[CIFS] Add support for posix open during lookup

This patch by utilizing lookup intents, and thus removing a network
roundtrip in the open path, improves performance dramatically on
open (30% or more) to Samba and other servers which support the
cifs posix extensions

Signed-off-by: Shirish Pargaonkar <shirishp@us.ibm.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 32 insertions, 33 deletions

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index dfd3e6c52a1e..48c9ae09f3d6 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -46,7 +46,7 @@ static inline struct cifsFileInfo *cifs_init_private(
         memset(private_data, 0, sizeof(struct cifsFileInfo));
         private_data->netfid = netfid;
         private_data->pid = current->tgid;
-        init_MUTEX(&private_data->fh_sem);
+        mutex_init(&private_data->fh_mutex);
         mutex_init(&private_data->lock_mutex);
         INIT_LIST_HEAD(&private_data->llist);
         private_data->pfile = file; /* needed for writepage */
@@ -284,35 +284,34 @@ int cifs_open(struct inode *inode, struct file *file)
         cifs_sb = CIFS_SB(inode->i_sb);
         tcon = cifs_sb->tcon;
 
-        if (file->f_flags & O_CREAT) {
-                /* 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) {
-                        rc = 0;
-                        FreeXid(xid);
-                        return rc;
-                } else {
-                        if (file->f_flags & O_EXCL)
-                                cERROR(1, ("could not find file instance for "
-                                           "new file %p", file));
+        /* 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) {
+                rc = 0;
+                FreeXid(xid);
+                return rc;
+        } else {
+                if ((file->f_flags & O_CREAT) && (file->f_flags & O_EXCL))
+                        cERROR(1, ("could not find file instance for "
+                                   "new file %p", file));
+        }
 
         full_path = build_path_from_dentry(file->f_path.dentry);
         if (full_path == NULL) {
@@ -500,9 +499,9 @@ static int cifs_reopen_file(struct file *file, bool can_flush)
                 return -EBADF;
 
         xid = GetXid();
-        down(&pCifsFile->fh_sem);
+        mutex_unlock(&pCifsFile->fh_mutex);
         if (!pCifsFile->invalidHandle) {
-                up(&pCifsFile->fh_sem);
+                mutex_lock(&pCifsFile->fh_mutex);
                 FreeXid(xid);
                 return 0;
         }
@@ -533,7 +532,7 @@ static int cifs_reopen_file(struct file *file, bool can_flush)
         if (full_path == NULL) {
                 rc = -ENOMEM;
 reopen_error_exit:
-                up(&pCifsFile->fh_sem);
+                mutex_lock(&pCifsFile->fh_mutex);
                 FreeXid(xid);
                 return rc;
         }
@@ -575,14 +574,14 @@ reopen_error_exit:
                          cifs_sb->local_nls, cifs_sb->mnt_cifs_flags &
                                 CIFS_MOUNT_MAP_SPECIAL_CHR);
         if (rc) {
-                up(&pCifsFile->fh_sem);
+                mutex_lock(&pCifsFile->fh_mutex);
                 cFYI(1, ("cifs_open returned 0x%x", rc));
                 cFYI(1, ("oplock: %d", oplock));
         } else {
 reopen_success:
                 pCifsFile->netfid = netfid;
                 pCifsFile->invalidHandle = false;
-                up(&pCifsFile->fh_sem);
+                mutex_lock(&pCifsFile->fh_mutex);
                 pCifsInode = CIFS_I(inode);
                 if (pCifsInode) {
                         if (can_flush) {