diff options
| author | Richard Weinberger <richard@nod.at> | 2022-01-27 22:40:36 +0100 |
|---|---|---|
| committer | Richard Weinberger <richard@nod.at> | 2022-01-27 22:47:51 +0100 |
| commit | 017e859dfb042293aa9eb6d34ff39d4600b4e2a8 (patch) | |
| tree | 15de880841a1e18149dd2dc7f906d34999ec1d19 | |
| parent | c8381a0efe17e890ebd892d573f1c3d287526245 (diff) | |
| download | nfs-utils-rw/reexport.tar.gz | |
export: Deal with NFS filesystemsrw/reexport
When a NFS filesystem is exported usually NFSD refuses
to export the filesystem because mountd was unable to provide
an UUID and the kernel cannot derive a dev it from the NFS client
super block.
To deal with this situation, teach uuid_by_path() how to generate
an UUID from a NFS filesystem.
Using /proc/fs/nfsfs/volumes it is possible to find the NFS fsid
from the backend and use it as seed for mountd's UUID mechanism.
Signed-off-by: Richard Weinberger <richard@nod.at>
| -rw-r--r-- | support/export/cache.c | 65 |
1 files changed, 61 insertions, 4 deletions
diff --git a/support/export/cache.c b/support/export/cache.c index a5823e92..053ad866 100644 --- a/support/export/cache.c +++ b/support/export/cache.c @@ -331,6 +331,51 @@ static const unsigned long nonblkid_filesystems[] = { 0 /* last */ }; +static int get_uuid_from_fsid(char *path, char *uuid_str, size_t len) +{ + unsigned int min_dev, maj_dev, min_fsid, maj_fsid; + int rc, n, found = 0, header_seen = 0; + struct stat stb; + FILE *nfsfs_fd; + char line[128]; + + rc = nfsd_path_stat(path, &stb); + if (rc) { + xlog(L_WARNING, "Unable to stat %s", path); + return 0; + } + + nfsfs_fd = fopen("/proc/fs/nfsfs/volumes", "r"); + if (nfsfs_fd == NULL) { + xlog(L_WARNING, "Unable to open nfsfs volume file: %m"); + return 0; + } + + while (fgets(line, sizeof(line), nfsfs_fd) != NULL) { + if (!header_seen) { + header_seen = 1; + continue; + } + n = sscanf(line, "v%*u %*x %*u %u:%u %x:%x %*s", &maj_dev, + &min_dev, &maj_fsid, &min_fsid); + + if (n != 4) { + xlog(L_WARNING, "Unable to parse nfsfs volume line: %d, %s", n, line); + continue; + } + + if (makedev(maj_dev, min_dev) == stb.st_dev) { + found = 1; + snprintf(uuid_str, len, "%08x%08x", maj_fsid, min_fsid); + break; + } + } + + fclose(nfsfs_fd); + + return found; +} + static int uuid_by_path(char *path, int type, size_t uuidlen, char *uuid) { /* get a uuid for the filesystem found at 'path'. @@ -362,7 +407,7 @@ static int uuid_by_path(char *path, int type, size_t uuidlen, char *uuid) */ struct statfs64 st; char fsid_val[17]; - const char *blkid_val = NULL; + const char *fsuuid_val = NULL; const char *val; int rc; @@ -375,7 +420,19 @@ static int uuid_by_path(char *path, int type, size_t uuidlen, char *uuid) break; } if (*bad == 0) - blkid_val = get_uuid_blkdev(path); + fsuuid_val = get_uuid_blkdev(path); + else if (*bad == 0x6969 /* NFS_SUPER_MAGIC */) { + char tmp[17]; + int ret = get_uuid_from_fsid(path, tmp, sizeof(tmp)); + + if (ret < 0) { + xlog(L_WARNING, "Unable to read nfsfs volume file: %i", ret); + } else if (ret == 0) { + xlog(L_WARNING, "Unable to find nfsfs volume entry for %s", path); + } else { + fsuuid_val = tmp; + } + } } if (rc == 0 && @@ -385,8 +442,8 @@ static int uuid_by_path(char *path, int type, size_t uuidlen, char *uuid) else fsid_val[0] = 0; - if (blkid_val && (type--) == 0) - val = blkid_val; + if (fsuuid_val && (type--) == 0) + val = fsuuid_val; else if (fsid_val[0] && (type--) == 0) val = fsid_val; else |