapshotted:

		 */

		if (uid && new_inode->bi_uid != uid) {

			ret = -EPERM;

			goto err;

		}



		flags |= BCH_CREATE_SUBVOL;

	}



	new_inum.inum	= new_inode->bi_inum;

	dir_target	= new_inode->bi_inum;

	dir_type	= mode_to_type(new_inode->bi_mode);



	if (flags & BCH_CREATE_SUBVOL) {

		u32 new_subvol, dir_snapshot;



		ret = bch2_subvolume_create(trans, new_inode->bi_inum,

					    snapshot_src.subvol,

					    &new_subvol, &snapshot,

					    (flags & BCH_CREATE_SNAPSHOT_RO) != 0);

		if (ret)

			goto err;



		new_inode->bi_parent_subvol	= dir.subvol;

		new_inode->bi_subvol		= new_subvol;

		new_inum.subvol			= new_subvol;

		dir_target			= new_subvol;

		dir_type			= DT_SUBVOL;



		ret = bch2_subvolume_get_snapshot(trans, dir.subvol, &dir_snapshot);

		if (ret)

			goto err;



		bch2_btree_iter_set_snapshot(&dir_iter, dir_snapshot);

		ret = bch2_btree_iter_traverse(&dir_iter);

		if (ret)

			goto err;

	}



	if (!(flags & BCH_CREATE_SNAPSHOT)) {

		if (default_acl) {

			ret = bch2_set_acl_trans(trans, new_inum, new_inode,

						 default_acl, ACL_TYPE_DEFAULT);
@@ -67,11 +155,13 @@ int bch2_create_trans(struct btree_trans *trans, 
			if (ret)

				goto err;

		}

	}



	if (name) {

	if (!(flags & BCH_CREATE_TMPFILE)) {

		struct bch_hash_info dir_hash = bch2_hash_info_init(c, dir_u);

		u64 dir_offset;



		if (S_ISDIR(new_inode->bi_mode))

		if (is_subdir_for_nlink(new_inode))

			dir_u->bi_nlink++;

		dir_u->bi_mtime = dir_u->bi_ctime = now;
@@ -87,12 +177,12 @@ int bch2_create_trans(struct btree_trans *trans, 
					 BCH_HASH_SET_MUST_CREATE);

		if (ret)

			goto err;

	}



		if (c->sb.version >= bcachefs_metadata_version_inode_backpointers) {

			new_inode->bi_dir		= dir_u->bi_inum;

			new_inode->bi_dir_offset	= dir_offset;

		}

	}



	inode_iter.flags &= ~BTREE_ITER_ALL_SNAPSHOTS;

	bch2_btree_iter_set_snapshot(&inode_iter, snapshot);
@@ -160,7 +250,8 @@ int bch2_unlink_trans(struct btree_trans *trans, 
		      subvol_inum dir,

		      struct bch_inode_unpacked *dir_u,

		      struct bch_inode_unpacked *inode_u,

		      const struct qstr *name)

		      const struct qstr *name,

		      int deleting_snapshot)

{

	struct bch_fs *c = trans->c;

	struct btree_iter dir_iter = { NULL };
@@ -169,6 +260,7 @@ int bch2_unlink_trans(struct btree_trans *trans, 
	struct bch_hash_info dir_hash;

	subvol_inum inum;

	u64 now = bch2_current_time(c);

	struct bkey_s_c k;

	int ret;



	ret = bch2_inode_peek(trans, &dir_iter, dir_u, dir, BTREE_ITER_INTENT);
@@ -187,29 +279,51 @@ int bch2_unlink_trans(struct btree_trans *trans, 
	if (ret)

		goto err;



	if (inode_u->bi_dir		== dirent_iter.pos.inode &&

	    inode_u->bi_dir_offset	== dirent_iter.pos.offset) {

		inode_u->bi_dir		= 0;

		inode_u->bi_dir_offset	= 0;

	if (deleting_snapshot == 1 && !inode_u->bi_subvol) {

		ret = -ENOENT;

		goto err;

	}



	if (S_ISDIR(inode_u->bi_mode)) {

	if (deleting_snapshot <= 0 && S_ISDIR(inode_u->bi_mode)) {

		ret = bch2_empty_dir_trans(trans, inum);

		if (ret)

			goto err;

	}



	if (dir.subvol != inum.subvol) {

		ret = bch2_subvolume_delete(trans, inum.subvol, false);

	if (inode_u->bi_subvol) {

		ret = bch2_subvolume_delete(trans, inode_u->bi_subvol,

					    deleting_snapshot);

		if (ret)

			goto err;



		k = bch2_btree_iter_peek_slot(&dirent_iter);

		ret = bkey_err(k);

		if (ret)

			goto err;



		/*

		 * If we're deleting a subvolume, we need to really delete the

		 * dirent, not just emit a whiteout in the current snapshot:

		 */

		bch2_btree_iter_set_snapshot(&dirent_iter, k.k->p.snapshot);

		ret = bch2_btree_iter_traverse(&dirent_iter);

		if (ret)

			goto err;

	}



	if (inode_u->bi_dir		== dirent_iter.pos.inode &&

	    inode_u->bi_dir_offset	== dirent_iter.pos.offset) {

		inode_u->bi_dir		= 0;

		inode_u->bi_dir_offset	= 0;

	}



	dir_u->bi_mtime = dir_u->bi_ctime = inode_u->bi_ctime = now;

	dir_u->bi_nlink -= S_ISDIR(inode_u->bi_mode);

	dir_u->bi_nlink -= is_subdir_for_nlink(inode_u);

	bch2_inode_nlink_dec(inode_u);



	ret =   bch2_dirent_delete_at(trans, &dir_hash, &dirent_iter) ?:

	ret =   bch2_hash_delete_at(trans, bch2_dirent_hash_desc,

				    &dir_hash, &dirent_iter,

				    BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE) ?:

		bch2_inode_write(trans, &dir_iter, dir_u) ?:

		bch2_inode_write(trans, &inode_iter, inode_u);

err:
@@ -348,12 +462,12 @@ int bch2_rename_trans(struct btree_trans *trans, 
		goto err;

	}



	if (S_ISDIR(src_inode_u->bi_mode)) {

	if (is_subdir_for_nlink(src_inode_u)) {

		src_dir_u->bi_nlink--;

		dst_dir_u->bi_nlink++;

	}



	if (dst_inum.inum && S_ISDIR(dst_inode_u->bi_mode)) {

	if (dst_inum.inum && is_subdir_for_nlink(dst_inode_u)) {

		dst_dir_u->bi_nlink--;

		src_dir_u->bi_nlink += mode == BCH_RENAME_EXCHANGE;

	}

fs/bcachefs/fs-common.h

+5 −2
Original line number Diff line number Diff line
@@ -5,6 +5,9 @@ 
struct posix_acl;



#define BCH_CREATE_TMPFILE		(1U << 0)

#define BCH_CREATE_SUBVOL		(1U << 1)

#define BCH_CREATE_SNAPSHOT		(1U << 2)

#define BCH_CREATE_SNAPSHOT_RO		(1U << 3)



int bch2_create_trans(struct btree_trans *, subvol_inum,

		      struct bch_inode_unpacked *,
@@ -13,7 +16,7 @@ int bch2_create_trans(struct btree_trans *, subvol_inum, 
		      uid_t, gid_t, umode_t, dev_t,

		      struct posix_acl *,

		      struct posix_acl *,

		      unsigned);

		      subvol_inum, unsigned);



int bch2_link_trans(struct btree_trans *,

		    subvol_inum, struct bch_inode_unpacked *,
@@ -23,7 +26,7 @@ int bch2_link_trans(struct btree_trans *, 
int bch2_unlink_trans(struct btree_trans *, subvol_inum,

		      struct bch_inode_unpacked *,

		      struct bch_inode_unpacked *,

		      const struct qstr *);

		      const struct qstr *, int);



int bch2_rename_trans(struct btree_trans *,

		      subvol_inum, struct bch_inode_unpacked *,

fs/bcachefs/fs-ioctl.c

+168 −0
Original line number Diff line number Diff line
@@ -10,7 +10,11 @@ 
#include "quota.h"



#include <linux/compat.h>

#include <linux/fsnotify.h>

#include <linux/mount.h>

#include <linux/namei.h>

#include <linux/security.h>

#include <linux/writeback.h>



#define FS_IOC_GOINGDOWN	     _IOR('X', 125, __u32)

#define FSOP_GOING_FLAGS_DEFAULT	0x0	/* going down */
@@ -292,6 +296,154 @@ static int bch2_ioc_goingdown(struct bch_fs *c, u32 __user *arg) 
	return ret;

}



static long bch2_ioctl_subvolume_create(struct bch_fs *c, struct file *filp,

				struct bch_ioctl_subvolume arg)

{

	struct inode *dir;

	struct bch_inode_info *inode;

	struct user_namespace *s_user_ns;

	struct dentry *dst_dentry;

	struct path src_path, dst_path;

	int how = LOOKUP_FOLLOW;

	int error;

	subvol_inum snapshot_src = { 0 };

	unsigned lookup_flags = 0;

	unsigned create_flags = BCH_CREATE_SUBVOL;



	if (arg.flags & ~(BCH_SUBVOL_SNAPSHOT_CREATE|

			  BCH_SUBVOL_SNAPSHOT_RO))

		return -EINVAL;



	if (!(arg.flags & BCH_SUBVOL_SNAPSHOT_CREATE) &&

	    (arg.src_ptr ||

	     (arg.flags & BCH_SUBVOL_SNAPSHOT_RO)))

		return -EINVAL;



	if (arg.flags & BCH_SUBVOL_SNAPSHOT_CREATE)

		create_flags |= BCH_CREATE_SNAPSHOT;



	if (arg.flags & BCH_SUBVOL_SNAPSHOT_RO)

		create_flags |= BCH_CREATE_SNAPSHOT_RO;



	/* why do we need this lock? */

	down_read(&c->vfs_sb->s_umount);



	if (arg.flags & BCH_SUBVOL_SNAPSHOT_CREATE)

		sync_inodes_sb(c->vfs_sb);

retry:

	if (arg.src_ptr) {

		error = user_path_at(arg.dirfd,

				(const char __user *)(unsigned long)arg.src_ptr,

				how, &src_path);

		if (error)

			goto err1;



		if (src_path.dentry->d_sb->s_fs_info != c) {

			path_put(&src_path);

			error = -EXDEV;

			goto err1;

		}



		snapshot_src = inode_inum(to_bch_ei(src_path.dentry->d_inode));

	}



	dst_dentry = user_path_create(arg.dirfd,

			(const char __user *)(unsigned long)arg.dst_ptr,

			&dst_path, lookup_flags);

	error = PTR_ERR_OR_ZERO(dst_dentry);

	if (error)

		goto err2;



	if (dst_dentry->d_sb->s_fs_info != c) {

		error = -EXDEV;

		goto err3;

	}



	if (dst_dentry->d_inode) {

		error = -EEXIST;

		goto err3;

	}



	dir = dst_path.dentry->d_inode;

	if (IS_DEADDIR(dir)) {

		error = -ENOENT;

		goto err3;

	}



	s_user_ns = dir->i_sb->s_user_ns;

	if (!kuid_has_mapping(s_user_ns, current_fsuid()) ||

	    !kgid_has_mapping(s_user_ns, current_fsgid())) {

		error = -EOVERFLOW;

		goto err3;

	}



	error = inode_permission(file_mnt_idmap(filp),

				 dir, MAY_WRITE | MAY_EXEC);

	if (error)

		goto err3;



	if (!IS_POSIXACL(dir))

		arg.mode &= ~current_umask();



	error = security_path_mkdir(&dst_path, dst_dentry, arg.mode);

	if (error)

		goto err3;



	if ((arg.flags & BCH_SUBVOL_SNAPSHOT_CREATE) &&

	    !arg.src_ptr)

		snapshot_src.subvol = to_bch_ei(dir)->ei_inode.bi_subvol;



	inode = __bch2_create(file_mnt_idmap(filp), to_bch_ei(dir),

			      dst_dentry, arg.mode|S_IFDIR,

			      0, snapshot_src, create_flags);

	error = PTR_ERR_OR_ZERO(inode);

	if (error)

		goto err3;



	d_instantiate(dst_dentry, &inode->v);

	fsnotify_mkdir(dir, dst_dentry);

err3:

	done_path_create(&dst_path, dst_dentry);

err2:

	if (arg.src_ptr)

		path_put(&src_path);



	if (retry_estale(error, lookup_flags)) {

		lookup_flags |= LOOKUP_REVAL;

		goto retry;

	}

err1:

	up_read(&c->vfs_sb->s_umount);



	return error;

}



static long bch2_ioctl_subvolume_destroy(struct bch_fs *c, struct file *filp,

				struct bch_ioctl_subvolume arg)

{

	struct path path;

	int ret = 0;



	if (arg.flags)

		return -EINVAL;



	ret = user_path_at(arg.dirfd,

			(const char __user *)(unsigned long)arg.dst_ptr,

			LOOKUP_FOLLOW, &path);

	if (ret)

		return ret;



	if (path.dentry->d_sb->s_fs_info != c) {

		path_put(&path);

		return -EXDEV;

	}



	ret = __bch2_unlink(path.dentry->d_parent->d_inode, path.dentry, 1);

	path_put(&path);



	return ret;

}



long bch2_fs_file_ioctl(struct file *file, unsigned cmd, unsigned long arg)

{

	struct bch_inode_info *inode = file_bch_inode(file);
@@ -322,6 +474,22 @@ long bch2_fs_file_ioctl(struct file *file, unsigned cmd, unsigned long arg) 
	case FS_IOC_GOINGDOWN:

		return bch2_ioc_goingdown(c, (u32 __user *) arg);



	case BCH_IOCTL_SUBVOLUME_CREATE: {

		struct bch_ioctl_subvolume i;



		if (copy_from_user(&i, (void __user *) arg, sizeof(i)))

			return -EFAULT;

		return bch2_ioctl_subvolume_create(c, file, i);

	}



	case BCH_IOCTL_SUBVOLUME_DESTROY: {

		struct bch_ioctl_subvolume i;



		if (copy_from_user(&i, (void __user *) arg, sizeof(i)))

			return -EFAULT;

		return bch2_ioctl_subvolume_destroy(c, file, i);

	}



	default:

		return bch2_fs_ioctl(c, cmd, (void __user *) arg);

	}