On Fri, 10 Sep 2010 01:06:38 +0530
Suresh Jayaraman <sjayaraman@xxxxxxx> wrote:
> NFS clients since 2.6.12 support flock locks by emulating fcntl byte-range
> locks. Due to this, some windows applications which seem to use both flock
> (share mode lock mapped as flock by Samba) and fcntl locks sequentially on
> the same file, can't lock as they falsely assume the file is already locked.
> The problem was reported on a setup with windows clients accessing excel files
> on a Samba exported share which is originally a NFS mount from a NetApp filer.
>
> Older NFS clients (< 2.6.12) did not see this problem as flock locks were
> considered local. To support legacy flock behavior, this patch adds a mount
> option "-olocal_lock=" which can take the following values:
>
> 'none' - Neither flock locks or fcntl/posix locks are local
> 'flock'/'posix' - flock locks are local
^^^^^^^
"posix" ought to be synonymous with "fcntl". "flock" was a BSD-ism.
It may be better to keep it simple though and drop either "posix" or
"fcntl". No need to add unneeded synonyms on a brand new mount option.
> 'fcntl' - fcntl locks are local
> 'all' - Both flock locks and fcntl/posix locks are local
>
> Testing:
>
> This patch was tested by using -olocal_lock option with different values and
> the NLM calls were noted from the network packet capture.
>
> 'none' - NLM calls were seen during both flock() and fcntl(), flock lock
> was granted, fcntl was denied
> 'flock' - no NLM calls for flock(), NLM call was seen for fcntl(),
> granted
> 'fcntl' - NLM call was seen for flock() - granted, no NLM call for fcntl()
> 'all' - no NLM calls were seen during both flock() and fcntl()
>
> Also, with these patches ensured that the exisiting behavior of '-olock' and
> '-onolock' didn't change.
>
> Cc: Neil Brown <neilb@xxxxxxx>
> Signed-off-by: Suresh Jayaraman <sjayaraman@xxxxxxx>
> ---
> fs/nfs/client.c | 6 +++-
> fs/nfs/file.c | 35 +++++++++++++++++++++++----------
> fs/nfs/super.c | 47 +++++++++++++++++++++++++++++++++++++++++++++
> include/linux/nfs_mount.h | 5 +++-
> 4 files changed, 79 insertions(+), 14 deletions(-)
>
> diff --git a/fs/nfs/client.c b/fs/nfs/client.c
> index 4e7df2a..5f01f42 100644
> --- a/fs/nfs/client.c
> +++ b/fs/nfs/client.c
> @@ -635,7 +635,8 @@ static int nfs_create_rpc_client(struct nfs_client *clp,
> */
> static void nfs_destroy_server(struct nfs_server *server)
> {
> - if (!(server->flags & NFS_MOUNT_NONLM))
> + if (!(server->flags & NFS_MOUNT_LOCAL_FLOCK) ||
> + !(server->flags & NFS_MOUNT_LOCAL_FCNTL))
> nlmclnt_done(server->nlm_host);
> }
>
> @@ -657,7 +658,8 @@ static int nfs_start_lockd(struct nfs_server *server)
>
> if (nlm_init.nfs_version > 3)
> return 0;
> - if (server->flags & NFS_MOUNT_NONLM)
> + if ((server->flags & NFS_MOUNT_LOCAL_FLOCK) &&
> + (server->flags & NFS_MOUNT_LOCAL_FCNTL))
> return 0;
>
> switch (clp->cl_proto) {
> diff --git a/fs/nfs/file.c b/fs/nfs/file.c
> index eb51bd6..e338d37 100644
> --- a/fs/nfs/file.c
> +++ b/fs/nfs/file.c
> @@ -684,7 +684,8 @@ static ssize_t nfs_file_splice_write(struct pipe_inode_info *pipe,
> return ret;
> }
>
> -static int do_getlk(struct file *filp, int cmd, struct file_lock *fl)
> +static int
> +do_getlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
> {
> struct inode *inode = filp->f_mapping->host;
> int status = 0;
> @@ -699,7 +700,7 @@ static int do_getlk(struct file *filp, int cmd, struct file_lock *fl)
> if (nfs_have_delegation(inode, FMODE_READ))
> goto out_noconflict;
>
> - if (NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)
> + if ((NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM) || is_local)
> goto out_noconflict;
>
> status = NFS_PROTO(inode)->lock(filp, cmd, fl);
> @@ -730,7 +731,8 @@ static int do_vfs_lock(struct file *file, struct file_lock *fl)
> return res;
> }
>
> -static int do_unlk(struct file *filp, int cmd, struct file_lock *fl)
> +static int
> +do_unlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
> {
> struct inode *inode = filp->f_mapping->host;
> int status;
> @@ -746,14 +748,15 @@ static int do_unlk(struct file *filp, int cmd, struct file_lock *fl)
> * still need to complete the unlock.
> */
> /* Use local locking if mounted with "-onolock" */
> - if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
> + if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM) || !is_local)
> status = NFS_PROTO(inode)->lock(filp, cmd, fl);
> else
> status = do_vfs_lock(filp, fl);
> return status;
> }
>
> -static int do_setlk(struct file *filp, int cmd, struct file_lock *fl)
> +static int
> +do_setlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
> {
> struct inode *inode = filp->f_mapping->host;
> int status;
> @@ -767,7 +770,7 @@ static int do_setlk(struct file *filp, int cmd, struct file_lock *fl)
> goto out;
>
> /* Use local locking if mounted with "-onolock" */
> - if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
> + if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM) || !is_local)
> status = NFS_PROTO(inode)->lock(filp, cmd, fl);
> else
> status = do_vfs_lock(filp, fl);
> @@ -791,6 +794,7 @@ static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
> {
> struct inode *inode = filp->f_mapping->host;
> int ret = -ENOLCK;
> + int is_local = 0;
>
> dprintk("NFS: lock(%s/%s, t=%x, fl=%x, r=%lld:%lld)\n",
> filp->f_path.dentry->d_parent->d_name.name,
> @@ -804,6 +808,9 @@ static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
> if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
> goto out_err;
>
> + if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FCNTL)
> + is_local = 1;
> +
> if (NFS_PROTO(inode)->lock_check_bounds != NULL) {
> ret = NFS_PROTO(inode)->lock_check_bounds(fl);
> if (ret < 0)
> @@ -811,11 +818,11 @@ static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
> }
>
> if (IS_GETLK(cmd))
> - ret = do_getlk(filp, cmd, fl);
> + ret = do_getlk(filp, cmd, fl, is_local);
> else if (fl->fl_type == F_UNLCK)
> - ret = do_unlk(filp, cmd, fl);
> + ret = do_unlk(filp, cmd, fl, is_local);
> else
> - ret = do_setlk(filp, cmd, fl);
> + ret = do_setlk(filp, cmd, fl, is_local);
> out_err:
> return ret;
> }
> @@ -825,6 +832,9 @@ out_err:
> */
> static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
> {
> + struct inode *inode = filp->f_mapping->host;
> + int is_local = 0;
> +
> dprintk("NFS: flock(%s/%s, t=%x, fl=%x)\n",
> filp->f_path.dentry->d_parent->d_name.name,
> filp->f_path.dentry->d_name.name,
> @@ -833,14 +843,17 @@ static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
> if (!(fl->fl_flags & FL_FLOCK))
> return -ENOLCK;
>
> + if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FLOCK)
> + is_local = 1;
> +
> /* We're simulating flock() locks using posix locks on the server */
> fl->fl_owner = (fl_owner_t)filp;
> fl->fl_start = 0;
> fl->fl_end = OFFSET_MAX;
>
> if (fl->fl_type == F_UNLCK)
> - return do_unlk(filp, cmd, fl);
> - return do_setlk(filp, cmd, fl);
> + return do_unlk(filp, cmd, fl, is_local);
> + return do_setlk(filp, cmd, fl, is_local);
> }
>
> /*
> diff --git a/fs/nfs/super.c b/fs/nfs/super.c
> index ec3966e..c0d51dc 100644
> --- a/fs/nfs/super.c
> +++ b/fs/nfs/super.c
> @@ -100,6 +100,7 @@ enum {
> Opt_addr, Opt_mountaddr, Opt_clientaddr,
> Opt_lookupcache,
> Opt_fscache_uniq,
> + Opt_local_lock,
>
> /* Special mount options */
> Opt_userspace, Opt_deprecated, Opt_sloppy,
> @@ -171,6 +172,7 @@ static const match_table_t nfs_mount_option_tokens = {
>
> { Opt_lookupcache, "lookupcache=%s" },
> { Opt_fscache_uniq, "fsc=%s" },
> + { Opt_local_lock, "local_lock=%s" },
>
> { Opt_err, NULL }
> };
> @@ -236,6 +238,23 @@ static match_table_t nfs_lookupcache_tokens = {
> { Opt_lookupcache_err, NULL }
> };
>
> +enum {
> + Opt_local_lock_all, Opt_local_lock_flock, Opt_local_lock_fcntl,
> + Opt_local_lock_none,
> +
> + Opt_local_lock_err
> +};
> +
> +static match_table_t nfs_local_lock_tokens = {
> + { Opt_local_lock_all, "all" },
> + { Opt_local_lock_flock, "flock" },
> + { Opt_local_lock_fcntl, "fcntl" },
> + { Opt_local_lock_fcntl, "posix" },
> + { Opt_local_lock_none, "none" },
> +
> + { Opt_local_lock_err, NULL }
> +};
> +
>
> static void nfs_umount_begin(struct super_block *);
> static int nfs_statfs(struct dentry *, struct kstatfs *);
> @@ -1412,6 +1431,34 @@ static int nfs_parse_mount_options(char *raw,
> mnt->fscache_uniq = string;
> mnt->options |= NFS_OPTION_FSCACHE;
> break;
> + case Opt_local_lock:
> + string = match_strdup(args);
> + if (string == NULL)
> + goto out_nomem;
> + token = match_token(string, nfs_local_lock_tokens,
> + args);
> + kfree(string);
> + switch (token) {
> + case Opt_local_lock_all:
> + mnt->flags |= (NFS_MOUNT_LOCAL_FLOCK |
> + NFS_MOUNT_LOCAL_FCNTL);
> + break;
> + case Opt_local_lock_flock:
> + mnt->flags |= NFS_MOUNT_LOCAL_FLOCK;
> + break;
> + case Opt_local_lock_fcntl:
> + mnt->flags |= NFS_MOUNT_LOCAL_FCNTL;
> + break;
> + case Opt_local_lock_none:
> + mnt->flags &= ~(NFS_MOUNT_LOCAL_FLOCK |
> + NFS_MOUNT_LOCAL_FCNTL);
> + break;
> + default:
> + dfprintk(MOUNT, "NFS: invalid "
> + "local_lock argument\n");
> + return 0;
> + };
> + break;
>
> /*
> * Special options
> diff --git a/include/linux/nfs_mount.h b/include/linux/nfs_mount.h
> index 5d59ae8..652d7e9 100644
> --- a/include/linux/nfs_mount.h
> +++ b/include/linux/nfs_mount.h
> @@ -56,7 +56,6 @@ struct nfs_mount_data {
> #define NFS_MOUNT_TCP 0x0040 /* 2 */
> #define NFS_MOUNT_VER3 0x0080 /* 3 */
> #define NFS_MOUNT_KERBEROS 0x0100 /* 3 */
> -#define NFS_MOUNT_NONLM 0x0200 /* 3 */
> #define NFS_MOUNT_BROKEN_SUID 0x0400 /* 4 */
> #define NFS_MOUNT_NOACL 0x0800 /* 4 */
> #define NFS_MOUNT_STRICTLOCK 0x1000 /* reserved for NFSv4 */
> @@ -71,4 +70,8 @@ struct nfs_mount_data {
> #define NFS_MOUNT_NORESVPORT 0x40000
> #define NFS_MOUNT_LEGACY_INTERFACE 0x80000
>
> +#define NFS_MOUNT_LOCAL_FLOCK 0x100000
> +#define NFS_MOUNT_LOCAL_FCNTL 0x200000
> +#define NFS_MOUNT_NONLM (NFS_MOUNT_LOCAL_FLOCK | NFS_MOUNT_LOCAL_FCNTL)
> +
> #endif
--
Jeff Layton <jlayton@xxxxxxxxxx>
--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
