cifs: have cifsFileInfo hold a reference to a tlink rather than tcon pointer

cifsFileInfo needs a pointer to a tcon, but it doesn't currently hold a
reference to it. Change it to keep a pointer to a tcon_link instead and
hold a reference to it.

That will keep the tcon from being freed until the file is closed.

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

9 files changed, 41 insertions, 33 deletions

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 898d2a5cfad2..b2fd075dc2e6 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -595,7 +595,8 @@ static int cifs_setlease(struct file *file, long arg, struct file_lock **lease)
             ((arg == F_WRLCK) &&
                 (CIFS_I(inode)->clientCanCacheAll)))
                 return generic_setlease(file, arg, lease);
-        else if (cfile->tcon->local_lease && !CIFS_I(inode)->clientCanCacheRead)
+        else if (tlink_tcon(cfile->tlink)->local_lease &&
+                 !CIFS_I(inode)->clientCanCacheRead)
                 /* If the server claims to support oplock on this
                    file, then we still need to check oplock even
                    if the local_lease mount option is set, but there
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index cdfd2db4e70d..d5324853203b 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -341,6 +341,12 @@ cifs_put_tlink(struct tcon_link *tlink)
         return;
 }
 
+static inline struct tcon_link *
+cifs_get_tlink(struct tcon_link *tlink)
+{
+        return tlink;
+}
+
 /* This function is always expected to succeed */
 static inline struct cifsTconInfo *
 cifs_sb_master_tcon(struct cifs_sb_info *cifs_sb)
@@ -389,7 +395,7 @@ struct cifsFileInfo {
         struct file *pfile; /* needed for writepage */
         struct inode *pInode; /* needed for oplock break */
         struct vfsmount *mnt;
-        struct cifsTconInfo *tcon;
+        struct tcon_link *tlink;
         struct mutex lock_mutex;
         struct list_head llist; /* list of byte range locks we have. */
         bool closePend:1;       /* file is marked to close */
@@ -411,6 +417,7 @@ static inline void cifsFileInfo_get(struct cifsFileInfo *cifs_file)
 static inline void cifsFileInfo_put(struct cifsFileInfo *cifs_file)
 {
         if (atomic_dec_and_test(&cifs_file->count)) {
+                cifs_put_tlink(cifs_file->tlink);
                 iput(cifs_file->pInode);
                 kfree(cifs_file);
         }
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 610b2263c9f3..7294723d0625 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -107,7 +107,7 @@ extern struct timespec cnvrtDosUnixTm(__le16 le_date, __le16 le_time,
 
 extern struct cifsFileInfo *cifs_new_fileinfo(struct inode *newinode,
                                 __u16 fileHandle, struct file *file,
-                                struct vfsmount *mnt, struct cifsTconInfo *tcon,
+                                struct vfsmount *mnt, struct tcon_link *tlink,
                                 unsigned int oflags, __u32 oplock);
 extern int cifs_posix_open(char *full_path, struct inode **pinode,
                                 struct super_block *sb,
diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index bb3ea06ca6f4..5adf47f28fed 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -132,7 +132,7 @@ cifs_bp_rename_retry:
 
 struct cifsFileInfo *
 cifs_new_fileinfo(struct inode *newinode, __u16 fileHandle, struct file *file,
-                  struct vfsmount *mnt, struct cifsTconInfo *tcon,
+                  struct vfsmount *mnt, struct tcon_link *tlink,
                   unsigned int oflags, __u32 oplock)
 {
         struct cifsFileInfo *pCifsFile;
@@ -149,7 +149,7 @@ cifs_new_fileinfo(struct inode *newinode, __u16 fileHandle, struct file *file,
         pCifsFile->pfile = file;
         pCifsFile->invalidHandle = false;
         pCifsFile->closePend = false;
-        pCifsFile->tcon = tcon;
+        pCifsFile->tlink = cifs_get_tlink(tlink);
         mutex_init(&pCifsFile->fh_mutex);
         mutex_init(&pCifsFile->lock_mutex);
         INIT_LIST_HEAD(&pCifsFile->llist);
@@ -157,7 +157,7 @@ cifs_new_fileinfo(struct inode *newinode, __u16 fileHandle, struct file *file,
         INIT_WORK(&pCifsFile->oplock_break, cifs_oplock_break);
 
         write_lock(&GlobalSMBSeslock);
-        list_add(&pCifsFile->tlist, &tcon->openFileList);
+        list_add(&pCifsFile->tlist, &(tlink_tcon(tlink)->openFileList));
         pCifsInode = CIFS_I(newinode);
         if (pCifsInode) {
                 /* if readable file instance put first in list*/
@@ -483,7 +483,7 @@ cifs_create_set_dentry:
                 }
 
                 pfile_info = cifs_new_fileinfo(newinode, fileHandle, filp,
-                                               nd->path.mnt, tcon, oflags,
+                                                nd->path.mnt, tlink, oflags,
                                                 oplock);
                 if (pfile_info == NULL) {
                         fput(filp);
@@ -758,7 +758,7 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
                         }
 
                         cfile = cifs_new_fileinfo(newInode, fileHandle, filp,
-                                                  nd->path.mnt, pTcon,
+                                                  nd->path.mnt, tlink,
                                                   nd->intent.open.flags,
                                                   oplock);
                         if (cfile == NULL) {
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 1e375abc5eb3..24332d437150 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -283,7 +283,7 @@ int cifs_open(struct inode *inode, struct file *file)
 
                         pCifsFile = cifs_new_fileinfo(inode, netfid, file,
                                                         file->f_path.mnt,
-                                                        tcon, oflags, oplock);
+                                                        tlink, oflags, oplock);
                         if (pCifsFile == NULL) {
                                 CIFSSMBClose(xid, tcon, netfid);
                                 rc = -ENOMEM;
@@ -376,7 +376,7 @@ int cifs_open(struct inode *inode, struct file *file)
                 goto out;
 
         pCifsFile = cifs_new_fileinfo(inode, netfid, file, file->f_path.mnt,
-                                        tcon, file->f_flags, oplock);
+                                        tlink, file->f_flags, oplock);
         if (pCifsFile == NULL) {
                 rc = -ENOMEM;
                 goto out;
@@ -468,7 +468,7 @@ static int cifs_reopen_file(struct file *file, bool can_flush)
         }
 
         cifs_sb = CIFS_SB(inode->i_sb);
-        tcon = pCifsFile->tcon;
+        tcon = tlink_tcon(pCifsFile->tlink);
 
 /* can not grab rename sem here because various ops, including
    those that already have the rename sem can end up causing writepage
@@ -582,7 +582,7 @@ int cifs_close(struct inode *inode, struct file *file)
         xid = GetXid();
 
         cifs_sb = CIFS_SB(inode->i_sb);
-        pTcon = pSMBFile->tcon;
+        pTcon = tlink_tcon(pSMBFile->tlink);
         if (pSMBFile) {
                 struct cifsLockInfo *li, *tmp;
                 write_lock(&GlobalSMBSeslock);
@@ -660,7 +660,7 @@ int cifs_closedir(struct inode *inode, struct file *file)
         xid = GetXid();
 
         if (pCFileStruct) {
-                struct cifsTconInfo *pTcon = pCFileStruct->tcon;
+                struct cifsTconInfo *pTcon = tlink_tcon(pCFileStruct->tlink);
 
                 cFYI(1, "Freeing private data in close dir");
                 write_lock(&GlobalSMBSeslock);
@@ -684,6 +684,7 @@ int cifs_closedir(struct inode *inode, struct file *file)
                         else
                                 cifs_buf_release(ptmp);
                 }
+                cifs_put_tlink(pCFileStruct->tlink);
                 kfree(file->private_data);
                 file->private_data = NULL;
         }
@@ -770,7 +771,7 @@ int cifs_lock(struct file *file, int cmd, struct file_lock *pfLock)
                 cFYI(1, "Unknown type of lock");
 
         cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
-        tcon = ((struct cifsFileInfo *)file->private_data)->tcon;
+        tcon = tlink_tcon(((struct cifsFileInfo *)file->private_data)->tlink);
 
         if (file->private_data == NULL) {
                 rc = -EBADF;
@@ -970,7 +971,7 @@ ssize_t cifs_user_write(struct file *file, const char __user *write_data,
                 return -EBADF;
 
         open_file = file->private_data;
-        pTcon = open_file->tcon;
+        pTcon = tlink_tcon(open_file->tlink);
 
         rc = generic_write_checks(file, poffset, &write_size, 0);
         if (rc)
@@ -1071,7 +1072,7 @@ static ssize_t cifs_write(struct file *file, const char *write_data,
         if (file->private_data == NULL)
                 return -EBADF;
         open_file = file->private_data;
-        pTcon = open_file->tcon;
+        pTcon = tlink_tcon(open_file->tlink);
 
         xid = GetXid();
 
@@ -1393,7 +1394,7 @@ static int cifs_writepages(struct address_space *mapping,
                 return generic_writepages(mapping, wbc);
         }
 
-        tcon = open_file->tcon;
+        tcon = tlink_tcon(open_file->tlink);
         if (!experimEnabled && tcon->ses->server->secMode &
                         (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED)) {
                 cifsFileInfo_put(open_file);
@@ -1672,7 +1673,7 @@ int cifs_fsync(struct file *file, int datasync)
         if (rc == 0) {
                 rc = CIFS_I(inode)->write_behind_rc;
                 CIFS_I(inode)->write_behind_rc = 0;
-                tcon = smbfile->tcon;
+                tcon = tlink_tcon(smbfile->tlink);
                 if (!rc && tcon && smbfile &&
                    !(CIFS_SB(inode->i_sb)->mnt_cifs_flags & CIFS_MOUNT_NOSSYNC))
                         rc = CIFSSMBFlush(xid, tcon, smbfile->netfid);
@@ -1764,7 +1765,7 @@ ssize_t cifs_user_read(struct file *file, char __user *read_data,
                 return rc;
         }
         open_file = file->private_data;
-        pTcon = open_file->tcon;
+        pTcon = tlink_tcon(open_file->tlink);
 
         if ((file->f_flags & O_ACCMODE) == O_WRONLY)
                 cFYI(1, "attempting read on write only file instance");
@@ -1845,7 +1846,7 @@ static ssize_t cifs_read(struct file *file, char *read_data, size_t read_size,
                 return rc;
         }
         open_file = file->private_data;
-        pTcon = open_file->tcon;
+        pTcon = tlink_tcon(open_file->tlink);
 
         if ((file->f_flags & O_ACCMODE) == O_WRONLY)
                 cFYI(1, "attempting read on write only file instance");
@@ -1981,7 +1982,7 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
         }
         open_file = file->private_data;
         cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
-        pTcon = open_file->tcon;
+        pTcon = tlink_tcon(open_file->tlink);
 
         /*
          * Reads as many pages as possible from fscache. Returns -ENOBUFS
@@ -2345,8 +2346,8 @@ void cifs_oplock_break(struct work_struct *work)
          * disconnected since oplock already released by the server
          */
         if (!cfile->closePend && !cfile->oplock_break_cancelled) {
-                rc = CIFSSMBLock(0, cfile->tcon, cfile->netfid, 0, 0, 0, 0,
-                                 LOCKING_ANDX_OPLOCK_RELEASE, false);
+                rc = CIFSSMBLock(0, tlink_tcon(cfile->tlink), cfile->netfid, 0,
+                                 0, 0, 0, LOCKING_ANDX_OPLOCK_RELEASE, false);
                 cFYI(1, "Oplock release rc = %d", rc);
         }
 
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index aa229692aef1..a39a1c451733 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -289,7 +289,7 @@ int cifs_get_file_info_unix(struct file *filp)
         struct inode *inode = filp->f_path.dentry->d_inode;
         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
         struct cifsFileInfo *cfile = filp->private_data;
-        struct cifsTconInfo *tcon = cfile->tcon;
+        struct cifsTconInfo *tcon = tlink_tcon(cfile->tlink);
 
         xid = GetXid();
         rc = CIFSSMBUnixQFileInfo(xid, tcon, cfile->netfid, &find_data);
@@ -546,7 +546,7 @@ int cifs_get_file_info(struct file *filp)
         struct inode *inode = filp->f_path.dentry->d_inode;
         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
         struct cifsFileInfo *cfile = filp->private_data;
-        struct cifsTconInfo *tcon = cfile->tcon;
+        struct cifsTconInfo *tcon = tlink_tcon(cfile->tlink);
 
         xid = GetXid();
         rc = CIFSSMBQFileInfo(xid, tcon, cfile->netfid, &find_data);
@@ -967,7 +967,7 @@ cifs_set_file_info(struct inode *inode, struct iattr *attrs, int xid,
         if (open_file) {
                 netfid = open_file->netfid;
                 netpid = open_file->pid;
-                pTcon = open_file->tcon;
+                pTcon = tlink_tcon(open_file->tlink);
                 goto set_via_filehandle;
         }
 
@@ -1696,7 +1696,7 @@ int cifs_revalidate_file(struct file *filp)
         if (!cifs_inode_needs_reval(inode))
                 goto check_inval;
 
-        if (cfile->tcon->unix_ext)
+        if (tlink_tcon(cfile->tlink)->unix_ext)
                 rc = cifs_get_file_info_unix(filp);
         else
                 rc = cifs_get_file_info(filp);
@@ -1817,7 +1817,7 @@ cifs_set_file_size(struct inode *inode, struct iattr *attrs,
         if (open_file) {
                 __u16 nfid = open_file->netfid;
                 __u32 npid = open_file->pid;
-                pTcon = open_file->tcon;
+                pTcon = tlink_tcon(open_file->tlink);
                 rc = CIFSSMBSetFileSize(xid, pTcon, attrs->ia_size, nfid,
                                         npid, false);
                 cifsFileInfo_put(open_file);
@@ -1982,7 +1982,7 @@ cifs_setattr_unix(struct dentry *direntry, struct iattr *attrs)
         if (open_file) {
                 u16 nfid = open_file->netfid;
                 u32 npid = open_file->pid;
-                pTcon = open_file->tcon;
+                pTcon = tlink_tcon(open_file->tlink);
                 rc = CIFSSMBUnixSetFileInfo(xid, pTcon, args, nfid, npid);
                 cifsFileInfo_put(open_file);
         } else {
diff --git a/fs/cifs/ioctl.c b/fs/cifs/ioctl.c
index cc70a61a47d2..077bf756f342 100644
--- a/fs/cifs/ioctl.c
+++ b/fs/cifs/ioctl.c
@@ -38,7 +38,7 @@ long cifs_ioctl(struct file *filep, unsigned int command, unsigned long arg)
         struct cifs_sb_info *cifs_sb;
 #ifdef CONFIG_CIFS_POSIX
         struct cifsFileInfo *pSMBFile = filep->private_data;
-        struct cifsTconInfo *tcon = pSMBFile->tcon;
+        struct cifsTconInfo *tcon = tlink_tcon(pSMBFile->tlink);
         __u64   ExtAttrBits = 0;
         __u64   ExtAttrMask = 0;
         __u64   caps = le64_to_cpu(tcon->fsUnixInfo.Capability);
diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index b38fe6704ad2..85cdbf831e7b 100644
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -346,7 +346,6 @@ cifs_hardlink(struct dentry *old_file, struct inode *inode,
                 goto cifs_hl_exit;
         }
 
-/*      if (cifs_sb_target->tcon->ses->capabilities & CAP_UNIX)*/
         if (pTcon->unix_ext)
                 rc = CIFSUnixCreateHardLink(xid, pTcon, fromName, toName,
                                             cifs_sb->local_nls,
diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
index 170047cf4522..1f0bd0f972d4 100644
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -245,7 +245,7 @@ static int initiate_cifs_search(const int xid, struct file *file)
         cifsFile = file->private_data;
         cifsFile->invalidHandle = true;
         cifsFile->srch_inf.endOfSearch = false;
-        cifsFile->tcon = pTcon;
+        cifsFile->tlink = cifs_get_tlink(tlink);
 
         full_path = build_path_from_dentry(file->f_path.dentry);
         if (full_path == NULL) {
@@ -838,7 +838,7 @@ int cifs_readdir(struct file *file, void *direntry, filldir_t filldir)
                         CIFSFindClose(xid, pTcon, cifsFile->netfid);
                 } */
 
-                pTcon = cifsFile->tcon;
+                pTcon = tlink_tcon(cifsFile->tlink);
                 rc = find_cifs_entry(xid, pTcon, file,
                                 &current_entry, &num_to_fill);
                 if (rc) {