copy_file_range support in GlusterFS

    * libglusterfs changes to add new fop

    * Fuse changes:
      - Changes in fuse bridge xlator to receive and send responses

    * posix changes to perform the op on the backend filesystem

    * protocol and rpc changes for sending and receiving the fop

    * gfapi changes for performing the fop

    * tools: glfs-copy-file-range tool for testing copy_file_range fop

      - Although, copy_file_range support has been added to the upstream
	    fuse kernel module, no release has been made yet of a kernel
        which contains the support. It is expected to come in the
        upcoming release of linux-4.20

        So, as of now, executing copy_file_range fop on a fused based
        filesystem results in fuse kernel module sending read on the
	    source fd and write on the destination fd.

	    Therefore a small gfapi based tool has been written to be able
        test the copy_file_range fop. This tool is similar (in functionality)
	    to the example program given in copy_file_range man page.

	    So, running regular copy_file_range on a fuse mount point and
	    running gfapi based glfs-copy-file-range tool gives some idea about
	    how fast, the copy_file_range (or reflink) can be.

	    On the local machine this was the result obtained.

	    mount -t glusterfs workstation:new /mnt/glusterfs
	    [root@workstation ~]# cd /mnt/glusterfs/
	    [root@workstation glusterfs]# ls
	    file
	    [root@workstation glusterfs]# cd
	    [root@workstation ~]# time /tmp/a.out /mnt/glusterfs/file /mnt/glusterfs/new
	    real  0m6.495s
	    user  0m0.000s
	    sys   0m1.439s
	    [root@workstation ~]# time glfs-copy-file-range $(hostname) new /tmp/glfs.log /file /rrr
	    OPEN_SRC: opening /file is success
	    OPEN_DST: opening /rrr is success
	    FSTAT_SRC: fstat on /rrr is success
	    copy_file_range successful

        real  0m0.309s
        user  0m0.039s
        sys   0m0.017s

        This tool needs following arguments
         1) hostname
         2) volume name
         3) log file path
         4) source file path (relative to the gluster volume root)
         5) destination file path (relative to the gluster volume root)

        "glfs-copy-file-range <hostname> <volume> <log file path> <source> <destination>"

      - Added a testcase as well to run glfs-copy-file-range tool

    * io-stats changes to capture the fop for profiling

    * NOTE:

      - Added conditional check to see whether the copy_file_range syscall
        is available or not. If not, then return ENOSYS.

      - Added conditional check for kernel minor version in fuse_kernel.h
        and fuse-bridge while referring to copy_file_range. And the kernel
        minor version is kept as it is. i.e. 24. Increment it in future
        when there is a kernel release which contains the support for
        copy_file_range fop in fuse kernel module.

    * The document which contains a writeup on this enhancement can be found at
      https://docs.google.com/document/d/1BSILbXr_knynNwxSyyu503JoTz5QFM_4suNIh2WwrSc/edit

Change-Id: I280069c814dd21ce6ec3be00a884fc24ab692367
updates: #536
Signed-off-by: Raghavendra Bhat <raghavendra@redhat.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/libglusterfs/src/glusterfs/syscall.h b/libglusterfs/src/glusterfs/syscall.h
index faaf694b22c..6b33c141a5e 100644
--- a/libglusterfs/src/glusterfs/syscall.h
+++ b/libglusterfs/src/glusterfs/syscall.h
@@ -17,6 +17,7 @@
 #include <sys/stat.h>
 #include <sys/time.h>
 #include <sys/socket.h>
+#include <stdio.h>
 
 /* GF follows the Linux XATTR definition, which differs in Darwin. */
 #define GF_XATTR_CREATE 0x1  /* set value, fail if attr already exists */
@@ -228,4 +229,32 @@ sys_socket(int domain, int type, int protocol);
 int
 sys_accept(int sock, struct sockaddr *sockaddr, socklen_t *socklen, int flags);
 
+#ifdef GF_BSD_HOST_OS
+#ifndef _OFF64_T_DECLARED
+/*
+ * Including <stdio.h> (done above) should actually define
+ * _OFF64_T_DECLARED with off64_t data type being available
+ * for consumption. But, off64_t data type is not recognizable
+ * for FreeBSD versions less than 11. Hence, int64_t is typedefed
+ * to off64_t.
+ */
+#define _OFF64_T_DECLARED
+typedef int64_t off64_t;
+#endif /* _OFF64_T_DECLARED */
+#endif /* GF_BSD_HOST_OS */
+
+/*
+ * According to the man page of copy_file_range, both off_in and off_out are
+ * pointers to the data type loff_t (i.e. loff_t *). But, freebsd does not
+ * have (and recognize) loff_t. Since loff_t is 64 bits, use off64_t
+ * instead.  Since it's a pointer type it should be okay. It just needs
+ * to be a pointer-to-64-bit pointer for both 32- and 64-bit platforms.
+ * off64_t is recognized by freebsd.
+ * TODO: In future, when freebsd can recognize loff_t, probably revisit this
+ *       and change the off_in and off_out to (loff_t *).
+ */
+ssize_t
+sys_copy_file_range(int fd_in, off64_t *off_in, int fd_out, off64_t *off_out,
+                    size_t len, unsigned int flags);
+
 #endif /* __SYSCALL_H__ */