nfsdcltrack: add a legacy transition mechanism

If the kernel passes the legacy recdir path in the environment, then we
can use that to transition from the old legacy tracker to the new one.

On a "check" operation, if there is no record of the client in the
database, check to see if there is a matching recoverydir. If there
isn't then just refuse the reclaim. If there is, then insert a new
record for this client into the db, and remove the legacy recoverydir.
If either of those operations fail, then refuse the reclaim.

On a "gracedone" operation, clean out the entire legacy recoverydir
after purging any unreclaimed records from the db. There's not much
we can do if this fails, so just log a warning if it does.

Note that this is a one-way conversion. If the user later boots back
into an older kernel, it will have no knowledge of the new database.

In principle, we could create a tool that would walk the clients
table, md5 hash the clientids and create directories in the
v4recovery dir. Doing that automatically would be pretty difficult
however.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve Dickson <steved@redhat.com>

1 files changed, 85 insertions, 0 deletions

diff --git a/utils/nfsdcltrack/nfsdcltrack.c b/utils/nfsdcltrack/nfsdcltrack.c
index 1d262a2..9801b9c 100644
--- a/utils/nfsdcltrack/nfsdcltrack.c
+++ b/utils/nfsdcltrack/nfsdcltrack.c
@@ -36,6 +36,7 @@
 #include <unistd.h>
 #include <libgen.h>
 #include <sys/inotify.h>
+#include <dirent.h>
 #ifdef HAVE_SYS_CAPABILITY_H
 #include <sys/prctl.h>
 #include <sys/capability.h>
@@ -296,6 +297,48 @@ cltrack_remove(const char *id)
 }
 
 static int
+cltrack_check_legacy(const unsigned char *blob, const ssize_t len)
+{
+	int ret;
+	struct stat st;
+	char *recdir = getenv("NFSDCLTRACK_LEGACY_RECDIR");
+
+	if (!recdir) {
+		xlog(D_GENERAL, "No NFSDCLTRACK_LEGACY_RECDIR env var");
+		return -EOPNOTSUPP;
+	}
+
+	/* fail recovery on any stat failure */
+	ret = stat(recdir, &st);
+	if (ret) {
+		xlog(D_GENERAL, "Unable to stat %s: %d", recdir, errno);
+		return -errno;
+	}
+
+	/* fail if it isn't a directory */
+	if (!S_ISDIR(st.st_mode)) {
+		xlog(D_GENERAL, "%s is not a directory: mode=0%o", recdir
+				, st.st_mode);
+		return -ENOTDIR;
+	}
+
+	/* Dir exists, try to insert record into db */
+	ret = sqlite_insert_client(blob, len);
+	if (ret) {
+		xlog(D_GENERAL, "Failed to insert client: %d", ret);
+		return -EREMOTEIO;
+	}
+
+	/* remove the legacy recoverydir */
+	ret = rmdir(recdir);
+	if (ret) {
+		xlog(D_GENERAL, "Failed to rmdir %s: %d", recdir, errno);
+		return -errno;
+	}
+	return 0;
+}
+
+static int
 cltrack_check(const char *id)
 {
 	int ret;
@@ -312,10 +355,50 @@ cltrack_check(const char *id)
 		return (int)len;
 
 	ret = sqlite_check_client(blob, len);
+	if (ret)
+		ret = cltrack_check_legacy(blob, len);
 
 	return ret ? -EPERM : ret;
 }
 
+/* Clean out the v4recoverydir -- best effort here */
+static void
+cltrack_legacy_gracedone(void)
+{
+	DIR *v4recovery;
+	struct dirent *entry;
+	char *dirname = getenv("NFSDCLTRACK_LEGACY_TOPDIR");
+
+	if (!dirname)
+		return;
+
+	v4recovery = opendir(dirname);
+	if (!v4recovery)
+		return;
+
+	while ((entry = readdir(v4recovery))) {
+		int len;
+
+		/* borrow the clientid blob for this */
+		len = snprintf((char *)blob, sizeof(blob), "%s/%s", dirname,
+				entry->d_name);
+
+		/* if there's a problem, then skip this entry */
+		if (len < 0 || (size_t)len >= sizeof(blob)) {
+			xlog(L_WARNING, "%s: unable to build filename for %s!",
+				__func__, entry->d_name);
+			continue;
+		}
+
+		len = rmdir((char *)blob);
+		if (len)
+			xlog(L_WARNING, "%s: unable to rmdir %s: %d", __func__,
+				(char *)blob, len);
+	}
+
+	closedir(v4recovery);
+}
+
 static int
 cltrack_gracedone(const char *timestr)
 {
@@ -343,6 +426,8 @@ cltrack_gracedone(const char *timestr)
 
 	ret = sqlite_remove_unreclaimed(gracetime);
 
+	cltrack_legacy_gracedone();
+
 	return ret ? -EREMOTEIO : ret;
 }