dir.c

Linux内核自带的cifs模块

/*
 *   fs/cifs/dir.c
 *
 *   vfs operations that deal with dentries
 *
 *   Copyright (C) International Business Machines  Corp., 2002,2005
 *   Author(s): Steve French ([e-mail])
 *
 *   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>
#include <linux/stat.h>
#include <linux/slab.h>
#include <linux/version.h>
#if LINUX_VERSION_CODE > KERNEL_VERSION(2, 5, 0)
#include <linux/namei.h>
#endif
#include "cifsfs.h"
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_debug.h"
#include "cifs_fs_sb.h"
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,9)
#include <linux/ctype.h>
#endif

static void
renew_parental_timestamps(struct dentry *direntry)
{
	/* BB check if there is a way to get the kernel to do this or if we
	   really need this */
	do {
		direntry->d_time = jiffies;
		direntry = direntry->d_parent;
	} while (!IS_ROOT(direntry));
}

/* Note: caller must free return buffer */
char *
build_path_from_dentry(struct dentry *direntry)
{
	struct dentry *temp;
	int namelen;
	int pplen;
	char *full_path;
	char dirsep;

	if (direntry == NULL)
		return NULL;  /* not much we can do if dentry is freed and
		we need to reopen the file after it was closed implicitly
		when the server crashed */

	dirsep = CIFS_DIR_SEP(CIFS_SB(direntry->d_sb));
	pplen = CIFS_SB(direntry->d_sb)->prepathlen;
cifs_bp_rename_retry:
	namelen = pplen;
	for (temp = direntry; !IS_ROOT(temp);) {
		namelen += (1 + temp->d_name.len);
		temp = temp->d_parent;
		if (temp == NULL) {
			cERROR(1, ("corrupt dentry"));
			return NULL;
		}
	}

	full_path = kmalloc(namelen+1, GFP_KERNEL);
	if (full_path == NULL)
		return full_path;
	full_path[namelen] = 0;	/* trailing null */
	for (temp = direntry; !IS_ROOT(temp);) {
		namelen -= 1 + temp->d_name.len;
		if (namelen < 0) {
			break;
		} else {
			full_path[namelen] = dirsep;
			strncpy(full_path + namelen + 1, temp->d_name.name,
				temp->d_name.len);
			cFYI(0, ("name: %s", full_path + namelen));
		}
		temp = temp->d_parent;
		if (temp == NULL) {
			cERROR(1, ("corrupt dentry"));
			kfree(full_path);
			return NULL;
		}
	}
	if (namelen != pplen) {
		cERROR(1,
		       ("did not end path lookup where expected namelen is %d",
			namelen));
		/* presumably this is only possible if racing with a rename
		of one of the parent directories  (we can not lock the dentries
		above us to prevent this, but retrying should be harmless) */
		kfree(full_path);
		goto cifs_bp_rename_retry;
	}
	/* DIR_SEP already set for byte  0 / vs \ but not for
	   subsequent slashes in prepath which currently must
	   be entered the right way - not sure if there is an alternative
	   since the '\' is a valid posix character so we can not switch
	   those safely to '/' if any are found in the middle of the prepath */
	/* BB test paths to Windows with '/' in the midst of prepath */
	strncpy(full_path, CIFS_SB(direntry->d_sb)->prepath, pplen);
	return full_path;
}

/* char * build_wildcard_path_from_dentry(struct dentry *direntry)
{
	if(full_path == NULL)
		return full_path;

	full_path[namelen] = '\\';
	full_path[namelen+1] = '*';
	full_path[namelen+2] = 0;
BB remove above eight lines BB */

/* Inode operations in similar order to how they appear in Linux file fs.h */

int
#if LINUX_VERSION_CODE > KERNEL_VERSION(2, 5, 0)
cifs_create(struct inode *inode, struct dentry *direntry, int mode,
		struct nameidata *nd)
#else
cifs_create(struct inode *inode, struct dentry *direntry, int mode)
#endif
{
	int rc = -ENOENT;
	int xid;
	int oplock = 0;
	int desiredAccess = GENERIC_READ | GENERIC_WRITE;
	__u16 fileHandle;
	struct cifs_sb_info *cifs_sb;
	struct cifsTconInfo *pTcon;
	char *full_path = NULL;
	FILE_ALL_INFO *buf = NULL;
	struct inode *newinode = NULL;
#if LINUX_VERSION_CODE > KERNEL_VERSION(2, 5, 0)
	struct cifsFileInfo *pCifsFile = NULL;
	struct cifsInodeInfo *pCifsInode;
	int write_only = FALSE;
#endif
	int disposition = FILE_OVERWRITE_IF;
	
	xid = GetXid();

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

	full_path = build_path_from_dentry(direntry);
	if (full_path == NULL) {
		FreeXid(xid);
		return -ENOMEM;
	}

#if LINUX_VERSION_CODE > KERNEL_VERSION(2, 5, 0)
	if(nd && (nd->flags & LOOKUP_OPEN)) {
#if LINUX_VERSION_CODE == KERNEL_VERSION(2,6,5) /* SUSE included Lustre patch */
		int oflags = nd->intent.it_flags;
#else
		int oflags = nd->intent.open.flags;
#endif

		desiredAccess = 0;
		if (oflags & FMODE_READ)
			desiredAccess |= GENERIC_READ;
		if (oflags & FMODE_WRITE) {
			desiredAccess |= GENERIC_WRITE;
			if (!(oflags & FMODE_READ))
				write_only = TRUE;
		}

		if ((oflags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
			disposition = FILE_CREATE;
		else if ((oflags & (O_CREAT | O_TRUNC)) == (O_CREAT | O_TRUNC))
			disposition = FILE_OVERWRITE_IF;
		else if ((oflags & O_CREAT) == O_CREAT)
			disposition = FILE_OPEN_IF;
		else {
			cFYI(1, ("Create flag not set in create function"));
		}
	}

	/* BB add processing to set equivalent of mode - e.g. via CreateX with
	   ACLs */
	if (oplockEnabled)
		oplock = REQ_OPLOCK;
#else
	desiredAccess = GENERIC_WRITE;
#endif

	buf = kmalloc(sizeof(FILE_ALL_INFO), GFP_KERNEL);
	if (buf == NULL) {
		kfree(full_path);
		FreeXid(xid);
		return -ENOMEM;
	}
	if (cifs_sb->tcon->ses->capabilities & CAP_NT_SMBS)
		rc = CIFSSMBOpen(xid, pTcon, full_path, disposition,
			 desiredAccess, CREATE_NOT_DIR,
			 &fileHandle, &oplock, buf, cifs_sb->local_nls,
			 cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
	else
		rc = -EIO; /* no NT SMB support fall into legacy open below */

	if (rc == -EIO) {
		/* old server, retry the open legacy style */
		rc = SMBLegacyOpen(xid, pTcon, full_path, disposition,
			desiredAccess, CREATE_NOT_DIR,
			&fileHandle, &oplock, buf, cifs_sb->local_nls,
			cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
	}
	if (rc) {
		cFYI(1, ("cifs_create returned 0x%x", rc));
	} else {
		/* If Open reported that we actually created a file
		then we now have to set the mode if possible */
		if ((pTcon->unix_ext) && (oplock & CIFS_CREATE_ACTION)) {
			mode &= ~current->fs->umask;
			if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SET_UID) {
				CIFSSMBUnixSetPerms(xid, pTcon, full_path, mode,
					(__u64)current->fsuid,
					(__u64)current->fsgid,
					0 /* dev */,
					cifs_sb->local_nls,
					cifs_sb->mnt_cifs_flags &
						CIFS_MOUNT_MAP_SPECIAL_CHR);
			} else {
				CIFSSMBUnixSetPerms(xid, pTcon, full_path, mode,
					(__u64)-1,
					(__u64)-1,
					0 /* dev */,
					cifs_sb->local_nls,
					cifs_sb->mnt_cifs_flags &
						CIFS_MOUNT_MAP_SPECIAL_CHR);
			}
		} else {
			/* BB implement mode setting via Windows security
			   descriptors e.g. */
			/* CIFSSMBWinSetPerms(xid,pTcon,path,mode,-1,-1,nls);*/

			/* Could set r/o dos attribute if mode & 0222 == 0 */
		}

		/* server might mask mode so we have to query for it */
		if (pTcon->unix_ext)
			rc = cifs_get_inode_info_unix(&newinode, full_path,
						 inode->i_sb, xid);
		else {
			rc = cifs_get_inode_info(&newinode, full_path,
						 buf, inode->i_sb, xid);
			if (newinode) {
				newinode->i_mode = mode;
				if ((oplock & CIFS_CREATE_ACTION) &&
				    (cifs_sb->mnt_cifs_flags &
				     CIFS_MOUNT_SET_UID)) {
					newinode->i_uid = current->fsuid;
					newinode->i_gid = current->fsgid;
				}
			}
		}

		if (rc != 0) {
			cFYI(1,
			     ("Create worked but get_inode_info failed rc = %d",
			      rc));
		} else {
			if (pTcon->nocase)
				direntry->d_op = &cifs_ci_dentry_ops;
			else
				direntry->d_op = &cifs_dentry_ops;
			d_instantiate(direntry, newinode);
		}
#if LINUX_VERSION_CODE > KERNEL_VERSION(2, 5, 0)
		if ((nd == NULL /* nfsd case - nfs srv does not set nd */) ||
			((nd->flags & LOOKUP_OPEN) == FALSE)) {
			/* mknod case - do not leave file open */
			CIFSSMBClose(xid, pTcon, fileHandle);
		} else if (newinode) {
			pCifsFile =
			   kzalloc(sizeof (struct cifsFileInfo), GFP_KERNEL);

			if (pCifsFile == NULL)
				goto cifs_create_out;
			pCifsFile->netfid = fileHandle;
			pCifsFile->pid = current->tgid;
			pCifsFile->pInode = newinode;
			pCifsFile->invalidHandle = FALSE;
			pCifsFile->closePend     = FALSE;
			init_MUTEX(&pCifsFile->fh_sem);
#if LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 17)
			mutex_init(&pCifsFile->lock_mutex);
#else
			init_MUTEX(&pCifsFile->lock_mutex);
#endif
			INIT_LIST_HEAD(&pCifsFile->llist);
			atomic_set(&pCifsFile->wrtPending, 0);

			/* set the following in open now
				pCifsFile->pfile = file; */
			write_lock(&GlobalSMBSeslock);
			list_add(&pCifsFile->tlist, &pTcon->openFileList);
			pCifsInode = CIFS_I(newinode);
			if (pCifsInode) {
				/* if readable file instance put first in list*/
				if (write_only == TRUE) {
					list_add_tail(&pCifsFile->flist,
						&pCifsInode->openFileList);
				} else {
					list_add(&pCifsFile->flist,
						&pCifsInode->openFileList);
				}
				if ((oplock & 0xF) == OPLOCK_EXCLUSIVE) {
					pCifsInode->clientCanCacheAll = TRUE;
					pCifsInode->clientCanCacheRead = TRUE;
					cFYI(1, ("Exclusive Oplock inode %p",