Ceph » CephFS

From mailing list. The patch below lets fstat take cap. Seems to work just fine with a single client (it gets the cap, doesn't do round trips to mds). With multiple clients, I see unexpected results. Running the following on one client yields very high iops. When another concurrent client starts it blocks. Expected behavior is that they both make round trips to MDS, but otherwise make progress.

fd = cephfs.open('file-1', 'w', 0755)
count = 0
start = time.time()
while True:
    stat = cephfs.fstat(fd)
    count += 1
    if time.time() > (start + 1):
        print(count)
        count = 0
        start = time.time()

Patch:

709840b - fsclient: fstat can take inode all cap (10 minutes ago) <Noah Watkins>
diff --git a/src/client/Client.cc b/src/client/Client.cc
index 7fcd907..94e4db5 100644
--- a/src/client/Client.cc
+++ b/src/client/Client.cc
@@ -8668,16 +8668,16 @@ int Client::_fsync(Fh *f, bool syncdataonly)
   return _fsync(f->inode.get(), syncdataonly);
 }

-int Client::fstat(int fd, struct stat *stbuf)
+int Client::fstat(int fd, struct stat *stbuf, int mask)
 {
   Mutex::Locker lock(client_lock);
-  tout(cct) << "fstat" << std::endl;
+  tout(cct) << "fstat" << " mask " << mask << std::endl;
   tout(cct) << fd << std::endl;

   Fh *f = get_filehandle(fd);
   if (!f)
     return -EBADF;
-  int r = _getattr(f->inode, -1);
+  int r = _getattr(f->inode, mask);
   if (r < 0)
     return r;
   fill_stat(f->inode, stbuf, NULL);
diff --git a/src/client/Client.h b/src/client/Client.h
index d912db0..860f28b 100644
--- a/src/client/Client.h
+++ b/src/client/Client.h
@@ -981,7 +981,7 @@ public:
   int fake_write_size(int fd, loff_t size);
   int ftruncate(int fd, loff_t size);
   int fsync(int fd, bool syncdataonly);
-  int fstat(int fd, struct stat *stbuf);
+  int fstat(int fd, struct stat *stbuf, int mask=CEPH_STAT_CAP_INODE_ALL);
   int fallocate(int fd, int mode, loff_t offset, loff_t length);