[CIFS] Allow disabling CIFS Unix Extensions as mount option

Previously the only way to do this was to umount all mounts to that server,
turn off a proc setting (/proc/fs/cifs/LinuxExtensionsEnabled).

Fixes Samba bugzilla bug number: 4582 (and also 2008)

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

9 files changed, 65 insertions, 46 deletions

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index a0a2f3186557..1cebb7e34215 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -316,10 +316,10 @@ cifs_show_options(struct seq_file *s, struct vfsmount *m)
                 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS)
                         seq_printf(s, ",posixpaths");
                 if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_OVERR_UID) ||
-                   !(cifs_sb->tcon->ses->capabilities & CAP_UNIX))
+                   !(cifs_sb->tcon->unix_ext))
                         seq_printf(s, ",uid=%d", cifs_sb->mnt_uid);
                 if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_OVERR_GID) ||
-                   !(cifs_sb->tcon->ses->capabilities & CAP_UNIX))
+                   !(cifs_sb->tcon->unix_ext))
                         seq_printf(s, ",gid=%d", cifs_sb->mnt_gid);
                 seq_printf(s, ",rsize=%d", cifs_sb->rsize);
                 seq_printf(s, ",wsize=%d", cifs_sb->wsize);
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 0a7813175a27..b98742fc3b5a 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -281,7 +281,9 @@ struct cifsTconInfo {
         FILE_SYSTEM_UNIX_INFO fsUnixInfo;
         unsigned retry:1;
         unsigned nocase:1;
-        /* BB add field for back pointer to sb struct? */
+        unsigned unix_ext:1; /* if off disable Linux extensions to CIFS protocol
+                                for this mount even if server would support */
+        /* BB add field for back pointer to sb struct(s)? */
 };
 
 /*
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index a6ff406ac6b4..8eb102f940d4 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -132,10 +132,10 @@ small_smb_init(int smb_command, int wct, struct cifsTconInfo *tcon,
                                 /* Give Demultiplex thread up to 10 seconds to
                                    reconnect, should be greater than cifs socket
                                    timeout which is 7 seconds */
-                        while(tcon->ses->server->tcpStatus ==
+                        while (tcon->ses->server->tcpStatus ==
                                                          CifsNeedReconnect) {
                                 wait_event_interruptible_timeout(tcon->ses->server->response_q,
-                                        (tcon->ses->server->tcpStatus == 
+                                        (tcon->ses->server->tcpStatus ==
                                                         CifsGood), 10 * HZ);
                                 if (tcon->ses->server->tcpStatus ==
                                                         CifsNeedReconnect) {
@@ -213,7 +213,7 @@ small_smb_init(int smb_command, int wct, struct cifsTconInfo *tcon,
         }
 
         header_assemble((struct smb_hdr *) *request_buf, smb_command,
-                        tcon,wct);
+                        tcon, wct);
 
         if (tcon != NULL)
                 cifs_stats_inc(&tcon->num_smbs_sent);
@@ -387,7 +387,7 @@ static int validate_t2(struct smb_t2_rsp *pSMB)
                         /* check that bcc is less than negotiated smb buffer */
                         total_size = le16_to_cpu(pSMB->t2_rsp.ParameterCount);
                         if (total_size < 512) {
-                                total_size += 
+                                total_size +=
                                         le16_to_cpu(pSMB->t2_rsp.DataCount);
                                 /* BCC le converted in SendReceive */
                                 pBCC = (pSMB->hdr.WordCount * 2) +
@@ -2758,7 +2758,7 @@ static __u16 ACL_to_cifs_posix(char *parm_data, const char *pACL,
                 return 0;
 
         count = posix_acl_xattr_count((size_t)buflen);
-        cFYI(1,("setting acl with %d entries from buf of length %d and "
+        cFYI(1, ("setting acl with %d entries from buf of length %d and "
                 "version of %d",
                 count, buflen, le32_to_cpu(local_acl->a_version)));
         if (le32_to_cpu(local_acl->a_version) != 2) {
@@ -3638,15 +3638,6 @@ int CIFSFindNext(const int xid, struct cifsTconInfo *tcon,
         pSMB->SearchHandle = searchHandle;      /* always kept as le */
         pSMB->SearchCount =
                 cpu_to_le16(CIFSMaxBufSize / sizeof (FILE_UNIX_INFO));
-        /* test for Unix extensions */
-/*      if (tcon->ses->capabilities & CAP_UNIX) {
-                pSMB->InformationLevel = cpu_to_le16(SMB_FIND_FILE_UNIX);
-                psrch_inf->info_level = SMB_FIND_FILE_UNIX;
-        } else {
-                pSMB->InformationLevel =
-                   cpu_to_le16(SMB_FIND_FILE_DIRECTORY_INFO);
-                psrch_inf->info_level = SMB_FIND_FILE_DIRECTORY_INFO;
-        } */
         pSMB->InformationLevel = cpu_to_le16(psrch_inf->info_level);
         pSMB->ResumeKey = psrch_inf->resume_key;
         pSMB->SearchFlags =
@@ -3966,7 +3957,7 @@ getDFSRetry:
                                         (8 /* sizeof start of data block */ +
                                         data_offset +
                                         (char *) &pSMBr->hdr.Protocol);
-                        cFYI(1,("num_referrals: %d dfs flags: 0x%x ... \n"
+                        cFYI(1, ("num_referrals: %d dfs flags: 0x%x ... \n"
                                 "for referral one refer size: 0x%x srv "
                                 "type: 0x%x refer flags: 0x%x ttl: 0x%x",
                                 le16_to_cpu(pSMBr->NumberOfReferrals),
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 8b341a8599f8..e93da7ad9002 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -85,6 +85,7 @@ struct smb_vol {
         unsigned direct_io:1;
         unsigned remap:1;   /* set to remap seven reserved chars in filenames */
         unsigned posix_paths:1;   /* unset to not ask for posix pathnames. */
+        unsigned no_linux_ext:1;
         unsigned sfu_emul:1;
         unsigned nullauth:1; /* attempt to authenticate with null user */
         unsigned nocase;     /* request case insensitive filenames */
@@ -1192,6 +1193,10 @@ cifs_parse_mount_options(char *options, const char *devname,
                         vol->posix_paths = 1;
                 } else if (strnicmp(data, "noposixpaths", 12) == 0) {
                         vol->posix_paths = 0;
+                } else if (strnicmp(data, "nounix", 6) == 0) {
+                        vol->no_linux_ext = 1;
+                } else if (strnicmp(data, "nolinux", 7) == 0) {
+                        vol->no_linux_ext = 1;
                 } else if ((strnicmp(data, "nocase", 6) == 0) ||
                            (strnicmp(data, "ignorecase", 10)  == 0)) {
                         vol->nocase = 1;
@@ -1665,6 +1670,18 @@ void reset_cifs_unix_caps(int xid, struct cifsTconInfo *tcon,
          * and once without posixacls or posix paths? */
         __u64 saved_cap = le64_to_cpu(tcon->fsUnixInfo.Capability);
 
+        if (vol_info && vol_info->no_linux_ext) {
+                tcon->fsUnixInfo.Capability = 0;
+                tcon->unix_ext = 0; /* Unix Extensions disabled */
+                cFYI(1, ("Linux protocol extensions disabled"));
+                return;
+        } else if (vol_info)
+                tcon->unix_ext = 1; /* Unix Extensions supported */
+
+        if (tcon->unix_ext == 0) {
+                cFYI(1, ("Unix extensions disabled so not set on reconnect"));
+                return;
+        }
 
         if (!CIFSSMBQFSUnixInfo(xid, tcon)) {
                 __u64 cap = le64_to_cpu(tcon->fsUnixInfo.Capability);
@@ -1678,10 +1695,6 @@ void reset_cifs_unix_caps(int xid, struct cifsTconInfo *tcon,
                                 cap &= ~CIFS_UNIX_POSIX_ACL_CAP;
                         if ((saved_cap & CIFS_UNIX_POSIX_PATHNAMES_CAP) == 0)
                                 cap &= ~CIFS_UNIX_POSIX_PATHNAMES_CAP;
-
-
-
-
                 }
 
                 cap &= CIFS_UNIX_CAP_MASK;
@@ -2176,13 +2189,17 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
 
                 /* tell server which Unix caps we support */
                 if (tcon->ses->capabilities & CAP_UNIX)
+                        /* reset of caps checks mount to see if unix extensions
+                           disabled for just this mount */
                         reset_cifs_unix_caps(xid, tcon, sb, &volume_info);
-                else if (cifs_sb->rsize > (1024 * 127)) {
+                else
+                        tcon->unix_ext = 0; /* server does not support them */
+
+                if ((tcon->unix_ext == 0) && (cifs_sb->rsize > (1024 * 127))) {
                         cifs_sb->rsize = 1024 * 127;
 #ifdef CONFIG_CIFS_DEBUG2
-                        cFYI(1, ("no very large read support, rsize 127K"));
+                        cFYI(1, ("no very large read support, rsize now 127K"));
 #endif
-
                 }
                 if (!(tcon->ses->capabilities & CAP_LARGE_WRITE_X))
                         cifs_sb->wsize = min(cifs_sb->wsize,
diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index def89f23fe55..4830acc86d74 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -207,8 +207,7 @@ cifs_create(struct inode *inode, struct dentry *direntry, int mode,
         } else {
                 /* If Open reported that we actually created a file
                 then we now have to set the mode if possible */
-                if ((cifs_sb->tcon->ses->capabilities & CAP_UNIX) &&
-                        (oplock & CIFS_CREATE_ACTION)) {
+                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,
@@ -235,8 +234,8 @@ cifs_create(struct inode *inode, struct dentry *direntry, int mode,
                         /* Could set r/o dos attribute if mode & 0222 == 0 */
                 }
 
-        /* BB server might mask mode so we have to query for Unix case*/
-                if (pTcon->ses->capabilities & CAP_UNIX)
+                /* 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 {
@@ -337,7 +336,7 @@ int cifs_mknod(struct inode *inode, struct dentry *direntry, int mode,
         full_path = build_path_from_dentry(direntry);
         if (full_path == NULL)
                 rc = -ENOMEM;
-        else if (pTcon->ses->capabilities & CAP_UNIX) {
+        else if (pTcon->unix_ext) {
                 mode &= ~current->fs->umask;
                 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SET_UID) {
                         rc = CIFSSMBUnixSetPerms(xid, pTcon, full_path,
@@ -491,7 +490,7 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
         cFYI(1,
              (" Full path: %s inode = 0x%p", full_path, direntry->d_inode));
 
-        if (pTcon->ses->capabilities & CAP_UNIX)
+        if (pTcon->unix_ext)
                 rc = cifs_get_inode_info_unix(&newInode, full_path,
                                               parent_dir_inode->i_sb, xid);
         else
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 0a39491280d1..e13592afca9c 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -138,7 +138,7 @@ static inline int cifs_open_inode_helper(struct inode *inode, struct file *file,
         }
 
 client_can_cache:
-        if (pTcon->ses->capabilities & CAP_UNIX)
+        if (pTcon->unix_ext)
                 rc = cifs_get_inode_info_unix(&file->f_path.dentry->d_inode,
                         full_path, inode->i_sb, xid);
         else
@@ -303,7 +303,7 @@ int cifs_open(struct inode *inode, struct file *file)
         if (oplock & CIFS_CREATE_ACTION) {
                 /* 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) {
+                if (pTcon->unix_ext) {
                         CIFSSMBUnixSetPerms(xid, pTcon, full_path,
                                             inode->i_mode,
                                             (__u64)-1, (__u64)-1, 0 /* dev */,
@@ -430,7 +430,7 @@ reopen_error_exit:
                            go to server to get inode info */
                                 pCifsInode->clientCanCacheAll = FALSE;
                                 pCifsInode->clientCanCacheRead = FALSE;
-                                if (pTcon->ses->capabilities & CAP_UNIX)
+                                if (pTcon->unix_ext)
                                         rc = cifs_get_inode_info_unix(&inode,
                                                 full_path, inode->i_sb, xid);
                                 else
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 3482879b3d3f..dd4167762a8e 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -583,7 +583,8 @@ void cifs_read_inode(struct inode *inode)
 
         cifs_sb = CIFS_SB(inode->i_sb);
         xid = GetXid();
-        if (cifs_sb->tcon->ses->capabilities & CAP_UNIX)
+
+        if (cifs_sb->tcon->unix_ext)
                 cifs_get_inode_info_unix(&inode, "", inode->i_sb, xid);
         else
                 cifs_get_inode_info(&inode, "", NULL, inode->i_sb, xid);
@@ -981,7 +982,7 @@ int cifs_mkdir(struct inode *inode, struct dentry *direntry, int mode)
         } else {
 mkdir_get_info:
                 inc_nlink(inode);
-                if (pTcon->ses->capabilities & CAP_UNIX)
+                if (pTcon->unix_ext)
                         rc = cifs_get_inode_info_unix(&newinode, full_path,
                                                       inode->i_sb, xid);
                 else
@@ -997,7 +998,7 @@ mkdir_get_info:
                   * failed to get it from the server or was set bogus */
                 if ((direntry->d_inode) && (direntry->d_inode->i_nlink < 2))
                                 direntry->d_inode->i_nlink = 2;
-                if (cifs_sb->tcon->ses->capabilities & CAP_UNIX) {
+                if (pTcon->unix_ext) {
                         mode &= ~current->fs->umask;
                         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SET_UID) {
                                 CIFSSMBUnixSetPerms(xid, pTcon, full_path,
@@ -1130,7 +1131,7 @@ int cifs_rename(struct inode *source_inode, struct dentry *source_direntry,
                         kmalloc(2 * sizeof(FILE_UNIX_BASIC_INFO), GFP_KERNEL);
                 if (info_buf_source != NULL) {
                         info_buf_target = info_buf_source + 1;
-                        if (pTcon->ses->capabilities & CAP_UNIX)
+                        if (pTcon->unix_ext)
                                 rc = CIFSSMBUnixQPathInfo(xid, pTcon, fromName,
                                         info_buf_source,
                                         cifs_sb_source->local_nls,
@@ -1258,7 +1259,7 @@ int cifs_revalidate(struct dentry *direntry)
         local_mtime = direntry->d_inode->i_mtime;
         local_size = direntry->d_inode->i_size;
 
-        if (cifs_sb->tcon->ses->capabilities & CAP_UNIX) {
+        if (cifs_sb->tcon->unix_ext) {
                 rc = cifs_get_inode_info_unix(&direntry->d_inode, full_path,
                                               direntry->d_sb, xid);
                 if (rc) {
@@ -1542,7 +1543,7 @@ int cifs_setattr(struct dentry *direntry, struct iattr *attrs)
                 mode = attrs->ia_mode;
         }
 
-        if ((cifs_sb->tcon->ses->capabilities & CAP_UNIX)
+        if ((pTcon->unix_ext)
             && (attrs->ia_valid & (ATTR_MODE | ATTR_GID | ATTR_UID)))
                 rc = CIFSSMBUnixSetPerms(xid, pTcon, full_path, mode, uid, gid,
                                          0 /* dev_t */, cifs_sb->local_nls,
diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index 7da755c6550a..6a85ef7b8797 100644
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -55,7 +55,8 @@ cifs_hardlink(struct dentry *old_file, struct inode *inode,
                 goto cifs_hl_exit;
         }
 
-        if (cifs_sb_target->tcon->ses->capabilities & CAP_UNIX)
+/*      if (cifs_sb_target->tcon->ses->capabilities & CAP_UNIX)*/
+        if (pTcon->unix_ext)
                 rc = CIFSUnixCreateHardLink(xid, pTcon, fromName, toName,
                                             cifs_sb_target->local_nls,
                                             cifs_sb_target->mnt_cifs_flags &
@@ -129,14 +130,19 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
                 goto out;
         }
 
-        /* BB add read reparse point symlink code and Unix extensions
-           symlink code here BB */
+        /* We could change this to:
+                if (pTcon->unix_ext)
+           but there does not seem any point in refusing to
+           get symlink info if we can, even if unix extensions
+           turned off for this mount */
+
         if (pTcon->ses->capabilities & CAP_UNIX)
                 rc = CIFSSMBUnixQuerySymLink(xid, pTcon, full_path,
                                              target_path,
                                              PATH_MAX-1,
                                              cifs_sb->local_nls);
         else {
+                /* BB add read reparse point symlink code here */
                 /* rc = CIFSSMBQueryReparseLinkInfo */
                 /* BB Add code to Query ReparsePoint info */
                 /* BB Add MAC style xsymlink check here if enabled */
@@ -186,7 +192,7 @@ cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
         cFYI(1, ("symname is %s", symname));
 
         /* BB what if DFS and this volume is on different share? BB */
-        if (cifs_sb->tcon->ses->capabilities & CAP_UNIX)
+        if (pTcon->unix_ext)
                 rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
                                            cifs_sb->local_nls);
         /* else
@@ -194,7 +200,7 @@ cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
                                         cifs_sb_target->local_nls); */
 
         if (rc == 0) {
-                if (pTcon->ses->capabilities & CAP_UNIX)
+                if (pTcon->unix_ext)
                         rc = cifs_get_inode_info_unix(&newinode, full_path,
                                                       inode->i_sb, xid);
                 else
@@ -266,6 +272,7 @@ cifs_readlink(struct dentry *direntry, char __user *pBuffer, int buflen)
 
 /* BB add read reparse point symlink code and
         Unix extensions symlink code here BB */
+/* We could disable this based on pTcon->unix_ext flag instead ... but why? */
         if (cifs_sb->tcon->ses->capabilities & CAP_UNIX)
                 rc = CIFSSMBUnixQuerySymLink(xid, pTcon, full_path,
                                 tmpbuffer,
diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
index 07f92531f74f..916df9431336 100644
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -463,7 +463,9 @@ static int initiate_cifs_search(const int xid, struct file *file)
 
 ffirst_retry:
         /* test for Unix extensions */
-        if (pTcon->ses->capabilities & CAP_UNIX) {
+        /* but now check for them on the share/mount not on the SMB session */
+/*      if (pTcon->ses->capabilities & CAP_UNIX) { */
+        if (pTcon->unix_ext) {
                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_UNIX;
         } else if ((pTcon->ses->capabilities &
                         (CAP_NT_SMBS | CAP_NT_FIND)) == 0) {