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, 122 insertions, 35 deletions

diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index da716d96dae6..aa229692aef1 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -313,16 +313,21 @@ int cifs_get_inode_info_unix(struct inode **pinode,
         FILE_UNIX_BASIC_INFO find_data;
         struct cifs_fattr fattr;
         struct cifsTconInfo *tcon;
+        struct tcon_link *tlink;
         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 
-        tcon = cifs_sb_tcon(cifs_sb);
-
         cFYI(1, "Getting info on %s", full_path);
 
+        tlink = cifs_sb_tlink(cifs_sb);
+        if (IS_ERR(tlink))
+                return PTR_ERR(tlink);
+        tcon = tlink_tcon(tlink);
+
         /* could have done a find first instead but this returns more info */
         rc = CIFSSMBUnixQPathInfo(xid, tcon, full_path, &find_data,
                                   cifs_sb->local_nls, cifs_sb->mnt_cifs_flags &
                                         CIFS_MOUNT_MAP_SPECIAL_CHR);
+        cifs_put_tlink(tlink);
 
         if (!rc) {
                 cifs_unix_basic_to_fattr(&fattr, &find_data, cifs_sb);
@@ -361,7 +366,8 @@ cifs_sfu_type(struct cifs_fattr *fattr, const unsigned char *path,
         int rc;
         int oplock = 0;
         __u16 netfid;
-        struct cifsTconInfo *pTcon = cifs_sb_tcon(cifs_sb);
+        struct tcon_link *tlink;
+        struct cifsTconInfo *tcon;
         char buf[24];
         unsigned int bytes_read;
         char *pbuf;
@@ -380,7 +386,12 @@ cifs_sfu_type(struct cifs_fattr *fattr, const unsigned char *path,
                 return -EINVAL;  /* EOPNOTSUPP? */
         }
 
-        rc = CIFSSMBOpen(xid, pTcon, path, FILE_OPEN, GENERIC_READ,
+        tlink = cifs_sb_tlink(cifs_sb);
+        if (IS_ERR(tlink))
+                return PTR_ERR(tlink);
+        tcon = tlink_tcon(tlink);
+
+        rc = CIFSSMBOpen(xid, tcon, path, FILE_OPEN, GENERIC_READ,
                          CREATE_NOT_DIR, &netfid, &oplock, NULL,
                          cifs_sb->local_nls,
                          cifs_sb->mnt_cifs_flags &
@@ -388,7 +399,7 @@ cifs_sfu_type(struct cifs_fattr *fattr, const unsigned char *path,
         if (rc == 0) {
                 int buf_type = CIFS_NO_BUFFER;
                         /* Read header */
-                rc = CIFSSMBRead(xid, pTcon, netfid,
+                rc = CIFSSMBRead(xid, tcon, netfid,
                                  24 /* length */, 0 /* offset */,
                                  &bytes_read, &pbuf, &buf_type);
                 if ((rc == 0) && (bytes_read >= 8)) {
@@ -430,8 +441,9 @@ cifs_sfu_type(struct cifs_fattr *fattr, const unsigned char *path,
                         fattr->cf_dtype = DT_REG;
                         rc = -EOPNOTSUPP; /* or some unknown SFU type */
                 }
-                CIFSSMBClose(xid, pTcon, netfid);
+                CIFSSMBClose(xid, tcon, netfid);
         }
+        cifs_put_tlink(tlink);
         return rc;
 }
 
@@ -449,11 +461,19 @@ static int cifs_sfu_mode(struct cifs_fattr *fattr, const unsigned char *path,
         ssize_t rc;
         char ea_value[4];
         __u32 mode;
+        struct tcon_link *tlink;
+        struct cifsTconInfo *tcon;
 
-        rc = CIFSSMBQAllEAs(xid, cifs_sb_tcon(cifs_sb), path, "SETFILEBITS",
+        tlink = cifs_sb_tlink(cifs_sb);
+        if (IS_ERR(tlink))
+                return PTR_ERR(tlink);
+        tcon = tlink_tcon(tlink);
+
+        rc = CIFSSMBQAllEAs(xid, tcon, path, "SETFILEBITS",
                             ea_value, 4 /* size of buf */, cifs_sb->local_nls,
                             cifs_sb->mnt_cifs_flags &
                                 CIFS_MOUNT_MAP_SPECIAL_CHR);
+        cifs_put_tlink(tlink);
         if (rc < 0)
                 return (int)rc;
         else if (rc > 3) {
@@ -564,26 +584,33 @@ int cifs_get_inode_info(struct inode **pinode,
 {
         int rc = 0, tmprc;
         struct cifsTconInfo *pTcon;
+        struct tcon_link *tlink;
         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
         char *buf = NULL;
         bool adjustTZ = false;
         struct cifs_fattr fattr;
 
-        pTcon = cifs_sb_tcon(cifs_sb);
+        tlink = cifs_sb_tlink(cifs_sb);
+        if (IS_ERR(tlink))
+                return PTR_ERR(tlink);
+        pTcon = tlink_tcon(tlink);
+
         cFYI(1, "Getting info on %s", full_path);
 
         if ((pfindData == NULL) && (*pinode != NULL)) {
                 if (CIFS_I(*pinode)->clientCanCacheRead) {
                         cFYI(1, "No need to revalidate cached inode sizes");
-                        return rc;
+                        goto cgii_exit;
                 }
         }
 
         /* 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;
+                if (buf == NULL) {
+                        rc = -ENOMEM;
+                        goto cgii_exit;
+                }
                 pfindData = (FILE_ALL_INFO *)buf;
 
                 /* could do find first instead but this returns more info */
@@ -688,6 +715,7 @@ int cifs_get_inode_info(struct inode **pinode,
 
 cgii_exit:
         kfree(buf);
+        cifs_put_tlink(tlink);
         return rc;
 }
 
@@ -895,6 +923,7 @@ cifs_set_file_info(struct inode *inode, struct iattr *attrs, int xid,
         struct cifsFileInfo *open_file;
         struct cifsInodeInfo *cifsInode = CIFS_I(inode);
         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+        struct tcon_link *tlink = NULL;
         struct cifsTconInfo *pTcon;
         FILE_BASIC_INFO info_buf;
 
@@ -942,7 +971,13 @@ cifs_set_file_info(struct inode *inode, struct iattr *attrs, int xid,
                 goto set_via_filehandle;
         }
 
-        pTcon = cifs_sb_tcon(cifs_sb);
+        tlink = cifs_sb_tlink(cifs_sb);
+        if (IS_ERR(tlink)) {
+                rc = PTR_ERR(tlink);
+                tlink = NULL;
+                goto out;
+        }
+        pTcon = tlink_tcon(tlink);
 
         /*
          * NT4 apparently returns success on this call, but it doesn't
@@ -987,6 +1022,8 @@ set_via_filehandle:
         else
                 cifsFileInfo_put(open_file);
 out:
+        if (tlink != NULL)
+                cifs_put_tlink(tlink);
         return rc;
 }
 
@@ -1004,10 +1041,16 @@ cifs_rename_pending_delete(char *full_path, struct dentry *dentry, int xid)
         struct inode *inode = dentry->d_inode;
         struct cifsInodeInfo *cifsInode = CIFS_I(inode);
         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
-        struct cifsTconInfo *tcon = cifs_sb_tcon(cifs_sb);
+        struct tcon_link *tlink;
+        struct cifsTconInfo *tcon;
         __u32 dosattr, origattr;
         FILE_BASIC_INFO *info_buf = NULL;
 
+        tlink = cifs_sb_tlink(cifs_sb);
+        if (IS_ERR(tlink))
+                return PTR_ERR(tlink);
+        tcon = tlink_tcon(tlink);
+
         rc = CIFSSMBOpen(xid, tcon, full_path, FILE_OPEN,
                          DELETE|FILE_WRITE_ATTRIBUTES, CREATE_NOT_DIR,
                          &netfid, &oplock, NULL, cifs_sb->local_nls,
@@ -1076,6 +1119,7 @@ out_close:
         CIFSSMBClose(xid, tcon, netfid);
 out:
         kfree(info_buf);
+        cifs_put_tlink(tlink);
         return rc;
 
         /*
@@ -1115,12 +1159,18 @@ int cifs_unlink(struct inode *dir, struct dentry *dentry)
         struct cifsInodeInfo *cifs_inode;
         struct super_block *sb = dir->i_sb;
         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
-        struct cifsTconInfo *tcon = cifs_sb_tcon(cifs_sb);
+        struct tcon_link *tlink;
+        struct cifsTconInfo *tcon;
         struct iattr *attrs = NULL;
         __u32 dosattr = 0, origattr = 0;
 
         cFYI(1, "cifs_unlink, dir=0x%p, dentry=0x%p", dir, dentry);
 
+        tlink = cifs_sb_tlink(cifs_sb);
+        if (IS_ERR(tlink))
+                return PTR_ERR(tlink);
+        tcon = tlink_tcon(tlink);
+
         xid = GetXid();
 
         /* Unlink can be called from rename so we can not take the
@@ -1128,8 +1178,7 @@ int cifs_unlink(struct inode *dir, struct dentry *dentry)
         full_path = build_path_from_dentry(dentry);
         if (full_path == NULL) {
                 rc = -ENOMEM;
-                FreeXid(xid);
-                return rc;
+                goto unlink_out;
         }
 
         if ((tcon->ses->capabilities & CAP_UNIX) &&
@@ -1195,10 +1244,11 @@ out_reval:
         dir->i_ctime = dir->i_mtime = current_fs_time(sb);
         cifs_inode = CIFS_I(dir);
         CIFS_I(dir)->time = 0;  /* force revalidate of dir as well */
-
+unlink_out:
         kfree(full_path);
         kfree(attrs);
         FreeXid(xid);
+        cifs_put_tlink(tlink);
         return rc;
 }
 
@@ -1207,6 +1257,7 @@ int cifs_mkdir(struct inode *inode, struct dentry *direntry, int mode)
         int rc = 0, tmprc;
         int xid;
         struct cifs_sb_info *cifs_sb;
+        struct tcon_link *tlink;
         struct cifsTconInfo *pTcon;
         char *full_path = NULL;
         struct inode *newinode = NULL;
@@ -1214,16 +1265,18 @@ int cifs_mkdir(struct inode *inode, struct dentry *direntry, int mode)
 
         cFYI(1, "In cifs_mkdir, mode = 0x%x inode = 0x%p", mode, inode);
 
-        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) {
                 rc = -ENOMEM;
-                FreeXid(xid);
-                return rc;
+                goto mkdir_out;
         }
 
         if ((pTcon->ses->capabilities & CAP_UNIX) &&
@@ -1381,6 +1434,7 @@ mkdir_get_info:
 mkdir_out:
         kfree(full_path);
         FreeXid(xid);
+        cifs_put_tlink(tlink);
         return rc;
 }
 
@@ -1389,6 +1443,7 @@ int cifs_rmdir(struct inode *inode, struct dentry *direntry)
         int rc = 0;
         int xid;
         struct cifs_sb_info *cifs_sb;
+        struct tcon_link *tlink;
         struct cifsTconInfo *pTcon;
         char *full_path = NULL;
         struct cifsInodeInfo *cifsInode;
@@ -1397,18 +1452,23 @@ int cifs_rmdir(struct inode *inode, struct dentry *direntry)
 
         xid = GetXid();
 
-        cifs_sb = CIFS_SB(inode->i_sb);
-        pTcon = cifs_sb_tcon(cifs_sb);
-
         full_path = build_path_from_dentry(direntry);
         if (full_path == NULL) {
                 rc = -ENOMEM;
-                FreeXid(xid);
-                return rc;
+                goto rmdir_exit;
+        }
+
+        cifs_sb = CIFS_SB(inode->i_sb);
+        tlink = cifs_sb_tlink(cifs_sb);
+        if (IS_ERR(tlink)) {
+                rc = PTR_ERR(tlink);
+                goto rmdir_exit;
         }
+        pTcon = tlink_tcon(tlink);
 
         rc = CIFSSMBRmDir(xid, pTcon, full_path, cifs_sb->local_nls,
                           cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
+        cifs_put_tlink(tlink);
 
         if (!rc) {
                 drop_nlink(inode);
@@ -1429,6 +1489,7 @@ int cifs_rmdir(struct inode *inode, struct dentry *direntry)
         direntry->d_inode->i_ctime = inode->i_ctime = inode->i_mtime =
                 current_fs_time(inode->i_sb);
 
+rmdir_exit:
         kfree(full_path);
         FreeXid(xid);
         return rc;
@@ -1439,10 +1500,16 @@ cifs_do_rename(int xid, struct dentry *from_dentry, const char *fromPath,
                 struct dentry *to_dentry, const char *toPath)
 {
         struct cifs_sb_info *cifs_sb = CIFS_SB(from_dentry->d_sb);
-        struct cifsTconInfo *pTcon = cifs_sb_tcon(cifs_sb);
+        struct tcon_link *tlink;
+        struct cifsTconInfo *pTcon;
         __u16 srcfid;
         int oplock, rc;
 
+        tlink = cifs_sb_tlink(cifs_sb);
+        if (IS_ERR(tlink))
+                return PTR_ERR(tlink);
+        pTcon = tlink_tcon(tlink);
+
         /* try path-based rename first */
         rc = CIFSSMBRename(xid, pTcon, fromPath, toPath, cifs_sb->local_nls,
                            cifs_sb->mnt_cifs_flags &
@@ -1454,11 +1521,11 @@ cifs_do_rename(int xid, struct dentry *from_dentry, const char *fromPath,
          * rename by filehandle to various Windows servers.
          */
         if (rc == 0 || rc != -ETXTBSY)
-                return rc;
+                goto do_rename_exit;
 
         /* open-file renames don't work across directories */
         if (to_dentry->d_parent != from_dentry->d_parent)
-                return rc;
+                goto do_rename_exit;
 
         /* open the file to be renamed -- we need DELETE perms */
         rc = CIFSSMBOpen(xid, pTcon, fromPath, FILE_OPEN, DELETE,
@@ -1474,7 +1541,8 @@ cifs_do_rename(int xid, struct dentry *from_dentry, const char *fromPath,
 
                 CIFSSMBClose(xid, pTcon, srcfid);
         }
-
+do_rename_exit:
+        cifs_put_tlink(tlink);
         return rc;
 }
 
@@ -1484,13 +1552,17 @@ int cifs_rename(struct inode *source_dir, struct dentry *source_dentry,
         char *fromName = NULL;
         char *toName = NULL;
         struct cifs_sb_info *cifs_sb;
+        struct tcon_link *tlink;
         struct cifsTconInfo *tcon;
         FILE_UNIX_BASIC_INFO *info_buf_source = NULL;
         FILE_UNIX_BASIC_INFO *info_buf_target;
         int xid, rc, tmprc;
 
         cifs_sb = CIFS_SB(source_dir->i_sb);
-        tcon = cifs_sb_tcon(cifs_sb);
+        tlink = cifs_sb_tlink(cifs_sb);
+        if (IS_ERR(tlink))
+                return PTR_ERR(tlink);
+        tcon = tlink_tcon(tlink);
 
         xid = GetXid();
 
@@ -1566,6 +1638,7 @@ cifs_rename_exit:
         kfree(fromName);
         kfree(toName);
         FreeXid(xid);
+        cifs_put_tlink(tlink);
         return rc;
 }
 
@@ -1728,6 +1801,7 @@ cifs_set_file_size(struct inode *inode, struct iattr *attrs,
         struct cifsFileInfo *open_file;
         struct cifsInodeInfo *cifsInode = CIFS_I(inode);
         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+        struct tcon_link *tlink = NULL;
         struct cifsTconInfo *pTcon = NULL;
 
         /*
@@ -1758,8 +1832,12 @@ cifs_set_file_size(struct inode *inode, struct iattr *attrs,
                 rc = -EINVAL;
 
         if (rc != 0) {
-                if (pTcon == NULL)
-                        pTcon = cifs_sb_tcon(cifs_sb);
+                if (pTcon == NULL) {
+                        tlink = cifs_sb_tlink(cifs_sb);
+                        if (IS_ERR(tlink))
+                                return PTR_ERR(tlink);
+                        pTcon = tlink_tcon(tlink);
+                }
 
                 /* Set file size by pathname rather than by handle
                    either because no valid, writeable file handle for
@@ -1790,6 +1868,8 @@ cifs_set_file_size(struct inode *inode, struct iattr *attrs,
                                 CIFSSMBClose(xid, pTcon, netfid);
                         }
                 }
+                if (tlink)
+                        cifs_put_tlink(tlink);
         }
 
         if (rc == 0) {
@@ -1810,6 +1890,7 @@ cifs_setattr_unix(struct dentry *direntry, struct iattr *attrs)
         struct inode *inode = direntry->d_inode;
         struct cifsInodeInfo *cifsInode = CIFS_I(inode);
         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+        struct tcon_link *tlink;
         struct cifsTconInfo *pTcon;
         struct cifs_unix_set_info_args *args = NULL;
         struct cifsFileInfo *open_file;
@@ -1905,11 +1986,17 @@ cifs_setattr_unix(struct dentry *direntry, struct iattr *attrs)
                 rc = CIFSSMBUnixSetFileInfo(xid, pTcon, args, nfid, npid);
                 cifsFileInfo_put(open_file);
         } else {
-                pTcon = cifs_sb_tcon(cifs_sb);
+                tlink = cifs_sb_tlink(cifs_sb);
+                if (IS_ERR(tlink)) {
+                        rc = PTR_ERR(tlink);
+                        goto out;
+                }
+                pTcon = tlink_tcon(tlink);
                 rc = CIFSSMBUnixSetPathInfo(xid, pTcon, full_path, args,
                                     cifs_sb->local_nls,
                                     cifs_sb->mnt_cifs_flags &
                                         CIFS_MOUNT_MAP_SPECIAL_CHR);
+                cifs_put_tlink(tlink);
         }
 
         if (rc)