Re: [RFC] patch to add support for leases to cifs

["Steve French" <smfrench@gmail.com>]

> Why not include it inlined in the mail body?

Inlined as requested.

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index c6aad77..aaa6f37 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -618,6 +618,26 @@ static loff_t cifs_llseek(struct file *file,
loff_t offset, int origin)
 	return generic_file_llseek_unlocked(file, offset, origin);
 }

+#ifdef CONFIG_CIFS_EXPERIMENTAL
+static int cifs_setlease(struct file *file, long arg, struct file_lock **lease)
+{
+	/* note that this is called by vfs setlease with the BKL held
+	   although I doubt that BKL is needed here in cifs */
+
+	if (!(S_ISREG(inode->i_mode))
+		return -EINVAL;
+
+	/* check if file is oplocked */
+	if (((arg == F_RDLCK) &&
+		(CIFS_I(file->f_path.dentry->d_inode)->clientCanCacheRead)) ||
+	    ((arg == F_WRLCK) &&
+		(CIFS_I(file->f_path.dentry->d_inode)->clientCanCacheAll)))
+		return generic_setlease(file, arg, lease);
+	else
+		return -EAGAIN;
+}
+#endif
+
 struct file_system_type cifs_fs_type = {
 	.owner = THIS_MODULE,
 	.name = "cifs",
@@ -696,6 +716,7 @@ const struct file_operations cifs_file_ops = {

 #ifdef CONFIG_CIFS_EXPERIMENTAL
 	.dir_notify = cifs_dir_notify,
+	.setlease = cifs_setlease,
 #endif /* CONFIG_CIFS_EXPERIMENTAL */
 };

@@ -716,6 +737,7 @@ const struct file_operations cifs_file_direct_ops = {
 	.llseek = cifs_llseek,
 #ifdef CONFIG_CIFS_EXPERIMENTAL
 	.dir_notify = cifs_dir_notify,
+	.setlease = cifs_setlease,
 #endif /* CONFIG_CIFS_EXPERIMENTAL */
 };
 const struct file_operations cifs_file_nobrl_ops = {
@@ -736,6 +758,7 @@ const struct file_operations cifs_file_nobrl_ops = {

 #ifdef CONFIG_CIFS_EXPERIMENTAL
 	.dir_notify = cifs_dir_notify,
+	.setlease = cifs_setlease,
 #endif /* CONFIG_CIFS_EXPERIMENTAL */
 };

@@ -755,6 +778,7 @@ const struct file_operations cifs_file_direct_nobrl_ops = {
 	.llseek = cifs_llseek,
 #ifdef CONFIG_CIFS_EXPERIMENTAL
 	.dir_notify = cifs_dir_notify,
+	.setlease = cifs_setlease,
 #endif /* CONFIG_CIFS_EXPERIMENTAL */
 };

@@ -946,6 +970,12 @@ static int cifs_oplock_thread(void *dummyarg)
 				the call */
 			/* mutex_lock(&inode->i_mutex);*/
 			if (S_ISREG(inode->i_mode)) {
+#ifdef CONFIG_CIFS_EXPERIMENTAL
+				if (CIFS_I(inode)->clientCanCacheAll == 0)
+					break_lease(inode, FMODE_READ);
+				else if (CIFS_I(inode)->clientCanCacheRead == 0)
+					break_lease(inode, FMODE_WRITE);
+#endif
 				rc = filemap_fdatawrite(inode->i_mapping);
 				if (CIFS_I(inode)->clientCanCacheRead == 0) {
 					waitrc = filemap_fdatawait(



> On Wed, Oct 22, 2008 at 6:03 AM, Steve French <smfrench@gmail.com> wrote:
>> fcntl(F_SETLEASE) currently is not exported by cifs (nor by local file
>> systems) so cifs grants leases based on how other local processes have
>> opened the file not by whether the file is cacheable (oplocked).  This
>> adds the check to make sure that the file is cacheable on the client
>> before checking whether we can grant the lease locally
>> (generic_setlease).





-- 
Thanks,

Steve