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6939f977c5
Comment above call already says this, but only EOPNOTSUPP is ignored, other failures are not. For example setting "user.*" will fail with EPERM on symlink/special. Ignore this error as well. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
1013 lines
23 KiB
C
1013 lines
23 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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*
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* Copyright (C) 2011 Novell Inc.
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*/
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#include <linux/module.h>
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#include <linux/fs.h>
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#include <linux/slab.h>
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#include <linux/file.h>
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#include <linux/splice.h>
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#include <linux/xattr.h>
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#include <linux/security.h>
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#include <linux/uaccess.h>
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#include <linux/sched/signal.h>
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#include <linux/cred.h>
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#include <linux/namei.h>
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#include <linux/fdtable.h>
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#include <linux/ratelimit.h>
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#include <linux/exportfs.h>
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#include "overlayfs.h"
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#define OVL_COPY_UP_CHUNK_SIZE (1 << 20)
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static int ovl_ccup_set(const char *buf, const struct kernel_param *param)
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{
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pr_warn("\"check_copy_up\" module option is obsolete\n");
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return 0;
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}
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static int ovl_ccup_get(char *buf, const struct kernel_param *param)
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{
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return sprintf(buf, "N\n");
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}
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module_param_call(check_copy_up, ovl_ccup_set, ovl_ccup_get, NULL, 0644);
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MODULE_PARM_DESC(check_copy_up, "Obsolete; does nothing");
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static bool ovl_must_copy_xattr(const char *name)
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{
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return !strcmp(name, XATTR_POSIX_ACL_ACCESS) ||
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!strcmp(name, XATTR_POSIX_ACL_DEFAULT) ||
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!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN);
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}
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int ovl_copy_xattr(struct super_block *sb, struct dentry *old,
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struct dentry *new)
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{
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ssize_t list_size, size, value_size = 0;
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char *buf, *name, *value = NULL;
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int error = 0;
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size_t slen;
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if (!(old->d_inode->i_opflags & IOP_XATTR) ||
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!(new->d_inode->i_opflags & IOP_XATTR))
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return 0;
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list_size = vfs_listxattr(old, NULL, 0);
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if (list_size <= 0) {
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if (list_size == -EOPNOTSUPP)
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return 0;
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return list_size;
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}
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buf = kzalloc(list_size, GFP_KERNEL);
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if (!buf)
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return -ENOMEM;
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list_size = vfs_listxattr(old, buf, list_size);
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if (list_size <= 0) {
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error = list_size;
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goto out;
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}
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for (name = buf; list_size; name += slen) {
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slen = strnlen(name, list_size) + 1;
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/* underlying fs providing us with an broken xattr list? */
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if (WARN_ON(slen > list_size)) {
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error = -EIO;
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break;
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}
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list_size -= slen;
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if (ovl_is_private_xattr(sb, name))
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continue;
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retry:
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size = vfs_getxattr(old, name, value, value_size);
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if (size == -ERANGE)
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size = vfs_getxattr(old, name, NULL, 0);
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if (size < 0) {
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error = size;
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break;
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}
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if (size > value_size) {
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void *new;
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new = krealloc(value, size, GFP_KERNEL);
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if (!new) {
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error = -ENOMEM;
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break;
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}
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value = new;
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value_size = size;
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goto retry;
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}
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error = security_inode_copy_up_xattr(name);
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if (error < 0 && error != -EOPNOTSUPP)
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break;
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if (error == 1) {
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error = 0;
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continue; /* Discard */
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}
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error = vfs_setxattr(new, name, value, size, 0);
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if (error) {
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if (error != -EOPNOTSUPP || ovl_must_copy_xattr(name))
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break;
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/* Ignore failure to copy unknown xattrs */
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error = 0;
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}
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}
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kfree(value);
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out:
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kfree(buf);
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return error;
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}
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static int ovl_copy_up_data(struct ovl_fs *ofs, struct path *old,
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struct path *new, loff_t len)
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{
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struct file *old_file;
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struct file *new_file;
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loff_t old_pos = 0;
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loff_t new_pos = 0;
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loff_t cloned;
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loff_t data_pos = -1;
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loff_t hole_len;
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bool skip_hole = false;
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int error = 0;
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if (len == 0)
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return 0;
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old_file = ovl_path_open(old, O_LARGEFILE | O_RDONLY);
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if (IS_ERR(old_file))
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return PTR_ERR(old_file);
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new_file = ovl_path_open(new, O_LARGEFILE | O_WRONLY);
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if (IS_ERR(new_file)) {
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error = PTR_ERR(new_file);
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goto out_fput;
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}
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/* Try to use clone_file_range to clone up within the same fs */
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cloned = do_clone_file_range(old_file, 0, new_file, 0, len, 0);
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if (cloned == len)
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goto out;
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/* Couldn't clone, so now we try to copy the data */
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/* Check if lower fs supports seek operation */
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if (old_file->f_mode & FMODE_LSEEK &&
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old_file->f_op->llseek)
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skip_hole = true;
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while (len) {
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size_t this_len = OVL_COPY_UP_CHUNK_SIZE;
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long bytes;
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if (len < this_len)
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this_len = len;
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if (signal_pending_state(TASK_KILLABLE, current)) {
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error = -EINTR;
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break;
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}
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/*
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* Fill zero for hole will cost unnecessary disk space
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* and meanwhile slow down the copy-up speed, so we do
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* an optimization for hole during copy-up, it relies
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* on SEEK_DATA implementation in lower fs so if lower
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* fs does not support it, copy-up will behave as before.
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*
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* Detail logic of hole detection as below:
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* When we detect next data position is larger than current
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* position we will skip that hole, otherwise we copy
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* data in the size of OVL_COPY_UP_CHUNK_SIZE. Actually,
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* it may not recognize all kind of holes and sometimes
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* only skips partial of hole area. However, it will be
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* enough for most of the use cases.
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*/
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if (skip_hole && data_pos < old_pos) {
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data_pos = vfs_llseek(old_file, old_pos, SEEK_DATA);
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if (data_pos > old_pos) {
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hole_len = data_pos - old_pos;
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len -= hole_len;
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old_pos = new_pos = data_pos;
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continue;
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} else if (data_pos == -ENXIO) {
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break;
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} else if (data_pos < 0) {
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skip_hole = false;
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}
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}
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bytes = do_splice_direct(old_file, &old_pos,
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new_file, &new_pos,
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this_len, SPLICE_F_MOVE);
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if (bytes <= 0) {
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error = bytes;
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break;
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}
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WARN_ON(old_pos != new_pos);
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len -= bytes;
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}
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out:
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if (!error && ovl_should_sync(ofs))
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error = vfs_fsync(new_file, 0);
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fput(new_file);
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out_fput:
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fput(old_file);
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return error;
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}
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static int ovl_set_size(struct dentry *upperdentry, struct kstat *stat)
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{
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struct iattr attr = {
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.ia_valid = ATTR_SIZE,
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.ia_size = stat->size,
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};
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return notify_change(upperdentry, &attr, NULL);
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}
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static int ovl_set_timestamps(struct dentry *upperdentry, struct kstat *stat)
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{
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struct iattr attr = {
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.ia_valid =
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ATTR_ATIME | ATTR_MTIME | ATTR_ATIME_SET | ATTR_MTIME_SET,
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.ia_atime = stat->atime,
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.ia_mtime = stat->mtime,
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};
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return notify_change(upperdentry, &attr, NULL);
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}
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int ovl_set_attr(struct dentry *upperdentry, struct kstat *stat)
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{
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int err = 0;
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if (!S_ISLNK(stat->mode)) {
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struct iattr attr = {
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.ia_valid = ATTR_MODE,
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.ia_mode = stat->mode,
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};
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err = notify_change(upperdentry, &attr, NULL);
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}
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if (!err) {
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struct iattr attr = {
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.ia_valid = ATTR_UID | ATTR_GID,
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.ia_uid = stat->uid,
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.ia_gid = stat->gid,
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};
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err = notify_change(upperdentry, &attr, NULL);
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}
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if (!err)
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ovl_set_timestamps(upperdentry, stat);
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return err;
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}
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struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real,
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bool is_upper)
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{
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struct ovl_fh *fh;
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int fh_type, dwords;
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int buflen = MAX_HANDLE_SZ;
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uuid_t *uuid = &real->d_sb->s_uuid;
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int err;
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/* Make sure the real fid stays 32bit aligned */
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BUILD_BUG_ON(OVL_FH_FID_OFFSET % 4);
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BUILD_BUG_ON(MAX_HANDLE_SZ + OVL_FH_FID_OFFSET > 255);
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fh = kzalloc(buflen + OVL_FH_FID_OFFSET, GFP_KERNEL);
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if (!fh)
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return ERR_PTR(-ENOMEM);
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/*
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* We encode a non-connectable file handle for non-dir, because we
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* only need to find the lower inode number and we don't want to pay
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* the price or reconnecting the dentry.
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*/
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dwords = buflen >> 2;
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fh_type = exportfs_encode_fh(real, (void *)fh->fb.fid, &dwords, 0);
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buflen = (dwords << 2);
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err = -EIO;
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if (WARN_ON(fh_type < 0) ||
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WARN_ON(buflen > MAX_HANDLE_SZ) ||
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WARN_ON(fh_type == FILEID_INVALID))
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goto out_err;
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fh->fb.version = OVL_FH_VERSION;
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fh->fb.magic = OVL_FH_MAGIC;
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fh->fb.type = fh_type;
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fh->fb.flags = OVL_FH_FLAG_CPU_ENDIAN;
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/*
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* When we will want to decode an overlay dentry from this handle
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* and all layers are on the same fs, if we get a disconncted real
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* dentry when we decode fid, the only way to tell if we should assign
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* it to upperdentry or to lowerstack is by checking this flag.
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*/
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if (is_upper)
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fh->fb.flags |= OVL_FH_FLAG_PATH_UPPER;
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fh->fb.len = sizeof(fh->fb) + buflen;
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if (ofs->config.uuid)
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fh->fb.uuid = *uuid;
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return fh;
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out_err:
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kfree(fh);
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return ERR_PTR(err);
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}
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int ovl_set_origin(struct ovl_fs *ofs, struct dentry *dentry,
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struct dentry *lower, struct dentry *upper)
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{
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const struct ovl_fh *fh = NULL;
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int err;
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/*
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* When lower layer doesn't support export operations store a 'null' fh,
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* so we can use the overlay.origin xattr to distignuish between a copy
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* up and a pure upper inode.
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*/
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if (ovl_can_decode_fh(lower->d_sb)) {
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fh = ovl_encode_real_fh(ofs, lower, false);
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if (IS_ERR(fh))
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return PTR_ERR(fh);
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}
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/*
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* Do not fail when upper doesn't support xattrs.
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*/
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err = ovl_check_setxattr(dentry, upper, OVL_XATTR_ORIGIN, fh->buf,
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fh ? fh->fb.len : 0, 0);
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kfree(fh);
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/* Ignore -EPERM from setting "user.*" on symlink/special */
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return err == -EPERM ? 0 : err;
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}
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/* Store file handle of @upper dir in @index dir entry */
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static int ovl_set_upper_fh(struct ovl_fs *ofs, struct dentry *upper,
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struct dentry *index)
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{
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const struct ovl_fh *fh;
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int err;
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fh = ovl_encode_real_fh(ofs, upper, true);
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if (IS_ERR(fh))
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return PTR_ERR(fh);
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err = ovl_do_setxattr(ofs, index, OVL_XATTR_UPPER, fh->buf, fh->fb.len);
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kfree(fh);
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return err;
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}
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/*
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* Create and install index entry.
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*
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* Caller must hold i_mutex on indexdir.
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*/
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static int ovl_create_index(struct dentry *dentry, struct dentry *origin,
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struct dentry *upper)
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{
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struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
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struct dentry *indexdir = ovl_indexdir(dentry->d_sb);
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struct inode *dir = d_inode(indexdir);
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struct dentry *index = NULL;
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struct dentry *temp = NULL;
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struct qstr name = { };
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int err;
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/*
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* For now this is only used for creating index entry for directories,
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* because non-dir are copied up directly to index and then hardlinked
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* to upper dir.
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*
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* TODO: implement create index for non-dir, so we can call it when
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* encoding file handle for non-dir in case index does not exist.
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*/
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if (WARN_ON(!d_is_dir(dentry)))
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return -EIO;
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/* Directory not expected to be indexed before copy up */
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if (WARN_ON(ovl_test_flag(OVL_INDEX, d_inode(dentry))))
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return -EIO;
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err = ovl_get_index_name(ofs, origin, &name);
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if (err)
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return err;
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temp = ovl_create_temp(indexdir, OVL_CATTR(S_IFDIR | 0));
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err = PTR_ERR(temp);
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if (IS_ERR(temp))
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goto free_name;
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err = ovl_set_upper_fh(ofs, upper, temp);
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if (err)
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goto out;
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index = lookup_one_len(name.name, indexdir, name.len);
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if (IS_ERR(index)) {
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err = PTR_ERR(index);
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} else {
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err = ovl_do_rename(dir, temp, dir, index, 0);
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dput(index);
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}
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out:
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if (err)
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ovl_cleanup(dir, temp);
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dput(temp);
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free_name:
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kfree(name.name);
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return err;
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}
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struct ovl_copy_up_ctx {
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struct dentry *parent;
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struct dentry *dentry;
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struct path lowerpath;
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struct kstat stat;
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struct kstat pstat;
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const char *link;
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struct dentry *destdir;
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struct qstr destname;
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struct dentry *workdir;
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bool origin;
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bool indexed;
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bool metacopy;
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};
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static int ovl_link_up(struct ovl_copy_up_ctx *c)
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{
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int err;
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struct dentry *upper;
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struct dentry *upperdir = ovl_dentry_upper(c->parent);
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struct inode *udir = d_inode(upperdir);
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/* Mark parent "impure" because it may now contain non-pure upper */
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err = ovl_set_impure(c->parent, upperdir);
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if (err)
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return err;
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err = ovl_set_nlink_lower(c->dentry);
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if (err)
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return err;
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inode_lock_nested(udir, I_MUTEX_PARENT);
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upper = lookup_one_len(c->dentry->d_name.name, upperdir,
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c->dentry->d_name.len);
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err = PTR_ERR(upper);
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if (!IS_ERR(upper)) {
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err = ovl_do_link(ovl_dentry_upper(c->dentry), udir, upper);
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dput(upper);
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if (!err) {
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/* Restore timestamps on parent (best effort) */
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ovl_set_timestamps(upperdir, &c->pstat);
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ovl_dentry_set_upper_alias(c->dentry);
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}
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}
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inode_unlock(udir);
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if (err)
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return err;
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err = ovl_set_nlink_upper(c->dentry);
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return err;
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}
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static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp)
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{
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struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
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int err;
|
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|
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/*
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* Copy up data first and then xattrs. Writing data after
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* xattrs will remove security.capability xattr automatically.
|
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*/
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if (S_ISREG(c->stat.mode) && !c->metacopy) {
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struct path upperpath, datapath;
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ovl_path_upper(c->dentry, &upperpath);
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if (WARN_ON(upperpath.dentry != NULL))
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return -EIO;
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upperpath.dentry = temp;
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|
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ovl_path_lowerdata(c->dentry, &datapath);
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err = ovl_copy_up_data(ofs, &datapath, &upperpath,
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c->stat.size);
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if (err)
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return err;
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}
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|
|
err = ovl_copy_xattr(c->dentry->d_sb, c->lowerpath.dentry, temp);
|
|
if (err)
|
|
return err;
|
|
|
|
/*
|
|
* Store identifier of lower inode in upper inode xattr to
|
|
* allow lookup of the copy up origin inode.
|
|
*
|
|
* Don't set origin when we are breaking the association with a lower
|
|
* hard link.
|
|
*/
|
|
if (c->origin) {
|
|
err = ovl_set_origin(ofs, c->dentry, c->lowerpath.dentry, temp);
|
|
if (err)
|
|
return err;
|
|
}
|
|
|
|
if (c->metacopy) {
|
|
err = ovl_check_setxattr(c->dentry, temp, OVL_XATTR_METACOPY,
|
|
NULL, 0, -EOPNOTSUPP);
|
|
if (err)
|
|
return err;
|
|
}
|
|
|
|
inode_lock(temp->d_inode);
|
|
if (S_ISREG(c->stat.mode))
|
|
err = ovl_set_size(temp, &c->stat);
|
|
if (!err)
|
|
err = ovl_set_attr(temp, &c->stat);
|
|
inode_unlock(temp->d_inode);
|
|
|
|
return err;
|
|
}
|
|
|
|
struct ovl_cu_creds {
|
|
const struct cred *old;
|
|
struct cred *new;
|
|
};
|
|
|
|
static int ovl_prep_cu_creds(struct dentry *dentry, struct ovl_cu_creds *cc)
|
|
{
|
|
int err;
|
|
|
|
cc->old = cc->new = NULL;
|
|
err = security_inode_copy_up(dentry, &cc->new);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
if (cc->new)
|
|
cc->old = override_creds(cc->new);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void ovl_revert_cu_creds(struct ovl_cu_creds *cc)
|
|
{
|
|
if (cc->new) {
|
|
revert_creds(cc->old);
|
|
put_cred(cc->new);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Copyup using workdir to prepare temp file. Used when copying up directories,
|
|
* special files or when upper fs doesn't support O_TMPFILE.
|
|
*/
|
|
static int ovl_copy_up_workdir(struct ovl_copy_up_ctx *c)
|
|
{
|
|
struct inode *inode;
|
|
struct inode *udir = d_inode(c->destdir), *wdir = d_inode(c->workdir);
|
|
struct dentry *temp, *upper;
|
|
struct ovl_cu_creds cc;
|
|
int err;
|
|
struct ovl_cattr cattr = {
|
|
/* Can't properly set mode on creation because of the umask */
|
|
.mode = c->stat.mode & S_IFMT,
|
|
.rdev = c->stat.rdev,
|
|
.link = c->link
|
|
};
|
|
|
|
/* workdir and destdir could be the same when copying up to indexdir */
|
|
err = -EIO;
|
|
if (lock_rename(c->workdir, c->destdir) != NULL)
|
|
goto unlock;
|
|
|
|
err = ovl_prep_cu_creds(c->dentry, &cc);
|
|
if (err)
|
|
goto unlock;
|
|
|
|
temp = ovl_create_temp(c->workdir, &cattr);
|
|
ovl_revert_cu_creds(&cc);
|
|
|
|
err = PTR_ERR(temp);
|
|
if (IS_ERR(temp))
|
|
goto unlock;
|
|
|
|
err = ovl_copy_up_inode(c, temp);
|
|
if (err)
|
|
goto cleanup;
|
|
|
|
if (S_ISDIR(c->stat.mode) && c->indexed) {
|
|
err = ovl_create_index(c->dentry, c->lowerpath.dentry, temp);
|
|
if (err)
|
|
goto cleanup;
|
|
}
|
|
|
|
upper = lookup_one_len(c->destname.name, c->destdir, c->destname.len);
|
|
err = PTR_ERR(upper);
|
|
if (IS_ERR(upper))
|
|
goto cleanup;
|
|
|
|
err = ovl_do_rename(wdir, temp, udir, upper, 0);
|
|
dput(upper);
|
|
if (err)
|
|
goto cleanup;
|
|
|
|
if (!c->metacopy)
|
|
ovl_set_upperdata(d_inode(c->dentry));
|
|
inode = d_inode(c->dentry);
|
|
ovl_inode_update(inode, temp);
|
|
if (S_ISDIR(inode->i_mode))
|
|
ovl_set_flag(OVL_WHITEOUTS, inode);
|
|
unlock:
|
|
unlock_rename(c->workdir, c->destdir);
|
|
|
|
return err;
|
|
|
|
cleanup:
|
|
ovl_cleanup(wdir, temp);
|
|
dput(temp);
|
|
goto unlock;
|
|
}
|
|
|
|
/* Copyup using O_TMPFILE which does not require cross dir locking */
|
|
static int ovl_copy_up_tmpfile(struct ovl_copy_up_ctx *c)
|
|
{
|
|
struct inode *udir = d_inode(c->destdir);
|
|
struct dentry *temp, *upper;
|
|
struct ovl_cu_creds cc;
|
|
int err;
|
|
|
|
err = ovl_prep_cu_creds(c->dentry, &cc);
|
|
if (err)
|
|
return err;
|
|
|
|
temp = ovl_do_tmpfile(c->workdir, c->stat.mode);
|
|
ovl_revert_cu_creds(&cc);
|
|
|
|
if (IS_ERR(temp))
|
|
return PTR_ERR(temp);
|
|
|
|
err = ovl_copy_up_inode(c, temp);
|
|
if (err)
|
|
goto out_dput;
|
|
|
|
inode_lock_nested(udir, I_MUTEX_PARENT);
|
|
|
|
upper = lookup_one_len(c->destname.name, c->destdir, c->destname.len);
|
|
err = PTR_ERR(upper);
|
|
if (!IS_ERR(upper)) {
|
|
err = ovl_do_link(temp, udir, upper);
|
|
dput(upper);
|
|
}
|
|
inode_unlock(udir);
|
|
|
|
if (err)
|
|
goto out_dput;
|
|
|
|
if (!c->metacopy)
|
|
ovl_set_upperdata(d_inode(c->dentry));
|
|
ovl_inode_update(d_inode(c->dentry), temp);
|
|
|
|
return 0;
|
|
|
|
out_dput:
|
|
dput(temp);
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* Copy up a single dentry
|
|
*
|
|
* All renames start with copy up of source if necessary. The actual
|
|
* rename will only proceed once the copy up was successful. Copy up uses
|
|
* upper parent i_mutex for exclusion. Since rename can change d_parent it
|
|
* is possible that the copy up will lock the old parent. At that point
|
|
* the file will have already been copied up anyway.
|
|
*/
|
|
static int ovl_do_copy_up(struct ovl_copy_up_ctx *c)
|
|
{
|
|
int err;
|
|
struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
|
|
bool to_index = false;
|
|
|
|
/*
|
|
* Indexed non-dir is copied up directly to the index entry and then
|
|
* hardlinked to upper dir. Indexed dir is copied up to indexdir,
|
|
* then index entry is created and then copied up dir installed.
|
|
* Copying dir up to indexdir instead of workdir simplifies locking.
|
|
*/
|
|
if (ovl_need_index(c->dentry)) {
|
|
c->indexed = true;
|
|
if (S_ISDIR(c->stat.mode))
|
|
c->workdir = ovl_indexdir(c->dentry->d_sb);
|
|
else
|
|
to_index = true;
|
|
}
|
|
|
|
if (S_ISDIR(c->stat.mode) || c->stat.nlink == 1 || to_index)
|
|
c->origin = true;
|
|
|
|
if (to_index) {
|
|
c->destdir = ovl_indexdir(c->dentry->d_sb);
|
|
err = ovl_get_index_name(ofs, c->lowerpath.dentry, &c->destname);
|
|
if (err)
|
|
return err;
|
|
} else if (WARN_ON(!c->parent)) {
|
|
/* Disconnected dentry must be copied up to index dir */
|
|
return -EIO;
|
|
} else {
|
|
/*
|
|
* Mark parent "impure" because it may now contain non-pure
|
|
* upper
|
|
*/
|
|
err = ovl_set_impure(c->parent, c->destdir);
|
|
if (err)
|
|
return err;
|
|
}
|
|
|
|
/* Should we copyup with O_TMPFILE or with workdir? */
|
|
if (S_ISREG(c->stat.mode) && ofs->tmpfile)
|
|
err = ovl_copy_up_tmpfile(c);
|
|
else
|
|
err = ovl_copy_up_workdir(c);
|
|
if (err)
|
|
goto out;
|
|
|
|
if (c->indexed)
|
|
ovl_set_flag(OVL_INDEX, d_inode(c->dentry));
|
|
|
|
if (to_index) {
|
|
/* Initialize nlink for copy up of disconnected dentry */
|
|
err = ovl_set_nlink_upper(c->dentry);
|
|
} else {
|
|
struct inode *udir = d_inode(c->destdir);
|
|
|
|
/* Restore timestamps on parent (best effort) */
|
|
inode_lock(udir);
|
|
ovl_set_timestamps(c->destdir, &c->pstat);
|
|
inode_unlock(udir);
|
|
|
|
ovl_dentry_set_upper_alias(c->dentry);
|
|
}
|
|
|
|
out:
|
|
if (to_index)
|
|
kfree(c->destname.name);
|
|
return err;
|
|
}
|
|
|
|
static bool ovl_need_meta_copy_up(struct dentry *dentry, umode_t mode,
|
|
int flags)
|
|
{
|
|
struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
|
|
|
|
if (!ofs->config.metacopy)
|
|
return false;
|
|
|
|
if (!S_ISREG(mode))
|
|
return false;
|
|
|
|
if (flags && ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC)))
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
static ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value)
|
|
{
|
|
ssize_t res;
|
|
char *buf;
|
|
|
|
res = vfs_getxattr(dentry, name, NULL, 0);
|
|
if (res == -ENODATA || res == -EOPNOTSUPP)
|
|
res = 0;
|
|
|
|
if (res > 0) {
|
|
buf = kzalloc(res, GFP_KERNEL);
|
|
if (!buf)
|
|
return -ENOMEM;
|
|
|
|
res = vfs_getxattr(dentry, name, buf, res);
|
|
if (res < 0)
|
|
kfree(buf);
|
|
else
|
|
*value = buf;
|
|
}
|
|
return res;
|
|
}
|
|
|
|
/* Copy up data of an inode which was copied up metadata only in the past. */
|
|
static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
|
|
{
|
|
struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
|
|
struct path upperpath, datapath;
|
|
int err;
|
|
char *capability = NULL;
|
|
ssize_t cap_size;
|
|
|
|
ovl_path_upper(c->dentry, &upperpath);
|
|
if (WARN_ON(upperpath.dentry == NULL))
|
|
return -EIO;
|
|
|
|
ovl_path_lowerdata(c->dentry, &datapath);
|
|
if (WARN_ON(datapath.dentry == NULL))
|
|
return -EIO;
|
|
|
|
if (c->stat.size) {
|
|
err = cap_size = ovl_getxattr(upperpath.dentry, XATTR_NAME_CAPS,
|
|
&capability);
|
|
if (cap_size < 0)
|
|
goto out;
|
|
}
|
|
|
|
err = ovl_copy_up_data(ofs, &datapath, &upperpath, c->stat.size);
|
|
if (err)
|
|
goto out_free;
|
|
|
|
/*
|
|
* Writing to upper file will clear security.capability xattr. We
|
|
* don't want that to happen for normal copy-up operation.
|
|
*/
|
|
if (capability) {
|
|
err = vfs_setxattr(upperpath.dentry, XATTR_NAME_CAPS,
|
|
capability, cap_size, 0);
|
|
if (err)
|
|
goto out_free;
|
|
}
|
|
|
|
|
|
err = ovl_do_removexattr(ofs, upperpath.dentry, OVL_XATTR_METACOPY);
|
|
if (err)
|
|
goto out_free;
|
|
|
|
ovl_set_upperdata(d_inode(c->dentry));
|
|
out_free:
|
|
kfree(capability);
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
|
|
int flags)
|
|
{
|
|
int err;
|
|
DEFINE_DELAYED_CALL(done);
|
|
struct path parentpath;
|
|
struct ovl_copy_up_ctx ctx = {
|
|
.parent = parent,
|
|
.dentry = dentry,
|
|
.workdir = ovl_workdir(dentry),
|
|
};
|
|
|
|
if (WARN_ON(!ctx.workdir))
|
|
return -EROFS;
|
|
|
|
ovl_path_lower(dentry, &ctx.lowerpath);
|
|
err = vfs_getattr(&ctx.lowerpath, &ctx.stat,
|
|
STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT);
|
|
if (err)
|
|
return err;
|
|
|
|
ctx.metacopy = ovl_need_meta_copy_up(dentry, ctx.stat.mode, flags);
|
|
|
|
if (parent) {
|
|
ovl_path_upper(parent, &parentpath);
|
|
ctx.destdir = parentpath.dentry;
|
|
ctx.destname = dentry->d_name;
|
|
|
|
err = vfs_getattr(&parentpath, &ctx.pstat,
|
|
STATX_ATIME | STATX_MTIME,
|
|
AT_STATX_SYNC_AS_STAT);
|
|
if (err)
|
|
return err;
|
|
}
|
|
|
|
/* maybe truncate regular file. this has no effect on dirs */
|
|
if (flags & O_TRUNC)
|
|
ctx.stat.size = 0;
|
|
|
|
if (S_ISLNK(ctx.stat.mode)) {
|
|
ctx.link = vfs_get_link(ctx.lowerpath.dentry, &done);
|
|
if (IS_ERR(ctx.link))
|
|
return PTR_ERR(ctx.link);
|
|
}
|
|
|
|
err = ovl_copy_up_start(dentry, flags);
|
|
/* err < 0: interrupted, err > 0: raced with another copy-up */
|
|
if (unlikely(err)) {
|
|
if (err > 0)
|
|
err = 0;
|
|
} else {
|
|
if (!ovl_dentry_upper(dentry))
|
|
err = ovl_do_copy_up(&ctx);
|
|
if (!err && parent && !ovl_dentry_has_upper_alias(dentry))
|
|
err = ovl_link_up(&ctx);
|
|
if (!err && ovl_dentry_needs_data_copy_up_locked(dentry, flags))
|
|
err = ovl_copy_up_meta_inode_data(&ctx);
|
|
ovl_copy_up_end(dentry);
|
|
}
|
|
do_delayed_call(&done);
|
|
|
|
return err;
|
|
}
|
|
|
|
static int ovl_copy_up_flags(struct dentry *dentry, int flags)
|
|
{
|
|
int err = 0;
|
|
const struct cred *old_cred = ovl_override_creds(dentry->d_sb);
|
|
bool disconnected = (dentry->d_flags & DCACHE_DISCONNECTED);
|
|
|
|
/*
|
|
* With NFS export, copy up can get called for a disconnected non-dir.
|
|
* In this case, we will copy up lower inode to index dir without
|
|
* linking it to upper dir.
|
|
*/
|
|
if (WARN_ON(disconnected && d_is_dir(dentry)))
|
|
return -EIO;
|
|
|
|
while (!err) {
|
|
struct dentry *next;
|
|
struct dentry *parent = NULL;
|
|
|
|
if (ovl_already_copied_up(dentry, flags))
|
|
break;
|
|
|
|
next = dget(dentry);
|
|
/* find the topmost dentry not yet copied up */
|
|
for (; !disconnected;) {
|
|
parent = dget_parent(next);
|
|
|
|
if (ovl_dentry_upper(parent))
|
|
break;
|
|
|
|
dput(next);
|
|
next = parent;
|
|
}
|
|
|
|
err = ovl_copy_up_one(parent, next, flags);
|
|
|
|
dput(parent);
|
|
dput(next);
|
|
}
|
|
revert_creds(old_cred);
|
|
|
|
return err;
|
|
}
|
|
|
|
static bool ovl_open_need_copy_up(struct dentry *dentry, int flags)
|
|
{
|
|
/* Copy up of disconnected dentry does not set upper alias */
|
|
if (ovl_already_copied_up(dentry, flags))
|
|
return false;
|
|
|
|
if (special_file(d_inode(dentry)->i_mode))
|
|
return false;
|
|
|
|
if (!ovl_open_flags_need_copy_up(flags))
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
int ovl_maybe_copy_up(struct dentry *dentry, int flags)
|
|
{
|
|
int err = 0;
|
|
|
|
if (ovl_open_need_copy_up(dentry, flags)) {
|
|
err = ovl_want_write(dentry);
|
|
if (!err) {
|
|
err = ovl_copy_up_flags(dentry, flags);
|
|
ovl_drop_write(dentry);
|
|
}
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
int ovl_copy_up_with_data(struct dentry *dentry)
|
|
{
|
|
return ovl_copy_up_flags(dentry, O_WRONLY);
|
|
}
|
|
|
|
int ovl_copy_up(struct dentry *dentry)
|
|
{
|
|
return ovl_copy_up_flags(dentry, 0);
|
|
}
|