[PATCH 1/5] CIFS: Add strictcache mount option

[PATCH 1/5] CIFS: Add strictcache mount option

[Pavel Shilovsky]

Use for switching on strict cache mode. In this mode the
client read from the cache all the time it has Oplock Level II,
otherwise - read from the server. All written data are stored
in the cache, but if the client doesn't have Exclusive Oplock,
it writes the data to the server.

Signed-off-by: Pavel Shilovsky <piastryyy-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 fs/cifs/README       |    5 +++++
 fs/cifs/cifs_fs_sb.h |    1 +
 fs/cifs/connect.c    |    5 +++++
 3 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/fs/cifs/README b/fs/cifs/README
index ee68d10..8fb6192 100644
--- a/fs/cifs/README
+++ b/fs/cifs/README
@@ -443,6 +443,11 @@ A partial list of the supported mount options follows:
 		if oplock (caching token) is granted and held. Note that
 		direct allows write operations larger than page size
 		to be sent to the server.
+  strictcache   Use for switching on strict cache mode. In this mode the
+		client read from the cache all the time it has Oplock Level II,
+		otherwise - read from the server. All written data are stored
+		in the cache, but if the client doesn't have Exclusive Oplock,
+		it writes the data to the server.
   acl   	Allow setfacl and getfacl to manage posix ACLs if server
 		supports them.  (default)
   noacl 	Do not allow setfacl and getfacl calls on this mount
diff --git a/fs/cifs/cifs_fs_sb.h b/fs/cifs/cifs_fs_sb.h
index 525ba59..b7b8b45 100644
--- a/fs/cifs/cifs_fs_sb.h
+++ b/fs/cifs/cifs_fs_sb.h
@@ -40,6 +40,7 @@
 #define CIFS_MOUNT_FSCACHE	0x8000 /* local caching enabled */
 #define CIFS_MOUNT_MF_SYMLINKS	0x10000 /* Minshall+French Symlinks enabled */
 #define CIFS_MOUNT_MULTIUSER	0x20000 /* multiuser mount */
+#define CIFS_MOUNT_STRICT_IO	0x40000 /* strict cache behavior */

 struct cifs_sb_info {
 	struct radix_tree_root tlink_tree;
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 7e73176..11125fb 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -84,6 +84,7 @@ struct smb_vol {
 	bool no_xattr:1;   /* set if xattr (EA) support should be disabled*/
 	bool server_ino:1; /* use inode numbers from server ie UniqueId */
 	bool direct_io:1;
+	bool strict_io:1; /* strict cache behavior */
 	bool remap:1;      /* set to remap seven reserved chars in filenames */
 	bool posix_paths:1; /* unset to not ask for posix pathnames. */
 	bool no_linux_ext:1;
@@ -1343,6 +1344,8 @@ cifs_parse_mount_options(char *options, const
char *devname,
 			vol->direct_io = 1;
 		} else if (strnicmp(data, "forcedirectio", 13) == 0) {
 			vol->direct_io = 1;
+		} else if (strnicmp(data, "strictcache", 11) == 0) {
+			vol->strict_io = 1;
 		} else if (strnicmp(data, "noac", 4) == 0) {
 			printk(KERN_WARNING "CIFS: Mount option noac not "
 				"supported. Instead set "
@@ -2582,6 +2585,8 @@ static void setup_cifs_sb(struct smb_vol *pvolume_info,
 	if (pvolume_info->multiuser)
 		cifs_sb->mnt_cifs_flags |= (CIFS_MOUNT_MULTIUSER |
 					    CIFS_MOUNT_NO_PERM);
+	if (pvolume_info->strict_io)
+		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_STRICT_IO;
 	if (pvolume_info->direct_io) {
 		cFYI(1, "mounting share using direct i/o");
 		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_DIRECT_IO;
-- 
1.7.2.3

Re: [PATCH 1/5] CIFS: Add strictcache mount option

[Jeff Layton]

On Sun, 31 Oct 2010 22:42:12 +0300
Pavel Shilovsky <piastryyy-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:

> Use for switching on strict cache mode. In this mode the
> client read from the cache all the time it has Oplock Level II,
> otherwise - read from the server. All written data are stored
> in the cache, but if the client doesn't have Exclusive Oplock,
> it writes the data to the server.
> 
> Signed-off-by: Pavel Shilovsky <piastryyy-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---
>  fs/cifs/README       |    5 +++++
>  fs/cifs/cifs_fs_sb.h |    1 +
>  fs/cifs/connect.c    |    5 +++++
>  3 files changed, 11 insertions(+), 0 deletions(-)
> 
> diff --git a/fs/cifs/README b/fs/cifs/README
> index ee68d10..8fb6192 100644
> --- a/fs/cifs/README
> +++ b/fs/cifs/README
> @@ -443,6 +443,11 @@ A partial list of the supported mount options follows:
>  		if oplock (caching token) is granted and held. Note that
>  		direct allows write operations larger than page size
>  		to be sent to the server.
> +  strictcache   Use for switching on strict cache mode. In this mode the
> +		client read from the cache all the time it has Oplock Level II,
> +		otherwise - read from the server. All written data are stored
> +		in the cache, but if the client doesn't have Exclusive Oplock,
> +		it writes the data to the server.
>    acl   	Allow setfacl and getfacl to manage posix ACLs if server
>  		supports them.  (default)
>    noacl 	Do not allow setfacl and getfacl calls on this mount
> diff --git a/fs/cifs/cifs_fs_sb.h b/fs/cifs/cifs_fs_sb.h
> index 525ba59..b7b8b45 100644
> --- a/fs/cifs/cifs_fs_sb.h
> +++ b/fs/cifs/cifs_fs_sb.h
> @@ -40,6 +40,7 @@
>  #define CIFS_MOUNT_FSCACHE	0x8000 /* local caching enabled */
>  #define CIFS_MOUNT_MF_SYMLINKS	0x10000 /* Minshall+French Symlinks enabled */
>  #define CIFS_MOUNT_MULTIUSER	0x20000 /* multiuser mount */
> +#define CIFS_MOUNT_STRICT_IO	0x40000 /* strict cache behavior */
> 
>  struct cifs_sb_info {
>  	struct radix_tree_root tlink_tree;
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index 7e73176..11125fb 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -84,6 +84,7 @@ struct smb_vol {
>  	bool no_xattr:1;   /* set if xattr (EA) support should be disabled*/
>  	bool server_ino:1; /* use inode numbers from server ie UniqueId */
>  	bool direct_io:1;
> +	bool strict_io:1; /* strict cache behavior */
>  	bool remap:1;      /* set to remap seven reserved chars in filenames */
>  	bool posix_paths:1; /* unset to not ask for posix pathnames. */
>  	bool no_linux_ext:1;
> @@ -1343,6 +1344,8 @@ cifs_parse_mount_options(char *options, const
> char *devname,
>  			vol->direct_io = 1;
>  		} else if (strnicmp(data, "forcedirectio", 13) == 0) {
>  			vol->direct_io = 1;
> +		} else if (strnicmp(data, "strictcache", 11) == 0) {
> +			vol->strict_io = 1;
>  		} else if (strnicmp(data, "noac", 4) == 0) {
>  			printk(KERN_WARNING "CIFS: Mount option noac not "
>  				"supported. Instead set "
> @@ -2582,6 +2585,8 @@ static void setup_cifs_sb(struct smb_vol *pvolume_info,
>  	if (pvolume_info->multiuser)
>  		cifs_sb->mnt_cifs_flags |= (CIFS_MOUNT_MULTIUSER |
>  					    CIFS_MOUNT_NO_PERM);
> +	if (pvolume_info->strict_io)
> +		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_STRICT_IO;
>  	if (pvolume_info->direct_io) {
>  		cFYI(1, "mounting share using direct i/o");
>  		cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_DIRECT_IO;


It might be better to add the mount flag when you first need to use it and
then add the option last (after the rest of the series).

Consider that git-bisect might cause someone to build a kernel with
only part of the set applied.

-- 
Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>

Re: [PATCH 1/5] CIFS: Add strictcache mount option

[Suresh Jayaraman]

On 11/01/2010 01:12 AM, Pavel Shilovsky wrote:
> Use for switching on strict cache mode. In this mode the
> client read from the cache all the time it has Oplock Level II,
> otherwise - read from the server. All written data are stored
> in the cache, but if the client doesn't have Exclusive Oplock,
> it writes the data to the server.
> 
> Signed-off-by: Pavel Shilovsky <piastryyy-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---
>  fs/cifs/README       |    5 +++++
>  fs/cifs/cifs_fs_sb.h |    1 +
>  fs/cifs/connect.c    |    5 +++++
>  3 files changed, 11 insertions(+), 0 deletions(-)
> 
> diff --git a/fs/cifs/README b/fs/cifs/README
> index ee68d10..8fb6192 100644
> --- a/fs/cifs/README
> +++ b/fs/cifs/README
> @@ -443,6 +443,11 @@ A partial list of the supported mount options follows:
>  		if oplock (caching token) is granted and held. Note that
>  		direct allows write operations larger than page size
>  		to be sent to the server.
> +  strictcache   Use for switching on strict cache mode. In this mode the
> +		client read from the cache all the time it has Oplock Level II,
> +		otherwise - read from the server. All written data are stored
> +		in the cache, but if the client doesn't have Exclusive Oplock,
> +		it writes the data to the server.

Could you remind me where this will be useful? Also, providing the same
information in README and mount.cifs man page is useful as well.


-- 
Suresh Jayaraman

Re: [PATCH 1/5] CIFS: Add strictcache mount option

[Pavel Shilovsky]

2010/11/3 Suresh Jayaraman <sjayaraman-l3A5Bk7waGM@public.gmane.org>:
> On 11/01/2010 01:12 AM, Pavel Shilovsky wrote:
>> Use for switching on strict cache mode. In this mode the
>> client read from the cache all the time it has Oplock Level II,
>> otherwise - read from the server. All written data are stored
>> in the cache, but if the client doesn't have Exclusive Oplock,
>> it writes the data to the server.
>>
>> Signed-off-by: Pavel Shilovsky <piastryyy-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>> ---
>>  fs/cifs/README       |    5 +++++
>>  fs/cifs/cifs_fs_sb.h |    1 +
>>  fs/cifs/connect.c    |    5 +++++
>>  3 files changed, 11 insertions(+), 0 deletions(-)
>>
>> diff --git a/fs/cifs/README b/fs/cifs/README
>> index ee68d10..8fb6192 100644
>> --- a/fs/cifs/README
>> +++ b/fs/cifs/README
>> @@ -443,6 +443,11 @@ A partial list of the supported mount options follows:
>>               if oplock (caching token) is granted and held. Note that
>>               direct allows write operations larger than page size
>>               to be sent to the server.
>> +  strictcache   Use for switching on strict cache mode. In this mode the
>> +             client read from the cache all the time it has Oplock Level II,
>> +             otherwise - read from the server. All written data are stored
>> +             in the cache, but if the client doesn't have Exclusive Oplock,
>> +             it writes the data to the server.
>
> Could you remind me where this will be useful? Also, providing the same
> information in README and mount.cifs man page is useful as well.
>

It is useful when we need to get the only the valida data from the
server. Ex. when the first process writes to the server and the second
reads this in the same time. Due to Samba server can delay mtime
change after writing, we can't trust to mtime and oef checkings and
have to process it according to oplock level we have.

It also works with the mandatory byte-range locking style which
Windows supports - that can let us to make Wine application work
togather with Windows ones on CIFS share where byte-range locks play
sinchronization role.

-- 
Best regards,
Pavel Shilovsky.