CIFS: Implement cifs_strict_fsync

Invalidate inode mapping if we don't have at least Level II oplock in
cifs_strict_fsync. Also remove filemap_write_and_wait call from cifs_fsync
because it is previously called from vfs_fsync_range. Add file operations'
structures for strict cache mode.
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

fs/cifs/cifsfs.c

@@ -733,6 +733,25 @@ const struct file_operations cifs_file_ops = {
 	.setlease = cifs_setlease,
 };
 
+const struct file_operations cifs_file_strict_ops = {
+	.read = do_sync_read,
+	.write = do_sync_write,
+	.aio_read = generic_file_aio_read,
+	.aio_write = cifs_file_aio_write,
+	.open = cifs_open,
+	.release = cifs_close,
+	.lock = cifs_lock,
+	.fsync = cifs_strict_fsync,
+	.flush = cifs_flush,
+	.mmap = cifs_file_mmap,
+	.splice_read = generic_file_splice_read,
+	.llseek = cifs_llseek,
+#ifdef CONFIG_CIFS_POSIX
+	.unlocked_ioctl	= cifs_ioctl,
+#endif /* CONFIG_CIFS_POSIX */
+	.setlease = cifs_setlease,
+};
+
 const struct file_operations cifs_file_direct_ops = {
 	/* no aio, no readv -
 	   BB reevaluate whether they can be done with directio, no cache */
@@ -751,6 +770,7 @@ const struct file_operations cifs_file_direct_ops = {
 	.llseek = cifs_llseek,
 	.setlease = cifs_setlease,
 };
+
 const struct file_operations cifs_file_nobrl_ops = {
 	.read = do_sync_read,
 	.write = do_sync_write,
@@ -769,6 +789,24 @@ const struct file_operations cifs_file_nobrl_ops = {
 	.setlease = cifs_setlease,
 };
 
+const struct file_operations cifs_file_strict_nobrl_ops = {
+	.read = do_sync_read,
+	.write = do_sync_write,
+	.aio_read = generic_file_aio_read,
+	.aio_write = cifs_file_aio_write,
+	.open = cifs_open,
+	.release = cifs_close,
+	.fsync = cifs_strict_fsync,
+	.flush = cifs_flush,
+	.mmap = cifs_file_mmap,
+	.splice_read = generic_file_splice_read,
+	.llseek = cifs_llseek,
+#ifdef CONFIG_CIFS_POSIX
+	.unlocked_ioctl	= cifs_ioctl,
+#endif /* CONFIG_CIFS_POSIX */
+	.setlease = cifs_setlease,
+};
+
 const struct file_operations cifs_file_direct_nobrl_ops = {
 	/* no mmap, no aio, no readv -
 	   BB reevaluate whether they can be done with directio, no cache */

fs/cifs/cifsfs.h

@@ -61,6 +61,7 @@ extern int cifs_rename(struct inode *, struct dentry *, struct inode *,
 		       struct dentry *);
 extern int cifs_revalidate_file(struct file *filp);
 extern int cifs_revalidate_dentry(struct dentry *);
+extern void cifs_invalidate_mapping(struct inode *inode);
 extern int cifs_getattr(struct vfsmount *, struct dentry *, struct kstat *);
 extern int cifs_setattr(struct dentry *, struct iattr *);
 
@@ -72,8 +73,10 @@ extern const struct inode_operations cifs_dfs_referral_inode_operations;
 /* Functions related to files and directories */
 extern const struct file_operations cifs_file_ops;
 extern const struct file_operations cifs_file_direct_ops; /* if directio mnt */
-extern const struct file_operations cifs_file_nobrl_ops;
-extern const struct file_operations cifs_file_direct_nobrl_ops; /* no brlocks */
+extern const struct file_operations cifs_file_strict_ops; /* if strictio mnt */
+extern const struct file_operations cifs_file_nobrl_ops; /* no brlocks */
+extern const struct file_operations cifs_file_direct_nobrl_ops;
+extern const struct file_operations cifs_file_strict_nobrl_ops;
 extern int cifs_open(struct inode *inode, struct file *file);
 extern int cifs_close(struct inode *inode, struct file *file);
 extern int cifs_closedir(struct inode *inode, struct file *file);
@@ -83,6 +86,7 @@ extern ssize_t cifs_user_write(struct file *file, const char __user *write_data,
 			 size_t write_size, loff_t *poffset);
 extern int cifs_lock(struct file *, int, struct file_lock *);
 extern int cifs_fsync(struct file *, int);
+extern int cifs_strict_fsync(struct file *, int);
 extern int cifs_flush(struct file *, fl_owner_t id);
 extern int cifs_file_mmap(struct file * , struct vm_area_struct *);
 extern const struct file_operations cifs_dir_ops;

fs/cifs/file.c

@@ -1528,27 +1528,47 @@ static int cifs_write_end(struct file *file, struct address_space *mapping,
 	return rc;
 }
 
-int cifs_fsync(struct file *file, int datasync)
+int cifs_strict_fsync(struct file *file, int datasync)
 {
 	int xid;
 	int rc = 0;
 	struct cifsTconInfo *tcon;
 	struct cifsFileInfo *smbfile = file->private_data;
 	struct inode *inode = file->f_path.dentry->d_inode;
+	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
 
 	xid = GetXid();
 
 	cFYI(1, "Sync file - name: %s datasync: 0x%x",
 		file->f_path.dentry->d_name.name, datasync);
 
-	rc = filemap_write_and_wait(inode->i_mapping);
-	if (rc == 0) {
-		struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+	if (!CIFS_I(inode)->clientCanCacheRead)
+		cifs_invalidate_mapping(inode);
 
-		tcon = tlink_tcon(smbfile->tlink);
-		if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOSSYNC))
-			rc = CIFSSMBFlush(xid, tcon, smbfile->netfid);
-	}
+	tcon = tlink_tcon(smbfile->tlink);
+	if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOSSYNC))
+		rc = CIFSSMBFlush(xid, tcon, smbfile->netfid);
+
+	FreeXid(xid);
+	return rc;
+}
+
+int cifs_fsync(struct file *file, int datasync)
+{
+	int xid;
+	int rc = 0;
+	struct cifsTconInfo *tcon;
+	struct cifsFileInfo *smbfile = file->private_data;
+	struct cifs_sb_info *cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
+
+	xid = GetXid();
+
+	cFYI(1, "Sync file - name: %s datasync: 0x%x",
+		file->f_path.dentry->d_name.name, datasync);
+
+	tcon = tlink_tcon(smbfile->tlink);
+	if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOSSYNC))
+		rc = CIFSSMBFlush(xid, tcon, smbfile->netfid);
 
 	FreeXid(xid);
 	return rc;

fs/cifs/inode.c

@@ -44,13 +44,17 @@ static void cifs_set_ops(struct inode *inode)
 				inode->i_fop = &cifs_file_direct_nobrl_ops;
 			else
 				inode->i_fop = &cifs_file_direct_ops;
+		} else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_STRICT_IO) {
+			if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_BRL)
+				inode->i_fop = &cifs_file_strict_nobrl_ops;
+			else
+				inode->i_fop = &cifs_file_strict_ops;
 		} else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_BRL)
 			inode->i_fop = &cifs_file_nobrl_ops;
 		else { /* not direct, send byte range locks */
 			inode->i_fop = &cifs_file_ops;
 		}
 
-
 		/* check if server can support readpages */
 		if (cifs_sb_master_tcon(cifs_sb)->ses->server->maxBuf <
 				PAGE_CACHE_SIZE + MAX_CIFS_HDR_SIZE)
@@ -1679,7 +1683,7 @@ cifs_inode_needs_reval(struct inode *inode)
 /*
  * Zap the cache. Called when invalid_mapping flag is set.
  */
-static void
+void
 cifs_invalidate_mapping(struct inode *inode)
 {
 	int rc;