cifs: add refcounted and timestamped container for holding tcons

Eventually, we'll need to track the use of tcons on a per-sb basis, so that
we know when it's ok to tear them down. Begin this conversion by adding a
new "tcon_link" struct and accessors that get it. For now, the core data
structures are untouched -- cifs_sb still just points to a single tcon and
the pointers are just cast to deal with the accessor functions. A later
patch will flesh this out.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 48 insertions, 17 deletions

diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index 23ec28a4c11f..bb3ea06ca6f4 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -137,7 +137,6 @@ cifs_new_fileinfo(struct inode *newinode, __u16 fileHandle, struct file *file,
 {
         struct cifsFileInfo *pCifsFile;
         struct cifsInodeInfo *pCifsInode;
-        struct cifs_sb_info *cifs_sb = CIFS_SB(mnt->mnt_sb);
 
         pCifsFile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
         if (pCifsFile == NULL)
@@ -191,7 +190,8 @@ int cifs_posix_open(char *full_path, struct inode **pinode,
         __u32 posix_flags = 0;
         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
         struct cifs_fattr fattr;
-        struct cifsTconInfo *tcon = cifs_sb_tcon(cifs_sb);
+        struct tcon_link *tlink;
+        struct cifsTconInfo *tcon;
 
         cFYI(1, "posix open %s", full_path);
 
@@ -226,10 +226,20 @@ int cifs_posix_open(char *full_path, struct inode **pinode,
                 posix_flags |= SMB_O_DIRECT;
 
         mode &= ~current_umask();
+
+        tlink = cifs_sb_tlink(cifs_sb);
+        if (IS_ERR(tlink)) {
+                rc = PTR_ERR(tlink);
+                goto posix_open_ret;
+        }
+
+        tcon = tlink_tcon(tlink);
         rc = CIFSPOSIXCreate(xid, tcon, posix_flags, mode, pnetfid, presp_data,
                              poplock, full_path, cifs_sb->local_nls,
                              cifs_sb->mnt_cifs_flags &
                                         CIFS_MOUNT_MAP_SPECIAL_CHR);
+        cifs_put_tlink(tlink);
+
         if (rc)
                 goto posix_open_ret;
 
@@ -290,6 +300,7 @@ cifs_create(struct inode *inode, struct dentry *direntry, int mode,
         int desiredAccess = GENERIC_READ | GENERIC_WRITE;
         __u16 fileHandle;
         struct cifs_sb_info *cifs_sb;
+        struct tcon_link *tlink;
         struct cifsTconInfo *tcon;
         char *full_path = NULL;
         FILE_ALL_INFO *buf = NULL;
@@ -299,13 +310,12 @@ cifs_create(struct inode *inode, struct dentry *direntry, int mode,
         xid = GetXid();
 
         cifs_sb = CIFS_SB(inode->i_sb);
-        tcon = cifs_sb_tcon(cifs_sb);
-
-        full_path = build_path_from_dentry(direntry);
-        if (full_path == NULL) {
-                rc = -ENOMEM;
-                goto cifs_create_out;
+        tlink = cifs_sb_tlink(cifs_sb);
+        if (IS_ERR(tlink)) {
+                FreeXid(xid);
+                return PTR_ERR(tlink);
         }
+        tcon = tlink_tcon(tlink);
 
         if (oplockEnabled)
                 oplock = REQ_OPLOCK;
@@ -315,6 +325,12 @@ cifs_create(struct inode *inode, struct dentry *direntry, int mode,
         else
                 oflags = FMODE_READ | SMB_O_CREAT;
 
+        full_path = build_path_from_dentry(direntry);
+        if (full_path == NULL) {
+                rc = -ENOMEM;
+                goto cifs_create_out;
+        }
+
         if (tcon->unix_ext && (tcon->ses->capabilities & CAP_UNIX) &&
             (CIFS_UNIX_POSIX_PATH_OPS_CAP &
                         le64_to_cpu(tcon->fsUnixInfo.Capability))) {
@@ -481,6 +497,7 @@ cifs_create_set_dentry:
 cifs_create_out:
         kfree(buf);
         kfree(full_path);
+        cifs_put_tlink(tlink);
         FreeXid(xid);
         return rc;
 }
@@ -491,6 +508,7 @@ int cifs_mknod(struct inode *inode, struct dentry *direntry, int mode,
         int rc = -EPERM;
         int xid;
         struct cifs_sb_info *cifs_sb;
+        struct tcon_link *tlink;
         struct cifsTconInfo *pTcon;
         char *full_path = NULL;
         struct inode *newinode = NULL;
@@ -503,10 +521,14 @@ int cifs_mknod(struct inode *inode, struct dentry *direntry, int mode,
         if (!old_valid_dev(device_number))
                 return -EINVAL;
 
-        xid = GetXid();
-
         cifs_sb = CIFS_SB(inode->i_sb);
-        pTcon = cifs_sb_tcon(cifs_sb);
+        tlink = cifs_sb_tlink(cifs_sb);
+        if (IS_ERR(tlink))
+                return PTR_ERR(tlink);
+
+        pTcon = tlink_tcon(tlink);
+
+        xid = GetXid();
 
         full_path = build_path_from_dentry(direntry);
         if (full_path == NULL) {
@@ -606,6 +628,7 @@ mknod_out:
         kfree(full_path);
         kfree(buf);
         FreeXid(xid);
+        cifs_put_tlink(tlink);
         return rc;
 }
 
@@ -619,6 +642,7 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
         __u16 fileHandle = 0;
         bool posix_open = false;
         struct cifs_sb_info *cifs_sb;
+        struct tcon_link *tlink;
         struct cifsTconInfo *pTcon;
         struct cifsFileInfo *cfile;
         struct inode *newInode = NULL;
@@ -633,7 +657,12 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
         /* check whether path exists */
 
         cifs_sb = CIFS_SB(parent_dir_inode->i_sb);
-        pTcon = cifs_sb_tcon(cifs_sb);
+        tlink = cifs_sb_tlink(cifs_sb);
+        if (IS_ERR(tlink)) {
+                FreeXid(xid);
+                return (struct dentry *)tlink;
+        }
+        pTcon = tlink_tcon(tlink);
 
         /*
          * Don't allow the separator character in a path component.
@@ -644,8 +673,8 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
                 for (i = 0; i < direntry->d_name.len; i++)
                         if (direntry->d_name.name[i] == '\\') {
                                 cFYI(1, "Invalid file name");
-                                FreeXid(xid);
-                                return ERR_PTR(-EINVAL);
+                                rc = -EINVAL;
+                                goto lookup_out;
                         }
         }
 
@@ -655,7 +684,8 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
          */
         if (nd && (nd->flags & LOOKUP_EXCL)) {
                 d_instantiate(direntry, NULL);
-                return NULL;
+                rc = 0;
+                goto lookup_out;
         }
 
         /* can not grab the rename sem here since it would
@@ -663,8 +693,8 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
         in which we already have the sb rename sem */
         full_path = build_path_from_dentry(direntry);
         if (full_path == NULL) {
-                FreeXid(xid);
-                return ERR_PTR(-ENOMEM);
+                rc = -ENOMEM;
+                goto lookup_out;
         }
 
         if (direntry->d_inode != NULL) {
@@ -760,6 +790,7 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
 
 lookup_out:
         kfree(full_path);
+        cifs_put_tlink(tlink);
         FreeXid(xid);
         return ERR_PTR(rc);
 }