[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>

3 files changed, 118 insertions, 80 deletions

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 7ae19868fdc4..df40ab64cd95 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -350,7 +350,7 @@ struct cifsFileInfo {
         bool invalidHandle:1;   /* file closed via session abend */
         bool messageMode:1;     /* for pipes: message vs byte mode */
         atomic_t wrtPending;   /* handle in use - defer close */
-        struct semaphore fh_sem; /* prevents reopen race after dead ses*/
+        struct mutex fh_mutex; /* prevents reopen race after dead ses*/
         struct cifs_search_info srch_inf;
 };
 
diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index e457e1434349..d9006b04324e 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -129,12 +129,64 @@ cifs_bp_rename_retry:
         return full_path;
 }
 
+static void
+cifs_fill_fileinfo(struct inode *newinode, __u16 fileHandle,
+                        struct cifsTconInfo *tcon, bool write_only)
+{
+        int oplock = 0;
+        struct cifsFileInfo *pCifsFile;
+        struct cifsInodeInfo *pCifsInode;
+
+        pCifsFile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
+
+        if (pCifsFile == NULL)
+                return;
+
+        if (oplockEnabled)
+                oplock = REQ_OPLOCK;
+
+        pCifsFile->netfid = fileHandle;
+        pCifsFile->pid = current->tgid;
+        pCifsFile->pInode = newinode;
+        pCifsFile->invalidHandle = false;
+        pCifsFile->closePend     = false;
+        mutex_init(&pCifsFile->fh_mutex);
+        mutex_init(&pCifsFile->lock_mutex);
+        INIT_LIST_HEAD(&pCifsFile->llist);
+        atomic_set(&pCifsFile->wrtPending, 0);
+
+        /* set the following in open now
+                        pCifsFile->pfile = file; */
+        write_lock(&GlobalSMBSeslock);
+        list_add(&pCifsFile->tlist, &tcon->openFileList);
+        pCifsInode = CIFS_I(newinode);
+        if (pCifsInode) {
+                /* if readable file instance put first in list*/
+                if (write_only) {
+                        list_add_tail(&pCifsFile->flist,
+                                      &pCifsInode->openFileList);
+                } else {
+                        list_add(&pCifsFile->flist,
+                                 &pCifsInode->openFileList);
+                }
+                if ((oplock & 0xF) == OPLOCK_EXCLUSIVE) {
+                        pCifsInode->clientCanCacheAll = true;
+                        pCifsInode->clientCanCacheRead = true;
+                        cFYI(1, ("Exclusive Oplock inode %p",
+                                newinode));
+                } else if ((oplock & 0xF) == OPLOCK_READ)
+                        pCifsInode->clientCanCacheRead = true;
+        }
+        write_unlock(&GlobalSMBSeslock);
+}
+
 int cifs_posix_open(char *full_path, struct inode **pinode,
                     struct super_block *sb, int mode, int oflags,
                     int *poplock, __u16 *pnetfid, int xid)
 {
         int rc;
         __u32 oplock;
+        bool write_only = false;
         FILE_UNIX_BASIC_INFO *presp_data;
         __u32 posix_flags = 0;
         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
@@ -172,6 +224,8 @@ int cifs_posix_open(char *full_path, struct inode **pinode,
         if (oflags & O_DIRECT)
                 posix_flags |= SMB_O_DIRECT;
 
+        if (!(oflags & FMODE_READ))
+                write_only = true;
 
         rc = CIFSPOSIXCreate(xid, cifs_sb->tcon, posix_flags, mode,
                         pnetfid, presp_data, &oplock, full_path,
@@ -200,6 +254,8 @@ int cifs_posix_open(char *full_path, struct inode **pinode,
 
         posix_fill_in_inode(*pinode, presp_data, 1);
 
+        cifs_fill_fileinfo(*pinode, *pnetfid, cifs_sb->tcon, write_only);
+
 posix_open_ret:
         kfree(presp_data);
         return rc;
@@ -241,7 +297,6 @@ cifs_create(struct inode *inode, struct dentry *direntry, int mode,
         char *full_path = NULL;
         FILE_ALL_INFO *buf = NULL;
         struct inode *newinode = NULL;
-        struct cifsInodeInfo *pCifsInode;
         int disposition = FILE_OVERWRITE_IF;
         bool write_only = false;
 
@@ -412,44 +467,8 @@ cifs_create_set_dentry:
                 /* mknod case - do not leave file open */
                 CIFSSMBClose(xid, tcon, fileHandle);
         } else if (newinode) {
-                struct cifsFileInfo *pCifsFile =
-                        kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
-
-                if (pCifsFile == NULL)
-                        goto cifs_create_out;
-                pCifsFile->netfid = fileHandle;
-                pCifsFile->pid = current->tgid;
-                pCifsFile->pInode = newinode;
-                pCifsFile->invalidHandle = false;
-                pCifsFile->closePend     = false;
-                init_MUTEX(&pCifsFile->fh_sem);
-                mutex_init(&pCifsFile->lock_mutex);
-                INIT_LIST_HEAD(&pCifsFile->llist);
-                atomic_set(&pCifsFile->wrtPending, 0);
-
-                /* set the following in open now
-                                pCifsFile->pfile = file; */
-                write_lock(&GlobalSMBSeslock);
-                list_add(&pCifsFile->tlist, &tcon->openFileList);
-                pCifsInode = CIFS_I(newinode);
-                if (pCifsInode) {
-                        /* if readable file instance put first in list*/
-                        if (write_only) {
-                                list_add_tail(&pCifsFile->flist,
-                                              &pCifsInode->openFileList);
-                        } else {
-                                list_add(&pCifsFile->flist,
-                                         &pCifsInode->openFileList);
-                        }
-                        if ((oplock & 0xF) == OPLOCK_EXCLUSIVE) {
-                                pCifsInode->clientCanCacheAll = true;
-                                pCifsInode->clientCanCacheRead = true;
-                                cFYI(1, ("Exclusive Oplock inode %p",
-                                        newinode));
-                        } else if ((oplock & 0xF) == OPLOCK_READ)
-                                pCifsInode->clientCanCacheRead = true;
-                }
-                write_unlock(&GlobalSMBSeslock);
+                        cifs_fill_fileinfo(newinode, fileHandle,
+                                        cifs_sb->tcon, write_only);
         }
 cifs_create_out:
         kfree(buf);
@@ -582,17 +601,21 @@ int cifs_mknod(struct inode *inode, struct dentry *direntry, int mode,
         return rc;
 }
 
-
 struct dentry *
 cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
             struct nameidata *nd)
 {
         int xid;
         int rc = 0; /* to get around spurious gcc warning, set to zero here */
+        int oplock = 0;
+        int mode;
+        __u16 fileHandle = 0;
+        bool posix_open = false;
         struct cifs_sb_info *cifs_sb;
         struct cifsTconInfo *pTcon;
         struct inode *newInode = NULL;
         char *full_path = NULL;
+        struct file *filp;
 
         xid = GetXid();
 
@@ -634,12 +657,27 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
         }
         cFYI(1, ("Full path: %s inode = 0x%p", full_path, direntry->d_inode));
 
-        if (pTcon->unix_ext)
-                rc = cifs_get_inode_info_unix(&newInode, full_path,
-                                              parent_dir_inode->i_sb, xid);
-        else
+        if (pTcon->unix_ext) {
+                if (!(nd->flags & (LOOKUP_PARENT | LOOKUP_DIRECTORY)) &&
+                                (nd->flags & LOOKUP_OPEN)) {
+                        if (!((nd->intent.open.flags & O_CREAT) &&
+                                        (nd->intent.open.flags & O_EXCL))) {
+                                mode = nd->intent.open.create_mode &
+                                                ~current->fs->umask;
+                                rc = cifs_posix_open(full_path, &newInode,
+                                        parent_dir_inode->i_sb, mode,
+                                        nd->intent.open.flags, &oplock,
+                                        &fileHandle, xid);
+                                if ((rc != -EINVAL) && (rc != -EOPNOTSUPP))
+                                        posix_open = true;
+                        }
+                }
+                if (!posix_open)
+                        rc = cifs_get_inode_info_unix(&newInode, full_path,
+                                                parent_dir_inode->i_sb, xid);
+        } else
                 rc = cifs_get_inode_info(&newInode, full_path, NULL,
-                                         parent_dir_inode->i_sb, xid, NULL);
+                                parent_dir_inode->i_sb, xid, NULL);
 
         if ((rc == 0) && (newInode != NULL)) {
                 if (pTcon->nocase)
@@ -647,7 +685,8 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
                 else
                         direntry->d_op = &cifs_dentry_ops;
                 d_add(direntry, newInode);
-
+                if (posix_open)
+                        filp = lookup_instantiate_filp(nd, direntry, NULL);
                 /* since paths are not looked up by component - the parent
                    directories are presumed to be good here */
                 renew_parental_timestamps(direntry);
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) {