cifs: replace /proc/fs/cifs/Experimental with a module parm

This flag currently only affects whether we allow "zero-copy" writes
with signing enabled. Typically we map pages in the pagecache directly
into the write request. If signing is enabled however and the contents
of the page change after the signature is calculated but before the
write is sent then the signature will be wrong. Servers typically
respond to this by closing down the socket.

Still, this can provide a performance benefit so the "Experimental" flag
was overloaded to allow this. That's really not a good place for this
option however since it's not clear what that flag does.

Move that flag instead to a new module parameter that better describes
its purpose. That's also better since it can be set at module insertion
time by configuring modprobe.d.

Reviewed-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 0 insertions, 43 deletions

diff --git a/fs/cifs/cifs_debug.c b/fs/cifs/cifs_debug.c
index 65829d3..30d01bc 100644
--- a/fs/cifs/cifs_debug.c
+++ b/fs/cifs/cifs_debug.c
@@ -423,7 +423,6 @@ static const struct file_operations cifs_lookup_cache_proc_fops;
 static const struct file_operations traceSMB_proc_fops;
 static const struct file_operations cifs_multiuser_mount_proc_fops;
 static const struct file_operations cifs_security_flags_proc_fops;
-static const struct file_operations cifs_experimental_proc_fops;
 static const struct file_operations cifs_linux_ext_proc_fops;
 
 void
@@ -441,8 +440,6 @@ cifs_proc_init(void)
 	proc_create("cifsFYI", 0, proc_fs_cifs, &cifsFYI_proc_fops);
 	proc_create("traceSMB", 0, proc_fs_cifs, &traceSMB_proc_fops);
 	proc_create("OplockEnabled", 0, proc_fs_cifs, &cifs_oplock_proc_fops);
-	proc_create("Experimental", 0, proc_fs_cifs,
-		    &cifs_experimental_proc_fops);
 	proc_create("LinuxExtensionsEnabled", 0, proc_fs_cifs,
 		    &cifs_linux_ext_proc_fops);
 	proc_create("MultiuserMount", 0, proc_fs_cifs,
@@ -469,7 +466,6 @@ cifs_proc_clean(void)
 	remove_proc_entry("OplockEnabled", proc_fs_cifs);
 	remove_proc_entry("SecurityFlags", proc_fs_cifs);
 	remove_proc_entry("LinuxExtensionsEnabled", proc_fs_cifs);
-	remove_proc_entry("Experimental", proc_fs_cifs);
 	remove_proc_entry("LookupCacheEnabled", proc_fs_cifs);
 	remove_proc_entry("fs/cifs", NULL);
 }
@@ -550,45 +546,6 @@ static const struct file_operations cifs_oplock_proc_fops = {
 	.write		= cifs_oplock_proc_write,
 };
 
-static int cifs_experimental_proc_show(struct seq_file *m, void *v)
-{
-	seq_printf(m, "%d\n", experimEnabled);
-	return 0;
-}
-
-static int cifs_experimental_proc_open(struct inode *inode, struct file *file)
-{
-	return single_open(file, cifs_experimental_proc_show, NULL);
-}
-
-static ssize_t cifs_experimental_proc_write(struct file *file,
-		const char __user *buffer, size_t count, loff_t *ppos)
-{
-	char c;
-	int rc;
-
-	rc = get_user(c, buffer);
-	if (rc)
-		return rc;
-	if (c == '0' || c == 'n' || c == 'N')
-		experimEnabled = 0;
-	else if (c == '1' || c == 'y' || c == 'Y')
-		experimEnabled = 1;
-	else if (c == '2')
-		experimEnabled = 2;
-
-	return count;
-}
-
-static const struct file_operations cifs_experimental_proc_fops = {
-	.owner		= THIS_MODULE,
-	.open		= cifs_experimental_proc_open,
-	.read		= seq_read,
-	.llseek		= seq_lseek,
-	.release	= single_release,
-	.write		= cifs_experimental_proc_write,
-};
-
 static int cifs_linux_ext_proc_show(struct seq_file *m, void *v)
 {
 	seq_printf(m, "%d\n", linuxExtEnabled);