file.c 53.9 KB
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/*
 *   fs/cifs/file.c
 *
 *   vfs operations that deal with files
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 *
 *   Copyright (C) International Business Machines  Corp., 2002,2007
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 *   Author(s): Steve French (sfrench@us.ibm.com)
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 *              Jeremy Allison (jra@samba.org)
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 *
 *   This library is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Lesser General Public License as published
 *   by the Free Software Foundation; either version 2.1 of the License, or
 *   (at your option) any later version.
 *
 *   This library is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
 *   the GNU Lesser General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser General Public License
 *   along with this library; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
#include <linux/fs.h>
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#include <linux/backing-dev.h>
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#include <linux/stat.h>
#include <linux/fcntl.h>
#include <linux/pagemap.h>
#include <linux/pagevec.h>
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#include <linux/writeback.h>
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#include <linux/task_io_accounting_ops.h>
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#include <linux/delay.h>
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#include <asm/div64.h>
#include "cifsfs.h"
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_unicode.h"
#include "cifs_debug.h"
#include "cifs_fs_sb.h"

static inline struct cifsFileInfo *cifs_init_private(
	struct cifsFileInfo *private_data, struct inode *inode,
	struct file *file, __u16 netfid)
{
	memset(private_data, 0, sizeof(struct cifsFileInfo));
	private_data->netfid = netfid;
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	private_data->pid = current->tgid;
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	init_MUTEX(&private_data->fh_sem);
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	mutex_init(&private_data->lock_mutex);
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	INIT_LIST_HEAD(&private_data->llist);
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	private_data->pfile = file; /* needed for writepage */
	private_data->pInode = inode;
	private_data->invalidHandle = FALSE;
	private_data->closePend = FALSE;
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	/* we have to track num writers to the inode, since writepages
	does not tell us which handle the write is for so there can
	be a close (overlapping with write) of the filehandle that
	cifs_writepages chose to use */
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	atomic_set(&private_data->wrtPending, 0);
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	return private_data;
}

static inline int cifs_convert_flags(unsigned int flags)
{
	if ((flags & O_ACCMODE) == O_RDONLY)
		return GENERIC_READ;
	else if ((flags & O_ACCMODE) == O_WRONLY)
		return GENERIC_WRITE;
	else if ((flags & O_ACCMODE) == O_RDWR) {
		/* GENERIC_ALL is too much permission to request
		   can cause unnecessary access denied on create */
		/* return GENERIC_ALL; */
		return (GENERIC_READ | GENERIC_WRITE);
	}

	return 0x20197;
}

static inline int cifs_get_disposition(unsigned int flags)
{
	if ((flags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
		return FILE_CREATE;
	else if ((flags & (O_CREAT | O_TRUNC)) == (O_CREAT | O_TRUNC))
		return FILE_OVERWRITE_IF;
	else if ((flags & O_CREAT) == O_CREAT)
		return FILE_OPEN_IF;
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	else if ((flags & O_TRUNC) == O_TRUNC)
		return FILE_OVERWRITE;
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	else
		return FILE_OPEN;
}

/* all arguments to this function must be checked for validity in caller */
static inline int cifs_open_inode_helper(struct inode *inode, struct file *file,
	struct cifsInodeInfo *pCifsInode, struct cifsFileInfo *pCifsFile,
	struct cifsTconInfo *pTcon, int *oplock, FILE_ALL_INFO *buf,
	char *full_path, int xid)
{
	struct timespec temp;
	int rc;

	/* want handles we can use to read with first
	   in the list so we do not have to walk the
	   list to search for one in prepare_write */
	if ((file->f_flags & O_ACCMODE) == O_WRONLY) {
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		list_add_tail(&pCifsFile->flist,
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			      &pCifsInode->openFileList);
	} else {
		list_add(&pCifsFile->flist,
			 &pCifsInode->openFileList);
	}
	write_unlock(&GlobalSMBSeslock);
	if (pCifsInode->clientCanCacheRead) {
		/* we have the inode open somewhere else
		   no need to discard cache data */
		goto client_can_cache;
	}

	/* BB need same check in cifs_create too? */
	/* if not oplocked, invalidate inode pages if mtime or file
	   size changed */
	temp = cifs_NTtimeToUnix(le64_to_cpu(buf->LastWriteTime));
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	if (timespec_equal(&file->f_path.dentry->d_inode->i_mtime, &temp) &&
			   (file->f_path.dentry->d_inode->i_size ==
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			    (loff_t)le64_to_cpu(buf->EndOfFile))) {
		cFYI(1, ("inode unchanged on server"));
	} else {
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		if (file->f_path.dentry->d_inode->i_mapping) {
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		/* BB no need to lock inode until after invalidate
		   since namei code should already have it locked? */
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			filemap_write_and_wait(file->f_path.dentry->d_inode->i_mapping);
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		}
		cFYI(1, ("invalidating remote inode since open detected it "
			 "changed"));
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		invalidate_remote_inode(file->f_path.dentry->d_inode);
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	}

client_can_cache:
	if (pTcon->ses->capabilities & CAP_UNIX)
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		rc = cifs_get_inode_info_unix(&file->f_path.dentry->d_inode,
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			full_path, inode->i_sb, xid);
	else
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		rc = cifs_get_inode_info(&file->f_path.dentry->d_inode,
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			full_path, buf, inode->i_sb, xid);

	if ((*oplock & 0xF) == OPLOCK_EXCLUSIVE) {
		pCifsInode->clientCanCacheAll = TRUE;
		pCifsInode->clientCanCacheRead = TRUE;
		cFYI(1, ("Exclusive Oplock granted on inode %p",
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			 file->f_path.dentry->d_inode));
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	} else if ((*oplock & 0xF) == OPLOCK_READ)
		pCifsInode->clientCanCacheRead = TRUE;

	return rc;
}

int cifs_open(struct inode *inode, struct file *file)
{
	int rc = -EACCES;
	int xid, oplock;
	struct cifs_sb_info *cifs_sb;
	struct cifsTconInfo *pTcon;
	struct cifsFileInfo *pCifsFile;
	struct cifsInodeInfo *pCifsInode;
	struct list_head *tmp;
	char *full_path = NULL;
	int desiredAccess;
	int disposition;
	__u16 netfid;
	FILE_ALL_INFO *buf = NULL;

	xid = GetXid();

	cifs_sb = CIFS_SB(inode->i_sb);
	pTcon = cifs_sb->tcon;

	if (file->f_flags & O_CREAT) {
		/* search inode for this file and fill in file->private_data */
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		pCifsInode = CIFS_I(file->f_path.dentry->d_inode);
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		read_lock(&GlobalSMBSeslock);
		list_for_each(tmp, &pCifsInode->openFileList) {
			pCifsFile = list_entry(tmp, struct cifsFileInfo,
					       flist);
			if ((pCifsFile->pfile == NULL) &&
			    (pCifsFile->pid == current->tgid)) {
				/* mode set in cifs_create */

				/* needed for writepage */
				pCifsFile->pfile = file;
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				file->private_data = pCifsFile;
				break;
			}
		}
		read_unlock(&GlobalSMBSeslock);
		if (file->private_data != NULL) {
			rc = 0;
			FreeXid(xid);
			return rc;
		} else {
			if (file->f_flags & O_EXCL)
				cERROR(1, ("could not find file instance for "
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					   "new file %p", file));
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		}
	}

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	full_path = build_path_from_dentry(file->f_path.dentry);
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	if (full_path == NULL) {
		FreeXid(xid);
		return -ENOMEM;
	}

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	cFYI(1, ("inode = 0x%p file flags are 0x%x for %s",
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		 inode, file->f_flags, full_path));
	desiredAccess = cifs_convert_flags(file->f_flags);

/*********************************************************************
 *  open flag mapping table:
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 *
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 *	POSIX Flag            CIFS Disposition
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 *	----------            ----------------
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 *	O_CREAT               FILE_OPEN_IF
 *	O_CREAT | O_EXCL      FILE_CREATE
 *	O_CREAT | O_TRUNC     FILE_OVERWRITE_IF
 *	O_TRUNC               FILE_OVERWRITE
 *	none of the above     FILE_OPEN
 *
 *	Note that there is not a direct match between disposition
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 *	FILE_SUPERSEDE (ie create whether or not file exists although
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 *	O_CREAT | O_TRUNC is similar but truncates the existing
 *	file rather than creating a new file as FILE_SUPERSEDE does
 *	(which uses the attributes / metadata passed in on open call)
 *?
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 *?  O_SYNC is a reasonable match to CIFS writethrough flag
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 *?  and the read write flags match reasonably.  O_LARGEFILE
 *?  is irrelevant because largefile support is always used
 *?  by this client. Flags O_APPEND, O_DIRECT, O_DIRECTORY,
 *	 O_FASYNC, O_NOFOLLOW, O_NONBLOCK need further investigation
 *********************************************************************/

	disposition = cifs_get_disposition(file->f_flags);

	if (oplockEnabled)
		oplock = REQ_OPLOCK;
	else
		oplock = FALSE;

	/* BB pass O_SYNC flag through on file attributes .. BB */

	/* Also refresh inode by passing in file_info buf returned by SMBOpen
	   and calling get_inode_info with returned buf (at least helps
	   non-Unix server case) */

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	/* BB we can not do this if this is the second open of a file
	   and the first handle has writebehind data, we might be
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	   able to simply do a filemap_fdatawrite/filemap_fdatawait first */
	buf = kmalloc(sizeof(FILE_ALL_INFO), GFP_KERNEL);
	if (!buf) {
		rc = -ENOMEM;
		goto out;
	}
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	if (cifs_sb->tcon->ses->capabilities & CAP_NT_SMBS)
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		rc = CIFSSMBOpen(xid, pTcon, full_path, disposition,
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			 desiredAccess, CREATE_NOT_DIR, &netfid, &oplock, buf,
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			 cifs_sb->local_nls, cifs_sb->mnt_cifs_flags
				 & CIFS_MOUNT_MAP_SPECIAL_CHR);
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	else
		rc = -EIO; /* no NT SMB support fall into legacy open below */

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	if (rc == -EIO) {
		/* Old server, try legacy style OpenX */
		rc = SMBLegacyOpen(xid, pTcon, full_path, disposition,
			desiredAccess, CREATE_NOT_DIR, &netfid, &oplock, buf,
			cifs_sb->local_nls, cifs_sb->mnt_cifs_flags
				& CIFS_MOUNT_MAP_SPECIAL_CHR);
	}
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	if (rc) {
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		cFYI(1, ("cifs_open returned 0x%x", rc));
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		goto out;
	}
	file->private_data =
		kmalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
	if (file->private_data == NULL) {
		rc = -ENOMEM;
		goto out;
	}
	pCifsFile = cifs_init_private(file->private_data, inode, file, netfid);
	write_lock(&GlobalSMBSeslock);
	list_add(&pCifsFile->tlist, &pTcon->openFileList);

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	pCifsInode = CIFS_I(file->f_path.dentry->d_inode);
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	if (pCifsInode) {
		rc = cifs_open_inode_helper(inode, file, pCifsInode,
					    pCifsFile, pTcon,
					    &oplock, buf, full_path, xid);
	} else {
		write_unlock(&GlobalSMBSeslock);
	}

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	if (oplock & CIFS_CREATE_ACTION) {
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		/* time to set mode which we can not set earlier due to
		   problems creating new read-only files */
		if (cifs_sb->tcon->ses->capabilities & CAP_UNIX) {
			CIFSSMBUnixSetPerms(xid, pTcon, full_path,
					    inode->i_mode,
					    (__u64)-1, (__u64)-1, 0 /* dev */,
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					    cifs_sb->local_nls,
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					    cifs_sb->mnt_cifs_flags &
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						CIFS_MOUNT_MAP_SPECIAL_CHR);
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		} else {
			/* BB implement via Windows security descriptors eg
			   CIFSSMBWinSetPerms(xid, pTcon, full_path, mode,
					      -1, -1, local_nls);
			   in the meantime could set r/o dos attribute when
			   perms are eg: mode & 0222 == 0 */
		}
	}

out:
	kfree(buf);
	kfree(full_path);
	FreeXid(xid);
	return rc;
}

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/* Try to reacquire byte range locks that were released when session */
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/* to server was lost */
static int cifs_relock_file(struct cifsFileInfo *cifsFile)
{
	int rc = 0;

/* BB list all locks open on this file and relock */

	return rc;
}

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static int cifs_reopen_file(struct file *file, int can_flush)
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{
	int rc = -EACCES;
	int xid, oplock;
	struct cifs_sb_info *cifs_sb;
	struct cifsTconInfo *pTcon;
	struct cifsFileInfo *pCifsFile;
	struct cifsInodeInfo *pCifsInode;
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	struct inode *inode;
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	char *full_path = NULL;
	int desiredAccess;
	int disposition = FILE_OPEN;
	__u16 netfid;

	if (file->private_data) {
		pCifsFile = (struct cifsFileInfo *)file->private_data;
	} else
		return -EBADF;

	xid = GetXid();
	down(&pCifsFile->fh_sem);
	if (pCifsFile->invalidHandle == FALSE) {
		up(&pCifsFile->fh_sem);
		FreeXid(xid);
		return 0;
	}

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	if (file->f_path.dentry == NULL) {
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		cERROR(1, ("no valid name if dentry freed"));
		dump_stack();
		rc = -EBADF;
		goto reopen_error_exit;
	}

	inode = file->f_path.dentry->d_inode;
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	if (inode == NULL) {
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		cERROR(1, ("inode not valid"));
		dump_stack();
		rc = -EBADF;
		goto reopen_error_exit;
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	}
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	cifs_sb = CIFS_SB(inode->i_sb);
	pTcon = cifs_sb->tcon;
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/* can not grab rename sem here because various ops, including
   those that already have the rename sem can end up causing writepage
   to get called and if the server was down that means we end up here,
   and we can never tell if the caller already has the rename_sem */
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	full_path = build_path_from_dentry(file->f_path.dentry);
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	if (full_path == NULL) {
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		rc = -ENOMEM;
reopen_error_exit:
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		up(&pCifsFile->fh_sem);
		FreeXid(xid);
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		return rc;
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	}

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	cFYI(1, ("inode = 0x%p file flags 0x%x for %s",
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		 inode, file->f_flags, full_path));
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	desiredAccess = cifs_convert_flags(file->f_flags);

	if (oplockEnabled)
		oplock = REQ_OPLOCK;
	else
		oplock = FALSE;

	/* Can not refresh inode by passing in file_info buf to be returned
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	   by SMBOpen and then calling get_inode_info with returned buf
	   since file might have write behind data that needs to be flushed
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	   and server version of file size can be stale. If we knew for sure
	   that inode was not dirty locally we could do this */

	rc = CIFSSMBOpen(xid, pTcon, full_path, disposition, desiredAccess,
			 CREATE_NOT_DIR, &netfid, &oplock, NULL,
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			 cifs_sb->local_nls, cifs_sb->mnt_cifs_flags &
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				CIFS_MOUNT_MAP_SPECIAL_CHR);
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	if (rc) {
		up(&pCifsFile->fh_sem);
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		cFYI(1, ("cifs_open returned 0x%x", rc));
		cFYI(1, ("oplock: %d", oplock));
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	} else {
		pCifsFile->netfid = netfid;
		pCifsFile->invalidHandle = FALSE;
		up(&pCifsFile->fh_sem);
		pCifsInode = CIFS_I(inode);
		if (pCifsInode) {
			if (can_flush) {
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				filemap_write_and_wait(inode->i_mapping);
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			/* temporarily disable caching while we
			   go to server to get inode info */
				pCifsInode->clientCanCacheAll = FALSE;
				pCifsInode->clientCanCacheRead = FALSE;
				if (pTcon->ses->capabilities & CAP_UNIX)
					rc = cifs_get_inode_info_unix(&inode,
						full_path, inode->i_sb, xid);
				else
					rc = cifs_get_inode_info(&inode,
						full_path, NULL, inode->i_sb,
						xid);
			} /* else we are writing out data to server already
			     and could deadlock if we tried to flush data, and
			     since we do not know if we have data that would
			     invalidate the current end of file on the server
			     we can not go to the server to get the new inod
			     info */
			if ((oplock & 0xF) == OPLOCK_EXCLUSIVE) {
				pCifsInode->clientCanCacheAll = TRUE;
				pCifsInode->clientCanCacheRead = TRUE;
				cFYI(1, ("Exclusive Oplock granted on inode %p",
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					 file->f_path.dentry->d_inode));
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			} else if ((oplock & 0xF) == OPLOCK_READ) {
				pCifsInode->clientCanCacheRead = TRUE;
				pCifsInode->clientCanCacheAll = FALSE;
			} else {
				pCifsInode->clientCanCacheRead = FALSE;
				pCifsInode->clientCanCacheAll = FALSE;
			}
			cifs_relock_file(pCifsFile);
		}
	}

	kfree(full_path);
	FreeXid(xid);
	return rc;
}

int cifs_close(struct inode *inode, struct file *file)
{
	int rc = 0;
	int xid;
	struct cifs_sb_info *cifs_sb;
	struct cifsTconInfo *pTcon;
	struct cifsFileInfo *pSMBFile =
		(struct cifsFileInfo *)file->private_data;

	xid = GetXid();

	cifs_sb = CIFS_SB(inode->i_sb);
	pTcon = cifs_sb->tcon;
	if (pSMBFile) {
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		struct cifsLockInfo *li, *tmp;

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		pSMBFile->closePend = TRUE;
		if (pTcon) {
			/* no sense reconnecting to close a file that is
			   already closed */
			if (pTcon->tidStatus != CifsNeedReconnect) {
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				int timeout = 2;
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				while ((atomic_read(&pSMBFile->wrtPending) != 0)
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					 && (timeout < 1000) ) {
					/* Give write a better chance to get to
					server ahead of the close.  We do not
					want to add a wait_q here as it would
					increase the memory utilization as
					the struct would be in each open file,
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					but this should give enough time to
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					clear the socket */
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#ifdef CONFIG_CIFS_DEBUG2
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					cFYI(1, ("close delay, write pending"));
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#endif /* DEBUG2 */
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					msleep(timeout);
					timeout *= 4;
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				}
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				if (atomic_read(&pSMBFile->wrtPending))
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					cERROR(1,("close with pending writes"));
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				rc = CIFSSMBClose(xid, pTcon,
						  pSMBFile->netfid);
			}
		}
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		/* Delete any outstanding lock records.
		   We'll lose them when the file is closed anyway. */
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		mutex_lock(&pSMBFile->lock_mutex);
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		list_for_each_entry_safe(li, tmp, &pSMBFile->llist, llist) {
			list_del(&li->llist);
			kfree(li);
		}
518
		mutex_unlock(&pSMBFile->lock_mutex);
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520
		write_lock(&GlobalSMBSeslock);
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		list_del(&pSMBFile->flist);
		list_del(&pSMBFile->tlist);
523
		write_unlock(&GlobalSMBSeslock);
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		kfree(pSMBFile->search_resume_name);
		kfree(file->private_data);
		file->private_data = NULL;
	} else
		rc = -EBADF;

	if (list_empty(&(CIFS_I(inode)->openFileList))) {
		cFYI(1, ("closing last open instance for inode %p", inode));
		/* if the file is not open we do not know if we can cache info
		   on this inode, much less write behind and read ahead */
		CIFS_I(inode)->clientCanCacheRead = FALSE;
		CIFS_I(inode)->clientCanCacheAll  = FALSE;
	}
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	if ((rc == 0) && CIFS_I(inode)->write_behind_rc)
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		rc = CIFS_I(inode)->write_behind_rc;
	FreeXid(xid);
	return rc;
}

int cifs_closedir(struct inode *inode, struct file *file)
{
	int rc = 0;
	int xid;
	struct cifsFileInfo *pCFileStruct =
	    (struct cifsFileInfo *)file->private_data;
	char *ptmp;

551
	cFYI(1, ("Closedir inode = 0x%p", inode));
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	xid = GetXid();

	if (pCFileStruct) {
		struct cifsTconInfo *pTcon;
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		struct cifs_sb_info *cifs_sb =
			CIFS_SB(file->f_path.dentry->d_sb);
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		pTcon = cifs_sb->tcon;

		cFYI(1, ("Freeing private data in close dir"));
563 564
		if ((pCFileStruct->srch_inf.endOfSearch == FALSE) &&
		   (pCFileStruct->invalidHandle == FALSE)) {
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			pCFileStruct->invalidHandle = TRUE;
			rc = CIFSFindClose(xid, pTcon, pCFileStruct->netfid);
			cFYI(1, ("Closing uncompleted readdir with rc %d",
				 rc));
			/* not much we can do if it fails anyway, ignore rc */
			rc = 0;
		}
		ptmp = pCFileStruct->srch_inf.ntwrk_buf_start;
		if (ptmp) {
574
			cFYI(1, ("closedir free smb buf in srch struct"));
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			pCFileStruct->srch_inf.ntwrk_buf_start = NULL;
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			if (pCFileStruct->srch_inf.smallBuf)
577 578 579
				cifs_small_buf_release(ptmp);
			else
				cifs_buf_release(ptmp);
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		}
		ptmp = pCFileStruct->search_resume_name;
		if (ptmp) {
583
			cFYI(1, ("closedir free resume name"));
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			pCFileStruct->search_resume_name = NULL;
			kfree(ptmp);
		}
		kfree(file->private_data);
		file->private_data = NULL;
	}
	/* BB can we lock the filestruct while this is going on? */
	FreeXid(xid);
	return rc;
}

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static int store_file_lock(struct cifsFileInfo *fid, __u64 len,
				__u64 offset, __u8 lockType)
{
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	struct cifsLockInfo *li =
		kmalloc(sizeof(struct cifsLockInfo), GFP_KERNEL);
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	if (li == NULL)
		return -ENOMEM;
	li->offset = offset;
	li->length = len;
	li->type = lockType;
605
	mutex_lock(&fid->lock_mutex);
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	list_add(&li->llist, &fid->llist);
607
	mutex_unlock(&fid->lock_mutex);
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	return 0;
}

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int cifs_lock(struct file *file, int cmd, struct file_lock *pfLock)
{
	int rc, xid;
	__u32 numLock = 0;
	__u32 numUnlock = 0;
	__u64 length;
	int wait_flag = FALSE;
	struct cifs_sb_info *cifs_sb;
	struct cifsTconInfo *pTcon;
620 621
	__u16 netfid;
	__u8 lockType = LOCKING_ANDX_LARGE_FILES;
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	int posix_locking;
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	length = 1 + pfLock->fl_end - pfLock->fl_start;
	rc = -EACCES;
	xid = GetXid();

	cFYI(1, ("Lock parm: 0x%x flockflags: "
		 "0x%x flocktype: 0x%x start: %lld end: %lld",
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		cmd, pfLock->fl_flags, pfLock->fl_type, pfLock->fl_start,
		pfLock->fl_end));
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	if (pfLock->fl_flags & FL_POSIX)
634
		cFYI(1, ("Posix"));
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	if (pfLock->fl_flags & FL_FLOCK)
636
		cFYI(1, ("Flock"));
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	if (pfLock->fl_flags & FL_SLEEP) {
638
		cFYI(1, ("Blocking lock"));
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		wait_flag = TRUE;
	}
	if (pfLock->fl_flags & FL_ACCESS)
		cFYI(1, ("Process suspended by mandatory locking - "
643
			 "not implemented yet"));
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	if (pfLock->fl_flags & FL_LEASE)
		cFYI(1, ("Lease on file - not implemented yet"));
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	if (pfLock->fl_flags &
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	    (~(FL_POSIX | FL_FLOCK | FL_SLEEP | FL_ACCESS | FL_LEASE)))
		cFYI(1, ("Unknown lock flags 0x%x", pfLock->fl_flags));

	if (pfLock->fl_type == F_WRLCK) {
		cFYI(1, ("F_WRLCK "));
		numLock = 1;
	} else if (pfLock->fl_type == F_UNLCK) {
654
		cFYI(1, ("F_UNLCK"));
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		numUnlock = 1;
656 657
		/* Check if unlock includes more than
		one lock range */
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	} else if (pfLock->fl_type == F_RDLCK) {
659
		cFYI(1, ("F_RDLCK"));
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		lockType |= LOCKING_ANDX_SHARED_LOCK;
		numLock = 1;
	} else if (pfLock->fl_type == F_EXLCK) {
663
		cFYI(1, ("F_EXLCK"));
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		numLock = 1;
	} else if (pfLock->fl_type == F_SHLCK) {
666
		cFYI(1, ("F_SHLCK"));
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		lockType |= LOCKING_ANDX_SHARED_LOCK;
		numLock = 1;
	} else
670
		cFYI(1, ("Unknown type of lock"));
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672
	cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
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	pTcon = cifs_sb->tcon;

	if (file->private_data == NULL) {
		FreeXid(xid);
		return -EBADF;
	}
679 680
	netfid = ((struct cifsFileInfo *)file->private_data)->netfid;

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	posix_locking = (cifs_sb->tcon->ses->capabilities & CAP_UNIX) &&
			(CIFS_UNIX_FCNTL_CAP & le64_to_cpu(cifs_sb->tcon->fsUnixInfo.Capability));
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684 685 686
	/* BB add code here to normalize offset and length to
	account for negative length which we can not accept over the
	wire */
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	if (IS_GETLK(cmd)) {
S
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		if (posix_locking) {
689
			int posix_lock_type;
S
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			if (lockType & LOCKING_ANDX_SHARED_LOCK)
691 692 693 694
				posix_lock_type = CIFS_RDLCK;
			else
				posix_lock_type = CIFS_WRLCK;
			rc = CIFSSMBPosixLock(xid, pTcon, netfid, 1 /* get */,
695
					length,	pfLock,
696 697 698 699 700 701 702 703
					posix_lock_type, wait_flag);
			FreeXid(xid);
			return rc;
		}

		/* BB we could chain these into one lock request BB */
		rc = CIFSSMBLock(xid, pTcon, netfid, length, pfLock->fl_start,
				 0, 1, lockType, 0 /* wait flag */ );
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		if (rc == 0) {
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			rc = CIFSSMBLock(xid, pTcon, netfid, length,
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					 pfLock->fl_start, 1 /* numUnlock */ ,
					 0 /* numLock */ , lockType,
					 0 /* wait flag */ );
			pfLock->fl_type = F_UNLCK;
			if (rc != 0)
				cERROR(1, ("Error unlocking previously locked "
712
					   "range %d during test of lock", rc));
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			rc = 0;

		} else {
			/* if rc == ERR_SHARING_VIOLATION ? */
			rc = 0;	/* do not change lock type to unlock
				   since range in use */
		}

		FreeXid(xid);
		return rc;
	}
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	if (!numLock && !numUnlock) {
		/* if no lock or unlock then nothing
		to do since we do not know what it is */
		FreeXid(xid);
		return -EOPNOTSUPP;
	}

	if (posix_locking) {
733
		int posix_lock_type;
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		if (lockType & LOCKING_ANDX_SHARED_LOCK)
735 736 737
			posix_lock_type = CIFS_RDLCK;
		else
			posix_lock_type = CIFS_WRLCK;
738

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		if (numUnlock == 1)
740
			posix_lock_type = CIFS_UNLCK;
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Jeremy Allison 已提交
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742
		rc = CIFSSMBPosixLock(xid, pTcon, netfid, 0 /* set */,
743
				      length, pfLock,
744
				      posix_lock_type, wait_flag);
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Jeremy Allison 已提交
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	} else {
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		struct cifsFileInfo *fid =
			(struct cifsFileInfo *)file->private_data;
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Jeremy Allison 已提交
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		if (numLock) {
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			rc = CIFSSMBLock(xid, pTcon, netfid, length,
					pfLock->fl_start,
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					0, numLock, lockType, wait_flag);

			if (rc == 0) {
				/* For Windows locks we must store them. */
				rc = store_file_lock(fid, length,
						pfLock->fl_start, lockType);
			}
		} else if (numUnlock) {
			/* For each stored lock that this unlock overlaps
			   completely, unlock it. */
			int stored_rc = 0;
			struct cifsLockInfo *li, *tmp;

765
			rc = 0;
766
			mutex_lock(&fid->lock_mutex);
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			list_for_each_entry_safe(li, tmp, &fid->llist, llist) {
				if (pfLock->fl_start <= li->offset &&
						length >= li->length) {
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					stored_rc = CIFSSMBLock(xid, pTcon,
							netfid,
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							li->length, li->offset,
							1, 0, li->type, FALSE);
					if (stored_rc)
						rc = stored_rc;

					list_del(&li->llist);
					kfree(li);
				}
			}
781
			mutex_unlock(&fid->lock_mutex);
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		}
	}

785
	if (pfLock->fl_flags & FL_POSIX)
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		posix_lock_file_wait(file, pfLock);
	FreeXid(xid);
	return rc;
}

ssize_t cifs_user_write(struct file *file, const char __user *write_data,
	size_t write_size, loff_t *poffset)
{
	int rc = 0;
	unsigned int bytes_written = 0;
	unsigned int total_written;
	struct cifs_sb_info *cifs_sb;
	struct cifsTconInfo *pTcon;
	int xid, long_op;
	struct cifsFileInfo *open_file;

802
	cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
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	pTcon = cifs_sb->tcon;

	/* cFYI(1,
	   (" write %d bytes to offset %lld of %s", write_size,
808
	   *poffset, file->f_path.dentry->d_name.name)); */
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	if (file->private_data == NULL)
		return -EBADF;
812
	open_file = (struct cifsFileInfo *) file->private_data;
813

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	xid = GetXid();

816
	if (*poffset > file->f_path.dentry->d_inode->i_size)
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		long_op = 2; /* writes past end of file can take a long time */
	else
		long_op = 1;

	for (total_written = 0; write_size > total_written;
	     total_written += bytes_written) {
		rc = -EAGAIN;
		while (rc == -EAGAIN) {
			if (file->private_data == NULL) {
				/* file has been closed on us */
				FreeXid(xid);
			/* if we have gotten here we have written some data
			   and blocked, and the file has been freed on us while
			   we blocked so return what we managed to write */
				return total_written;
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			}
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			if (open_file->closePend) {
				FreeXid(xid);
				if (total_written)
					return total_written;
				else
					return -EBADF;
			}
			if (open_file->invalidHandle) {
				/* we could deadlock if we called
				   filemap_fdatawait from here so tell
				   reopen_file not to flush data to server
				   now */
845
				rc = cifs_reopen_file(file, FALSE);
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				if (rc != 0)
					break;
			}

			rc = CIFSSMBWrite(xid, pTcon,
				open_file->netfid,
				min_t(const int, cifs_sb->wsize,
				      write_size - total_written),
				*poffset, &bytes_written,
				NULL, write_data + total_written, long_op);
		}
		if (rc || (bytes_written == 0)) {
			if (total_written)
				break;
			else {
				FreeXid(xid);
				return rc;
			}
		} else
			*poffset += bytes_written;
		long_op = FALSE; /* subsequent writes fast -
				    15 seconds is plenty */
	}

870
	cifs_stats_bytes_written(pTcon, total_written);
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	/* since the write may have blocked check these pointers again */
873 874
	if ((file->f_path.dentry) && (file->f_path.dentry->d_inode)) {
		struct inode *inode = file->f_path.dentry->d_inode;
S
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/* Do not update local mtime - server will set its actual value on write
 *		inode->i_ctime = inode->i_mtime =
877 878 879 880 881
 * 			current_fs_time(inode->i_sb);*/
		if (total_written > 0) {
			spin_lock(&inode->i_lock);
			if (*poffset > file->f_path.dentry->d_inode->i_size)
				i_size_write(file->f_path.dentry->d_inode,
L
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					*poffset);
883
			spin_unlock(&inode->i_lock);
L
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884
		}
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		mark_inode_dirty_sync(file->f_path.dentry->d_inode);
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	}
	FreeXid(xid);
	return total_written;
}

static ssize_t cifs_write(struct file *file, const char *write_data,
	size_t write_size, loff_t *poffset)
{
	int rc = 0;
	unsigned int bytes_written = 0;
	unsigned int total_written;
	struct cifs_sb_info *cifs_sb;
	struct cifsTconInfo *pTcon;
	int xid, long_op;
	struct cifsFileInfo *open_file;

902
	cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
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	pTcon = cifs_sb->tcon;

S
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906
	cFYI(1, ("write %zd bytes to offset %lld of %s", write_size,
907
	   *poffset, file->f_path.dentry->d_name.name));
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	if (file->private_data == NULL)
		return -EBADF;
911
	open_file = (struct cifsFileInfo *)file->private_data;
912

L
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913 914
	xid = GetXid();

915
	if (*poffset > file->f_path.dentry->d_inode->i_size)
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916 917 918 919 920 921 922 923 924 925 926 927 928
		long_op = 2; /* writes past end of file can take a long time */
	else
		long_op = 1;

	for (total_written = 0; write_size > total_written;
	     total_written += bytes_written) {
		rc = -EAGAIN;
		while (rc == -EAGAIN) {
			if (file->private_data == NULL) {
				/* file has been closed on us */
				FreeXid(xid);
			/* if we have gotten here we have written some data
			   and blocked, and the file has been freed on us
S
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			   while we blocked so return what we managed to
L
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			   write */
				return total_written;
S
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			}
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			if (open_file->closePend) {
				FreeXid(xid);
				if (total_written)
					return total_written;
				else
					return -EBADF;
			}
			if (open_file->invalidHandle) {
				/* we could deadlock if we called
				   filemap_fdatawait from here so tell
S
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				   reopen_file not to flush data to
L
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				   server now */
945
				rc = cifs_reopen_file(file, FALSE);
L
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946 947 948
				if (rc != 0)
					break;
			}
S
Steve French 已提交
949 950
			if (experimEnabled || (pTcon->ses->server &&
				((pTcon->ses->server->secMode &
S
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951
				(SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
S
Steve French 已提交
952
				== 0))) {
953 954 955
				struct kvec iov[2];
				unsigned int len;

956
				len = min((size_t)cifs_sb->wsize,
957 958 959 960 961
					  write_size - total_written);
				/* iov[0] is reserved for smb header */
				iov[1].iov_base = (char *)write_data +
						  total_written;
				iov[1].iov_len = len;
962
				rc = CIFSSMBWrite2(xid, pTcon,
963
						open_file->netfid, len,
964
						*poffset, &bytes_written,
965
						iov, 1, long_op);
966
			} else
967 968 969 970 971 972 973
				rc = CIFSSMBWrite(xid, pTcon,
					 open_file->netfid,
					 min_t(const int, cifs_sb->wsize,
					       write_size - total_written),
					 *poffset, &bytes_written,
					 write_data + total_written,
					 NULL, long_op);
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		}
		if (rc || (bytes_written == 0)) {
			if (total_written)
				break;
			else {
				FreeXid(xid);
				return rc;
			}
		} else
			*poffset += bytes_written;
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984
		long_op = FALSE; /* subsequent writes fast -
L
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985 986 987
				    15 seconds is plenty */
	}

988
	cifs_stats_bytes_written(pTcon, total_written);
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Linus Torvalds 已提交
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	/* since the write may have blocked check these pointers again */
991
	if ((file->f_path.dentry) && (file->f_path.dentry->d_inode)) {
992
/*BB We could make this contingent on superblock ATIME flag too */
993 994 995 996 997 998 999 1000
/*		file->f_path.dentry->d_inode->i_ctime =
		file->f_path.dentry->d_inode->i_mtime = CURRENT_TIME;*/
		if (total_written > 0) {
			spin_lock(&file->f_path.dentry->d_inode->i_lock);
			if (*poffset > file->f_path.dentry->d_inode->i_size)
				i_size_write(file->f_path.dentry->d_inode,
					     *poffset);
			spin_unlock(&file->f_path.dentry->d_inode->i_lock);
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		}
1002
		mark_inode_dirty_sync(file->f_path.dentry->d_inode);
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	}
	FreeXid(xid);
	return total_written;
}

1008
struct cifsFileInfo *find_writable_file(struct cifsInodeInfo *cifs_inode)
1009 1010
{
	struct cifsFileInfo *open_file;
1011
	int rc;
1012

1013 1014 1015 1016
	/* Having a null inode here (because mapping->host was set to zero by
	the VFS or MM) should not happen but we had reports of on oops (due to
	it being zero) during stress testcases so we need to check for it */

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	if (cifs_inode == NULL) {
		cERROR(1, ("Null inode passed to cifs_writeable_file"));
1019 1020 1021 1022
		dump_stack();
		return NULL;
	}

1023 1024 1025 1026 1027 1028 1029
	read_lock(&GlobalSMBSeslock);
	list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
		if (open_file->closePend)
			continue;
		if (open_file->pfile &&
		    ((open_file->pfile->f_flags & O_RDWR) ||
		     (open_file->pfile->f_flags & O_WRONLY))) {
1030
			atomic_inc(&open_file->wrtPending);
1031
			read_unlock(&GlobalSMBSeslock);
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			if ((open_file->invalidHandle) &&
1033
			   (!open_file->closePend) /* BB fixme -since the second clause can not be true remove it BB */) {
1034
				rc = cifs_reopen_file(open_file->pfile, FALSE);
1035 1036
				/* if it fails, try another handle - might be */
				/* dangerous to hold up writepages with retry */
S
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1037
				if (rc) {
1038 1039
					cFYI(1,
					      ("failed on reopen file in wp"));
1040
					read_lock(&GlobalSMBSeslock);
1041 1042 1043 1044
					/* can not use this handle, no write
					pending on this one after all */
					atomic_dec
					     (&open_file->wrtPending);
1045 1046 1047
					continue;
				}
			}
1048 1049 1050 1051 1052 1053 1054
			return open_file;
		}
	}
	read_unlock(&GlobalSMBSeslock);
	return NULL;
}

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static int cifs_partialpagewrite(struct page *page, unsigned from, unsigned to)
{
	struct address_space *mapping = page->mapping;
	loff_t offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
	char *write_data;
	int rc = -EFAULT;
	int bytes_written = 0;
	struct cifs_sb_info *cifs_sb;
	struct cifsTconInfo *pTcon;
	struct inode *inode;
1065
	struct cifsFileInfo *open_file;
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1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090

	if (!mapping || !mapping->host)
		return -EFAULT;

	inode = page->mapping->host;
	cifs_sb = CIFS_SB(inode->i_sb);
	pTcon = cifs_sb->tcon;

	offset += (loff_t)from;
	write_data = kmap(page);
	write_data += from;

	if ((to > PAGE_CACHE_SIZE) || (from > to)) {
		kunmap(page);
		return -EIO;
	}

	/* racing with truncate? */
	if (offset > mapping->host->i_size) {
		kunmap(page);
		return 0; /* don't care */
	}

	/* check to make sure that we are not extending the file */
	if (mapping->host->i_size - offset < (loff_t)to)
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		to = (unsigned)(mapping->host->i_size - offset);
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1093 1094 1095 1096
	open_file = find_writable_file(CIFS_I(mapping->host));
	if (open_file) {
		bytes_written = cifs_write(open_file->pfile, write_data,
					   to-from, &offset);
1097
		atomic_dec(&open_file->wrtPending);
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		/* Does mm or vfs already set times? */
1099 1100 1101 1102 1103 1104
		inode->i_atime = inode->i_mtime = current_fs_time(inode->i_sb);
		if ((bytes_written > 0) && (offset)) {
			rc = 0;
		} else if (bytes_written < 0) {
			if (rc != -EBADF)
				rc = bytes_written;
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		}
1106
	} else {
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		cFYI(1, ("No writeable filehandles for inode"));
		rc = -EIO;
	}

	kunmap(page);
	return rc;
}

static int cifs_writepages(struct address_space *mapping,
1116
			   struct writeback_control *wbc)
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{
1118 1119 1120 1121 1122
	struct backing_dev_info *bdi = mapping->backing_dev_info;
	unsigned int bytes_to_write;
	unsigned int bytes_written;
	struct cifs_sb_info *cifs_sb;
	int done = 0;
1123
	pgoff_t end;
1124
	pgoff_t index;
S
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1125 1126
	int range_whole = 0;
	struct kvec *iov;
1127
	int len;
1128 1129 1130 1131
	int n_iov = 0;
	pgoff_t next;
	int nr_pages;
	__u64 offset = 0;
1132
	struct cifsFileInfo *open_file;
1133 1134 1135 1136
	struct page *page;
	struct pagevec pvec;
	int rc = 0;
	int scanned = 0;
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1137 1138
	int xid;

1139
	cifs_sb = CIFS_SB(mapping->host->i_sb);
1140

1141 1142 1143 1144 1145 1146 1147
	/*
	 * If wsize is smaller that the page cache size, default to writing
	 * one page at a time via cifs_writepage
	 */
	if (cifs_sb->wsize < PAGE_CACHE_SIZE)
		return generic_writepages(mapping, wbc);

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1148 1149 1150 1151
	if ((cifs_sb->tcon->ses) && (cifs_sb->tcon->ses->server))
		if (cifs_sb->tcon->ses->server->secMode &
				(SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
			if (!experimEnabled)
1152
				return generic_writepages(mapping, wbc);
1153

1154
	iov = kmalloc(32 * sizeof(struct kvec), GFP_KERNEL);
S
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1155
	if (iov == NULL)
1156 1157 1158
		return generic_writepages(mapping, wbc);


1159 1160 1161 1162 1163 1164
	/*
	 * BB: Is this meaningful for a non-block-device file system?
	 * If it is, we should test it again after we do I/O
	 */
	if (wbc->nonblocking && bdi_write_congested(bdi)) {
		wbc->encountered_congestion = 1;
1165
		kfree(iov);
1166 1167 1168
		return 0;
	}

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1169 1170
	xid = GetXid();

1171
	pagevec_init(&pvec, 0);
1172
	if (wbc->range_cyclic) {
1173
		index = mapping->writeback_index; /* Start from prev offset */
1174 1175 1176 1177 1178 1179
		end = -1;
	} else {
		index = wbc->range_start >> PAGE_CACHE_SHIFT;
		end = wbc->range_end >> PAGE_CACHE_SHIFT;
		if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
			range_whole = 1;
1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214
		scanned = 1;
	}
retry:
	while (!done && (index <= end) &&
	       (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
			PAGECACHE_TAG_DIRTY,
			min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1))) {
		int first;
		unsigned int i;

		first = -1;
		next = 0;
		n_iov = 0;
		bytes_to_write = 0;

		for (i = 0; i < nr_pages; i++) {
			page = pvec.pages[i];
			/*
			 * At this point we hold neither mapping->tree_lock nor
			 * lock on the page itself: the page may be truncated or
			 * invalidated (changing page->mapping to NULL), or even
			 * swizzled back from swapper_space to tmpfs file
			 * mapping
			 */

			if (first < 0)
				lock_page(page);
			else if (TestSetPageLocked(page))
				break;

			if (unlikely(page->mapping != mapping)) {
				unlock_page(page);
				break;
			}

1215
			if (!wbc->range_cyclic && page->index > end) {
1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230
				done = 1;
				unlock_page(page);
				break;
			}

			if (next && (page->index != next)) {
				/* Not next consecutive page */
				unlock_page(page);
				break;
			}

			if (wbc->sync_mode != WB_SYNC_NONE)
				wait_on_page_writeback(page);

			if (PageWriteback(page) ||
1231
					!clear_page_dirty_for_io(page)) {
1232 1233 1234
				unlock_page(page);
				break;
			}
1235

1236 1237 1238 1239 1240 1241
			/*
			 * This actually clears the dirty bit in the radix tree.
			 * See cifs_writepage() for more commentary.
			 */
			set_page_writeback(page);

1242 1243 1244
			if (page_offset(page) >= mapping->host->i_size) {
				done = 1;
				unlock_page(page);
1245
				end_page_writeback(page);
1246 1247 1248
				break;
			}

1249 1250 1251 1252 1253
			/*
			 * BB can we get rid of this?  pages are held by pvec
			 */
			page_cache_get(page);

1254 1255 1256
			len = min(mapping->host->i_size - page_offset(page),
				  (loff_t)PAGE_CACHE_SIZE);

1257 1258 1259
			/* reserve iov[0] for the smb header */
			n_iov++;
			iov[n_iov].iov_base = kmap(page);
1260 1261
			iov[n_iov].iov_len = len;
			bytes_to_write += len;
1262 1263 1264 1265 1266 1267 1268 1269 1270 1271

			if (first < 0) {
				first = i;
				offset = page_offset(page);
			}
			next = page->index + 1;
			if (bytes_to_write + PAGE_CACHE_SIZE > cifs_sb->wsize)
				break;
		}
		if (n_iov) {
1272 1273 1274 1275 1276 1277 1278 1279
			/* Search for a writable handle every time we call
			 * CIFSSMBWrite2.  We can't rely on the last handle
			 * we used to still be valid
			 */
			open_file = find_writable_file(CIFS_I(mapping->host));
			if (!open_file) {
				cERROR(1, ("No writable handles for inode"));
				rc = -EBADF;
S
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			} else {
1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296
				rc = CIFSSMBWrite2(xid, cifs_sb->tcon,
						   open_file->netfid,
						   bytes_to_write, offset,
						   &bytes_written, iov, n_iov,
						   1);
				atomic_dec(&open_file->wrtPending);
				if (rc || bytes_written < bytes_to_write) {
					cERROR(1,("Write2 ret %d, written = %d",
						  rc, bytes_written));
					/* BB what if continued retry is
					   requested via mount flags? */
					set_bit(AS_EIO, &mapping->flags);
				} else {
					cifs_stats_bytes_written(cifs_sb->tcon,
								 bytes_written);
				}
1297 1298 1299
			}
			for (i = 0; i < n_iov; i++) {
				page = pvec.pages[first + i];
1300 1301 1302 1303
				/* Should we also set page error on
				success rc but too little data written? */
				/* BB investigate retry logic on temporary
				server crash cases and how recovery works
S
Steve French 已提交
1304 1305
				when page marked as error */
				if (rc)
1306
					SetPageError(page);
1307 1308
				kunmap(page);
				unlock_page(page);
1309
				end_page_writeback(page);
1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326
				page_cache_release(page);
			}
			if ((wbc->nr_to_write -= n_iov) <= 0)
				done = 1;
			index = next;
		}
		pagevec_release(&pvec);
	}
	if (!scanned && !done) {
		/*
		 * We hit the last page and there is more work to be done: wrap
		 * back to the start of the file
		 */
		scanned = 1;
		index = 0;
		goto retry;
	}
1327
	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
1328 1329
		mapping->writeback_index = index;

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1330
	FreeXid(xid);
1331
	kfree(iov);
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1332 1333 1334
	return rc;
}

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1335
static int cifs_writepage(struct page *page, struct writeback_control *wbc)
L
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1336 1337 1338 1339 1340 1341 1342
{
	int rc = -EFAULT;
	int xid;

	xid = GetXid();
/* BB add check for wbc flags */
	page_cache_get(page);
S
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1343
	if (!PageUptodate(page)) {
L
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1344 1345
		cFYI(1, ("ppw - page not up to date"));
	}
1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356

	/*
	 * Set the "writeback" flag, and clear "dirty" in the radix tree.
	 *
	 * A writepage() implementation always needs to do either this,
	 * or re-dirty the page with "redirty_page_for_writepage()" in
	 * the case of a failure.
	 *
	 * Just unlocking the page will cause the radix tree tag-bits
	 * to fail to update with the state of the page correctly.
	 */
S
Steve French 已提交
1357
	set_page_writeback(page);
L
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1358 1359 1360
	rc = cifs_partialpagewrite(page, 0, PAGE_CACHE_SIZE);
	SetPageUptodate(page); /* BB add check for error and Clearuptodate? */
	unlock_page(page);
1361 1362
	end_page_writeback(page);
	page_cache_release(page);
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1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376
	FreeXid(xid);
	return rc;
}

static int cifs_commit_write(struct file *file, struct page *page,
	unsigned offset, unsigned to)
{
	int xid;
	int rc = 0;
	struct inode *inode = page->mapping->host;
	loff_t position = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
	char *page_data;

	xid = GetXid();
S
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1377
	cFYI(1, ("commit write for page %p up to position %lld for %d",
L
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1378
		 page, position, to));
1379
	spin_lock(&inode->i_lock);
L
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1380 1381 1382
	if (position > inode->i_size) {
		i_size_write(inode, position);
	}
1383
	spin_unlock(&inode->i_lock);
L
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1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404
	if (!PageUptodate(page)) {
		position =  ((loff_t)page->index << PAGE_CACHE_SHIFT) + offset;
		/* can not rely on (or let) writepage write this data */
		if (to < offset) {
			cFYI(1, ("Illegal offsets, can not copy from %d to %d",
				offset, to));
			FreeXid(xid);
			return rc;
		}
		/* this is probably better than directly calling
		   partialpage_write since in this function the file handle is
		   known which we might as well	leverage */
		/* BB check if anything else missing out of ppw
		   such as updating last write time */
		page_data = kmap(page);
		rc = cifs_write(file, page_data + offset, to-offset,
				&position);
		if (rc > 0)
			rc = 0;
		/* else if (rc < 0) should we set writebehind rc? */
		kunmap(page);
S
Steve French 已提交
1405
	} else {
L
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1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416
		set_page_dirty(page);
	}

	FreeXid(xid);
	return rc;
}

int cifs_fsync(struct file *file, struct dentry *dentry, int datasync)
{
	int xid;
	int rc = 0;
1417
	struct inode *inode = file->f_path.dentry->d_inode;
L
Linus Torvalds 已提交
1418 1419 1420

	xid = GetXid();

S
Steve French 已提交
1421
	cFYI(1, ("Sync file - name: %s datasync: 0x%x",
L
Linus Torvalds 已提交
1422
		dentry->d_name.name, datasync));
1423

L
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1424 1425 1426 1427 1428 1429 1430
	rc = filemap_fdatawrite(inode->i_mapping);
	if (rc == 0)
		CIFS_I(inode)->write_behind_rc = 0;
	FreeXid(xid);
	return rc;
}

1431
/* static void cifs_sync_page(struct page *page)
L
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1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444
{
	struct address_space *mapping;
	struct inode *inode;
	unsigned long index = page->index;
	unsigned int rpages = 0;
	int rc = 0;

	cFYI(1, ("sync page %p",page));
	mapping = page->mapping;
	if (!mapping)
		return 0;
	inode = mapping->host;
	if (!inode)
1445
		return; */
L
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1446

S
Steve French 已提交
1447
/*	fill in rpages then
L
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1448 1449
	result = cifs_pagein_inode(inode, index, rpages); */ /* BB finish */

1450
/*	cFYI(1, ("rpages is %d for sync page of Index %ld", rpages, index));
L
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1451

1452
#if 0
L
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1453 1454 1455
	if (rc < 0)
		return rc;
	return 0;
1456
#endif
L
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1457 1458 1459 1460 1461 1462
} */

/*
 * As file closes, flush all cached write data for this inode checking
 * for write behind errors.
 */
1463
int cifs_flush(struct file *file, fl_owner_t id)
L
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1464
{
S
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1465
	struct inode *inode = file->f_path.dentry->d_inode;
L
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1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479
	int rc = 0;

	/* Rather than do the steps manually:
	   lock the inode for writing
	   loop through pages looking for write behind data (dirty pages)
	   coalesce into contiguous 16K (or smaller) chunks to write to server
	   send to server (prefer in parallel)
	   deal with writebehind errors
	   unlock inode for writing
	   filemapfdatawrite appears easier for the time being */

	rc = filemap_fdatawrite(inode->i_mapping);
	if (!rc) /* reset wb rc if we were able to write out dirty pages */
		CIFS_I(inode)->write_behind_rc = 0;
1480

S
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1481
	cFYI(1, ("Flush inode %p file %p rc %d", inode, file, rc));
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1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501

	return rc;
}

ssize_t cifs_user_read(struct file *file, char __user *read_data,
	size_t read_size, loff_t *poffset)
{
	int rc = -EACCES;
	unsigned int bytes_read = 0;
	unsigned int total_read = 0;
	unsigned int current_read_size;
	struct cifs_sb_info *cifs_sb;
	struct cifsTconInfo *pTcon;
	int xid;
	struct cifsFileInfo *open_file;
	char *smb_read_data;
	char __user *current_offset;
	struct smb_com_read_rsp *pSMBr;

	xid = GetXid();
1502
	cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
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1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516
	pTcon = cifs_sb->tcon;

	if (file->private_data == NULL) {
		FreeXid(xid);
		return -EBADF;
	}
	open_file = (struct cifsFileInfo *)file->private_data;

	if ((file->f_flags & O_ACCMODE) == O_WRONLY) {
		cFYI(1, ("attempting read on write only file instance"));
	}
	for (total_read = 0, current_offset = read_data;
	     read_size > total_read;
	     total_read += bytes_read, current_offset += bytes_read) {
S
Steve French 已提交
1517
		current_read_size = min_t(const int, read_size - total_read,
L
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1518 1519 1520 1521
					  cifs_sb->rsize);
		rc = -EAGAIN;
		smb_read_data = NULL;
		while (rc == -EAGAIN) {
1522
			int buf_type = CIFS_NO_BUFFER;
S
Steve French 已提交
1523
			if ((open_file->invalidHandle) &&
L
Linus Torvalds 已提交
1524
			    (!open_file->closePend)) {
1525
				rc = cifs_reopen_file(file, TRUE);
L
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1526 1527 1528
				if (rc != 0)
					break;
			}
1529
			rc = CIFSSMBRead(xid, pTcon,
1530 1531 1532 1533
					 open_file->netfid,
					 current_read_size, *poffset,
					 &bytes_read, &smb_read_data,
					 &buf_type);
L
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1534 1535
			pSMBr = (struct smb_com_read_rsp *)smb_read_data;
			if (smb_read_data) {
1536 1537 1538 1539 1540 1541 1542 1543
				if (copy_to_user(current_offset,
						smb_read_data +
						4 /* RFC1001 length field */ +
						le16_to_cpu(pSMBr->DataOffset),
						bytes_read)) {
					rc = -EFAULT;
				}

S
Steve French 已提交
1544
				if (buf_type == CIFS_SMALL_BUFFER)
1545
					cifs_small_buf_release(smb_read_data);
S
Steve French 已提交
1546
				else if (buf_type == CIFS_LARGE_BUFFER)
1547
					cifs_buf_release(smb_read_data);
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1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558
				smb_read_data = NULL;
			}
		}
		if (rc || (bytes_read == 0)) {
			if (total_read) {
				break;
			} else {
				FreeXid(xid);
				return rc;
			}
		} else {
1559
			cifs_stats_bytes_read(pTcon, bytes_read);
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			*poffset += bytes_read;
		}
	}
	FreeXid(xid);
	return total_read;
}


static ssize_t cifs_read(struct file *file, char *read_data, size_t read_size,
	loff_t *poffset)
{
	int rc = -EACCES;
	unsigned int bytes_read = 0;
	unsigned int total_read;
	unsigned int current_read_size;
	struct cifs_sb_info *cifs_sb;
	struct cifsTconInfo *pTcon;
	int xid;
	char *current_offset;
	struct cifsFileInfo *open_file;
1580
	int buf_type = CIFS_NO_BUFFER;
L
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1581 1582

	xid = GetXid();
1583
	cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
L
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1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594
	pTcon = cifs_sb->tcon;

	if (file->private_data == NULL) {
		FreeXid(xid);
		return -EBADF;
	}
	open_file = (struct cifsFileInfo *)file->private_data;

	if ((file->f_flags & O_ACCMODE) == O_WRONLY)
		cFYI(1, ("attempting read on write only file instance"));

S
Steve French 已提交
1595
	for (total_read = 0, current_offset = read_data;
L
Linus Torvalds 已提交
1596 1597 1598 1599
	     read_size > total_read;
	     total_read += bytes_read, current_offset += bytes_read) {
		current_read_size = min_t(const int, read_size - total_read,
					  cifs_sb->rsize);
1600 1601
		/* For windows me and 9x we do not want to request more
		than it negotiated since it will refuse the read then */
S
Steve French 已提交
1602
		if ((pTcon->ses) &&
1603 1604 1605 1606
			!(pTcon->ses->capabilities & CAP_LARGE_FILES)) {
			current_read_size = min_t(const int, current_read_size,
					pTcon->ses->server->maxBuf - 128);
		}
L
Linus Torvalds 已提交
1607 1608
		rc = -EAGAIN;
		while (rc == -EAGAIN) {
S
Steve French 已提交
1609
			if ((open_file->invalidHandle) &&
L
Linus Torvalds 已提交
1610
			    (!open_file->closePend)) {
1611
				rc = cifs_reopen_file(file, TRUE);
L
Linus Torvalds 已提交
1612 1613 1614
				if (rc != 0)
					break;
			}
1615
			rc = CIFSSMBRead(xid, pTcon,
1616 1617 1618 1619
					 open_file->netfid,
					 current_read_size, *poffset,
					 &bytes_read, &current_offset,
					 &buf_type);
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Linus Torvalds 已提交
1620 1621 1622 1623 1624 1625 1626 1627 1628
		}
		if (rc || (bytes_read == 0)) {
			if (total_read) {
				break;
			} else {
				FreeXid(xid);
				return rc;
			}
		} else {
1629
			cifs_stats_bytes_read(pTcon, total_read);
L
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1630 1631 1632 1633 1634 1635 1636 1637 1638
			*poffset += bytes_read;
		}
	}
	FreeXid(xid);
	return total_read;
}

int cifs_file_mmap(struct file *file, struct vm_area_struct *vma)
{
1639
	struct dentry *dentry = file->f_path.dentry;
L
Linus Torvalds 已提交
1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654
	int rc, xid;

	xid = GetXid();
	rc = cifs_revalidate(dentry);
	if (rc) {
		cFYI(1, ("Validation prior to mmap failed, error=%d", rc));
		FreeXid(xid);
		return rc;
	}
	rc = generic_file_mmap(file, vma);
	FreeXid(xid);
	return rc;
}


S
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1655
static void cifs_copy_cache_pages(struct address_space *mapping,
L
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1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672
	struct list_head *pages, int bytes_read, char *data,
	struct pagevec *plru_pvec)
{
	struct page *page;
	char *target;

	while (bytes_read > 0) {
		if (list_empty(pages))
			break;

		page = list_entry(pages->prev, struct page, lru);
		list_del(&page->lru);

		if (add_to_page_cache(page, mapping, page->index,
				      GFP_KERNEL)) {
			page_cache_release(page);
			cFYI(1, ("Add page cache failed"));
1673 1674
			data += PAGE_CACHE_SIZE;
			bytes_read -= PAGE_CACHE_SIZE;
L
Linus Torvalds 已提交
1675 1676 1677
			continue;
		}

S
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1678
		target = kmap_atomic(page, KM_USER0);
L
Linus Torvalds 已提交
1679 1680 1681 1682

		if (PAGE_CACHE_SIZE > bytes_read) {
			memcpy(target, data, bytes_read);
			/* zero the tail end of this partial page */
S
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1683
			memset(target + bytes_read, 0,
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Linus Torvalds 已提交
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			       PAGE_CACHE_SIZE - bytes_read);
			bytes_read = 0;
		} else {
			memcpy(target, data, PAGE_CACHE_SIZE);
			bytes_read -= PAGE_CACHE_SIZE;
		}
		kunmap_atomic(target, KM_USER0);

		flush_dcache_page(page);
		SetPageUptodate(page);
		unlock_page(page);
		if (!pagevec_add(plru_pvec, page))
			__pagevec_lru_add(plru_pvec);
		data += PAGE_CACHE_SIZE;
	}
	return;
}

static int cifs_readpages(struct file *file, struct address_space *mapping,
	struct list_head *page_list, unsigned num_pages)
{
	int rc = -EACCES;
	int xid;
	loff_t offset;
	struct page *page;
	struct cifs_sb_info *cifs_sb;
	struct cifsTconInfo *pTcon;
	int bytes_read = 0;
S
Steve French 已提交
1712
	unsigned int read_size, i;
L
Linus Torvalds 已提交
1713 1714 1715 1716
	char *smb_read_data = NULL;
	struct smb_com_read_rsp *pSMBr;
	struct pagevec lru_pvec;
	struct cifsFileInfo *open_file;
1717
	int buf_type = CIFS_NO_BUFFER;
L
Linus Torvalds 已提交
1718 1719 1720 1721 1722 1723 1724

	xid = GetXid();
	if (file->private_data == NULL) {
		FreeXid(xid);
		return -EBADF;
	}
	open_file = (struct cifsFileInfo *)file->private_data;
1725
	cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
L
Linus Torvalds 已提交
1726
	pTcon = cifs_sb->tcon;
1727

L
Linus Torvalds 已提交
1728
	pagevec_init(&lru_pvec, 0);
1729
#ifdef CONFIG_CIFS_DEBUG2
S
Steve French 已提交
1730 1731
		cFYI(1, ("rpages: num pages %d", num_pages));
#endif
L
Linus Torvalds 已提交
1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744
	for (i = 0; i < num_pages; ) {
		unsigned contig_pages;
		struct page *tmp_page;
		unsigned long expected_index;

		if (list_empty(page_list))
			break;

		page = list_entry(page_list->prev, struct page, lru);
		offset = (loff_t)page->index << PAGE_CACHE_SHIFT;

		/* count adjacent pages that we will read into */
		contig_pages = 0;
S
Steve French 已提交
1745
		expected_index =
L
Linus Torvalds 已提交
1746
			list_entry(page_list->prev, struct page, lru)->index;
S
Steve French 已提交
1747
		list_for_each_entry_reverse(tmp_page, page_list, lru) {
L
Linus Torvalds 已提交
1748 1749 1750 1751
			if (tmp_page->index == expected_index) {
				contig_pages++;
				expected_index++;
			} else
S
Steve French 已提交
1752
				break;
L
Linus Torvalds 已提交
1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763
		}
		if (contig_pages + i >  num_pages)
			contig_pages = num_pages - i;

		/* for reads over a certain size could initiate async
		   read ahead */

		read_size = contig_pages * PAGE_CACHE_SIZE;
		/* Read size needs to be in multiples of one page */
		read_size = min_t(const unsigned int, read_size,
				  cifs_sb->rsize & PAGE_CACHE_MASK);
1764
#ifdef CONFIG_CIFS_DEBUG2
S
Steve French 已提交
1765
		cFYI(1, ("rpages: read size 0x%x  contiguous pages %d",
1766
				read_size, contig_pages));
S
Steve French 已提交
1767
#endif
L
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1768 1769
		rc = -EAGAIN;
		while (rc == -EAGAIN) {
S
Steve French 已提交
1770
			if ((open_file->invalidHandle) &&
L
Linus Torvalds 已提交
1771
			    (!open_file->closePend)) {
1772
				rc = cifs_reopen_file(file, TRUE);
L
Linus Torvalds 已提交
1773 1774 1775 1776
				if (rc != 0)
					break;
			}

1777
			rc = CIFSSMBRead(xid, pTcon,
1778 1779 1780 1781
					 open_file->netfid,
					 read_size, offset,
					 &bytes_read, &smb_read_data,
					 &buf_type);
1782
			/* BB more RC checks ? */
S
Steve French 已提交
1783
			if (rc == -EAGAIN) {
L
Linus Torvalds 已提交
1784
				if (smb_read_data) {
S
Steve French 已提交
1785
					if (buf_type == CIFS_SMALL_BUFFER)
1786
						cifs_small_buf_release(smb_read_data);
S
Steve French 已提交
1787
					else if (buf_type == CIFS_LARGE_BUFFER)
1788
						cifs_buf_release(smb_read_data);
L
Linus Torvalds 已提交
1789 1790 1791 1792 1793 1794 1795 1796
					smb_read_data = NULL;
				}
			}
		}
		if ((rc < 0) || (smb_read_data == NULL)) {
			cFYI(1, ("Read error in readpages: %d", rc));
			break;
		} else if (bytes_read > 0) {
1797
			task_io_account_read(bytes_read);
L
Linus Torvalds 已提交
1798 1799 1800 1801 1802 1803
			pSMBr = (struct smb_com_read_rsp *)smb_read_data;
			cifs_copy_cache_pages(mapping, page_list, bytes_read,
				smb_read_data + 4 /* RFC1001 hdr */ +
				le16_to_cpu(pSMBr->DataOffset), &lru_pvec);

			i +=  bytes_read >> PAGE_CACHE_SHIFT;
1804
			cifs_stats_bytes_read(pTcon, bytes_read);
L
Linus Torvalds 已提交
1805 1806 1807
			if ((int)(bytes_read & PAGE_CACHE_MASK) != bytes_read) {
				i++; /* account for partial page */

S
Steve French 已提交
1808
				/* server copy of file can have smaller size
L
Linus Torvalds 已提交
1809
				   than client */
S
Steve French 已提交
1810 1811
				/* BB do we need to verify this common case ?
				   this case is ok - if we are at server EOF
L
Linus Torvalds 已提交
1812 1813
				   we will hit it on next read */

O
OGAWA Hirofumi 已提交
1814
				/* break; */
L
Linus Torvalds 已提交
1815 1816 1817 1818 1819
			}
		} else {
			cFYI(1, ("No bytes read (%d) at offset %lld . "
				 "Cleaning remaining pages from readahead list",
				 bytes_read, offset));
S
Steve French 已提交
1820
			/* BB turn off caching and do new lookup on
L
Linus Torvalds 已提交
1821 1822 1823 1824
			   file size at server? */
			break;
		}
		if (smb_read_data) {
S
Steve French 已提交
1825
			if (buf_type == CIFS_SMALL_BUFFER)
1826
				cifs_small_buf_release(smb_read_data);
S
Steve French 已提交
1827
			else if (buf_type == CIFS_LARGE_BUFFER)
1828
				cifs_buf_release(smb_read_data);
L
Linus Torvalds 已提交
1829 1830 1831 1832 1833 1834 1835 1836 1837
			smb_read_data = NULL;
		}
		bytes_read = 0;
	}

	pagevec_lru_add(&lru_pvec);

/* need to free smb_read_data buf before exit */
	if (smb_read_data) {
S
Steve French 已提交
1838
		if (buf_type == CIFS_SMALL_BUFFER)
1839
			cifs_small_buf_release(smb_read_data);
S
Steve French 已提交
1840
		else if (buf_type == CIFS_LARGE_BUFFER)
1841
			cifs_buf_release(smb_read_data);
L
Linus Torvalds 已提交
1842
		smb_read_data = NULL;
S
Steve French 已提交
1843
	}
L
Linus Torvalds 已提交
1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857

	FreeXid(xid);
	return rc;
}

static int cifs_readpage_worker(struct file *file, struct page *page,
	loff_t *poffset)
{
	char *read_data;
	int rc;

	page_cache_get(page);
	read_data = kmap(page);
	/* for reads over a certain size could initiate async read ahead */
S
Steve French 已提交
1858

L
Linus Torvalds 已提交
1859
	rc = cifs_read(file, read_data, PAGE_CACHE_SIZE, poffset);
S
Steve French 已提交
1860

L
Linus Torvalds 已提交
1861 1862 1863
	if (rc < 0)
		goto io_error;
	else
S
Steve French 已提交
1864 1865
		cFYI(1, ("Bytes read %d", rc));

1866 1867
	file->f_path.dentry->d_inode->i_atime =
		current_fs_time(file->f_path.dentry->d_inode->i_sb);
S
Steve French 已提交
1868

L
Linus Torvalds 已提交
1869 1870 1871 1872 1873 1874
	if (PAGE_CACHE_SIZE > rc)
		memset(read_data + rc, 0, PAGE_CACHE_SIZE - rc);

	flush_dcache_page(page);
	SetPageUptodate(page);
	rc = 0;
S
Steve French 已提交
1875

L
Linus Torvalds 已提交
1876
io_error:
S
Steve French 已提交
1877
	kunmap(page);
L
Linus Torvalds 已提交
1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894
	page_cache_release(page);
	return rc;
}

static int cifs_readpage(struct file *file, struct page *page)
{
	loff_t offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
	int rc = -EACCES;
	int xid;

	xid = GetXid();

	if (file->private_data == NULL) {
		FreeXid(xid);
		return -EBADF;
	}

S
Steve French 已提交
1895
	cFYI(1, ("readpage %p at offset %d 0x%x\n",
L
Linus Torvalds 已提交
1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908
		 page, (int)offset, (int)offset));

	rc = cifs_readpage_worker(file, page, &offset);

	unlock_page(page);

	FreeXid(xid);
	return rc;
}

/* We do not want to update the file size from server for inodes
   open for write - to avoid races with writepage extending
   the file - in the future we could consider allowing
S
Steve French 已提交
1909
   refreshing the inode only on increases in the file size
L
Linus Torvalds 已提交
1910 1911
   but this is tricky to do without racing with writebehind
   page caching in the current Linux kernel design */
1912
int is_size_safe_to_change(struct cifsInodeInfo *cifsInode, __u64 end_of_file)
L
Linus Torvalds 已提交
1913
{
1914 1915 1916 1917
	struct cifsFileInfo *open_file = NULL;

	if (cifsInode)
		open_file =  find_writable_file(cifsInode);
1918

S
Steve French 已提交
1919
	if (open_file) {
1920 1921
		struct cifs_sb_info *cifs_sb;

1922 1923 1924 1925
		/* there is not actually a write pending so let
		this handle go free and allow it to
		be closable if needed */
		atomic_dec(&open_file->wrtPending);
1926 1927 1928

		cifs_sb = CIFS_SB(cifsInode->vfs_inode.i_sb);
		if ( cifs_sb->mnt_cifs_flags & CIFS_MOUNT_DIRECT_IO ) {
S
Steve French 已提交
1929
			/* since no page cache to corrupt on directio
1930 1931 1932 1933
			we can change size safely */
			return 1;
		}

S
Steve French 已提交
1934
		if (i_size_read(&cifsInode->vfs_inode) < end_of_file)
1935 1936
			return 1;

1937
		return 0;
1938
	} else
1939
		return 1;
L
Linus Torvalds 已提交
1940 1941 1942 1943 1944 1945
}

static int cifs_prepare_write(struct file *file, struct page *page,
	unsigned from, unsigned to)
{
	int rc = 0;
1946 1947 1948
	loff_t i_size;
	loff_t offset;

S
Steve French 已提交
1949
	cFYI(1, ("prepare write for page %p from %d to %d", page, from, to));
1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971
	if (PageUptodate(page))
		return 0;

	/* If we are writing a full page it will be up to date,
	   no need to read from the server */
	if ((to == PAGE_CACHE_SIZE) && (from == 0)) {
		SetPageUptodate(page);
		return 0;
	}

	offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
	i_size = i_size_read(page->mapping->host);

	if ((offset >= i_size) ||
	    ((from == 0) && (offset + to) >= i_size)) {
		/*
		 * We don't need to read data beyond the end of the file.
		 * zero it, and set the page uptodate
		 */
		void *kaddr = kmap_atomic(page, KM_USER0);

		if (from)
L
Linus Torvalds 已提交
1972
			memset(kaddr, 0, from);
1973
		if (to < PAGE_CACHE_SIZE)
L
Linus Torvalds 已提交
1974
			memset(kaddr + to, 0, PAGE_CACHE_SIZE - to);
1975 1976 1977 1978
		flush_dcache_page(page);
		kunmap_atomic(kaddr, KM_USER0);
		SetPageUptodate(page);
	} else if ((file->f_flags & O_ACCMODE) != O_WRONLY) {
L
Linus Torvalds 已提交
1979
		/* might as well read a page, it is fast enough */
1980 1981 1982 1983 1984 1985
		rc = cifs_readpage_worker(file, page, &offset);
	} else {
		/* we could try using another file handle if there is one -
		   but how would we lock it to prevent close of that handle
		   racing with this read? In any case
		   this will be written out by commit_write so is fine */
L
Linus Torvalds 已提交
1986 1987
	}

S
Steve French 已提交
1988 1989
	/* we do not need to pass errors back
	   e.g. if we do not have read access to the file
1990 1991
	   because cifs_commit_write will do the right thing.  -- shaggy */

L
Linus Torvalds 已提交
1992 1993 1994
	return 0;
}

1995
const struct address_space_operations cifs_addr_ops = {
L
Linus Torvalds 已提交
1996 1997 1998
	.readpage = cifs_readpage,
	.readpages = cifs_readpages,
	.writepage = cifs_writepage,
1999
	.writepages = cifs_writepages,
L
Linus Torvalds 已提交
2000 2001 2002 2003 2004 2005
	.prepare_write = cifs_prepare_write,
	.commit_write = cifs_commit_write,
	.set_page_dirty = __set_page_dirty_nobuffers,
	/* .sync_page = cifs_sync_page, */
	/* .direct_IO = */
};
D
Dave Kleikamp 已提交
2006 2007 2008 2009 2010 2011

/*
 * cifs_readpages requires the server to support a buffer large enough to
 * contain the header plus one complete page of data.  Otherwise, we need
 * to leave cifs_readpages out of the address space operations.
 */
2012
const struct address_space_operations cifs_addr_ops_smallbuf = {
D
Dave Kleikamp 已提交
2013 2014 2015 2016 2017 2018 2019 2020 2021
	.readpage = cifs_readpage,
	.writepage = cifs_writepage,
	.writepages = cifs_writepages,
	.prepare_write = cifs_prepare_write,
	.commit_write = cifs_commit_write,
	.set_page_dirty = __set_page_dirty_nobuffers,
	/* .sync_page = cifs_sync_page, */
	/* .direct_IO = */
};