Re: [Qemu-devel] [PATCH for-2.7 07/15] qemu-io: Add "-L" option for BDRV_O_NO_LOCK

[Fam Zheng <famz@redhat.com>]

On Thu, 04/14 10:06, Denis V. Lunev wrote:
> On 04/13/2016 12:09 PM, Fam Zheng wrote:
> >Signed-off-by: Fam Zheng <famz@redhat.com>
> >---
> >  qemu-io.c | 22 ++++++++++++++++++++--
> >  1 file changed, 20 insertions(+), 2 deletions(-)
> >
> >diff --git a/qemu-io.c b/qemu-io.c
> >index 288bba8..6bb6232 100644
> >--- a/qemu-io.c
> >+++ b/qemu-io.c
> >@@ -107,6 +107,7 @@ static void open_help(void)
> >  " -r, -- open file read-only\n"
> >  " -s, -- use snapshot file\n"
> >  " -n, -- disable host cache\n"
> >+" -L, -- disable image lock\n"
> >  " -o, -- options to be given to the block driver"
> >  "\n");
> >  }
> >@@ -139,12 +140,13 @@ static int open_f(BlockBackend *blk, int argc, char **argv)
> >  {
> >      int flags = 0;
> >      int readonly = 0;
> >+    int nolock = 0;
> >      bool writethrough = true;
> >      int c;
> >      QemuOpts *qopts;
> >      QDict *opts;
> >-    while ((c = getopt(argc, argv, "snrgo:")) != -1) {
> >+    while ((c = getopt(argc, argv, "snrgLo:")) != -1) {
> >          switch (c) {
> >          case 's':
> >              flags |= BDRV_O_SNAPSHOT;
> >@@ -156,6 +158,9 @@ static int open_f(BlockBackend *blk, int argc, char **argv)
> >          case 'r':
> >              readonly = 1;
> >              break;
> >+        case 'L':
> >+            nolock = 1;
> >+            break;
> >          case 'o':
> >              if (imageOpts) {
> >                  printf("--image-opts and 'open -o' are mutually exclusive\n");
> >@@ -176,6 +181,10 @@ static int open_f(BlockBackend *blk, int argc, char **argv)
> >          flags |= BDRV_O_RDWR;
> >      }
> >+    if (nolock) {
> >+        flags |= BDRV_O_NO_LOCK;
> >+    }
> >+
> >      if (imageOpts && (optind == argc - 1)) {
> >          if (!qemu_opts_parse_noisily(&empty_opts, argv[optind], false)) {
> >              qemu_opts_reset(&empty_opts);
> >@@ -410,7 +419,8 @@ static QemuOptsList file_opts = {
> >  int main(int argc, char **argv)
> >  {
> >      int readonly = 0;
> >-    const char *sopt = "hVc:d:f:rsnmgkt:T:";
> >+    int nolock = 0;
> >+    const char *sopt = "hVc:d:f:rLsnmgkt:T:";
> >      const struct option lopt[] = {
> >          { "help", no_argument, NULL, 'h' },
> >          { "version", no_argument, NULL, 'V' },
> >@@ -418,6 +428,7 @@ int main(int argc, char **argv)
> >          { "cmd", required_argument, NULL, 'c' },
> >          { "format", required_argument, NULL, 'f' },
> >          { "read-only", no_argument, NULL, 'r' },
> >+        { "no-lock", no_argument, NULL, 'L' },
> >          { "snapshot", no_argument, NULL, 's' },
> >          { "nocache", no_argument, NULL, 'n' },
> >          { "misalign", no_argument, NULL, 'm' },
> >@@ -477,6 +488,9 @@ int main(int argc, char **argv)
> >          case 'r':
> >              readonly = 1;
> >              break;
> >+        case 'L':
> >+            nolock = 1;
> >+            break;
> >          case 'm':
> >              qemuio_misalign = true;
> >              break;
> >@@ -558,6 +572,10 @@ int main(int argc, char **argv)
> >          flags |= BDRV_O_RDWR;
> >      }
> >+    if (nolock) {
> >+        flags |= BDRV_O_NO_LOCK;
> >+    }
> >+
> >      if ((argc - optind) == 1) {
> >          if (imageOpts) {
> >              QemuOpts *qopts = NULL;
> I think that we should do the same for qemu-img.
> 
> There are some operations like 'qemu-img info' which
> are widely used to query f.e. block size of the image.

Yes, I can extend this series to add "nolock" option to qemu-img sub commands.

Fam