[Qemu-devel] [PATCH v3 19/44] qemu-io: Switch to byte-based block access

[Eric Blake <eblake@redhat.com>]

blk_write() and blk_read() are now very simple wrappers around
blk_pwrite() and blk_pread().  There's no reason to require
the user to pass in aligned numbers.  Keep 'read -p' and
'write -p' so that I don't have to hunt down and update all
users of qemu-io, but make the default 'read' and 'write' now
do the same behavior that used to require -p.

Signed-off-by: Eric Blake <eblake@redhat.com>
---
 qemu-io-cmds.c | 75 +++++++++++++---------------------------------------------
 1 file changed, 16 insertions(+), 59 deletions(-)

diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
index e26e543..4184fb8 100644
--- a/qemu-io-cmds.c
+++ b/qemu-io-cmds.c
@@ -419,40 +419,6 @@ fail:
     return buf;
 }

-static int do_read(BlockBackend *blk, char *buf, int64_t offset, int64_t count,
-                   int64_t *total)
-{
-    int ret;
-
-    if (count >> 9 > INT_MAX) {
-        return -ERANGE;
-    }
-
-    ret = blk_read(blk, offset >> 9, (uint8_t *)buf, count >> 9);
-    if (ret < 0) {
-        return ret;
-    }
-    *total = count;
-    return 1;
-}
-
-static int do_write(BlockBackend *blk, char *buf, int64_t offset, int64_t count,
-                    int64_t *total)
-{
-    int ret;
-
-    if (count >> 9 > INT_MAX) {
-        return -ERANGE;
-    }
-
-    ret = blk_write(blk, offset >> 9, (uint8_t *)buf, count >> 9);
-    if (ret < 0) {
-        return ret;
-    }
-    *total = count;
-    return 1;
-}
-
 static int do_pread(BlockBackend *blk, char *buf, int64_t offset,
                     int64_t count, int64_t *total)
 {
@@ -671,7 +637,7 @@ static void read_help(void)
 " -b, -- read from the VM state rather than the virtual disk\n"
 " -C, -- report statistics in a machine parsable format\n"
 " -l, -- length for pattern verification (only with -P)\n"
-" -p, -- use blk_pread to read the file\n"
+" -p, -- ignored for back-compat\n"
 " -P, -- use a pattern to verify read data\n"
 " -q, -- quiet mode, do not show I/O statistics\n"
 " -s, -- start offset for pattern verification (only with -P)\n"
@@ -687,7 +653,7 @@ static const cmdinfo_t read_cmd = {
     .cfunc      = read_f,
     .argmin     = 2,
     .argmax     = -1,
-    .args       = "[-abCpqv] [-P pattern [-s off] [-l len]] off len",
+    .args       = "[-abCqv] [-P pattern [-s off] [-l len]] off len",
     .oneline    = "reads a number of bytes at a specified offset",
     .help       = read_help,
 };
@@ -695,7 +661,7 @@ static const cmdinfo_t read_cmd = {
 static int read_f(BlockBackend *blk, int argc, char **argv)
 {
     struct timeval t1, t2;
-    int Cflag = 0, pflag = 0, qflag = 0, vflag = 0;
+    int Cflag = 0, qflag = 0, vflag = 0;
     int Pflag = 0, sflag = 0, lflag = 0, bflag = 0;
     int c, cnt;
     char *buf;
@@ -723,7 +689,7 @@ static int read_f(BlockBackend *blk, int argc, char **argv)
             }
             break;
         case 'p':
-            pflag = 1;
+            /* Ignored for back-compat */
             break;
         case 'P':
             Pflag = 1;
@@ -755,11 +721,6 @@ static int read_f(BlockBackend *blk, int argc, char **argv)
         return qemuio_command_usage(&read_cmd);
     }

-    if (bflag && pflag) {
-        printf("-b and -p cannot be specified at the same time\n");
-        return 0;
-    }
-
     offset = cvtnum(argv[optind]);
     if (offset < 0) {
         print_cvtnum_err(offset, argv[optind]);
@@ -790,7 +751,7 @@ static int read_f(BlockBackend *blk, int argc, char **argv)
         return 0;
     }

-    if (!pflag) {
+    if (bflag) {
         if (offset & 0x1ff) {
             printf("offset %" PRId64 " is not sector aligned\n",
                    offset);
@@ -806,12 +767,10 @@ static int read_f(BlockBackend *blk, int argc, char **argv)
     buf = qemu_io_alloc(blk, count, 0xab);

     gettimeofday(&t1, NULL);
-    if (pflag) {
-        cnt = do_pread(blk, buf, offset, count, &total);
-    } else if (bflag) {
+    if (bflag) {
         cnt = do_load_vmstate(blk, buf, offset, count, &total);
     } else {
-        cnt = do_read(blk, buf, offset, count, &total);
+        cnt = do_pread(blk, buf, offset, count, &total);
     }
     gettimeofday(&t2, NULL);

@@ -991,7 +950,7 @@ static void write_help(void)
 " filled with a set pattern (0xcdcdcdcd).\n"
 " -b, -- write to the VM state rather than the virtual disk\n"
 " -c, -- write compressed data with blk_write_compressed\n"
-" -p, -- use blk_pwrite to write the file\n"
+" -p, -- ignored for back-compat\n"
 " -P, -- use different pattern to fill file\n"
 " -C, -- report statistics in a machine parsable format\n"
 " -q, -- quiet mode, do not show I/O statistics\n"
@@ -1007,7 +966,7 @@ static const cmdinfo_t write_cmd = {
     .cfunc      = write_f,
     .argmin     = 2,
     .argmax     = -1,
-    .args       = "[-bcCpqz] [-P pattern ] off len",
+    .args       = "[-bcCqz] [-P pattern ] off len",
     .oneline    = "writes a number of bytes at a specified offset",
     .help       = write_help,
 };
@@ -1015,7 +974,7 @@ static const cmdinfo_t write_cmd = {
 static int write_f(BlockBackend *blk, int argc, char **argv)
 {
     struct timeval t1, t2;
-    int Cflag = 0, pflag = 0, qflag = 0, bflag = 0, Pflag = 0, zflag = 0;
+    int Cflag = 0, qflag = 0, bflag = 0, Pflag = 0, zflag = 0;
     int cflag = 0;
     int c, cnt;
     char *buf = NULL;
@@ -1037,7 +996,7 @@ static int write_f(BlockBackend *blk, int argc, char **argv)
             Cflag = 1;
             break;
         case 'p':
-            pflag = 1;
+            /* Ignored for back-compat */
             break;
         case 'P':
             Pflag = 1;
@@ -1061,8 +1020,8 @@ static int write_f(BlockBackend *blk, int argc, char **argv)
         return qemuio_command_usage(&write_cmd);
     }

-    if (bflag + pflag + zflag > 1) {
-        printf("-b, -p, or -z cannot be specified at the same time\n");
+    if (bflag + zflag > 1) {
+        printf("-b and -z cannot be specified at the same time\n");
         return 0;
     }

@@ -1088,7 +1047,7 @@ static int write_f(BlockBackend *blk, int argc, char **argv)
         return 0;
     }

-    if (!pflag) {
+    if (bflag || cflag || zflag) {
         if (offset & 0x1ff) {
             printf("offset %" PRId64 " is not sector aligned\n",
                    offset);
@@ -1107,16 +1066,14 @@ static int write_f(BlockBackend *blk, int argc, char **argv)
     }

     gettimeofday(&t1, NULL);
-    if (pflag) {
-        cnt = do_pwrite(blk, buf, offset, count, &total);
-    } else if (bflag) {
+    if (bflag) {
         cnt = do_save_vmstate(blk, buf, offset, count, &total);
     } else if (zflag) {
         cnt = do_co_write_zeroes(blk, offset, count, &total);
     } else if (cflag) {
         cnt = do_write_compressed(blk, buf, offset, count, &total);
     } else {
-        cnt = do_write(blk, buf, offset, count, &total);
+        cnt = do_pwrite(blk, buf, offset, count, &total);
     }
     gettimeofday(&t2, NULL);

-- 
2.5.5