cifs: pass instantiated filp back after open call

The current scheme of sticking open files on a list and assuming that
cifs_open will scoop them off of it is broken and leads to "Busy
inodes after umount..." errors at unmount time.

The problem is that there is no guarantee that cifs_open will always
be called after a ->lookup or ->create operation. If there are
permissions or other problems, then it's quite likely that it *won't*
be called.

Fix this by fully instantiating the filp whenever the file is created
and pass that filp back to the VFS. If there is a problem, the VFS
can clean up the references.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-and-Tested-by: Suresh Jayaraman <sjayaraman@suse.de>

2 files changed, 29 insertions, 50 deletions

diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index f49afb9980e7..e7ae78b66fa1 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -25,6 +25,7 @@
 #include <linux/slab.h>
 #include <linux/namei.h>
 #include <linux/mount.h>
+#include <linux/file.h>
 #include "cifsfs.h"
 #include "cifspdu.h"
 #include "cifsglob.h"
@@ -184,6 +185,8 @@ cifs_new_fileinfo(struct inode *newinode, __u16 fileHandle,
         }
         write_unlock(&GlobalSMBSeslock);
 
+        file->private_data = pCifsFile;
+
         return pCifsFile;
 }
 
@@ -463,14 +466,22 @@ cifs_create_set_dentry:
 
         if (newinode && nd && (nd->flags & LOOKUP_OPEN)) {
                 struct cifsFileInfo *pfile_info;
-                /*
-                 * cifs_fill_filedata() takes care of setting cifsFileInfo
-                 * pointer to file->private_data.
-                 */
-                pfile_info = cifs_new_fileinfo(newinode, fileHandle, NULL,
+                struct file *filp;
+
+                filp = lookup_instantiate_filp(nd, direntry, generic_file_open);
+                if (IS_ERR(filp)) {
+                        rc = PTR_ERR(filp);
+                        CIFSSMBClose(xid, tcon, fileHandle);
+                        goto cifs_create_out;
+                }
+
+                pfile_info = cifs_new_fileinfo(newinode, fileHandle, filp,
                                                nd->path.mnt, oflags);
-                if (pfile_info == NULL)
+                if (pfile_info == NULL) {
+                        fput(filp);
+                        CIFSSMBClose(xid, tcon, fileHandle);
                         rc = -ENOMEM;
+                }
         } else {
                 CIFSSMBClose(xid, tcon, fileHandle);
         }
@@ -717,15 +728,23 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
                         direntry->d_op = &cifs_dentry_ops;
                 d_add(direntry, newInode);
                 if (posix_open) {
-                        cfile = cifs_new_fileinfo(newInode, fileHandle, NULL,
+                        filp = lookup_instantiate_filp(nd, direntry,
+                                                       generic_file_open);
+                        if (IS_ERR(filp)) {
+                                rc = PTR_ERR(filp);
+                                CIFSSMBClose(xid, pTcon, fileHandle);
+                                goto lookup_out;
+                        }
+
+                        cfile = cifs_new_fileinfo(newInode, fileHandle, filp,
                                                   nd->path.mnt,
                                                   nd->intent.open.flags);
                         if (cfile == NULL) {
+                                fput(filp);
                                 CIFSSMBClose(xid, pTcon, fileHandle);
                                 rc = -ENOMEM;
                                 goto lookup_out;
                         }
-                        filp = lookup_instantiate_filp(nd, direntry, NULL);
                 }
                 /* since paths are not looked up by component - the parent
                    directories are presumed to be good here */
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 542e0c874d64..9cbf0f097a39 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -162,38 +162,6 @@ psx_client_can_cache:
         return 0;
 }
 
-static struct cifsFileInfo *
-cifs_fill_filedata(struct file *file)
-{
-        struct list_head *tmp;
-        struct cifsFileInfo *pCifsFile = NULL;
-        struct cifsInodeInfo *pCifsInode = NULL;
-
-        /* search inode for this file and fill in file->private_data */
-        pCifsInode = CIFS_I(file->f_path.dentry->d_inode);
-        read_lock(&GlobalSMBSeslock);
-        list_for_each(tmp, &pCifsInode->openFileList) {
-                pCifsFile = list_entry(tmp, struct cifsFileInfo, flist);
-                if ((pCifsFile->pfile == NULL) &&
-                    (pCifsFile->pid == current->tgid)) {
-                        /* mode set in cifs_create */
-
-                        /* needed for writepage */
-                        pCifsFile->pfile = file;
-                        file->private_data = pCifsFile;
-                        break;
-                }
-        }
-        read_unlock(&GlobalSMBSeslock);
-
-        if (file->private_data != NULL) {
-                return pCifsFile;
-        } else if ((file->f_flags & O_CREAT) && (file->f_flags & O_EXCL))
-                        cERROR(1, "could not find file instance for "
-                                   "new file %p", file);
-        return NULL;
-}
-
 /* all arguments to this function must be checked for validity in caller */
 static inline int cifs_open_inode_helper(struct inode *inode, struct file *file,
         struct cifsInodeInfo *pCifsInode, struct cifsFileInfo *pCifsFile,
@@ -256,7 +224,7 @@ int cifs_open(struct inode *inode, struct file *file)
         __u32 oplock;
         struct cifs_sb_info *cifs_sb;
         struct cifsTconInfo *tcon;
-        struct cifsFileInfo *pCifsFile;
+        struct cifsFileInfo *pCifsFile = NULL;
         struct cifsInodeInfo *pCifsInode;
         char *full_path = NULL;
         int desiredAccess;
@@ -270,12 +238,6 @@ int cifs_open(struct inode *inode, struct file *file)
         tcon = cifs_sb->tcon;
 
         pCifsInode = CIFS_I(file->f_path.dentry->d_inode);
-        pCifsFile = cifs_fill_filedata(file);
-        if (pCifsFile) {
-                rc = 0;
-                FreeXid(xid);
-                return rc;
-        }
 
         full_path = build_path_from_dentry(file->f_path.dentry);
         if (full_path == NULL) {
@@ -315,7 +277,6 @@ int cifs_open(struct inode *inode, struct file *file)
                                 rc = -ENOMEM;
                                 goto out;
                         }
-                        file->private_data = pCifsFile;
 
                         cifs_posix_open_inode_helper(inode, file, pCifsInode,
                                                      oplock, netfid);
@@ -401,8 +362,7 @@ int cifs_open(struct inode *inode, struct file *file)
 
         pCifsFile = cifs_new_fileinfo(inode, netfid, file, file->f_path.mnt,
                                         file->f_flags);
-        file->private_data = pCifsFile;
-        if (file->private_data == NULL) {
+        if (pCifsFile == NULL) {
                 rc = -ENOMEM;
                 goto out;
         }