378ff1a53b
It really needs to check that src is non-directory *and* use
{un,}lock_two_nodirectories(). As it is, it's trivial to cause
double-lock (ioctl(fd, CIFS_IOC_COPYCHUNK_FILE, fd)) and if the
last argument is an fd of directory, we are asking for trouble
by violating the locking order - all directories go before all
non-directories. If the last argument is an fd of parent
directory, it has 50% odds of locking child before parent,
which will cause AB-BA deadlock if we race with unlink().
Cc: stable@vger.kernel.org @ 3.13+
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
217 lines
6.1 KiB
C
217 lines
6.1 KiB
C
/*
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* fs/cifs/ioctl.c
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*
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* vfs operations that deal with io control
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*
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* Copyright (C) International Business Machines Corp., 2005,2013
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* Author(s): Steve French (sfrench@us.ibm.com)
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*
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* This library is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published
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* by the Free Software Foundation; either version 2.1 of the License, or
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* (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
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* the GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/fs.h>
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#include <linux/file.h>
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#include <linux/mount.h>
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#include <linux/mm.h>
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#include <linux/pagemap.h>
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#include "cifspdu.h"
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#include "cifsglob.h"
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#include "cifsproto.h"
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#include "cifs_debug.h"
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#include "cifsfs.h"
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#define CIFS_IOCTL_MAGIC 0xCF
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#define CIFS_IOC_COPYCHUNK_FILE _IOW(CIFS_IOCTL_MAGIC, 3, int)
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static long cifs_ioctl_clone(unsigned int xid, struct file *dst_file,
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unsigned long srcfd, u64 off, u64 len, u64 destoff)
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{
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int rc;
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struct cifsFileInfo *smb_file_target = dst_file->private_data;
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struct inode *target_inode = file_inode(dst_file);
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struct cifs_tcon *target_tcon;
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struct fd src_file;
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struct cifsFileInfo *smb_file_src;
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struct inode *src_inode;
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struct cifs_tcon *src_tcon;
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cifs_dbg(FYI, "ioctl clone range\n");
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/* the destination must be opened for writing */
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if (!(dst_file->f_mode & FMODE_WRITE)) {
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cifs_dbg(FYI, "file target not open for write\n");
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return -EINVAL;
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}
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/* check if target volume is readonly and take reference */
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rc = mnt_want_write_file(dst_file);
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if (rc) {
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cifs_dbg(FYI, "mnt_want_write failed with rc %d\n", rc);
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return rc;
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}
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src_file = fdget(srcfd);
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if (!src_file.file) {
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rc = -EBADF;
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goto out_drop_write;
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}
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if ((!src_file.file->private_data) || (!dst_file->private_data)) {
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rc = -EBADF;
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cifs_dbg(VFS, "missing cifsFileInfo on copy range src file\n");
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goto out_fput;
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}
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rc = -EXDEV;
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smb_file_target = dst_file->private_data;
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smb_file_src = src_file.file->private_data;
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src_tcon = tlink_tcon(smb_file_src->tlink);
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target_tcon = tlink_tcon(smb_file_target->tlink);
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/* check if source and target are on same tree connection */
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if (src_tcon != target_tcon) {
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cifs_dbg(VFS, "file copy src and target on different volume\n");
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goto out_fput;
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}
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src_inode = file_inode(src_file.file);
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rc = -EINVAL;
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if (S_ISDIR(src_inode->i_mode))
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goto out_fput;
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/*
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* Note: cifs case is easier than btrfs since server responsible for
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* checks for proper open modes and file type and if it wants
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* server could even support copy of range where source = target
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*/
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lock_two_nondirectories(target_inode, src_inode);
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/* determine range to clone */
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rc = -EINVAL;
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if (off + len > src_inode->i_size || off + len < off)
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goto out_unlock;
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if (len == 0)
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len = src_inode->i_size - off;
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cifs_dbg(FYI, "about to flush pages\n");
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/* should we flush first and last page first */
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truncate_inode_pages_range(&target_inode->i_data, destoff,
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PAGE_CACHE_ALIGN(destoff + len)-1);
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if (target_tcon->ses->server->ops->clone_range)
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rc = target_tcon->ses->server->ops->clone_range(xid,
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smb_file_src, smb_file_target, off, len, destoff);
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/* force revalidate of size and timestamps of target file now
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that target is updated on the server */
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CIFS_I(target_inode)->time = 0;
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out_unlock:
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/* although unlocking in the reverse order from locking is not
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strictly necessary here it is a little cleaner to be consistent */
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unlock_two_nondirectories(src_inode, target_inode);
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out_fput:
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fdput(src_file);
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out_drop_write:
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mnt_drop_write_file(dst_file);
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return rc;
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}
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long cifs_ioctl(struct file *filep, unsigned int command, unsigned long arg)
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{
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struct inode *inode = file_inode(filep);
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int rc = -ENOTTY; /* strange error - but the precedent */
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unsigned int xid;
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struct cifs_sb_info *cifs_sb;
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struct cifsFileInfo *pSMBFile = filep->private_data;
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struct cifs_tcon *tcon;
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__u64 ExtAttrBits = 0;
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__u64 caps;
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xid = get_xid();
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cifs_dbg(FYI, "ioctl file %p cmd %u arg %lu\n", filep, command, arg);
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cifs_sb = CIFS_SB(inode->i_sb);
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switch (command) {
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case FS_IOC_GETFLAGS:
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if (pSMBFile == NULL)
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break;
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tcon = tlink_tcon(pSMBFile->tlink);
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caps = le64_to_cpu(tcon->fsUnixInfo.Capability);
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#ifdef CONFIG_CIFS_POSIX
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if (CIFS_UNIX_EXTATTR_CAP & caps) {
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__u64 ExtAttrMask = 0;
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rc = CIFSGetExtAttr(xid, tcon,
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pSMBFile->fid.netfid,
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&ExtAttrBits, &ExtAttrMask);
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if (rc == 0)
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rc = put_user(ExtAttrBits &
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FS_FL_USER_VISIBLE,
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(int __user *)arg);
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if (rc != EOPNOTSUPP)
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break;
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}
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#endif /* CONFIG_CIFS_POSIX */
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rc = 0;
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if (CIFS_I(inode)->cifsAttrs & ATTR_COMPRESSED) {
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/* add in the compressed bit */
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ExtAttrBits = FS_COMPR_FL;
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rc = put_user(ExtAttrBits & FS_FL_USER_VISIBLE,
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(int __user *)arg);
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}
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break;
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case FS_IOC_SETFLAGS:
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if (pSMBFile == NULL)
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break;
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tcon = tlink_tcon(pSMBFile->tlink);
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caps = le64_to_cpu(tcon->fsUnixInfo.Capability);
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if (get_user(ExtAttrBits, (int __user *)arg)) {
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rc = -EFAULT;
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break;
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}
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/*
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* if (CIFS_UNIX_EXTATTR_CAP & caps)
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* rc = CIFSSetExtAttr(xid, tcon,
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* pSMBFile->fid.netfid,
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* extAttrBits,
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* &ExtAttrMask);
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* if (rc != EOPNOTSUPP)
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* break;
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*/
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/* Currently only flag we can set is compressed flag */
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if ((ExtAttrBits & FS_COMPR_FL) == 0)
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break;
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/* Try to set compress flag */
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if (tcon->ses->server->ops->set_compression) {
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rc = tcon->ses->server->ops->set_compression(
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xid, tcon, pSMBFile);
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cifs_dbg(FYI, "set compress flag rc %d\n", rc);
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}
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break;
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case CIFS_IOC_COPYCHUNK_FILE:
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rc = cifs_ioctl_clone(xid, filep, arg, 0, 0, 0);
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break;
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default:
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cifs_dbg(FYI, "unsupported ioctl\n");
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break;
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}
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free_xid(xid);
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return rc;
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}
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