inode.c

Linux内核自带的cifs模块

/*
 *   fs/cifs/inode.c
 *
 *   Copyright (C) International Business Machines  Corp., 2002,2007
 *   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/pagemap.h>
#include <asm/div64.h>
#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, 5, 0)
#include <linux/buffer_head.h>
#endif

#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 19)
static inline void clear_nlink(struct inode *inode)
{
	inode->i_nlink = 0;
}
static inline void drop_nlink(struct inode *inode)
{
	inode->i_nlink--;
}

static inline void inc_nlink(struct inode *inode)
{
	inode->i_nlink++;
}
#endif


int cifs_get_inode_info_unix(struct inode **pinode,
	const unsigned char *search_path, struct super_block *sb, int xid)
{
	int rc = 0;
	FILE_UNIX_BASIC_INFO findData;
	struct cifsTconInfo *pTcon;
	struct inode *inode;
	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
	char *tmp_path;

	pTcon = cifs_sb->tcon;
	cFYI(1, ("Getting info on %s", search_path));
	/* could have done a find first instead but this returns more info */
	rc = CIFSSMBUnixQPathInfo(xid, pTcon, search_path, &findData,
				  cifs_sb->local_nls, cifs_sb->mnt_cifs_flags &
					CIFS_MOUNT_MAP_SPECIAL_CHR);
/*	dump_mem("\nUnixQPathInfo return data", &findData,
		 sizeof(findData)); */
	if (rc) {
		if (rc == -EREMOTE) {
			tmp_path =
			    kmalloc(strnlen(pTcon->treeName,
					    MAX_TREE_SIZE + 1) +
				    strnlen(search_path, MAX_PATHCONF) + 1,
				    GFP_KERNEL);
			if (tmp_path == NULL) {
				return -ENOMEM;
			}
			/* have to skip first of the double backslash of
			   UNC name */
			strncpy(tmp_path, pTcon->treeName, MAX_TREE_SIZE);
			strncat(tmp_path, search_path, MAX_PATHCONF);
			rc = connect_to_dfs_path(xid, pTcon->ses,
						 /* treename + */ tmp_path,
						 cifs_sb->local_nls,
						 cifs_sb->mnt_cifs_flags &
						    CIFS_MOUNT_MAP_SPECIAL_CHR);
			kfree(tmp_path);

			/* BB fix up inode etc. */
		} else if (rc) {
			return rc;
		}
	} else {
		struct cifsInodeInfo *cifsInfo;
		__u32 type = le32_to_cpu(findData.Type);
		__u64 num_of_bytes = le64_to_cpu(findData.NumOfBytes);
		__u64 end_of_file = le64_to_cpu(findData.EndOfFile);

		/* get new inode */
		if (*pinode == NULL) {
			*pinode = new_inode(sb);
			if (*pinode == NULL)
				return -ENOMEM;
			/* Is an i_ino of zero legal? */
			/* Are there sanity checks we can use to ensure that
			   the server is really filling in that field? */
			if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
				(*pinode)->i_ino =
					(unsigned long)findData.UniqueId;
			} /* note ino incremented to unique num in new_inode */
			if (sb->s_flags & MS_NOATIME)
				(*pinode)->i_flags |= S_NOATIME | S_NOCMTIME;

			insert_inode_hash(*pinode);
		}

		inode = *pinode;
		cifsInfo = CIFS_I(inode);

		cFYI(1, ("Old time %ld", cifsInfo->time));
		cifsInfo->time = jiffies;
		cFYI(1, ("New time %ld", cifsInfo->time));
		/* this is ok to set on every inode revalidate */
		atomic_set(&cifsInfo->inUse, 1);

		inode->i_atime =
		    cifs_NTtimeToUnix(le64_to_cpu(findData.LastAccessTime));
		inode->i_mtime =
		    cifs_NTtimeToUnix(le64_to_cpu
				(findData.LastModificationTime));
		inode->i_ctime =
		    cifs_NTtimeToUnix(le64_to_cpu(findData.LastStatusChange));
		inode->i_mode = le64_to_cpu(findData.Permissions);
		/* since we set the inode type below we need to mask off
		   to avoid strange results if bits set above */
			inode->i_mode &= ~S_IFMT;
		if (type == UNIX_FILE) {
			inode->i_mode |= S_IFREG;
		} else if (type == UNIX_SYMLINK) {
			inode->i_mode |= S_IFLNK;
		} else if (type == UNIX_DIR) {
			inode->i_mode |= S_IFDIR;
		} else if (type == UNIX_CHARDEV) {
			inode->i_mode |= S_IFCHR;
			inode->i_rdev = MKDEV(le64_to_cpu(findData.DevMajor),
				le64_to_cpu(findData.DevMinor) & MINORMASK);
		} else if (type == UNIX_BLOCKDEV) {
			inode->i_mode |= S_IFBLK;
			inode->i_rdev = MKDEV(le64_to_cpu(findData.DevMajor),
				le64_to_cpu(findData.DevMinor) & MINORMASK);
		} else if (type == UNIX_FIFO) {
			inode->i_mode |= S_IFIFO;
		} else if (type == UNIX_SOCKET) {
			inode->i_mode |= S_IFSOCK;
		} else {
			/* safest to call it a file if we do not know */
			inode->i_mode |= S_IFREG;
			cFYI(1, ("unknown type %d", type));
		}

		if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_OVERR_UID)
			inode->i_uid = cifs_sb->mnt_uid;
		else
			inode->i_uid = le64_to_cpu(findData.Uid);

		if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_OVERR_GID)
			inode->i_gid = cifs_sb->mnt_gid;
		else
			inode->i_gid = le64_to_cpu(findData.Gid);

		inode->i_nlink = le64_to_cpu(findData.Nlinks);

		spin_lock(&inode->i_lock);
		if (is_size_safe_to_change(cifsInfo, end_of_file)) {
		/* can not safely change the file size here if the
		   client is writing to it due to potential races */
			i_size_write(inode, end_of_file);

		/* blksize needs to be multiple of two. So safer to default to
		blksize and blkbits set in superblock so 2**blkbits and blksize
		will match rather than setting to:
		(pTcon->ses->server->maxBuf - MAX_CIFS_HDR_SIZE) & 0xFFFFFE00;*/

		/* This seems incredibly stupid but it turns out that i_blocks
		   is not related to (i_size / i_blksize), instead 512 byte size
		   is required for calculating num blocks */

		/* 512 bytes (2**9) is the fake blocksize that must be used */
		/* for this calculation */
			inode->i_blocks = (512 - 1 + num_of_bytes) >> 9;
		}
		spin_unlock(&inode->i_lock);

		if (num_of_bytes < end_of_file)
			cFYI(1, ("allocation size less than end of file"));
		cFYI(1, ("Size %ld and blocks %llu",
			(unsigned long) inode->i_size,
			(unsigned long long)inode->i_blocks));
		if (S_ISREG(inode->i_mode)) {
			cFYI(1, ("File inode"));
			inode->i_op = &cifs_file_inode_ops;
			if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_DIRECT_IO) {
				if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_BRL)
					inode->i_fop =
						&cifs_file_direct_nobrl_ops;
				else
					inode->i_fop = &cifs_file_direct_ops;
			} else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_BRL)
				inode->i_fop = &cifs_file_nobrl_ops;
			else /* not direct, send byte range locks */
				inode->i_fop = &cifs_file_ops;

			/* check if server can support readpages */
			if (pTcon->ses->server->maxBuf <
			    PAGE_CACHE_SIZE + MAX_CIFS_HDR_SIZE)
				inode->i_data.a_ops = &cifs_addr_ops_smallbuf;
			else
				inode->i_data.a_ops = &cifs_addr_ops;
		} else if (S_ISDIR(inode->i_mode)) {
			cFYI(1, ("Directory inode"));
			inode->i_op = &cifs_dir_inode_ops;
			inode->i_fop = &cifs_dir_ops;
		} else if (S_ISLNK(inode->i_mode)) {
			cFYI(1, ("Symbolic Link inode"));
			inode->i_op = &cifs_symlink_inode_ops;
		/* tmp_inode->i_fop = */ /* do not need to set to anything */
		} else {
			cFYI(1, ("Init special inode"));
			init_special_inode(inode, inode->i_mode,
					   inode->i_rdev);
		}
	}
	return rc;
}

static int decode_sfu_inode(struct inode *inode, __u64 size,
			    const unsigned char *path,
			    struct cifs_sb_info *cifs_sb, int xid)
{
	int rc;
	int oplock = FALSE;
	__u16 netfid;
	struct cifsTconInfo *pTcon = cifs_sb->tcon;
	char buf[24];
	unsigned int bytes_read;
	char *pbuf;

	pbuf = buf;

	if (size == 0) {
		inode->i_mode |= S_IFIFO;
		return 0;
	} else if (size < 8) {
		return -EINVAL;	 /* EOPNOTSUPP? */
	}

	rc = CIFSSMBOpen(xid, pTcon, path, FILE_OPEN, GENERIC_READ,
			 CREATE_NOT_DIR, &netfid, &oplock, NULL,
			 cifs_sb->local_nls,
			 cifs_sb->mnt_cifs_flags &
				CIFS_MOUNT_MAP_SPECIAL_CHR);
	if (rc == 0) {
		int buf_type = CIFS_NO_BUFFER;
			/* Read header */
		rc = CIFSSMBRead(xid, pTcon,
				 netfid,
				 24 /* length */, 0 /* offset */,
				 &bytes_read, &pbuf, &buf_type);
		if ((rc == 0) && (bytes_read >= 8)) {
			if (memcmp("IntxBLK", pbuf, 8) == 0) {
				cFYI(1, ("Block device"));
				inode->i_mode |= S_IFBLK;
				if (bytes_read == 24) {
					/* we have enough to decode dev num */
					__u64 mjr; /* major */
					__u64 mnr; /* minor */
					mjr = le64_to_cpu(*(__le64 *)(pbuf+8));
					mnr = le64_to_cpu(*(__le64 *)(pbuf+16));
					inode->i_rdev = MKDEV(mjr, mnr);
				}
			} else if (memcmp("IntxCHR", pbuf, 8) == 0) {
				cFYI(1, ("Char device"));
				inode->i_mode |= S_IFCHR;
				if (bytes_read == 24) {
					/* we have enough to decode dev num */
					__u64 mjr; /* major */
					__u64 mnr; /* minor */
					mjr = le64_to_cpu(*(__le64 *)(pbuf+8));
					mnr = le64_to_cpu(*(__le64 *)(pbuf+16));
					inode->i_rdev = MKDEV(mjr, mnr);
				}
			} else if (memcmp("IntxLNK", pbuf, 7) == 0) {
				cFYI(1, ("Symlink"));
				inode->i_mode |= S_IFLNK;
			} else {
				inode->i_mode |= S_IFREG; /* file? */
				rc = -EOPNOTSUPP;
			}
		} else {
			inode->i_mode |= S_IFREG; /* then it is a file */
			rc = -EOPNOTSUPP; /* or some unknown SFU type */
		}
		CIFSSMBClose(xid, pTcon, netfid);
	}
	return rc;
}

#define SFBITS_MASK (S_ISVTX | S_ISGID | S_ISUID)  /* SETFILEBITS valid bits */

static int get_sfu_uid_mode(struct inode *inode,
			const unsigned char *path,
			struct cifs_sb_info *cifs_sb, int xid)
{
#ifdef CONFIG_CIFS_XATTR
	ssize_t rc;
	char ea_value[4];
	__u32 mode;

	rc = CIFSSMBQueryEA(xid, cifs_sb->tcon, path, "SETFILEBITS",
			ea_value, 4 /* size of buf */, cifs_sb->local_nls,
		cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
	if (rc < 0)
		return (int)rc;
	else if (rc > 3) {
		mode = le32_to_cpu(*((__le32 *)ea_value));
		inode->i_mode &= ~SFBITS_MASK;
		cFYI(1, ("special bits 0%o org mode 0%o", mode, inode->i_mode));
		inode->i_mode = (mode &  SFBITS_MASK) | inode->i_mode;
		cFYI(1, ("special mode bits 0%o", mode));
		return 0;
	} else {
		return 0;
	}
#else
	return -EOPNOTSUPP;
#endif
}

int cifs_get_inode_info(struct inode **pinode,
	const unsigned char *search_path, FILE_ALL_INFO *pfindData,
	struct super_block *sb, int xid)
{
	int rc = 0;
	struct cifsTconInfo *pTcon;
	struct inode *inode;
	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
	char *tmp_path;
	char *buf = NULL;
	int adjustTZ = FALSE;

	pTcon = cifs_sb->tcon;
	cFYI(1, ("Getting info on %s", search_path));

	if ((pfindData == NULL) && (*pinode != NULL)) {
		if (CIFS_I(*pinode)->clientCanCacheRead) {
			cFYI(1, ("No need to revalidate cached inode sizes"));
			return rc;
		}
	}

	/* if file info not passed in then get it from server */
	if (pfindData == NULL) {
		buf = kmalloc(sizeof(FILE_ALL_INFO), GFP_KERNEL);
		if (buf == NULL)
			return -ENOMEM;
		pfindData = (FILE_ALL_INFO *)buf;
		/* could do find first instead but this returns more info */
		rc = CIFSSMBQPathInfo(xid, pTcon, search_path, pfindData,
			      0 /* not legacy */,
			      cifs_sb->local_nls, cifs_sb->mnt_cifs_flags &
				CIFS_MOUNT_MAP_SPECIAL_CHR);
		/* BB optimize code so we do not make the above call
		when server claims no NT SMB support and the above call
		failed at least once - set flag in tcon or mount */
		if ((rc == -EOPNOTSUPP) || (rc == -EINVAL)) {
			rc = SMBQueryInformation(xid, pTcon, search_path,
					pfindData, cifs_sb->local_nls,
					cifs_sb->mnt_cifs_flags &
					  CIFS_MOUNT_MAP_SPECIAL_CHR);
			adjustTZ = TRUE;
		}
	}
	/* dump_mem("\nQPathInfo return data",&findData, sizeof(findData)); */
	if (rc) {
		if (rc == -EREMOTE) {
			tmp_path =
			    kmalloc(strnlen
				    (pTcon->treeName,
				     MAX_TREE_SIZE + 1) +
				    strnlen(search_path, MAX_PATHCONF) + 1,
				    GFP_KERNEL);
			if (tmp_path == NULL) {
				kfree(buf);
				return -ENOMEM;
			}

			strncpy(tmp_path, pTcon->treeName, MAX_TREE_SIZE);
			strncat(tmp_path, search_path, MAX_PATHCONF);
			rc = connect_to_dfs_path(xid, pTcon->ses,
						 /* treename + */ tmp_path,
						 cifs_sb->local_nls,
						 cifs_sb->mnt_cifs_flags &
						   CIFS_MOUNT_MAP_SPECIAL_CHR);
			kfree(tmp_path);
			/* BB fix up inode etc. */
		} else if (rc) {
			kfree(buf);
			return rc;
		}
	} else {
		struct cifsInodeInfo *cifsInfo;
		__u32 attr = le32_to_cpu(pfindData->Attributes);

		/* get new inode */
		if (*pinode == NULL) {
			*pinode = new_inode(sb);
			if (*pinode == NULL) {
				kfree(buf);
				return -ENOMEM;
			}
			/* Is an i_ino of zero legal? Can we use that to check
			   if the server supports returning inode numbers?  Are
			   there other sanity checks we can use to ensure that
			   the server is really filling in that field? */

			/* We can not use the IndexNumber field by default from
			   Windows or Samba (in ALL_INFO buf) but we can request
			   it explicitly.  It may not be unique presumably if
			   the server has multiple devices mounted under one
			   share */

			/* There may be higher info levels that work but are