Patchwork [PATCHv2] iscsi: add iscsi_truncate support

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Submitter Peter Lieven
Date Feb. 15, 2013, 2:35 p.m.
Message ID <511E47B8.4070901@dlhnet.de>
Download mbox | patch
Permalink /patch/220751/
State New
Headers show

Comments

Peter Lieven - Feb. 15, 2013, 2:35 p.m.
this patch adds iscsi_truncate which effectively allows for online
resizing of iscsi volumes. for this to work you have to resize
the volume on your storage and then call block_resize command
in qemu which will issue a readcapacity16 to update the capacity.

v2:
  - add a general bdrv_drain_all() before bdrv_truncate() to avoid
    in-flight AIOs while the device is truncated
  - since no AIOs are in flight we can use a sync libiscsi call
    to re-read the capacity
  - factor out the readcapacity16 logic as it is redundant
    to iscsi_open() and iscsi_truncate().

Signed-off-by: Peter Lieven <pl@kamp.de>
---
  block.c       |    4 ++++
  block/iscsi.c |   65 +++++++++++++++++++++++++++++++++++++++++++++------------
  2 files changed, 56 insertions(+), 13 deletions(-)
Paolo Bonzini - Feb. 15, 2013, 3:06 p.m.
Il 15/02/2013 15:35, Peter Lieven ha scritto:
> this patch adds iscsi_truncate which effectively allows for online
> resizing of iscsi volumes. for this to work you have to resize
> the volume on your storage and then call block_resize command
> in qemu which will issue a readcapacity16 to update the capacity.
> 
> v2:
>  - add a general bdrv_drain_all() before bdrv_truncate() to avoid
>    in-flight AIOs while the device is truncated
>  - since no AIOs are in flight we can use a sync libiscsi call
>    to re-read the capacity
>  - factor out the readcapacity16 logic as it is redundant
>    to iscsi_open() and iscsi_truncate().

Please move the entire switch statement of iscsi_open, the code should
be cleaner.  Also please separate bdrv_drain_all() to a separate patch
and Cc qemu-stable on that one (Kevin's message should provide a good
skeleton for a commit messages).

Paolo

> Signed-off-by: Peter Lieven <pl@kamp.de>
> ---
>  block.c       |    4 ++++
>  block/iscsi.c |   65
> +++++++++++++++++++++++++++++++++++++++++++++------------
>  2 files changed, 56 insertions(+), 13 deletions(-)
> 
> diff --git a/block.c b/block.c
> index 50dab8e..d8880e3 100644
> --- a/block.c
> +++ b/block.c
> @@ -2427,6 +2427,10 @@ int bdrv_truncate(BlockDriverState *bs, int64_t
> offset)
>          return -EACCES;
>      if (bdrv_in_use(bs))
>          return -EBUSY;
> +
> +    /* there should be better no AIOs in flight when we truncate the
> device */
> +    bdrv_drain_all();
> +
>      ret = drv->bdrv_truncate(bs, offset);
>      if (ret == 0) {
>          ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
> diff --git a/block/iscsi.c b/block/iscsi.c
> index deb3b68..dd41943 100644
> --- a/block/iscsi.c
> +++ b/block/iscsi.c
> @@ -823,6 +823,35 @@ static void iscsi_nop_timed_event(void *opaque)
>  }
>  #endif
> 
> +static int iscsi_disk_readcapacity16_sync(IscsiLun *iscsilun) {
> +    struct scsi_task *task = NULL;
> +    struct scsi_readcapacity16 *rc16 = NULL;
> +
> +    task = iscsi_readcapacity16_sync(iscsilun->iscsi, iscsilun->lun);
> +    if (task == NULL) {
> +        error_report("iSCSI: failed to send readcapacity16 command.");
> +        return -EINVAL;
> +    }
> +    if (task->status != SCSI_STATUS_GOOD) {
> +        error_report("iSCSI: failed to send readcapacity16 command.");
> +        scsi_free_scsi_task(task);
> +        return -EINVAL;
> +    }
> +    rc16 = scsi_datain_unmarshall(task);
> +    if (rc16 == NULL) {
> +        error_report("iSCSI: Failed to unmarshall readcapacity16 data.");
> +        scsi_free_scsi_task(task);
> +        return -EINVAL;
> +    }
> +
> +    iscsilun->block_size = rc16->block_length;
> +    iscsilun->num_blocks = rc16->returned_lba + 1;
> +
> +    scsi_free_scsi_task(task);
> +
> +    return 0;
> +}
> +
>  /*
>   * We support iscsi url's on the form
>   * iscsi://[<username>%<password>@]<host>[:<port>]/<targetname>/<lun>
> @@ -835,7 +864,6 @@ static int iscsi_open(BlockDriverState *bs, const
> char *filename, int flags)
>      struct scsi_task *task = NULL;
>      struct scsi_inquiry_standard *inq = NULL;
>      struct scsi_readcapacity10 *rc10 = NULL;
> -    struct scsi_readcapacity16 *rc16 = NULL;
>      char *initiator_name = NULL;
>      int ret;
> 
> @@ -926,23 +954,13 @@ static int iscsi_open(BlockDriverState *bs, const
> char *filename, int flags)
>      iscsilun->type = inq->periperal_device_type;
> 
>      scsi_free_scsi_task(task);
> +    task = NULL;
> 
>      switch (iscsilun->type) {
>      case TYPE_DISK:
> -        task = iscsi_readcapacity16_sync(iscsi, iscsilun->lun);
> -        if (task == NULL || task->status != SCSI_STATUS_GOOD) {
> -            error_report("iSCSI: failed to send readcapacity16 command.");
> -            ret = -EINVAL;
> +        if ((ret = iscsi_disk_readcapacity16_sync(iscsilun))) {
>              goto out;
>          }
> -        rc16 = scsi_datain_unmarshall(task);
> -        if (rc16 == NULL) {
> -            error_report("iSCSI: Failed to unmarshall readcapacity16
> data.");
> -            ret = -EINVAL;
> -            goto out;
> -        }
> -        iscsilun->block_size = rc16->block_length;
> -        iscsilun->num_blocks = rc16->returned_lba + 1;
>          break;
>      case TYPE_ROM:
>          task = iscsi_readcapacity10_sync(iscsi, iscsilun->lun, 0, 0);
> @@ -1023,6 +1041,26 @@ static void iscsi_close(BlockDriverState *bs)
>      memset(iscsilun, 0, sizeof(IscsiLun));
>  }
> 
> +static int iscsi_truncate(BlockDriverState *bs, int64_t offset)
> +{
> +    IscsiLun *iscsilun = bs->opaque;
> +    int ret = 0;
> +
> +    if (iscsilun->type != TYPE_DISK) {
> +        return -ENOTSUP;
> +    }
> +
> +    if ((ret = iscsi_disk_readcapacity16_sync(iscsilun))) {
> +        return ret;
> +    }
> +
> +    if (offset > iscsi_getlength(bs)) {
> +        return -EINVAL;
> +    }
> +
> +    return 0;
> +}
> +
>  static int iscsi_has_zero_init(BlockDriverState *bs)
>  {
>      return 0;
> @@ -1093,6 +1131,7 @@ static BlockDriver bdrv_iscsi = {
>      .create_options  = iscsi_create_options,
> 
>      .bdrv_getlength  = iscsi_getlength,
> +    .bdrv_truncate   = iscsi_truncate,
> 
>      .bdrv_aio_readv  = iscsi_aio_readv,
>      .bdrv_aio_writev = iscsi_aio_writev,

Patch

diff --git a/block.c b/block.c
index 50dab8e..d8880e3 100644
--- a/block.c
+++ b/block.c
@@ -2427,6 +2427,10 @@  int bdrv_truncate(BlockDriverState *bs, int64_t offset)
          return -EACCES;
      if (bdrv_in_use(bs))
          return -EBUSY;
+
+    /* there should be better no AIOs in flight when we truncate the device */
+    bdrv_drain_all();
+
      ret = drv->bdrv_truncate(bs, offset);
      if (ret == 0) {
          ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
diff --git a/block/iscsi.c b/block/iscsi.c
index deb3b68..dd41943 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -823,6 +823,35 @@  static void iscsi_nop_timed_event(void *opaque)
  }
  #endif

+static int iscsi_disk_readcapacity16_sync(IscsiLun *iscsilun) {
+    struct scsi_task *task = NULL;
+    struct scsi_readcapacity16 *rc16 = NULL;
+
+    task = iscsi_readcapacity16_sync(iscsilun->iscsi, iscsilun->lun);
+    if (task == NULL) {
+        error_report("iSCSI: failed to send readcapacity16 command.");
+        return -EINVAL;
+    }
+    if (task->status != SCSI_STATUS_GOOD) {
+        error_report("iSCSI: failed to send readcapacity16 command.");
+        scsi_free_scsi_task(task);
+        return -EINVAL;
+    }
+    rc16 = scsi_datain_unmarshall(task);
+    if (rc16 == NULL) {
+        error_report("iSCSI: Failed to unmarshall readcapacity16 data.");
+        scsi_free_scsi_task(task);
+        return -EINVAL;
+    }
+
+    iscsilun->block_size = rc16->block_length;
+    iscsilun->num_blocks = rc16->returned_lba + 1;
+
+    scsi_free_scsi_task(task);
+
+    return 0;
+}
+
  /*
   * We support iscsi url's on the form
   * iscsi://[<username>%<password>@]<host>[:<port>]/<targetname>/<lun>
@@ -835,7 +864,6 @@  static int iscsi_open(BlockDriverState *bs, const char *filename, int flags)
      struct scsi_task *task = NULL;
      struct scsi_inquiry_standard *inq = NULL;
      struct scsi_readcapacity10 *rc10 = NULL;
-    struct scsi_readcapacity16 *rc16 = NULL;
      char *initiator_name = NULL;
      int ret;

@@ -926,23 +954,13 @@  static int iscsi_open(BlockDriverState *bs, const char *filename, int flags)
      iscsilun->type = inq->periperal_device_type;

      scsi_free_scsi_task(task);
+    task = NULL;

      switch (iscsilun->type) {
      case TYPE_DISK:
-        task = iscsi_readcapacity16_sync(iscsi, iscsilun->lun);
-        if (task == NULL || task->status != SCSI_STATUS_GOOD) {
-            error_report("iSCSI: failed to send readcapacity16 command.");
-            ret = -EINVAL;
+        if ((ret = iscsi_disk_readcapacity16_sync(iscsilun))) {
              goto out;
          }
-        rc16 = scsi_datain_unmarshall(task);
-        if (rc16 == NULL) {
-            error_report("iSCSI: Failed to unmarshall readcapacity16 data.");
-            ret = -EINVAL;
-            goto out;
-        }
-        iscsilun->block_size = rc16->block_length;
-        iscsilun->num_blocks = rc16->returned_lba + 1;
          break;
      case TYPE_ROM:
          task = iscsi_readcapacity10_sync(iscsi, iscsilun->lun, 0, 0);
@@ -1023,6 +1041,26 @@  static void iscsi_close(BlockDriverState *bs)
      memset(iscsilun, 0, sizeof(IscsiLun));
  }

+static int iscsi_truncate(BlockDriverState *bs, int64_t offset)
+{
+    IscsiLun *iscsilun = bs->opaque;
+    int ret = 0;
+
+    if (iscsilun->type != TYPE_DISK) {
+        return -ENOTSUP;
+    }
+
+    if ((ret = iscsi_disk_readcapacity16_sync(iscsilun))) {
+        return ret;
+    }
+
+    if (offset > iscsi_getlength(bs)) {
+        return -EINVAL;
+    }
+
+    return 0;
+}
+
  static int iscsi_has_zero_init(BlockDriverState *bs)
  {
      return 0;
@@ -1093,6 +1131,7 @@  static BlockDriver bdrv_iscsi = {
      .create_options  = iscsi_create_options,

      .bdrv_getlength  = iscsi_getlength,
+    .bdrv_truncate   = iscsi_truncate,

      .bdrv_aio_readv  = iscsi_aio_readv,
      .bdrv_aio_writev = iscsi_aio_writev,