[CIFS] UID/GID override on CIFS mounts to Samba

When CIFS Unix Extensions are negotiated we get the Unix uid and gid
owners of the file from the server (on the Unix Query Path Info
levels), but if the server's uids don't match the client uid's users
were having to disable the Unix Extensions (which turned off features
they still wanted).   The changeset patch allows users to override uid
and/or gid for file/directory owner with a default uid and/or gid
specified at mount (as is often done when mounting from Linux cifs
client to Windows server).  This changeset also displays the uid
and gid used by default in /proc/mounts (if applicable).

Also cleans up code by adding some of the missing spaces after
"if" keywords per-kernel style guidelines (as suggested by Randy Dunlap
when he reviewed the patch).

Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 43 insertions, 36 deletions

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index c1af1599568..1f4bc718170 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -75,6 +75,8 @@ struct smb_vol {
         unsigned retry:1;
         unsigned intr:1;
         unsigned setuids:1;
+        unsigned override_uid:1;
+        unsigned override_gid:1;
         unsigned noperm:1;
         unsigned no_psx_acl:1; /* set if posix acl support should be disabled */
         unsigned cifs_acl:1;
@@ -972,7 +974,7 @@ cifs_parse_mount_options(char *options, const char *devname,struct smb_vol *vol)
                         }
                         if ((temp_len = strnlen(value, 300)) < 300) {
                                 vol->UNC = kmalloc(temp_len+1,GFP_KERNEL);
-                                if(vol->UNC == NULL)
+                                if (vol->UNC == NULL)
                                         return 1;
                                 strcpy(vol->UNC,value);
                                 if (strncmp(vol->UNC, "//", 2) == 0) {
@@ -1009,12 +1011,12 @@ cifs_parse_mount_options(char *options, const char *devname,struct smb_vol *vol)
                                 return 1;       /* needs_arg; */
                         }
                         if ((temp_len = strnlen(value, 1024)) < 1024) {
-                                if(value[0] != '/')
+                                if (value[0] != '/')
                                         temp_len++;  /* missing leading slash */
                                 vol->prepath = kmalloc(temp_len+1,GFP_KERNEL);
-                                if(vol->prepath == NULL)
+                                if (vol->prepath == NULL)
                                         return 1;
-                                if(value[0] != '/') {
+                                if (value[0] != '/') {
                                         vol->prepath[0] = '/';
                                         strcpy(vol->prepath+1,value);
                                 } else
@@ -1030,7 +1032,7 @@ cifs_parse_mount_options(char *options, const char *devname,struct smb_vol *vol)
                                 return 1;       /* needs_arg; */
                         }
                         if (strnlen(value, 65) < 65) {
-                                if(strnicmp(value,"default",7))
+                                if (strnicmp(value,"default",7))
                                         vol->iocharset = value;
                                 /* if iocharset not set load_nls_default used by caller */
                                 cFYI(1, ("iocharset set to %s",value));
@@ -1042,11 +1044,13 @@ cifs_parse_mount_options(char *options, const char *devname,struct smb_vol *vol)
                         if (value && *value) {
                                 vol->linux_uid =
                                         simple_strtoul(value, &value, 0);
+                                vol->override_uid = 1;
                         }
                 } else if (strnicmp(data, "gid", 3) == 0) {
                         if (value && *value) {
                                 vol->linux_gid =
                                         simple_strtoul(value, &value, 0);
+                                vol->override_gid = 1;
                         }
                 } else if (strnicmp(data, "file_mode", 4) == 0) {
                         if (value && *value) {
@@ -1101,7 +1105,7 @@ cifs_parse_mount_options(char *options, const char *devname,struct smb_vol *vol)
                                 }
                                 /* The string has 16th byte zero still from
                                 set at top of the function  */
-                                if((i==15) && (value[i] != 0))
+                                if ((i==15) && (value[i] != 0))
                                         printk(KERN_WARNING "CIFS: netbiosname longer than 15 truncated.\n");
                         }
                 } else if (strnicmp(data, "servern", 7) == 0) {
@@ -1125,7 +1129,7 @@ cifs_parse_mount_options(char *options, const char *devname,struct smb_vol *vol)
                                 }
                                 /* The string has 16th byte zero still from
                                    set at top of the function  */
-                                if((i==15) && (value[i] != 0))
+                                if ((i==15) && (value[i] != 0))
                                         printk(KERN_WARNING "CIFS: server netbiosname longer than 15 truncated.\n");
                         }
                 } else if (strnicmp(data, "credentials", 4) == 0) {
@@ -1232,13 +1236,13 @@ cifs_parse_mount_options(char *options, const char *devname,struct smb_vol *vol)
                         printk(KERN_WARNING "CIFS: Unknown mount option %s\n",data);
         }
         if (vol->UNC == NULL) {
-                if(devname == NULL) {
+                if (devname == NULL) {
                         printk(KERN_WARNING "CIFS: Missing UNC name for mount target\n");
                         return 1;
                 }
                 if ((temp_len = strnlen(devname, 300)) < 300) {
                         vol->UNC = kmalloc(temp_len+1,GFP_KERNEL);
-                        if(vol->UNC == NULL)
+                        if (vol->UNC == NULL)
                                 return 1;
                         strcpy(vol->UNC,devname);
                         if (strncmp(vol->UNC, "//", 2) == 0) {
@@ -1813,7 +1817,7 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
         if (srvTcp) {
                 cFYI(1, ("Existing tcp session with server found"));                
         } else {        /* create socket */
-                if(volume_info.port)
+                if (volume_info.port)
                         sin_server.sin_port = htons(volume_info.port);
                 else
                         sin_server.sin_port = 0;
@@ -1829,7 +1833,7 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
                 if (rc < 0) {
                         cERROR(1,
                                ("Error connecting to IPv4 socket. Aborting operation"));                               
-                        if(csocket != NULL)
+                        if (csocket != NULL)
                                 sock_release(csocket);
                         kfree(volume_info.UNC);
                         kfree(volume_info.password);
@@ -1863,7 +1867,7 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
                         srvTcp->tcpStatus = CifsNew;
                         init_MUTEX(&srvTcp->tcpSem);
                         srvTcp->tsk = kthread_run((void *)(void *)cifs_demultiplex_thread, srvTcp, "cifsd");
-                        if( IS_ERR(srvTcp->tsk) ) {
+                        if ( IS_ERR(srvTcp->tsk) ) {
                                 rc = PTR_ERR(srvTcp->tsk);
                                 cERROR(1,("error %d create cifsd thread", rc));
                                 srvTcp->tsk = NULL;
@@ -1909,7 +1913,7 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
                                 int len = strlen(volume_info.domainname);
                                 pSesInfo->domainName = 
                                         kmalloc(len + 1, GFP_KERNEL);
-                                if(pSesInfo->domainName)
+                                if (pSesInfo->domainName)
                                         strcpy(pSesInfo->domainName,
                                                 volume_info.domainname);
                         }
@@ -1919,7 +1923,7 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
                         /* BB FIXME need to pass vol->secFlgs BB */
                         rc = cifs_setup_session(xid,pSesInfo, cifs_sb->local_nls);
                         up(&pSesInfo->sesSem);
-                        if(!rc)
+                        if (!rc)
                                 atomic_inc(&srvTcp->socketUseCount);
                 } else
                         kfree(volume_info.password);
@@ -1927,7 +1931,7 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
     
         /* search for existing tcon to this server share */
         if (!rc) {
-                if(volume_info.rsize > CIFSMaxBufSize) {
+                if (volume_info.rsize > CIFSMaxBufSize) {
                         cERROR(1,("rsize %d too large, using MaxBufSize",
                                 volume_info.rsize));
                         cifs_sb->rsize = CIFSMaxBufSize;
@@ -1936,11 +1940,11 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
                 else /* default */
                         cifs_sb->rsize = CIFSMaxBufSize;
 
-                if(volume_info.wsize > PAGEVEC_SIZE * PAGE_CACHE_SIZE) {
+                if (volume_info.wsize > PAGEVEC_SIZE * PAGE_CACHE_SIZE) {
                         cERROR(1,("wsize %d too large using 4096 instead",
                                   volume_info.wsize));
                         cifs_sb->wsize = 4096;
-                } else if(volume_info.wsize)
+                } else if (volume_info.wsize)
                         cifs_sb->wsize = volume_info.wsize;
                 else
                         cifs_sb->wsize = 
@@ -1953,14 +1957,14 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
                            conjunction with 52K kvec constraint on arch with 4K
                            page size  */
 
-                if(cifs_sb->rsize < 2048) {
+                if (cifs_sb->rsize < 2048) {
                         cifs_sb->rsize = 2048; 
                         /* Windows ME may prefer this */
                         cFYI(1,("readsize set to minimum 2048"));
                 }
                 /* calculate prepath */
                 cifs_sb->prepath = volume_info.prepath;
-                if(cifs_sb->prepath) {
+                if (cifs_sb->prepath) {
                         cifs_sb->prepathlen = strlen(cifs_sb->prepath);
                         cifs_sb->prepath[0] = CIFS_DIR_SEP(cifs_sb);
                         volume_info.prepath = NULL;
@@ -1973,24 +1977,27 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
                 cFYI(1,("file mode: 0x%x  dir mode: 0x%x",
                         cifs_sb->mnt_file_mode,cifs_sb->mnt_dir_mode));
 
-                if(volume_info.noperm)
+                if (volume_info.noperm)
                         cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NO_PERM;
-                if(volume_info.setuids)
+                if (volume_info.setuids)
                         cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_SET_UID;
-                if(volume_info.server_ino)
+                if (volume_info.server_ino)
                         cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_SERVER_INUM;
-                if(volume_info.remap)
+                if (volume_info.remap)
                         cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_MAP_SPECIAL_CHR;
-                if(volume_info.no_xattr)
+                if (volume_info.no_xattr)
                         cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NO_XATTR;
-                if(volume_info.sfu_emul)
+                if (volume_info.sfu_emul)
                         cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_UNX_EMUL;
-                if(volume_info.nobrl)
+                if (volume_info.nobrl)
                         cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NO_BRL;
-                if(volume_info.cifs_acl)
+                if (volume_info.cifs_acl)
                         cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_CIFS_ACL;
-
-                if(volume_info.direct_io) {
+                if (volume_info.override_uid)
+                        cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_OVERR_UID;
+                if (volume_info.override_gid)
+                        cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_OVERR_GID;
+                if (volume_info.direct_io) {
                         cFYI(1,("mounting share using direct i/o"));
                         cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_DIRECT_IO;
                 }
@@ -2043,7 +2050,7 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
                         }
                 }
         }
-        if(pSesInfo) {
+        if (pSesInfo) {
                 if (pSesInfo->capabilities & CAP_LARGE_FILES) {
                         sb->s_maxbytes = (u64) 1 << 63;
                 } else
@@ -2057,11 +2064,11 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
         if (rc) {
                 /* if session setup failed, use count is zero but
                 we still need to free cifsd thread */
-                if(atomic_read(&srvTcp->socketUseCount) == 0) {
+                if (atomic_read(&srvTcp->socketUseCount) == 0) {
                         spin_lock(&GlobalMid_Lock);
                         srvTcp->tcpStatus = CifsExiting;
                         spin_unlock(&GlobalMid_Lock);
-                        if(srvTcp->tsk) {
+                        if (srvTcp->tsk) {
                                 send_sig(SIGKILL,srvTcp->tsk,1);
                                 kthread_stop(srvTcp->tsk);
                         }
@@ -2076,7 +2083,7 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
                                         int temp_rc;
                                         temp_rc = CIFSSMBLogoff(xid, pSesInfo);
                                         /* if the socketUseCount is now zero */
-                                        if((temp_rc == -ESHUTDOWN) &&
+                                        if ((temp_rc == -ESHUTDOWN) &&
                                            (pSesInfo->server) && (pSesInfo->server->tsk)) {
                                                 send_sig(SIGKILL,pSesInfo->server->tsk,1);
                                                 kthread_stop(pSesInfo->server->tsk);
@@ -2140,7 +2147,7 @@ CIFSSessSetup(unsigned int xid, struct cifsSesInfo *ses,
         __u16 count;
 
         cFYI(1, ("In sesssetup"));
-        if(ses == NULL)
+        if (ses == NULL)
                 return -EINVAL;
         user = ses->userName;
         domain = ses->domainName;
@@ -2195,7 +2202,7 @@ CIFSSessSetup(unsigned int xid, struct cifsSesInfo *ses,
                         *bcc_ptr = 0;
                         bcc_ptr++;
                 }
-                if(user == NULL)
+                if (user == NULL)
                         bytes_returned = 0; /* skip null user */
                 else
                         bytes_returned =
@@ -2229,7 +2236,7 @@ CIFSSessSetup(unsigned int xid, struct cifsSesInfo *ses,
                 bcc_ptr += 2 * bytes_returned;
                 bcc_ptr += 2;
         } else {
-                if(user != NULL) {                
+                if (user != NULL) {                
                     strncpy(bcc_ptr, user, 200);
                     bcc_ptr += strnlen(user, 200);
                 }