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700b794052
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
130 lines
2.7 KiB
C
130 lines
2.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2007 Red Hat. All rights reserved.
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*/
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#include <linux/fs.h>
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#include <linux/string.h>
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#include <linux/xattr.h>
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#include <linux/posix_acl_xattr.h>
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#include <linux/posix_acl.h>
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#include <linux/sched.h>
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#include <linux/sched/mm.h>
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#include <linux/slab.h>
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#include "ctree.h"
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#include "btrfs_inode.h"
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#include "xattr.h"
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#include "acl.h"
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struct posix_acl *btrfs_get_acl(struct inode *inode, int type, bool rcu)
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{
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int size;
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const char *name;
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char *value = NULL;
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struct posix_acl *acl;
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if (rcu)
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return ERR_PTR(-ECHILD);
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switch (type) {
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case ACL_TYPE_ACCESS:
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name = XATTR_NAME_POSIX_ACL_ACCESS;
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break;
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case ACL_TYPE_DEFAULT:
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name = XATTR_NAME_POSIX_ACL_DEFAULT;
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break;
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default:
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return ERR_PTR(-EINVAL);
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}
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size = btrfs_getxattr(inode, name, NULL, 0);
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if (size > 0) {
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value = kzalloc(size, GFP_KERNEL);
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if (!value)
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return ERR_PTR(-ENOMEM);
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size = btrfs_getxattr(inode, name, value, size);
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}
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if (size > 0)
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acl = posix_acl_from_xattr(&init_user_ns, value, size);
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else if (size == -ENODATA || size == 0)
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acl = NULL;
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else
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acl = ERR_PTR(size);
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kfree(value);
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return acl;
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}
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int __btrfs_set_acl(struct btrfs_trans_handle *trans, struct inode *inode,
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struct posix_acl *acl, int type)
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{
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int ret, size = 0;
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const char *name;
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char *value = NULL;
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switch (type) {
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case ACL_TYPE_ACCESS:
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name = XATTR_NAME_POSIX_ACL_ACCESS;
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break;
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case ACL_TYPE_DEFAULT:
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if (!S_ISDIR(inode->i_mode))
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return acl ? -EINVAL : 0;
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name = XATTR_NAME_POSIX_ACL_DEFAULT;
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break;
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default:
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return -EINVAL;
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}
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if (acl) {
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unsigned int nofs_flag;
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size = posix_acl_xattr_size(acl->a_count);
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/*
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* We're holding a transaction handle, so use a NOFS memory
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* allocation context to avoid deadlock if reclaim happens.
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*/
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nofs_flag = memalloc_nofs_save();
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value = kmalloc(size, GFP_KERNEL);
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memalloc_nofs_restore(nofs_flag);
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if (!value) {
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ret = -ENOMEM;
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goto out;
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}
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ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
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if (ret < 0)
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goto out;
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}
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if (trans)
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ret = btrfs_setxattr(trans, inode, name, value, size, 0);
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else
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ret = btrfs_setxattr_trans(inode, name, value, size, 0);
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out:
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kfree(value);
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if (!ret)
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set_cached_acl(inode, type, acl);
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return ret;
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}
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int btrfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
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struct posix_acl *acl, int type)
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{
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int ret;
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struct inode *inode = d_inode(dentry);
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umode_t old_mode = inode->i_mode;
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if (type == ACL_TYPE_ACCESS && acl) {
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ret = posix_acl_update_mode(idmap, inode,
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&inode->i_mode, &acl);
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if (ret)
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return ret;
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}
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ret = __btrfs_set_acl(NULL, inode, acl, type);
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if (ret)
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inode->i_mode = old_mode;
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return ret;
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}
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