ext2fs: check if Lustre filesystem is mounted

Add a check to ext2fs_check_mount_point() to loo in /proc/fs/lustre/*
to see if Lustre is mounted, since st_rdev of the mountpoint does not
match st_rdev of the block device itself, which confuses libext2fs.

  LU-6093 ext2fs: don't confuse mke2fs by Lustre zfs mount

  check_if_lustre_mounted() by efb735 will mistakenly report the
  device is mounted when there is a ZFS-based Lustre mount.

  This patch fix it by parsing the real device name from the pool
  name exported in Lustre proc file with "zpool" command.

  It also includes a typo fix in check_if_lustre_mounted() and a
  few other code cleanups.

  Signed-off-by: Niu Yawei <yawei.niu@intel.com>
  Change-Id: I43dabbcd6fa721c569cd9cc0f4a6de93ab761392
  Reviewed-on: http://review.whamcloud.com/14223
  Reviewed-by: John L. Hammond <john.hammond@intel.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>

diff --git a/lib/ext2fs/ismounted.c b/lib/ext2fs/ismounted.c
index 6c6ecff..be71179 100644 (file)
--- a/lib/ext2fs/ismounted.c
+++ b/lib/ext2fs/ismounted.c
@@ -38,6 +38,8 @@
 #endif /* HAVE_GETMNTINFO */
 #include <string.h>
 #include <sys/stat.h>
+#include <sys/types.h>
+#include <dirent.h>
 
 #include "ext2_fs.h"
 #include "ext2fs.h"
@@ -335,6 +337,194 @@ leave:
        return ret;
 }
 
+static int check_lustre_zfs(char *mnt_device, const char *real_devname)
+{
+       char *real_mnt_device, *buf, *ptr;
+       FILE *fp;
+       int rc = 0;
+
+       real_mnt_device = malloc(PATH_MAX);
+       if (real_mnt_device == NULL) {
+               fprintf(stderr, "Cannot allocate memory to store path\n");
+               return 1;
+       }
+
+       buf = malloc(PATH_MAX);
+       if (buf == NULL) {
+               fprintf(stderr, "Cannot allocate memory to store command\n");
+               free(real_mnt_device);
+               return 1;
+       }
+
+       /* Get the pool name from mnt_device */
+       ptr = strchr(mnt_device, '/');
+       if (ptr)
+               *ptr = '\0';
+
+       memset(buf, 0, PATH_MAX);
+       sprintf(buf, "zpool list -Hv %s", mnt_device);
+
+       fp = popen(buf, "r");
+       if (fp) {
+               int line = 0;
+               while (!feof(fp)) {
+                       memset(buf, 0, PATH_MAX);
+                       fscanf(fp, "%s%*[^\n]", buf);
+                       /* skip the first line */
+                       if (line++ == 0)
+                               continue;
+                       /* skip empty line */
+                       if (strlen(buf) == 0)
+                               continue;
+
+                       if (realpath(buf, real_mnt_device) == NULL)
+                               continue;
+                       if (strcmp(real_devname, real_mnt_device) == 0) {
+                               fprintf(stderr, "device %s mounted by Lustre\n",
+                                       real_devname);
+                               rc = -1;
+                               break;
+                       }
+               }
+               pclose(fp);
+       }
+
+       return rc;
+}
+
+static int check_lustre_ldiskfs(const char *mnt_device,
+                               const char *real_devname)
+{
+       char *real_mnt_device;
+
+       real_mnt_device = malloc(PATH_MAX);
+       if (real_mnt_device == NULL) {
+               fprintf(stderr, "Cannot allocate memory to store path\n");
+               return 1;
+       }
+
+       memset(real_mnt_device, 0, PATH_MAX);
+       if (realpath(mnt_device, real_mnt_device) == NULL) {
+               fprintf(stderr, "Cannot resolve mntdev %s\n", mnt_device);
+               free(real_mnt_device);
+               return 1;
+       }
+
+       if (strcmp(real_devname, real_mnt_device) == 0) {
+               fprintf(stderr, "device %s mounted by lustre\n", real_devname);
+               free(real_mnt_device);
+               return -1;
+       }
+
+       free(real_mnt_device);
+       return 0;
+}
+
+static int check_lustre_proc_vals(const char *procname,const char *real_devname)
+{
+       struct dirent *direntp;
+       DIR *dirp;
+       int rc = 0;
+       char  *mnt_device, *proc_val;
+
+       mnt_device = malloc(PATH_MAX);
+       if (mnt_device == NULL) {
+               fprintf(stderr, "Cannot allocate memory to store device\n");
+               return 1;
+       }
+       proc_val = malloc(PATH_MAX);
+       if (proc_val == NULL) {
+               fprintf(stderr, "Cannot allocate memory to store proc\n");
+               free(mnt_device);
+               return 1;
+       }
+
+       dirp = opendir(procname);
+       if (dirp) {
+               do {
+                       int fd, numr;
+                       char *ptr;
+
+                       direntp = readdir(dirp);
+                       if (direntp == NULL)
+                               break;
+                       if ((strncmp(direntp->d_name, ".", 1) == 0) ||
+                           (strncmp(direntp->d_name, "..", 2) == 0)) {
+                               continue;
+                       }
+
+                       memset(proc_val, 0, PATH_MAX);
+                       snprintf(proc_val, PATH_MAX, "%s/%s/mntdev", procname,
+                                direntp->d_name);
+                       fd = open(proc_val, O_RDONLY);
+                       if (fd < 0)  {
+                               if (errno == ENOENT || errno == ENOTDIR)
+                                       continue;
+                               fprintf(stderr, "Cannot open %s: %s\n",
+                                       proc_val, strerror(errno));
+                               rc = 1;
+                               break;
+                       }
+
+                       memset(mnt_device, 0, PATH_MAX);
+                       numr = read(fd, mnt_device, PATH_MAX);
+                       if (numr < 0) {
+                               fprintf(stderr, "Failure to get mntdev info\n");
+                               rc = 1;
+                               close(fd);
+                               break;
+                       }
+                       close(fd);
+
+                       ptr = strchr(mnt_device, '\n');
+                       if (ptr)
+                               *ptr = '\0';
+
+                       if (strstr(procname, "osd-zfs") != NULL)
+                               rc = check_lustre_zfs(mnt_device, real_devname);
+                       else
+                               rc = check_lustre_ldiskfs(mnt_device,
+                                                         real_devname);
+
+               } while (direntp != NULL && rc == 0);
+
+               closedir(dirp);
+       }
+
+       free(proc_val);
+       free(mnt_device);
+
+       return rc;
+}
+
+static errcode_t check_if_lustre_mounted(const char *device, int *mount_flags)
+{
+       char *real_device;
+       int rc = 0;
+
+       real_device = malloc(PATH_MAX);
+       if (real_device == NULL) {
+               fprintf(stderr, "Cannot allocate memory to store path\n");
+               return EXT2_ET_NO_MEMORY;
+       }
+
+       if (realpath(device, real_device) == NULL) {
+               fprintf(stderr, "Cannot resolve path %s\n", device);
+               return EXT2_ET_BAD_DEVICE_NAME;
+       }
+
+       rc = check_lustre_proc_vals("/proc/fs/lustre/osd-ldiskfs", real_device);
+       if (!rc)
+               rc = check_lustre_proc_vals("/proc/fs/lustre/osd-zfs",
+                                           real_device);
+       if (rc)
+               *mount_flags |= EXT2_MF_MOUNTED;
+
+       free(real_device);
+
+       return 0;
+}
+
 
 /*
  * ext2fs_check_mount_point() fills determines if the device is
@@ -387,6 +577,8 @@ errcode_t ext2fs_check_mount_point(const char *device, int *mount_flags,
        }
 #endif
 
+       retval = check_if_lustre_mounted(device, mount_flags);
+
        return 0;
 }