Hi, Jeff
I wrote a POC patch, use name_to_handle_at to get nfs root filehandle
instead of /proc/fs/nfsd/filehandle.
I did some simple tests and it works.
Pls check the POC patch below:
---
support/export/cache.c | 95 +++++++++++++++++++++++++++++++++++++++++-
1 file changed, 93 insertions(+), 2 deletions(-)
diff --git a/support/export/cache.c b/support/export/cache.c
index 6c0a44a3..adecac2e 100644
--- a/support/export/cache.c
+++ b/support/export/cache.c
@@ -43,6 +43,25 @@
#include "blkid/blkid.h"
#endif
+#define NFS4_FHSIZE 128
+
+struct knfsd_fh {
+ unsigned int fh_size; /*
+ * Points to the current size while
+ * building a new file handle.
+ */
+ union {
+ char fh_raw[NFS4_FHSIZE];
+ struct {
+ uint8_t fh_version; /* == 1 */
+ uint8_t fh_auth_type; /* deprecated */
+ uint8_t fh_fsid_type;
+ uint8_t fh_fileid_type;
+ uint32_t fh_fsid[]; /* flexible-array member */
+ };
+ };
+};
+
enum nfsd_fsid {
FSID_DEV = 0,
FSID_NUM,
@@ -1827,8 +1846,8 @@ int cache_export(nfs_export *exp, char *path)
* read filehandle <&0
* } <> /proc/fs/nfsd/filehandle
*/
-struct nfs_fh_len *
-cache_get_filehandle(nfs_export *exp, int len, char *p)
+static struct nfs_fh_len *
+cache_get_filehandle_by_proc(nfs_export *exp, int len, char *p)
{
static struct nfs_fh_len fh;
char buf[RPC_CHAN_BUF_SIZE], *bp;
@@ -1862,6 +1881,78 @@ cache_get_filehandle(nfs_export *exp, int len, char *p)
return &fh;
}
+static struct nfs_fh_len *
+cache_get_filehandle_by_name(nfs_export *exp, char *name)
+{
+ static struct nfs_fh_len fh;
+ struct {
+ struct file_handle fh;
+ unsigned char handle[128];
+ } file_fh;
+ char buf[RPC_CHAN_BUF_SIZE] = {0};
+ char *mesg = buf;
+ int len, mnt_id;
+ unsigned int e_fsid;
+ struct knfsd_fh kfh;
+ char u[16];
+
+ memset(fh.fh_handle, 0, sizeof(fh.fh_handle));
+
+ file_fh.fh.handle_bytes = 128;
+ if (name_to_handle_at(AT_FDCWD, name, &file_fh.fh, &mnt_id, 0) < 0)
+ return NULL;
+
+ memset(fh.fh_handle, 0, sizeof(fh.fh_handle));
+ memset(&kfh, 0, sizeof(struct knfsd_fh));
+ kfh.fh_version = 1;
+ kfh.fh_auth_type = 0;
+ e_fsid = exp->m_export.e_fsid;
+
+ if (e_fsid > 0) {
+ len = 12;
+ fh.fh_size = 8;
+ kfh.fh_size = 12;
+ kfh.fh_fsid_type = 1;
+ kfh.fh_fsid[0] = e_fsid;
+ } else {
+ len = file_fh.fh.handle_bytes + 8;
+ fh.fh_size = file_fh.fh.handle_bytes;
+ kfh.fh_size = file_fh.fh.handle_bytes + sizeof(kfh.fh_size);
+ kfh.fh_fsid_type = FSID_UUID16_INUM;
+ if (file_fh.fh.handle_bytes <= 12) {
+ kfh.fh_fsid[0] = *(uint32_t *)file_fh.fh.f_handle;
+ kfh.fh_fsid[1] = 0;
+ } else {
+ kfh.fh_fsid[0] = *(uint32_t *)file_fh.fh.f_handle;
+ kfh.fh_fsid[1] = *((uint32_t *)file_fh.fh.f_handle + 1);
+ }
+ }
+ kfh.fh_fileid_type = 0; // FILEID_ROOT
+
+ qword_addhex(&mesg, &len, kfh.fh_raw, kfh.fh_size);
+ mesg = buf;
+ len = qword_get(&mesg, (char *)fh.fh_handle, NFS3_FHSIZE);
+ if (e_fsid == 0) {
+ len = 16;
+ uuid_by_path(name, 0, 16, u);
+ memcpy((char *)fh.fh_handle+12, u, 16);
+ fh.fh_size += 16;
+ }
+
+ return &fh;
+}
+
+struct nfs_fh_len *
+cache_get_filehandle(nfs_export *exp, int len, char *p)
+{
+ struct nfs_fh_len *fh;
+ fh = cache_get_filehandle_by_name(exp, p);
+ if (!fh)
+ fh = cache_get_filehandle_by_proc(exp, len, p);
+
+ return fh;
+}
+
/* Wait for all worker child processes to exit and reap them */
void
cache_wait_for_workers(char *prog)
--
2.39.1
