cifs: don't pass superblock to cifs_mount()

To close sget() races we'll need to be able to set cifs_sb up before
we get the superblock, so we'll want to be able to do cifs_mount()
earlier.  Fortunately, it's easy to do - setting ->s_maxbytes can
be done in cifs_read_super(), ditto for ->s_time_gran and as for
putting MS_POSIXACL into ->s_flags, we can mirror it in ->mnt_cifs_flags
until cifs_read_super() is called.  Kill unused 'devname' argument,
while we are at it...

Acked-by: Pavel Shilovsky <piastryyy@gmail.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

4 files changed, 26 insertions, 22 deletions

diff --git a/fs/cifs/cifs_fs_sb.h b/fs/cifs/cifs_fs_sb.h
index ffb1459dc6ec..7260e11e21f8 100644
--- a/fs/cifs/cifs_fs_sb.h
+++ b/fs/cifs/cifs_fs_sb.h
@@ -42,6 +42,7 @@
 #define CIFS_MOUNT_MULTIUSER    0x20000 /* multiuser mount */
 #define CIFS_MOUNT_STRICT_IO    0x40000 /* strict cache mode */
 #define CIFS_MOUNT_RWPIDFORWARD 0x80000 /* use pid forwarding for rw */
+#define CIFS_MOUNT_POSIXACL     0x100000 /* mirror of MS_POSIXACL in mnt_cifs_flags */
 
 struct cifs_sb_info {
         struct rb_root tlink_tree;
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index bfab2bc83726..8f7451f3c8e6 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -116,7 +116,7 @@ cifs_read_super(struct super_block *sb, struct smb_vol *volume_info,
         spin_lock_init(&cifs_sb->tlink_tree_lock);
         cifs_sb->tlink_tree = RB_ROOT;
 
-        rc = cifs_mount(sb, cifs_sb, volume_info, devname);
+        rc = cifs_mount(cifs_sb, volume_info);
 
         if (rc) {
                 if (!silent)
@@ -124,6 +124,17 @@ cifs_read_super(struct super_block *sb, struct smb_vol *volume_info,
                 return rc;
         }
 
+        if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIXACL)
+                sb->s_flags |= MS_POSIXACL;
+
+        if (cifs_sb_master_tcon(cifs_sb)->ses->capabilities & CAP_LARGE_FILES)
+                sb->s_maxbytes = MAX_LFS_FILESIZE;
+        else
+                sb->s_maxbytes = MAX_NON_LFS;
+
+        /* BB FIXME fix time_gran to be larger for LANMAN sessions */
+        sb->s_time_gran = 100;
+
         sb->s_magic = CIFS_MAGIC_NUMBER;
         sb->s_op = &cifs_super_ops;
         sb->s_bdi = &cifs_sb->bdi;
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 953f84413c77..5814fe543f95 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -157,8 +157,7 @@ extern int cifs_match_super(struct super_block *, void *);
 extern void cifs_cleanup_volume_info(struct smb_vol **pvolume_info);
 extern int cifs_setup_volume_info(struct smb_vol **pvolume_info,
                                   char *mount_data, const char *devname);
-extern int cifs_mount(struct super_block *, struct cifs_sb_info *,
-                      struct smb_vol *, const char *);
+extern int cifs_mount(struct cifs_sb_info *, struct smb_vol *);
 extern int cifs_umount(struct super_block *, struct cifs_sb_info *);
 extern void cifs_dfs_release_automount_timer(void);
 void cifs_proc_init(void);
@@ -218,7 +217,8 @@ extern int get_dfs_path(int xid, struct cifs_ses *pSesInfo,
                         struct dfs_info3_param **preferrals,
                         int remap);
 extern void reset_cifs_unix_caps(int xid, struct cifs_tcon *tcon,
-                                 struct super_block *sb, struct smb_vol *vol);
+                                 struct cifs_sb_info *cifs_sb,
+                                 struct smb_vol *vol);
 extern int CIFSSMBQFSInfo(const int xid, struct cifs_tcon *tcon,
                         struct kstatfs *FSData);
 extern int SMBOldQFSInfo(const int xid, struct cifs_tcon *tcon,
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 78fd7557e35d..3011ac8c9249 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2546,7 +2546,7 @@ ip_connect(struct TCP_Server_Info *server)
 }
 
 void reset_cifs_unix_caps(int xid, struct cifs_tcon *tcon,
-                          struct super_block *sb, struct smb_vol *vol_info)
+                          struct cifs_sb_info *cifs_sb, struct smb_vol *vol_info)
 {
         /* if we are reconnecting then should we check to see if
          * any requested capabilities changed locally e.g. via
@@ -2600,22 +2600,23 @@ void reset_cifs_unix_caps(int xid, struct cifs_tcon *tcon,
                         cap &= ~CIFS_UNIX_POSIX_ACL_CAP;
                 else if (CIFS_UNIX_POSIX_ACL_CAP & cap) {
                         cFYI(1, "negotiated posix acl support");
-                        if (sb)
-                                sb->s_flags |= MS_POSIXACL;
+                        if (cifs_sb)
+                                cifs_sb->mnt_cifs_flags |=
+                                        CIFS_MOUNT_POSIXACL;
                 }
 
                 if (vol_info && vol_info->posix_paths == 0)
                         cap &= ~CIFS_UNIX_POSIX_PATHNAMES_CAP;
                 else if (cap & CIFS_UNIX_POSIX_PATHNAMES_CAP) {
                         cFYI(1, "negotiate posix pathnames");
-                        if (sb)
-                                CIFS_SB(sb)->mnt_cifs_flags |=
+                        if (cifs_sb)
+                                cifs_sb->mnt_cifs_flags |=
                                         CIFS_MOUNT_POSIX_PATHS;
                 }
 
-                if (sb && (CIFS_SB(sb)->rsize > 127 * 1024)) {
+                if (cifs_sb && (cifs_sb->rsize > 127 * 1024)) {
                         if ((cap & CIFS_UNIX_LARGE_READ_CAP) == 0) {
-                                CIFS_SB(sb)->rsize = 127 * 1024;
+                                cifs_sb->rsize = 127 * 1024;
                                 cFYI(DBG2, "larger reads not supported by srv");
                         }
                 }
@@ -2971,8 +2972,7 @@ out:
 }
 
 int
-cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
-           struct smb_vol *volume_info, const char *devname)
+cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *volume_info)
 {
         int rc = 0;
         int xid;
@@ -3026,14 +3026,6 @@ try_mount_again:
                 goto mount_fail_check;
         }
 
-        if (pSesInfo->capabilities & CAP_LARGE_FILES)
-                sb->s_maxbytes = MAX_LFS_FILESIZE;
-        else
-                sb->s_maxbytes = MAX_NON_LFS;
-
-        /* BB FIXME fix time_gran to be larger for LANMAN sessions */
-        sb->s_time_gran = 100;
-
         /* search for existing tcon to this server share */
         tcon = cifs_get_tcon(pSesInfo, volume_info);
         if (IS_ERR(tcon)) {
@@ -3046,7 +3038,7 @@ try_mount_again:
         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);
+                reset_cifs_unix_caps(xid, tcon, cifs_sb, volume_info);
                 if ((tcon->ses->server->tcpStatus == CifsNeedReconnect) &&
                     (le64_to_cpu(tcon->fsUnixInfo.Capability) &
                      CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP)) {