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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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a087349066
We are holding a transaction handle when setting an acl, therefore we can
not allocate the xattr value buffer using GFP_KERNEL, as we could deadlock
if reclaim is triggered by the allocation, therefore setup a nofs context.
Fixes: 39a27ec100 ("btrfs: use GFP_KERNEL for xattr and acl allocations")
CC: stable@vger.kernel.org # 4.9+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
152 lines
3.1 KiB
C
152 lines
3.1 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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struct posix_acl *btrfs_get_acl(struct inode *inode, int type)
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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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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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static int __btrfs_set_acl(struct btrfs_trans_handle *trans,
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struct inode *inode, 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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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 inode *inode, struct posix_acl *acl, int type)
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{
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int ret;
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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(inode, &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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int btrfs_init_acl(struct btrfs_trans_handle *trans,
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struct inode *inode, struct inode *dir)
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{
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struct posix_acl *default_acl, *acl;
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int ret = 0;
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/* this happens with subvols */
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if (!dir)
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return 0;
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ret = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
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if (ret)
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return ret;
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if (default_acl) {
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ret = __btrfs_set_acl(trans, inode, default_acl,
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ACL_TYPE_DEFAULT);
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posix_acl_release(default_acl);
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}
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if (acl) {
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if (!ret)
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ret = __btrfs_set_acl(trans, inode, acl,
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ACL_TYPE_ACCESS);
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posix_acl_release(acl);
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}
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if (!default_acl && !acl)
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cache_no_acl(inode);
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return ret;
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}
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