alloc: upgrade to fallocate

Update this utility to use fallocate to preallocate/reserve space to a
file so that we're not so dependent on legacy XFS ioctls.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>

diff --git a/src/alloc.c b/src/alloc.c
index 57a91f811d52568778c27dd565f2996509980611..4a446ca827d8e1d377b53ffd5eb79b157ca541f7 100644 (file)
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -118,6 +118,50 @@ bozo!
     }
 }
 
     }
 }
 

+#ifdef HAVE_FALLOCATE
+# define USE_LINUX_PREALLOCATE
+enum linux_opno {
+       FREESP = 0,
+       ALLOCSP,
+       UNRESVSP,
+       RESVSP,
+};
+
+/* emulate the irix preallocation functions with linux vfs calls */
+static int
+linux_preallocate(
+       int                     fd,
+       enum linux_opno         opno,
+       const struct flock64    *f)
+{
+       struct stat             sbuf;
+       int                     ret;
+
+       assert(f->l_whence == SEEK_SET);
+
+       switch (opno) {
+       case FREESP:
+               return ftruncate(fd, f->l_start);
+       case ALLOCSP:
+               ret = fstat(fd, &sbuf);
+               if (ret)
+                       return ret;
+
+               return fallocate(fd, 0, sbuf.st_size,
+                               f->l_start - sbuf.st_size);
+       case UNRESVSP:
+               return fallocate(fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
+                               f->l_start, f->l_len);
+       case RESVSP:
+               return fallocate(fd, FALLOC_FL_KEEP_SIZE, f->l_start, f->l_len);
+       }
+
+       /* should never get here */
+       errno = EINVAL;
+       return -1;
+}
+#endif
+

 int
 main(int argc, char **argv)
 {
 int
 main(int argc, char **argv)
 {


@@ -136,23 +180,23 @@ main(int argc, char **argv)
                                       "resvsp" };
        int             opno;
 
                                       "resvsp" };
        int             opno;
 

-       /* Assume that if we have FREESP64 then we have the rest */
-#ifdef XFS_IOC_FREESP64
+#if defined(HAVE_FALLOCATE)
+       /* see static function above */
+#elif defined(XFS_IOC_FREESP64)

 #define USE_XFSCTL
 #define USE_XFSCTL

+       /* Assume that if we have FREESP64 then we have the rest */

        static int      optab[] = { XFS_IOC_FREESP64,
                                    XFS_IOC_ALLOCSP64,
                                    XFS_IOC_UNRESVSP64,
                                    XFS_IOC_RESVSP64 };
        static int      optab[] = { XFS_IOC_FREESP64,
                                    XFS_IOC_ALLOCSP64,
                                    XFS_IOC_UNRESVSP64,
                                    XFS_IOC_RESVSP64 };

-#else
-#ifdef F_FREESP64
+#elif defined(F_FREESP64)

 #define USE_FCNTL
        static int      optab[] = { F_FREESP64,
                                    F_ALLOCSP64,
                                    F_UNRESVSP64,
                                    F_RESVSP64 };
 #else
 #define USE_FCNTL
        static int      optab[] = { F_FREESP64,
                                    F_ALLOCSP64,
                                    F_UNRESVSP64,
                                    F_RESVSP64 };
 #else

-bozo!
-#endif
+# error Dont know how to preallocate space!

 #endif
        int             rflag = 0;
        struct statvfs64        svfs;
 #endif
        int             rflag = 0;
        struct statvfs64        svfs;


@@ -311,14 +355,14 @@ bozo!
                                 opnames[opno], (long long)off, (long long)len);
                         
                        f.l_len = len;
                                 opnames[opno], (long long)off, (long long)len);
                         
                        f.l_len = len;

-#ifdef USE_XFSCTL
+#if defined(USE_LINUX_PREALLOCATE)
+                       c = linux_preallocate(fd, opno, &f);
+#elif defined(USE_XFSCTL)

                        c = xfsctl(filename, fd, optab[opno], &f);
                        c = xfsctl(filename, fd, optab[opno], &f);

-#else
-#ifdef USE_FCNTL
+#elif defined(USE_FCNTL)

                        c = fcntl(fd, optab[opno], &f);
 #else
                        c = fcntl(fd, optab[opno], &f);
 #else

-bozo!
-#endif
+# error Dont know how to preallocate space!

 #endif
                        if (c < 0) {
                                perror(opnames[opno]);
 #endif
                        if (c < 0) {
                                perror(opnames[opno]);