[Qemu-devel] [PATCH v2 for-2.10 0/8] RBD reopen, read_only cleanup

[Qemu-devel] [PATCH v2 for-2.10 0/8] RBD reopen, read_only cleanup

[Jeff Cody]

Changes from v1:

Patch 2: Has v1 patch 8 (do not blindly xset bs->read_only) squashed into it
         (thanks Stefan)
         COW -> "copy-on-read" (Thanks John)
         Drop unneeded call in vvfat, and bypass enable_write_target (Stefan)

Patch 5: Rename bdrv_try_... to bdrv_can_set_read_only() (Thanks John, Stefan)

Patch 6: Use "reopen_state->flags" not "reopen_state->bs->open_flags"
         (Thanks John)



This series does two things:

1.) Cleans up some of the logic behind setting the read_only flag
    for a BDS in the block layer, so that it is done consistently
    (and rules are applied consistently), and

2.) Adds .bdrv_reopen_prepare() implementation for RBD, so that block
    jobs can be run on backing chains that have rbd protocol nodes.

Jeff Cody (8):
  block: add bdrv_set_read_only() helper function
  block: do not set BDS read_only if copy_on_read enabled
  block: honor BDRV_O_ALLOW_RDWR when clearing bs->read_only
  block: code movement
  block: introduce bdrv_can_set_read_only()
  block: use bdrv_can_set_read_only() during reopen
  block/rbd - update variable names to more apt names
  block/rbd: Add support for reopen()

 block.c               | 56 +++++++++++++++++++++++++++++++++++---------
 block/bochs.c         |  5 +++-
 block/cloop.c         |  5 +++-
 block/dmg.c           |  6 ++++-
 block/rbd.c           | 65 +++++++++++++++++++++++++++++++++++++--------------
 block/vvfat.c         | 19 +++++++++++----
 include/block/block.h |  2 ++
 7 files changed, 123 insertions(+), 35 deletions(-)

-- 
2.9.3

[Qemu-devel] [PATCH v2 for-2.10 1/8] block: add bdrv_set_read_only() helper function

[Jeff Cody]

We have a helper wrapper for checking for the BDS read_only flag,
add a helper wrapper to set the read_only flag as well.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Jeff Cody <jcody@redhat.com>
---
 block.c               | 5 +++++
 block/bochs.c         | 2 +-
 block/cloop.c         | 2 +-
 block/dmg.c           | 2 +-
 block/rbd.c           | 2 +-
 block/vvfat.c         | 4 ++--
 include/block/block.h | 1 +
 7 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/block.c b/block.c
index 927ba89..7b4c7ef 100644
--- a/block.c
+++ b/block.c
@@ -192,6 +192,11 @@ void path_combine(char *dest, int dest_size,
     }
 }
 
+void bdrv_set_read_only(BlockDriverState *bs, bool read_only)
+{
+    bs->read_only = read_only;
+}
+
 void bdrv_get_full_backing_filename_from_filename(const char *backed,
                                                   const char *backing,
                                                   char *dest, size_t sz,
diff --git a/block/bochs.c b/block/bochs.c
index 516da56..bdc2831 100644
--- a/block/bochs.c
+++ b/block/bochs.c
@@ -110,7 +110,7 @@ static int bochs_open(BlockDriverState *bs, QDict *options, int flags,
         return -EINVAL;
     }
 
-    bs->read_only = true; /* no write support yet */
+    bdrv_set_read_only(bs, true); /* no write support yet */
 
     ret = bdrv_pread(bs->file, 0, &bochs, sizeof(bochs));
     if (ret < 0) {
diff --git a/block/cloop.c b/block/cloop.c
index a6c7b9d..11f17c8 100644
--- a/block/cloop.c
+++ b/block/cloop.c
@@ -72,7 +72,7 @@ static int cloop_open(BlockDriverState *bs, QDict *options, int flags,
         return -EINVAL;
     }
 
-    bs->read_only = true;
+    bdrv_set_read_only(bs, true);
 
     /* read header */
     ret = bdrv_pread(bs->file, 128, &s->block_size, 4);
diff --git a/block/dmg.c b/block/dmg.c
index a7d25fc..27ce4a6 100644
--- a/block/dmg.c
+++ b/block/dmg.c
@@ -420,7 +420,7 @@ static int dmg_open(BlockDriverState *bs, QDict *options, int flags,
     }
 
     block_module_load_one("dmg-bz2");
-    bs->read_only = true;
+    bdrv_set_read_only(bs, true);
 
     s->n_chunks = 0;
     s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL;
diff --git a/block/rbd.c b/block/rbd.c
index 1ceeeb5..6ad2904 100644
--- a/block/rbd.c
+++ b/block/rbd.c
@@ -641,7 +641,7 @@ static int qemu_rbd_open(BlockDriverState *bs, QDict *options, int flags,
         goto failed_open;
     }
 
-    bs->read_only = (s->snap != NULL);
+    bdrv_set_read_only(bs, (s->snap != NULL));
 
     qemu_opts_del(opts);
     return 0;
diff --git a/block/vvfat.c b/block/vvfat.c
index af5153d..d4ce6d7 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -1157,7 +1157,7 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags,
     s->current_cluster=0xffffffff;
 
     /* read only is the default for safety */
-    bs->read_only = true;
+    bdrv_set_read_only(bs, true);
     s->qcow = NULL;
     s->qcow_filename = NULL;
     s->fat2 = NULL;
@@ -1173,7 +1173,7 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags,
         if (ret < 0) {
             goto fail;
         }
-        bs->read_only = false;
+        bdrv_set_read_only(bs, false);
     }
 
     bs->total_sectors = cyls * heads * secs;
diff --git a/include/block/block.h b/include/block/block.h
index 5149260..06c9032 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -426,6 +426,7 @@ int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
                             int64_t sector_num, int nb_sectors, int *pnum);
 
 bool bdrv_is_read_only(BlockDriverState *bs);
+void bdrv_set_read_only(BlockDriverState *bs, bool read_only);
 bool bdrv_is_sg(BlockDriverState *bs);
 bool bdrv_is_inserted(BlockDriverState *bs);
 int bdrv_media_changed(BlockDriverState *bs);
-- 
2.9.3

[Qemu-devel] [PATCH v2 for-2.10 2/8] block: do not set BDS read_only if copy_on_read enabled

[Jeff Cody]

A few block drivers will set the BDS read_only flag from their
.bdrv_open() function.  This means the bs->read_only flag could
be set after we enable copy_on_read, as the BDRV_O_COPY_ON_READ
flag check occurs prior to the call to bdrv->bdrv_open().

This adds an error return to bdrv_set_read_only(), and an error will be
return if we try to set the BDS to read_only while copy_on_read is
enabled.

This patch also changes the behavior of vvfat.  Before, vvfat could
override the drive 'readonly' flag with its own, internal 'rw' flag.

For instance, this -drive parameter would result in a writable image:

"-drive format=vvfat,dir=/tmp/vvfat,rw,if=virtio,readonly=on"

This is not correct.  Now, attempting to use the above -drive parameter
will result in an error (i.e., 'rw' is incompatible with 'readonly=on').

Signed-off-by: Jeff Cody <jcody@redhat.com>
---
 block.c               | 10 +++++++++-
 block/bochs.c         |  5 ++++-
 block/cloop.c         |  5 ++++-
 block/dmg.c           |  6 +++++-
 block/rbd.c           | 11 ++++++++++-
 block/vvfat.c         | 19 +++++++++++++++----
 include/block/block.h |  2 +-
 7 files changed, 48 insertions(+), 10 deletions(-)

diff --git a/block.c b/block.c
index 7b4c7ef..c9eb613 100644
--- a/block.c
+++ b/block.c
@@ -192,9 +192,17 @@ void path_combine(char *dest, int dest_size,
     }
 }
 
-void bdrv_set_read_only(BlockDriverState *bs, bool read_only)
+int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp)
 {
+    /* Do not set read_only if copy_on_read is enabled */
+    if (bs->copy_on_read && read_only) {
+        error_setg(errp, "Can't set node '%s' to r/o with copy-on-read enabled",
+                   bdrv_get_device_or_node_name(bs));
+        return -EINVAL;
+    }
+
     bs->read_only = read_only;
+    return 0;
 }
 
 void bdrv_get_full_backing_filename_from_filename(const char *backed,
diff --git a/block/bochs.c b/block/bochs.c
index bdc2831..a759b6e 100644
--- a/block/bochs.c
+++ b/block/bochs.c
@@ -110,7 +110,10 @@ static int bochs_open(BlockDriverState *bs, QDict *options, int flags,
         return -EINVAL;
     }
 
-    bdrv_set_read_only(bs, true); /* no write support yet */
+    ret = bdrv_set_read_only(bs, true, errp); /* no write support yet */
+    if (ret < 0) {
+        return ret;
+    }
 
     ret = bdrv_pread(bs->file, 0, &bochs, sizeof(bochs));
     if (ret < 0) {
diff --git a/block/cloop.c b/block/cloop.c
index 11f17c8..d6597fc 100644
--- a/block/cloop.c
+++ b/block/cloop.c
@@ -72,7 +72,10 @@ static int cloop_open(BlockDriverState *bs, QDict *options, int flags,
         return -EINVAL;
     }
 
-    bdrv_set_read_only(bs, true);
+    ret = bdrv_set_read_only(bs, true, errp);
+    if (ret < 0) {
+        return ret;
+    }
 
     /* read header */
     ret = bdrv_pread(bs->file, 128, &s->block_size, 4);
diff --git a/block/dmg.c b/block/dmg.c
index 27ce4a6..900ae5a 100644
--- a/block/dmg.c
+++ b/block/dmg.c
@@ -419,8 +419,12 @@ static int dmg_open(BlockDriverState *bs, QDict *options, int flags,
         return -EINVAL;
     }
 
+    ret = bdrv_set_read_only(bs, true, errp);
+    if (ret < 0) {
+        return ret;
+    }
+
     block_module_load_one("dmg-bz2");
-    bdrv_set_read_only(bs, true);
 
     s->n_chunks = 0;
     s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL;
diff --git a/block/rbd.c b/block/rbd.c
index 6ad2904..1c43171 100644
--- a/block/rbd.c
+++ b/block/rbd.c
@@ -635,13 +635,22 @@ static int qemu_rbd_open(BlockDriverState *bs, QDict *options, int flags,
         goto failed_shutdown;
     }
 
+    /* rbd_open is always r/w */
     r = rbd_open(s->io_ctx, s->name, &s->image, s->snap);
     if (r < 0) {
         error_setg_errno(errp, -r, "error reading header from %s", s->name);
         goto failed_open;
     }
 
-    bdrv_set_read_only(bs, (s->snap != NULL));
+    /* If we are using an rbd snapshot, we must be r/o, otherwise
+     * leave as-is */
+    if (s->snap != NULL) {
+        r = bdrv_set_read_only(bs, true, &local_err);
+        if (r < 0) {
+            error_propagate(errp, local_err);
+            goto failed_open;
+        }
+    }
 
     qemu_opts_del(opts);
     return 0;
diff --git a/block/vvfat.c b/block/vvfat.c
index d4ce6d7..b509d55 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -1156,8 +1156,6 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags,
 
     s->current_cluster=0xffffffff;
 
-    /* read only is the default for safety */
-    bdrv_set_read_only(bs, true);
     s->qcow = NULL;
     s->qcow_filename = NULL;
     s->fat2 = NULL;
@@ -1169,11 +1167,24 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags,
     s->sector_count = cyls * heads * secs - (s->first_sectors_number - 1);
 
     if (qemu_opt_get_bool(opts, "rw", false)) {
-        ret = enable_write_target(bs, errp);
+        if (!bdrv_is_read_only(bs)) {
+            ret = enable_write_target(bs, errp);
+            if (ret < 0) {
+                goto fail;
+            }
+        } else {
+            ret = -EPERM;
+            error_setg(errp,
+                       "Unable to set VVFAT to 'rw' when drive is read-only");
+            goto fail;
+        }
+    } else  {
+        /* read only is the default for safety */
+        ret = bdrv_set_read_only(bs, true, &local_err);
         if (ret < 0) {
+            error_propagate(errp, local_err);
             goto fail;
         }
-        bdrv_set_read_only(bs, false);
     }
 
     bs->total_sectors = cyls * heads * secs;
diff --git a/include/block/block.h b/include/block/block.h
index 06c9032..beb563a 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -426,7 +426,7 @@ int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
                             int64_t sector_num, int nb_sectors, int *pnum);
 
 bool bdrv_is_read_only(BlockDriverState *bs);
-void bdrv_set_read_only(BlockDriverState *bs, bool read_only);
+int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp);
 bool bdrv_is_sg(BlockDriverState *bs);
 bool bdrv_is_inserted(BlockDriverState *bs);
 int bdrv_media_changed(BlockDriverState *bs);
-- 
2.9.3

[Qemu-devel] [PATCH v2 for-2.10 3/8] block: honor BDRV_O_ALLOW_RDWR when clearing bs->read_only

[Jeff Cody]

The BDRV_O_ALLOW_RDWR flag allows / prohibits the changing of
the BDS 'read_only' state, but there are a few places where it
is ignored.  In the bdrv_set_read_only() helper, make sure to
honor the flag.

Signed-off-by: Jeff Cody <jcody@redhat.com>
---
 block.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/block.c b/block.c
index c9eb613..68a18b0 100644
--- a/block.c
+++ b/block.c
@@ -201,6 +201,13 @@ int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp)
         return -EINVAL;
     }
 
+    /* Do not clear read_only if it is prohibited */
+    if (!read_only && !(bs->open_flags & BDRV_O_ALLOW_RDWR)) {
+        error_setg(errp, "Node '%s' is read only",
+                   bdrv_get_device_or_node_name(bs));
+        return -EPERM;
+    }
+
     bs->read_only = read_only;
     return 0;
 }
-- 
2.9.3

[Qemu-devel] [PATCH v2 for-2.10 4/8] block: code movement

[Jeff Cody]

Move bdrv_is_read_only() up with its friends.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Jeff Cody <jcody@redhat.com>
---
 block.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/block.c b/block.c
index 68a18b0..a05ad48 100644
--- a/block.c
+++ b/block.c
@@ -192,6 +192,11 @@ void path_combine(char *dest, int dest_size,
     }
 }
 
+bool bdrv_is_read_only(BlockDriverState *bs)
+{
+    return bs->read_only;
+}
+
 int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp)
 {
     /* Do not set read_only if copy_on_read is enabled */
@@ -3367,11 +3372,6 @@ void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr)
     *nb_sectors_ptr = nb_sectors < 0 ? 0 : nb_sectors;
 }
 
-bool bdrv_is_read_only(BlockDriverState *bs)
-{
-    return bs->read_only;
-}
-
 bool bdrv_is_sg(BlockDriverState *bs)
 {
     return bs->sg;
-- 
2.9.3

[Qemu-devel] [PATCH v2 for-2.10 5/8] block: introduce bdrv_can_set_read_only()

[Jeff Cody]

Introduce check function for setting read_only flags.  Will return < 0 on
error, with appropriate Error value set.  Does not alter any flags.

Signed-off-by: Jeff Cody <jcody@redhat.com>
---
 block.c               | 14 +++++++++++++-
 include/block/block.h |  1 +
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/block.c b/block.c
index a05ad48..1514ae9 100644
--- a/block.c
+++ b/block.c
@@ -197,7 +197,7 @@ bool bdrv_is_read_only(BlockDriverState *bs)
     return bs->read_only;
 }
 
-int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp)
+int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only, Error **errp)
 {
     /* Do not set read_only if copy_on_read is enabled */
     if (bs->copy_on_read && read_only) {
@@ -213,6 +213,18 @@ int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp)
         return -EPERM;
     }
 
+    return 0;
+}
+
+int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp)
+{
+    int ret = 0;
+
+    ret = bdrv_can_set_read_only(bs, read_only, errp);
+    if (ret < 0) {
+        return ret;
+    }
+
     bs->read_only = read_only;
     return 0;
 }
diff --git a/include/block/block.h b/include/block/block.h
index beb563a..dfd8694 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -426,6 +426,7 @@ int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
                             int64_t sector_num, int nb_sectors, int *pnum);
 
 bool bdrv_is_read_only(BlockDriverState *bs);
+int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only, Error **errp);
 int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp);
 bool bdrv_is_sg(BlockDriverState *bs);
 bool bdrv_is_inserted(BlockDriverState *bs);
-- 
2.9.3

[Qemu-devel] [PATCH v2 for-2.10 6/8] block: use bdrv_can_set_read_only() during reopen

[Jeff Cody]

Signed-off-by: Jeff Cody <jcody@redhat.com>
---
 block.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/block.c b/block.c
index 1514ae9..5d560f5 100644
--- a/block.c
+++ b/block.c
@@ -2785,6 +2785,7 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue,
     BlockDriver *drv;
     QemuOpts *opts;
     const char *value;
+    bool read_only;
 
     assert(reopen_state != NULL);
     assert(reopen_state->bs->drv != NULL);
@@ -2813,12 +2814,13 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue,
         qdict_put(reopen_state->options, "driver", qstring_from_str(value));
     }
 
-    /* if we are to stay read-only, do not allow permission change
-     * to r/w */
-    if (!(reopen_state->bs->open_flags & BDRV_O_ALLOW_RDWR) &&
-        reopen_state->flags & BDRV_O_RDWR) {
-        error_setg(errp, "Node '%s' is read only",
-                   bdrv_get_device_or_node_name(reopen_state->bs));
+    /* If we are to stay read-only, do not allow permission change
+     * to r/w. Attempting to set to r/w may fail if either BDRV_O_ALLOW_RDWR is
+     * not set, or if the BDS still has copy_on_read enabled */
+    read_only = !(reopen_state->flags & BDRV_O_RDWR);
+    ret = bdrv_can_set_read_only(reopen_state->bs, read_only, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
         goto error;
     }
 
-- 
2.9.3

[Qemu-devel] [PATCH v2 for-2.10 7/8] block/rbd - update variable names to more apt names

[Jeff Cody]

Update 'clientname' to be 'user', which tracks better with both
the QAPI and rados variable naming.

Update 'name' to be 'image_name', as it indicates the rbd image.
Naming it 'image' would have been ideal, but we are using that for
the rados_image_t value returned by rbd_open().

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Jeff Cody <jcody@redhat.com>
---
 block/rbd.c | 33 +++++++++++++++++----------------
 1 file changed, 17 insertions(+), 16 deletions(-)

diff --git a/block/rbd.c b/block/rbd.c
index 1c43171..35853c9 100644
--- a/block/rbd.c
+++ b/block/rbd.c
@@ -94,7 +94,7 @@ typedef struct BDRVRBDState {
     rados_t cluster;
     rados_ioctx_t io_ctx;
     rbd_image_t image;
-    char *name;
+    char *image_name;
     char *snap;
 } BDRVRBDState;
 
@@ -350,7 +350,7 @@ static int qemu_rbd_create(const char *filename, QemuOpts *opts, Error **errp)
     int64_t bytes = 0;
     int64_t objsize;
     int obj_order = 0;
-    const char *pool, *name, *conf, *clientname, *keypairs;
+    const char *pool, *image_name, *conf, *user, *keypairs;
     const char *secretid;
     rados_t cluster;
     rados_ioctx_t io_ctx;
@@ -393,11 +393,11 @@ static int qemu_rbd_create(const char *filename, QemuOpts *opts, Error **errp)
      */
     pool       = qdict_get_try_str(options, "pool");
     conf       = qdict_get_try_str(options, "conf");
-    clientname = qdict_get_try_str(options, "user");
-    name       = qdict_get_try_str(options, "image");
+    user       = qdict_get_try_str(options, "user");
+    image_name = qdict_get_try_str(options, "image");
     keypairs   = qdict_get_try_str(options, "=keyvalue-pairs");
 
-    ret = rados_create(&cluster, clientname);
+    ret = rados_create(&cluster, user);
     if (ret < 0) {
         error_setg_errno(errp, -ret, "error initializing");
         goto exit;
@@ -434,7 +434,7 @@ static int qemu_rbd_create(const char *filename, QemuOpts *opts, Error **errp)
         goto shutdown;
     }
 
-    ret = rbd_create(io_ctx, name, bytes, &obj_order);
+    ret = rbd_create(io_ctx, image_name, bytes, &obj_order);
     if (ret < 0) {
         error_setg_errno(errp, -ret, "error rbd create");
     }
@@ -540,7 +540,7 @@ static int qemu_rbd_open(BlockDriverState *bs, QDict *options, int flags,
                          Error **errp)
 {
     BDRVRBDState *s = bs->opaque;
-    const char *pool, *snap, *conf, *clientname, *name, *keypairs;
+    const char *pool, *snap, *conf, *user, *image_name, *keypairs;
     const char *secretid;
     QemuOpts *opts;
     Error *local_err = NULL;
@@ -567,24 +567,24 @@ static int qemu_rbd_open(BlockDriverState *bs, QDict *options, int flags,
     pool           = qemu_opt_get(opts, "pool");
     conf           = qemu_opt_get(opts, "conf");
     snap           = qemu_opt_get(opts, "snapshot");
-    clientname     = qemu_opt_get(opts, "user");
-    name           = qemu_opt_get(opts, "image");
+    user           = qemu_opt_get(opts, "user");
+    image_name     = qemu_opt_get(opts, "image");
     keypairs       = qemu_opt_get(opts, "=keyvalue-pairs");
 
-    if (!pool || !name) {
+    if (!pool || !image_name) {
         error_setg(errp, "Parameters 'pool' and 'image' are required");
         r = -EINVAL;
         goto failed_opts;
     }
 
-    r = rados_create(&s->cluster, clientname);
+    r = rados_create(&s->cluster, user);
     if (r < 0) {
         error_setg_errno(errp, -r, "error initializing");
         goto failed_opts;
     }
 
     s->snap = g_strdup(snap);
-    s->name = g_strdup(name);
+    s->image_name = g_strdup(image_name);
 
     /* try default location when conf=NULL, but ignore failure */
     r = rados_conf_read_file(s->cluster, conf);
@@ -636,9 +636,10 @@ static int qemu_rbd_open(BlockDriverState *bs, QDict *options, int flags,
     }
 
     /* rbd_open is always r/w */
-    r = rbd_open(s->io_ctx, s->name, &s->image, s->snap);
+    r = rbd_open(s->io_ctx, s->image_name, &s->image, s->snap);
     if (r < 0) {
-        error_setg_errno(errp, -r, "error reading header from %s", s->name);
+        error_setg_errno(errp, -r, "error reading header from %s",
+                         s->image_name);
         goto failed_open;
     }
 
@@ -660,7 +661,7 @@ failed_open:
 failed_shutdown:
     rados_shutdown(s->cluster);
     g_free(s->snap);
-    g_free(s->name);
+    g_free(s->image_name);
 failed_opts:
     qemu_opts_del(opts);
     g_free(mon_host);
@@ -674,7 +675,7 @@ static void qemu_rbd_close(BlockDriverState *bs)
     rbd_close(s->image);
     rados_ioctx_destroy(s->io_ctx);
     g_free(s->snap);
-    g_free(s->name);
+    g_free(s->image_name);
     rados_shutdown(s->cluster);
 }
 
-- 
2.9.3

[Qemu-devel] [PATCH v2 for-2.10 8/8] block/rbd: Add support for reopen()

[Jeff Cody]

This adds support for reopen in rbd, for changing between r/w and r/o.

Note, that this is only a flag change, but we will block a change from
r/o to r/w if we are using an RBD internal snapshot.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Jeff Cody <jcody@redhat.com>
---
 block/rbd.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/block/rbd.c b/block/rbd.c
index 35853c9..6471f4f 100644
--- a/block/rbd.c
+++ b/block/rbd.c
@@ -668,6 +668,26 @@ failed_opts:
     return r;
 }
 
+
+/* Since RBD is currently always opened R/W via the API,
+ * we just need to check if we are using a snapshot or not, in
+ * order to determine if we will allow it to be R/W */
+static int qemu_rbd_reopen_prepare(BDRVReopenState *state,
+                                   BlockReopenQueue *queue, Error **errp)
+{
+    BDRVRBDState *s = state->bs->opaque;
+    int ret = 0;
+
+    if (s->snap && state->flags & BDRV_O_RDWR) {
+        error_setg(errp,
+                   "Cannot change node '%s' to r/w when using RBD snapshot",
+                   bdrv_get_device_or_node_name(state->bs));
+        ret = -EINVAL;
+    }
+
+    return ret;
+}
+
 static void qemu_rbd_close(BlockDriverState *bs)
 {
     BDRVRBDState *s = bs->opaque;
@@ -1074,6 +1094,7 @@ static BlockDriver bdrv_rbd = {
     .bdrv_parse_filename    = qemu_rbd_parse_filename,
     .bdrv_file_open         = qemu_rbd_open,
     .bdrv_close             = qemu_rbd_close,
+    .bdrv_reopen_prepare    = qemu_rbd_reopen_prepare,
     .bdrv_create            = qemu_rbd_create,
     .bdrv_has_zero_init     = bdrv_has_zero_init_1,
     .bdrv_get_info          = qemu_rbd_getinfo,
-- 
2.9.3

Re: [Qemu-devel] [PATCH v2 for-2.10 0/8] RBD reopen, read_only cleanup

[Stefan Hajnoczi]

[-- Attachment #1: Type: text/plain, Size: 1810 bytes --]

On Fri, Apr 07, 2017 at 04:55:24PM -0400, Jeff Cody wrote:
> 
> Changes from v1:
> 
> Patch 2: Has v1 patch 8 (do not blindly xset bs->read_only) squashed into it
>          (thanks Stefan)
>          COW -> "copy-on-read" (Thanks John)
>          Drop unneeded call in vvfat, and bypass enable_write_target (Stefan)
> 
> Patch 5: Rename bdrv_try_... to bdrv_can_set_read_only() (Thanks John, Stefan)
> 
> Patch 6: Use "reopen_state->flags" not "reopen_state->bs->open_flags"
>          (Thanks John)
> 
> 
> 
> This series does two things:
> 
> 1.) Cleans up some of the logic behind setting the read_only flag
>     for a BDS in the block layer, so that it is done consistently
>     (and rules are applied consistently), and
> 
> 2.) Adds .bdrv_reopen_prepare() implementation for RBD, so that block
>     jobs can be run on backing chains that have rbd protocol nodes.
> 
> Jeff Cody (8):
>   block: add bdrv_set_read_only() helper function
>   block: do not set BDS read_only if copy_on_read enabled
>   block: honor BDRV_O_ALLOW_RDWR when clearing bs->read_only
>   block: code movement
>   block: introduce bdrv_can_set_read_only()
>   block: use bdrv_can_set_read_only() during reopen
>   block/rbd - update variable names to more apt names
>   block/rbd: Add support for reopen()
> 
>  block.c               | 56 +++++++++++++++++++++++++++++++++++---------
>  block/bochs.c         |  5 +++-
>  block/cloop.c         |  5 +++-
>  block/dmg.c           |  6 ++++-
>  block/rbd.c           | 65 +++++++++++++++++++++++++++++++++++++--------------
>  block/vvfat.c         | 19 +++++++++++----
>  include/block/block.h |  2 ++
>  7 files changed, 123 insertions(+), 35 deletions(-)
> 
> -- 
> 2.9.3
> 

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 455 bytes --]

Re: [Qemu-devel] [PATCH v2 for-2.10 0/8] RBD reopen, read_only cleanup

[John Snow]

On 04/07/2017 04:55 PM, Jeff Cody wrote:
> Changes from v1:
> 
> Patch 2: Has v1 patch 8 (do not blindly xset bs->read_only) squashed into it
>          (thanks Stefan)
>          COW -> "copy-on-read" (Thanks John)
>          Drop unneeded call in vvfat, and bypass enable_write_target (Stefan)
> 
> Patch 5: Rename bdrv_try_... to bdrv_can_set_read_only() (Thanks John, Stefan)
> 
> Patch 6: Use "reopen_state->flags" not "reopen_state->bs->open_flags"
>          (Thanks John)
> 
> 
> 
> This series does two things:
> 
> 1.) Cleans up some of the logic behind setting the read_only flag
>     for a BDS in the block layer, so that it is done consistently
>     (and rules are applied consistently), and
> 
> 2.) Adds .bdrv_reopen_prepare() implementation for RBD, so that block
>     jobs can be run on backing chains that have rbd protocol nodes.
> 
> Jeff Cody (8):
>   block: add bdrv_set_read_only() helper function
>   block: do not set BDS read_only if copy_on_read enabled
>   block: honor BDRV_O_ALLOW_RDWR when clearing bs->read_only
>   block: code movement
>   block: introduce bdrv_can_set_read_only()
>   block: use bdrv_can_set_read_only() during reopen
>   block/rbd - update variable names to more apt names
>   block/rbd: Add support for reopen()
> 
>  block.c               | 56 +++++++++++++++++++++++++++++++++++---------
>  block/bochs.c         |  5 +++-
>  block/cloop.c         |  5 +++-
>  block/dmg.c           |  6 ++++-
>  block/rbd.c           | 65 +++++++++++++++++++++++++++++++++++++--------------
>  block/vvfat.c         | 19 +++++++++++----
>  include/block/block.h |  2 ++
>  7 files changed, 123 insertions(+), 35 deletions(-)
> 

Reviewed-by: John Snow <jsnow@redhat.com>

Re: [Qemu-devel] [PATCH v2 for-2.10 0/8] RBD reopen, read_only cleanup

[Jeff Cody]

On Fri, Apr 07, 2017 at 04:55:24PM -0400, Jeff Cody wrote:
> 
> Changes from v1:
> 
> Patch 2: Has v1 patch 8 (do not blindly xset bs->read_only) squashed into it
>          (thanks Stefan)
>          COW -> "copy-on-read" (Thanks John)
>          Drop unneeded call in vvfat, and bypass enable_write_target (Stefan)
> 
> Patch 5: Rename bdrv_try_... to bdrv_can_set_read_only() (Thanks John, Stefan)
> 
> Patch 6: Use "reopen_state->flags" not "reopen_state->bs->open_flags"
>          (Thanks John)
> 
> 
> 
> This series does two things:
> 
> 1.) Cleans up some of the logic behind setting the read_only flag
>     for a BDS in the block layer, so that it is done consistently
>     (and rules are applied consistently), and
> 
> 2.) Adds .bdrv_reopen_prepare() implementation for RBD, so that block
>     jobs can be run on backing chains that have rbd protocol nodes.
> 
> Jeff Cody (8):
>   block: add bdrv_set_read_only() helper function
>   block: do not set BDS read_only if copy_on_read enabled
>   block: honor BDRV_O_ALLOW_RDWR when clearing bs->read_only
>   block: code movement
>   block: introduce bdrv_can_set_read_only()
>   block: use bdrv_can_set_read_only() during reopen
>   block/rbd - update variable names to more apt names
>   block/rbd: Add support for reopen()
> 
>  block.c               | 56 +++++++++++++++++++++++++++++++++++---------
>  block/bochs.c         |  5 +++-
>  block/cloop.c         |  5 +++-
>  block/dmg.c           |  6 ++++-
>  block/rbd.c           | 65 +++++++++++++++++++++++++++++++++++++--------------
>  block/vvfat.c         | 19 +++++++++++----
>  include/block/block.h |  2 ++
>  7 files changed, 123 insertions(+), 35 deletions(-)
> 
> -- 
> 2.9.3
> 

Thanks,

Applied to my block branch:

git://github.com/codyprime/qemu-kvm-jtc block

-Jeff