Commit 0d72ab35 authored by Kent Overstreet's avatar Kent Overstreet
Browse files

bcachefs: make RO snapshots actually RO 



Add checks to all the VFS paths for "are we in a RO snapshot?".

Note - we don't check this when setting inode options via our xattr
interface, since those generally only affect data placement, not
contents of data.

Signed-off-by: default avatarKent Overstreet <kent.overstreet@linux.dev>
Reported-by: default avatar"Carl E. Thompson" <list-bcachefs@carlthompson.net>
parent 84f16387

fs/bcachefs/acl.c

+2 −1
Original line number Diff line number Diff line
@@ -366,7 +366,8 @@ int bch2_set_acl(struct mnt_idmap *idmap, 
	bch2_trans_begin(trans);

	acl = _acl;



	ret = bch2_inode_peek(trans, &inode_iter, &inode_u, inode_inum(inode),

	ret   = bch2_subvol_is_ro_trans(trans, inode->ei_subvol) ?:

		bch2_inode_peek(trans, &inode_iter, &inode_u, inode_inum(inode),

			      BTREE_ITER_INTENT);

	if (ret)

		goto btree_err;

fs/bcachefs/fs-ioctl.c

+5 −7
Original line number Diff line number Diff line
@@ -100,7 +100,8 @@ static int bch2_ioc_setflags(struct bch_fs *c, 
	}



	mutex_lock(&inode->ei_update_lock);

	ret = bch2_write_inode(c, inode, bch2_inode_flags_set, &s,

	ret   = bch2_subvol_is_ro(c, inode->ei_subvol) ?:

		bch2_write_inode(c, inode, bch2_inode_flags_set, &s,

			       ATTR_CTIME);

	mutex_unlock(&inode->ei_update_lock);
@@ -183,13 +184,10 @@ static int bch2_ioc_fssetxattr(struct bch_fs *c, 
	}



	mutex_lock(&inode->ei_update_lock);

	ret = bch2_set_projid(c, inode, fa.fsx_projid);

	if (ret)

		goto err_unlock;



	ret = bch2_write_inode(c, inode, fssetxattr_inode_update_fn, &s,

	ret   = bch2_subvol_is_ro(c, inode->ei_subvol) ?:

		bch2_set_projid(c, inode, fa.fsx_projid) ?:

		bch2_write_inode(c, inode, fssetxattr_inode_update_fn, &s,

			       ATTR_CTIME);

err_unlock:

	mutex_unlock(&inode->ei_update_lock);

err:

	inode_unlock(&inode->v);

fs/bcachefs/fs.c

+33 −5
Original line number Diff line number Diff line
@@ -258,7 +258,8 @@ __bch2_create(struct mnt_idmap *idmap, 
retry:

	bch2_trans_begin(trans);



	ret   = bch2_create_trans(trans,

	ret   = bch2_subvol_is_ro_trans(trans, dir->ei_subvol) ?:

		bch2_create_trans(trans,

				  inode_inum(dir), &dir_u, &inode_u,

				  !(flags & BCH_CREATE_TMPFILE)

				  ? &dentry->d_name : NULL,
@@ -430,7 +431,9 @@ static int bch2_link(struct dentry *old_dentry, struct inode *vdir, 


	lockdep_assert_held(&inode->v.i_rwsem);



	ret = __bch2_link(c, inode, dir, dentry);

	ret   = bch2_subvol_is_ro(c, dir->ei_subvol) ?:

		bch2_subvol_is_ro(c, inode->ei_subvol) ?:

		__bch2_link(c, inode, dir, dentry);

	if (unlikely(ret))

		return ret;
@@ -481,7 +484,11 @@ int __bch2_unlink(struct inode *vdir, struct dentry *dentry, 


static int bch2_unlink(struct inode *vdir, struct dentry *dentry)

{

	return __bch2_unlink(vdir, dentry, false);

	struct bch_inode_info *dir= to_bch_ei(vdir);

	struct bch_fs *c = dir->v.i_sb->s_fs_info;



	return bch2_subvol_is_ro(c, dir->ei_subvol) ?:

		__bch2_unlink(vdir, dentry, false);

}



static int bch2_symlink(struct mnt_idmap *idmap,
@@ -562,6 +569,11 @@ static int bch2_rename2(struct mnt_idmap *idmap, 
			 src_inode,

			 dst_inode);



	ret   = bch2_subvol_is_ro_trans(trans, src_dir->ei_subvol) ?:

		bch2_subvol_is_ro_trans(trans, dst_dir->ei_subvol);

	if (ret)

		goto err;



	if (inode_attr_changing(dst_dir, src_inode, Inode_opt_project)) {

		ret = bch2_fs_quota_transfer(c, src_inode,

					     dst_dir->ei_qid,
@@ -783,11 +795,13 @@ static int bch2_setattr(struct mnt_idmap *idmap, 
			struct dentry *dentry, struct iattr *iattr)

{

	struct bch_inode_info *inode = to_bch_ei(dentry->d_inode);

	struct bch_fs *c = inode->v.i_sb->s_fs_info;

	int ret;



	lockdep_assert_held(&inode->v.i_rwsem);



	ret = setattr_prepare(idmap, dentry, iattr);

	ret   = bch2_subvol_is_ro(c, inode->ei_subvol) ?:

		setattr_prepare(idmap, dentry, iattr);

	if (ret)

		return ret;
@@ -1010,12 +1024,26 @@ static int bch2_vfs_readdir(struct file *file, struct dir_context *ctx) 
	return bch2_err_class(ret);

}



static int bch2_open(struct inode *vinode, struct file *file)

{

	if (file->f_flags & (O_WRONLY|O_RDWR)) {

		struct bch_inode_info *inode = to_bch_ei(vinode);

		struct bch_fs *c = inode->v.i_sb->s_fs_info;



		int ret = bch2_subvol_is_ro(c, inode->ei_subvol);

		if (ret)

			return ret;

	}



	return generic_file_open(vinode, file);

}



static const struct file_operations bch_file_operations = {

	.open		= bch2_open,

	.llseek		= bch2_llseek,

	.read_iter	= bch2_read_iter,

	.write_iter	= bch2_write_iter,

	.mmap		= bch2_mmap,

	.open		= generic_file_open,

	.fsync		= bch2_fsync,

	.splice_read	= filemap_splice_read,

	.splice_write	= iter_file_splice_write,

fs/bcachefs/subvolume.c

+18 −0
Original line number Diff line number Diff line
@@ -146,6 +146,24 @@ int bch2_subvolume_get(struct btree_trans *trans, unsigned subvol, 
	return bch2_subvolume_get_inlined(trans, subvol, inconsistent_if_not_found, iter_flags, s);

}



int bch2_subvol_is_ro_trans(struct btree_trans *trans, u32 subvol)

{

	struct bch_subvolume s;

	int ret = bch2_subvolume_get_inlined(trans, subvol, true, 0, &s);

	if (ret)

		return ret;



	if (BCH_SUBVOLUME_RO(&s))

		return -EROFS;

	return 0;

}



int bch2_subvol_is_ro(struct bch_fs *c, u32 subvol)

{

	return bch2_trans_do(c, NULL, NULL, 0,

		bch2_subvol_is_ro_trans(trans, subvol));

}



int bch2_snapshot_get_subvol(struct btree_trans *trans, u32 snapshot,

			     struct bch_subvolume *subvol)

{

fs/bcachefs/subvolume.h

+3 −0
Original line number Diff line number Diff line
@@ -23,6 +23,9 @@ int bch2_subvolume_get(struct btree_trans *, unsigned, 
		       bool, int, struct bch_subvolume *);

int bch2_subvolume_get_snapshot(struct btree_trans *, u32, u32 *);



int bch2_subvol_is_ro_trans(struct btree_trans *, u32);

int bch2_subvol_is_ro(struct bch_fs *, u32);



int bch2_delete_dead_snapshots(struct bch_fs *);

void bch2_delete_dead_snapshots_async(struct bch_fs *);