On Wed, Oct 24, 2012 at 10:30:17AM -0400, Jeff Layton wrote:
> The usermodehelper upcall program can then decide to use this info as
> a (one-way) transition mechanism to the new scheme. When a "check"
> upcall occurs and the client doesn't exist in the database, we can
> look to see whether the directory exists. If it does, then we'd add
> the client to the database, remove the legacy recdir, and return
> success to the kernel to allow the recovery to proceed.
>
> For gracedone, we simply pass the v4recovery "topdir" so that the
> upcall can clean it out prior to returning to the kernel.
I don't understand why the kernel needs to be involved here--can't
userspace find the old directory on its own?
--b.
>
> A module parm is also added to disable the legacy conversion if
> the admin chooses.
>
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
> fs/nfsd/nfs4recover.c | 90 ++++++++++++++++++++++++++++++++++++++++++++++-----
> 1 file changed, 82 insertions(+), 8 deletions(-)
>
> diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
> index aa165fd..782168d 100644
> --- a/fs/nfsd/nfs4recover.c
> +++ b/fs/nfsd/nfs4recover.c
> @@ -932,10 +932,75 @@ module_param_string(cltrack_prog, cltrack_prog, sizeof(cltrack_prog),
> S_IRUGO|S_IWUSR);
> MODULE_PARM_DESC(cltrack_prog, "Path to the nfsdcltrack upcall program");
>
> +static bool cltrack_legacy_disable;
> +module_param(cltrack_legacy_disable, bool, S_IRUGO|S_IWUSR);
> +MODULE_PARM_DESC(cltrack_legacy_disable,
> + "Disable legacy recoverydir conversion. Default: false");
> +
> +#define LEGACY_TOPDIR_ENV_PREFIX "NFSDCLTRACK_LEGACY_TOPDIR="
> +#define LEGACY_RECDIR_ENV_PREFIX "NFSDCLTRACK_LEGACY_RECDIR="
> +
> +static char *
> +nfsd4_cltrack_legacy_topdir(void)
> +{
> + int copied;
> + size_t len;
> + char *result;
> +
> + if (cltrack_legacy_disable)
> + return NULL;
> +
> + len = strlen(LEGACY_TOPDIR_ENV_PREFIX) +
> + strlen(nfs4_recoverydir()) + 1;
> +
> + result = kmalloc(len, GFP_KERNEL);
> + if (!result)
> + return result;
> +
> + copied = snprintf(result, len, LEGACY_TOPDIR_ENV_PREFIX "%s",
> + nfs4_recoverydir());
> + if (copied >= len) {
> + /* just return nothing if output was truncated */
> + kfree(result);
> + return NULL;
> + }
> +
> + return result;
> +}
> +
> +static char *
> +nfsd4_cltrack_legacy_recdir(const char *recdir)
> +{
> + int copied;
> + size_t len;
> + char *result;
> +
> + if (cltrack_legacy_disable)
> + return NULL;
> +
> + /* +1 is for '/' between "topdir" and "recdir" */
> + len = strlen(LEGACY_RECDIR_ENV_PREFIX) +
> + strlen(nfs4_recoverydir()) + 1 + HEXDIR_LEN;
> +
> + result = kmalloc(len, GFP_KERNEL);
> + if (!result)
> + return result;
> +
> + copied = snprintf(result, len, LEGACY_RECDIR_ENV_PREFIX "%s/%s",
> + nfs4_recoverydir(), recdir);
> + if (copied >= len) {
> + /* just return nothing if output was truncated */
> + kfree(result);
> + return NULL;
> + }
> +
> + return result;
> +}
> +
> static int
> -nfsd4_umh_cltrack_upcall(char *cmd, char *arg)
> +nfsd4_umh_cltrack_upcall(char *cmd, char *arg, char *legacy)
> {
> - char *envp[] = { NULL };
> + char *envp[2];
> char *argv[4];
> int ret;
>
> @@ -946,6 +1011,10 @@ nfsd4_umh_cltrack_upcall(char *cmd, char *arg)
>
> dprintk("%s: cmd: %s\n", __func__, cmd);
> dprintk("%s: arg: %s\n", __func__, arg ? arg : "(null)");
> + dprintk("%s: legacy: %s\n", __func__, legacy ? legacy : "(null)");
> +
> + envp[0] = legacy;
> + envp[1] = NULL;
>
> argv[0] = (char *)cltrack_prog;
> argv[1] = cmd;
> @@ -991,7 +1060,7 @@ bin_to_hex_dup(const unsigned char *src, int srclen)
> static int
> nfsd4_umh_cltrack_init(struct net __attribute__((unused)) *net)
> {
> - return nfsd4_umh_cltrack_upcall("init", NULL);
> + return nfsd4_umh_cltrack_upcall("init", NULL, NULL);
> }
>
> static void
> @@ -1004,7 +1073,7 @@ nfsd4_umh_cltrack_create(struct nfs4_client *clp)
> dprintk("%s: can't allocate memory for upcall!\n", __func__);
> return;
> }
> - nfsd4_umh_cltrack_upcall("create", hexid);
> + nfsd4_umh_cltrack_upcall("create", hexid, NULL);
> kfree(hexid);
> }
>
> @@ -1018,7 +1087,7 @@ nfsd4_umh_cltrack_remove(struct nfs4_client *clp)
> dprintk("%s: can't allocate memory for upcall!\n", __func__);
> return;
> }
> - nfsd4_umh_cltrack_upcall("remove", hexid);
> + nfsd4_umh_cltrack_upcall("remove", hexid, NULL);
> kfree(hexid);
> }
>
> @@ -1026,14 +1095,16 @@ static int
> nfsd4_umh_cltrack_check(struct nfs4_client *clp)
> {
> int ret;
> - char *hexid;
> + char *hexid, *legacy;
>
> hexid = bin_to_hex_dup(clp->cl_name.data, clp->cl_name.len);
> if (!hexid) {
> dprintk("%s: can't allocate memory for upcall!\n", __func__);
> return -ENOMEM;
> }
> - ret = nfsd4_umh_cltrack_upcall("check", hexid);
> + legacy = nfsd4_cltrack_legacy_recdir(clp->cl_recdir);
> + ret = nfsd4_umh_cltrack_upcall("check", hexid, legacy);
> + kfree(legacy);
> kfree(hexid);
> return ret;
> }
> @@ -1042,10 +1113,13 @@ static void
> nfsd4_umh_cltrack_grace_done(struct net __attribute__((unused)) *net,
> time_t boot_time)
> {
> + char *legacy;
> char timestr[22]; /* FIXME: better way to determine max size? */
>
> sprintf(timestr, "%ld", boot_time);
> - nfsd4_umh_cltrack_upcall("gracedone", timestr);
> + legacy = nfsd4_cltrack_legacy_topdir();
> + nfsd4_umh_cltrack_upcall("gracedone", timestr, legacy);
> + kfree(legacy);
> }
>
> static struct nfsd4_client_tracking_ops nfsd4_umh_tracking_ops = {
> --
> 1.7.11.7
>
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