[Qemu-devel] [PATCH v2 0/4] block: more read-only changes, related to backing files

[Qemu-devel] [PATCH v2 0/4] block: more read-only changes, related to backing files

[Naphtali Sprei]

This is version 2. The change between previous patch (only 3/4) is the order of closing/re-opening the image.

The read-only changes broke qemu-img create with read-only base image
These changes fix it.
It also make things a little safer, opening the backing file for read-only,
upgrading to read-write only for commit, and back to read-only when done.

Naphtali Sprei (4):
  Add open_flags to BlockDriverState Will be used later
  qemu-img: Fix qemu-img can't create qcow image based on read-only
    image
  Block: readonly changes
  Open backing file read-only also for snapshot mode

[Qemu-devel] [PATCH v2 1/4] Add open_flags to BlockDriverState Will be used later

[Naphtali Sprei]

Signed-off-by: Naphtali Sprei <nsprei@redhat.com>
---
 block.c     |    1 +
 block_int.h |    1 +
 2 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/block.c b/block.c
index 1919d19..66564de 100644
--- a/block.c
+++ b/block.c
@@ -363,6 +363,7 @@ int bdrv_open2(BlockDriverState *bs, const char *filename, int flags,
     bs->is_temporary = 0;
     bs->encrypted = 0;
     bs->valid_key = 0;
+    bs->open_flags = flags;
     /* buffer_alignment defaulted to 512, drivers can change this value */
     bs->buffer_alignment = 512;
 
diff --git a/block_int.h b/block_int.h
index a0ebd90..9144d37 100644
--- a/block_int.h
+++ b/block_int.h
@@ -130,6 +130,7 @@ struct BlockDriverState {
     int64_t total_sectors; /* if we are reading a disk image, give its
                               size in sectors */
     int read_only; /* if true, the media is read only */
+    int open_flags; /* flags used to open the file */
     int removable; /* if true, the media can be removed */
     int locked;    /* if true, the media cannot temporarily be ejected */
     int encrypted; /* if true, the media is encrypted */
-- 
1.6.3.3

[Qemu-devel] [PATCH v2 2/4] qemu-img: Fix qemu-img can't create qcow image based on read-only image

[Naphtali Sprei]

Open image file read-only where possible
Patch originally written by Sheng Yang <sheng@linux.intel.com>

Signed-off-by: Naphtali Sprei <nsprei@redhat.com>
---
 qemu-img.c |   15 ++++++++++-----
 1 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/qemu-img.c b/qemu-img.c
index cbba4fc..b0ac9eb 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -188,11 +188,13 @@ static int read_password(char *buf, int buf_size)
 #endif
 
 static BlockDriverState *bdrv_new_open(const char *filename,
-                                       const char *fmt)
+                                       const char *fmt,
+                                       int readonly)
 {
     BlockDriverState *bs;
     BlockDriver *drv;
     char password[256];
+    int flags = BRDV_O_FLAGS;
 
     bs = bdrv_new("");
     if (!bs)
@@ -204,7 +206,10 @@ static BlockDriverState *bdrv_new_open(const char *filename,
     } else {
         drv = NULL;
     }
-    if (bdrv_open2(bs, filename, BRDV_O_FLAGS | BDRV_O_RDWR, drv) < 0) {
+    if (!readonly) {
+        flags |= BDRV_O_RDWR;
+    }
+    if (bdrv_open2(bs, filename, flags, drv) < 0) {
         error("Could not open '%s'", filename);
     }
     if (bdrv_is_encrypted(bs)) {
@@ -343,7 +348,7 @@ static int img_create(int argc, char **argv)
                 }
             }
 
-            bs = bdrv_new_open(backing_file->value.s, fmt);
+            bs = bdrv_new_open(backing_file->value.s, fmt, 1);
             bdrv_get_geometry(bs, &size);
             size *= 512;
             bdrv_delete(bs);
@@ -627,7 +632,7 @@ static int img_convert(int argc, char **argv)
 
     total_sectors = 0;
     for (bs_i = 0; bs_i < bs_n; bs_i++) {
-        bs[bs_i] = bdrv_new_open(argv[optind + bs_i], fmt);
+        bs[bs_i] = bdrv_new_open(argv[optind + bs_i], fmt, 1);
         if (!bs[bs_i])
             error("Could not open '%s'", argv[optind + bs_i]);
         bdrv_get_geometry(bs[bs_i], &bs_sectors);
@@ -685,7 +690,7 @@ static int img_convert(int argc, char **argv)
         }
     }
 
-    out_bs = bdrv_new_open(out_filename, out_fmt);
+    out_bs = bdrv_new_open(out_filename, out_fmt, 0);
 
     bs_i = 0;
     bs_offset = 0;
-- 
1.6.3.3

[Qemu-devel] [PATCH v2 2/4] qemu-img: Fix qemu-img can't create qcow image based on read-only image

[Naphtali Sprei]

Open image file read-only where possible
Patch originally written by Sheng Yang <sheng@linux.intel.com>

Signed-off-by: Naphtali Sprei <nsprei@redhat.com>
---
 qemu-img.c |   15 ++++++++++-----
 1 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/qemu-img.c b/qemu-img.c
index cbba4fc..b0ac9eb 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -188,11 +188,13 @@ static int read_password(char *buf, int buf_size)
 #endif
 
 static BlockDriverState *bdrv_new_open(const char *filename,
-                                       const char *fmt)
+                                       const char *fmt,
+                                       int readonly)
 {
     BlockDriverState *bs;
     BlockDriver *drv;
     char password[256];
+    int flags = BRDV_O_FLAGS;
 
     bs = bdrv_new("");
     if (!bs)
@@ -204,7 +206,10 @@ static BlockDriverState *bdrv_new_open(const char *filename,
     } else {
         drv = NULL;
     }
-    if (bdrv_open2(bs, filename, BRDV_O_FLAGS | BDRV_O_RDWR, drv) < 0) {
+    if (!readonly) {
+        flags |= BDRV_O_RDWR;
+    }
+    if (bdrv_open2(bs, filename, flags, drv) < 0) {
         error("Could not open '%s'", filename);
     }
     if (bdrv_is_encrypted(bs)) {
@@ -343,7 +348,7 @@ static int img_create(int argc, char **argv)
                 }
             }
 
-            bs = bdrv_new_open(backing_file->value.s, fmt);
+            bs = bdrv_new_open(backing_file->value.s, fmt, 1);
             bdrv_get_geometry(bs, &size);
             size *= 512;
             bdrv_delete(bs);
@@ -627,7 +632,7 @@ static int img_convert(int argc, char **argv)
 
     total_sectors = 0;
     for (bs_i = 0; bs_i < bs_n; bs_i++) {
-        bs[bs_i] = bdrv_new_open(argv[optind + bs_i], fmt);
+        bs[bs_i] = bdrv_new_open(argv[optind + bs_i], fmt, 1);
         if (!bs[bs_i])
             error("Could not open '%s'", argv[optind + bs_i]);
         bdrv_get_geometry(bs[bs_i], &bs_sectors);
@@ -685,7 +690,7 @@ static int img_convert(int argc, char **argv)
         }
     }
 
-    out_bs = bdrv_new_open(out_filename, out_fmt);
+    out_bs = bdrv_new_open(out_filename, out_fmt, 0);
 
     bs_i = 0;
     bs_offset = 0;
-- 
1.6.3.3

[Qemu-devel] Re: [PATCH v2 0/4] block: more read-only changes, related to backing files

[Naphtali Sprei]

Naphtali Sprei wrote:
> This is version 2. The change between previous patch (only 3/4) is the order of closing/re-opening the image.

Sorry,
patch sent without the change of version 2 (in 3/4).
Will send later.

  Naphtali