[linux-cifs-client][patch] utilize lookup intents to open in lookup

[Shirish Pargaonkar <shirishpargaonkar@gmail.com>]

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Hi,

Patch to expolint lookup intents in cifs lookup during open, thus
reducing network traffick and speedier opens
Have also converted a semphore to mutex as per Jeff Layton's comments.

Trong, Al, your feedback is really appreciated.

Regards,

Shirish

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diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 9fbf4df..9a8368f 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 f9b6f68..3ccb900 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -129,12 +129,67 @@ 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;
+
+	cERROR(1, ("cifs_fill_fileinfo enter\n"));
+
+	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);
+	cERROR(1, ("cifs_fill_fileinfo exit\n"));
+}
+
 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 +227,8 @@ 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,
@@ -198,6 +255,8 @@ 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;
@@ -239,7 +298,6 @@ 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;
 
@@ -410,44 +468,8 @@ 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);
@@ -580,17 +602,21 @@ 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();
 
@@ -632,12 +658,27 @@ 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)
@@ -645,7 +686,8 @@ 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 81747ac..c3f51de 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) {