On Wed, Nov 08 2017, Joshua Watt wrote:
> Specifying the forcekill mount option causes umount() with the MNT_FORCE
> flag to not only kill all currently pending RPC tasks with -EIO, but
> also all future RPC tasks. This prevents the long delays caused by tasks
> queuing after rpc_killall_tasks() that can occur if the server drops off
> the network.
>
> Signed-off-by: Joshua Watt <JPEWhacker@xxxxxxxxx>
> ---
> fs/nfs/super.c | 17 ++++++++++++++---
> include/uapi/linux/nfs_mount.h | 1 +
> 2 files changed, 15 insertions(+), 3 deletions(-)
>
> diff --git a/fs/nfs/super.c b/fs/nfs/super.c
> index 66fda2dcadd0..d972f6289aca 100644
> --- a/fs/nfs/super.c
> +++ b/fs/nfs/super.c
> @@ -90,6 +90,7 @@ enum {
> Opt_resvport, Opt_noresvport,
> Opt_fscache, Opt_nofscache,
> Opt_migration, Opt_nomigration,
> + Opt_forcekill, Opt_noforcekill,
>
> /* Mount options that take integer arguments */
> Opt_port,
> @@ -151,6 +152,8 @@ static const match_table_t nfs_mount_option_tokens = {
> { Opt_nofscache, "nofsc" },
> { Opt_migration, "migration" },
> { Opt_nomigration, "nomigration" },
> + { Opt_forcekill, "forcekill" },
> + { Opt_noforcekill, "noforcekill" },
>
> { Opt_port, "port=%s" },
> { Opt_rsize, "rsize=%s" },
> @@ -637,6 +640,7 @@ static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss,
> { NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
> { NFS_MOUNT_UNSHARED, ",nosharecache", "" },
> { NFS_MOUNT_NORESVPORT, ",noresvport", "" },
> + { NFS_MOUNT_FORCEKILL, ",forcekill", ",noforcekill" },
> { 0, NULL, NULL }
> };
> const struct proc_nfs_info *nfs_infop;
> @@ -896,17 +900,18 @@ EXPORT_SYMBOL_GPL(nfs_show_stats);
> */
> void nfs_umount_begin(struct super_block *sb)
> {
> - struct nfs_server *server;
> + struct nfs_server *server = NFS_SB(sb);
> struct rpc_clnt *rpc;
> + int kill_new_tasks = !!(server->flags & NFS_MOUNT_FORCEKILL);
>
> server = NFS_SB(sb);
Now that you initialized 'server' at declaration, you should really
remove this (re)initialization.
I'm not sure what I think of this patchset...
You are setting a flag which causes "umount -f" to set a different flag.
Why not just have "mount -o remount,XX" set the flag that you actually
want to set.
e.g
mount -o remount,serverfailed /mountpoint
causes all rpcs to fail, and
mount -o remount,noserverfailed /mountpoint
causes all rpcs to be sent to the server.
(or pick a different name than 'serverfailed').
It isn't clear what the indirection buys us.
Thanks,
NeilBrown
> /* -EIO all pending I/O */
> rpc = server->client_acl;
> if (!IS_ERR(rpc))
> - rpc_killall_tasks(rpc, 0);
> + rpc_killall_tasks(rpc, kill_new_tasks);
> rpc = server->client;
> if (!IS_ERR(rpc))
> - rpc_killall_tasks(rpc, 0);
> + rpc_killall_tasks(rpc, kill_new_tasks);
> }
> EXPORT_SYMBOL_GPL(nfs_umount_begin);
>
> @@ -1334,6 +1339,12 @@ static int nfs_parse_mount_options(char *raw,
> case Opt_nomigration:
> mnt->options &= ~NFS_OPTION_MIGRATION;
> break;
> + case Opt_forcekill:
> + mnt->flags |= NFS_MOUNT_FORCEKILL;
> + break;
> + case Opt_noforcekill:
> + mnt->flags &= ~NFS_MOUNT_FORCEKILL;
> + break;
>
> /*
> * options that take numeric values
> diff --git a/include/uapi/linux/nfs_mount.h b/include/uapi/linux/nfs_mount.h
> index e44e00616ab5..66821542a38f 100644
> --- a/include/uapi/linux/nfs_mount.h
> +++ b/include/uapi/linux/nfs_mount.h
> @@ -74,5 +74,6 @@ struct nfs_mount_data {
>
> #define NFS_MOUNT_LOCAL_FLOCK 0x100000
> #define NFS_MOUNT_LOCAL_FCNTL 0x200000
> +#define NFS_MOUNT_FORCEKILL 0x400000
>
> #endif
> --
> 2.13.6
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