On Tue, Oct 11, 2011 at 10:12 AM, Jeff Layton <jlayton@xxxxxxxxxx> wrote:
> On Tue, 11 Oct 2011 10:03:31 -0500
> Steve French <smfrench@xxxxxxxxx> wrote:
>
>> On Tue, Oct 11, 2011 at 6:08 AM, Suresh Jayaraman <sjayaraman@xxxxxxx> wrote:
>> > On 10/11/2011 04:02 PM, Jeff Layton wrote:
>> >> On Tue, 11 Oct 2011 15:06:43 +0530
>> >> Suresh Jayaraman <sjayaraman@xxxxxxx> wrote:
>> >>
>> >>> Thus spake Jeff Layton:
>> >>>
>> >>> "Making that a module parm would allow you to set that parameter at boot
>> >>> time without needing to add special startup scripts. IMO, all of the
>> >>> procfile "switches" under /proc/fs/cifs should be module parms
>> >>> instead."
>> >>>
>> >>> This seems reasonable so this patch makes OplockEnabled a module
>> >>> parameter and rename it to enable_oplocks to comply with the coding
>> >>> conventions. This patch removes the proc file handling pertaining to
>> >>> /proc/fs/cifs/OplockEnabled which would no longer be required if this
>> >>> patch gets accepted.
>> >>>
>> >>> This patch doesn't alter the default behavior (Oplocks enabled by
>> >>> default). To disable oplocks when loading the module, use
>> >>>
>> >>> modprobe cifs enable_oplocks=0
>> >>>
>> >>> Note:
>> >>> (a) I'm little worried about eliminating an already known interace to
>> >>> enable/disable Oplocks. An update to README file mentioning this info
>> >>> is planned. Do we need to warn users before pulling it off? Any
>> >>> suggestions on how we could do this?
>> >>> (b) Most of the /proc/fs/cifs switches could be converted to a module
>> >>> param for e.g. LookupCacheEnabled, LinuxExtensionsEnabled,
>> >>> MultiuserMount etc. I'll post further patches once this gets
>> >>> accepted.
>> >>>
>> >>
>> >> Yeah, I don't think we ought to just rip out these interfaces
>> >> unannounced. What should probably happen is this:
>> >>
>> >> Add the new module parms, and a patch that makes a printk pop when the
>> >> old interfaces are used. The printk should announce something like:
>> >>
>> >> "The /proc/fs/cifs/foo interface will be removed in kernel version 3.x.
>> >> Please migrate to using the 'enable_foo' module parameter in cifs.ko."
>> >>
>> >> Make the 3.x version be 2 releases out. Then have patches ready to go
>> >> to remove those interfaces when the 3.x merge window opens.
>> >
>> > Makes sense. Thanks.
>> >
>> >>> Reported-by: Alexander Swen <alex@xxxxxxx>
>> >>> Cc: Jeff Layton <jlayton@xxxxxxxxxx>
>> >>> Signed-off-by: Suresh Jayaraman <sjayaraman@xxxxxxx>
>> >>> ---
>> >>> fs/cifs/cifs_debug.c | 40 ----------------------------------------
>> >>> fs/cifs/cifsfs.c | 4 +++-
>> >>> fs/cifs/cifsglob.h | 4 +++-
>> >>> fs/cifs/dir.c | 2 +-
>> >>> fs/cifs/file.c | 4 ++--
>> >>> 5 files changed, 9 insertions(+), 45 deletions(-)
>> >>>
>> >>> diff --git a/fs/cifs/cifs_debug.c b/fs/cifs/cifs_debug.c
>> >>> index 2fe3cf1..393b37b 100644
>> >>> --- a/fs/cifs/cifs_debug.c
>> >>> +++ b/fs/cifs/cifs_debug.c
>> >>> @@ -418,7 +418,6 @@ static const struct file_operations cifs_stats_proc_fops = {
>> >>>
>> >>> static struct proc_dir_entry *proc_fs_cifs;
>> >>> static const struct file_operations cifsFYI_proc_fops;
>> >>> -static const struct file_operations cifs_oplock_proc_fops;
>> >>> 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;
>> >>> @@ -439,7 +438,6 @@ cifs_proc_init(void)
>> >>> #endif /* STATS */
>> >>> 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("LinuxExtensionsEnabled", 0, proc_fs_cifs,
>> >>> &cifs_linux_ext_proc_fops);
>> >>> proc_create("MultiuserMount", 0, proc_fs_cifs,
>> >>> @@ -463,7 +461,6 @@ cifs_proc_clean(void)
>> >>> remove_proc_entry("Stats", proc_fs_cifs);
>> >>> #endif
>> >>> remove_proc_entry("MultiuserMount", proc_fs_cifs);
>> >>> - remove_proc_entry("OplockEnabled", proc_fs_cifs);
>> >>> remove_proc_entry("SecurityFlags", proc_fs_cifs);
>> >>> remove_proc_entry("LinuxExtensionsEnabled", proc_fs_cifs);
>> >>> remove_proc_entry("LookupCacheEnabled", proc_fs_cifs);
>> >>> @@ -509,43 +506,6 @@ static const struct file_operations cifsFYI_proc_fops = {
>> >>> .write = cifsFYI_proc_write,
>> >>> };
>> >>>
>> >>> -static int cifs_oplock_proc_show(struct seq_file *m, void *v)
>> >>> -{
>> >>> - seq_printf(m, "%d\n", oplockEnabled);
>> >>> - return 0;
>> >>> -}
>> >>> -
>> >>> -static int cifs_oplock_proc_open(struct inode *inode, struct file *file)
>> >>> -{
>> >>> - return single_open(file, cifs_oplock_proc_show, NULL);
>> >>> -}
>> >>> -
>> >>> -static ssize_t cifs_oplock_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')
>> >>> - oplockEnabled = 0;
>> >>> - else if (c == '1' || c == 'y' || c == 'Y')
>> >>> - oplockEnabled = 1;
>> >>> -
>> >>> - return count;
>> >>> -}
>> >>> -
>> >>> -static const struct file_operations cifs_oplock_proc_fops = {
>> >>> - .owner = THIS_MODULE,
>> >>> - .open = cifs_oplock_proc_open,
>> >>> - .read = seq_read,
>> >>> - .llseek = seq_lseek,
>> >>> - .release = single_release,
>> >>> - .write = cifs_oplock_proc_write,
>> >>> -};
>> >>> -
>> >>> static int cifs_linux_ext_proc_show(struct seq_file *m, void *v)
>> >>> {
>> >>> seq_printf(m, "%d\n", linuxExtEnabled);
>> >>> diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
>> >>> index 3e29899..37c2fbb 100644
>> >>> --- a/fs/cifs/cifsfs.c
>> >>> +++ b/fs/cifs/cifsfs.c
>> >>> @@ -52,7 +52,6 @@
>> >>> int cifsFYI = 0;
>> >>> int cifsERROR = 1;
>> >>> int traceSMB = 0;
>> >>> -unsigned int oplockEnabled = 1;
>> >>> unsigned int linuxExtEnabled = 1;
>> >>> unsigned int lookupCacheEnabled = 1;
>> >>> unsigned int multiuser_mount = 0;
>> >>> @@ -81,6 +80,9 @@ module_param(echo_retries, ushort, 0644);
>> >>> MODULE_PARM_DESC(echo_retries, "Number of echo attempts before giving up and "
>> >>> "reconnecting server. Default: 5. 0 means "
>> >>> "never reconnect.");
>> >>> +unsigned int enable_oplocks = 1;
>> >>> +module_param(enable_oplocks, bool, 0644);
>> >>> +MODULE_PARM_DESC(enable_oplocks, "Enable or disable oplocks (bool). Default: 1.");
>> >>
>> >> I think you want this as "Default: true" since this is a bool?
>> >>
>> >
>> > No. From the definition of module_param:
>> >
>> > (snip)
>> > * Standard types are:
>> > * byte, short, ushort, int, uint, long, ulong
>> > * charp: a character pointer
>> > * bool: a bool, values 0/1, y/n, Y/N.
>> > */
>> > #define module_param(name, type, perm) \
>> > module_param_named(name, name, type, perm)
>> >
>> > I should perhaps add y/Y.
>>
>> I don't mind adding a module parm to change the default but it seems
>> odd, and removing the ability to temporarily turn off oplock seems to
>> make things worse not better. But I am not convinced of a good use
>> case for disabling oplocks on module load (rather than the more
>> granular "forcedirectio" on mount, or the temporary ie at runtime via
>> /proc). If oplock/caching on the client were broken, then we would
>> fix the bug rather than ask users to load with oplock off, if oplock
>> were broken on a server, we would not want to disable it for mounts to
>> all servers (as would a module parm) but just to workaround the broken
>> server.
>>
>
> This doesn't prevent you from changing this setting after the module is
> loaded. It just moves the control to a more standard location
> (/sys/module/cifs/parameters).
If "echo 1 > /sys/module/cifs/parameters/oplock_enabled" would work at runtime,
then I fine with the change. We could leave them both in for one release,
and throw a onetime syslog message if you use the one in /proc/fs/cifs/ (so
that users know that the old interface is going away)??
--
Thanks,
Steve
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