rofs: report fsid (filesystem ID) properly

This patch slightly enhances ROFS to report non-zero unique fsid which is important to later integrate it with pagecache laye that relies on unique combination of inode and st_dev that comes from fsid. Signed-off-by: Waldemar Kozaczuk <[email protected]>
cloudius-systems · Apr 29, 2020 · 80be3ce · 80be3ce
1 parent c193437
commit 80be3ce
Show file tree

Hide file tree

Showing 3 changed files with 14 additions and 0 deletions.
diff --git a/fs/rofs/rofs_vfsops.cc b/fs/rofs/rofs_vfsops.cc
@@ -26,6 +26,7 @@
 #include <sys/types.h>
 #include <osv/device.h>
 #include <osv/debug.h>
+#include <fs/vfs/vfs_id.h>
 #include <iomanip>
 #include <iostream>
 
@@ -44,6 +45,8 @@ std::atomic<long> rofs_cache_reads(0);
 std::atomic<long> rofs_cache_misses(0);
 #endif
 
+std::atomic<long> rofs_mounts(0);
+
 struct vfsops rofs_vfsops = {
     rofs_mount,		/* mount */
     rofs_unmount,	/* unmount */
@@ -168,6 +171,10 @@ rofs_mount(struct mount *mp, const char *dev, int flags, const void *data)
     mp->m_data = rofs;
     mp->m_dev = device;
 
+    rofs_mounts += 1;
+    mp->m_fsid.__val[0] = rofs_mounts.load();
+    mp->m_fsid.__val[1] = ROFS_ID >> 32;
+
     rofs_set_vnode(mp->m_root->d_vnode, rofs->inodes);
 
     print("[rofs] returning from mount\n");
@@ -197,6 +204,9 @@ static int rofs_statfs(struct mount *mp, struct statfs *statp)
 
     statp->f_namelen = 0; //FIXME - unlimited ROFS_FILENAME_MAXLEN;
 
+    statp->f_fsid.__val[0] = mp->m_fsid.__val[0];
+    statp->f_fsid.__val[1] = mp->m_fsid.__val[1];
+
     return 0;
 }
 

diff --git a/fs/rofs/rofs_vnops.cc b/fs/rofs/rofs_vnops.cc
@@ -269,6 +269,9 @@ static int rofs_getattr(struct vnode *vnode, struct vattr *attr)
     attr->va_nodeid = vnode->v_ino;
     attr->va_size = vnode->v_size;
 
+    auto *fsid = &vnode->v_mount->m_fsid;
+    attr->va_fsid = ((uint32_t)fsid->__val[0]) | ((dev_t) ((uint32_t)fsid->__val[1]) << 32);
+
     return 0;
 }
 

diff --git a/tests/tst-zfs-mount.cc b/tests/tst-zfs-mount.cc
@@ -173,6 +173,7 @@ int main(int argc, char **argv)
 
     printf("file size = %lld\n", s.st_size);
 
+    report(statfs("/tmp", &st) == 0, "stat /tmp");
     dev_t f_fsid = ((uint32_t)st.f_fsid.__val[0]) | ((dev_t) ((uint32_t)st.f_fsid.__val[1]) << 32);
     report(f_fsid == s.st_dev, "st_dev must be equals to f_fsid");