[stgt] [PATCH] 1/1 Honour media capacity

[FUJITA Tomonori]

On Wed, 14 Oct 2009 06:44:02 +1100
Mark Harvey <markh794 at gmail.com> wrote:

> >From 8838e603da133001d3284f0ee1f0a6c71f906d09 Mon Sep 17 00:00:00 2001
> From: Mark Harvey <markh794 at gmail.com>
> Date: Tue, 13 Oct 2009 18:36:15 +1100
> Subject: Honour media capacity.
> 
> Return NO_SENSE with 'EOM' set once 'media capacity' number of bytes
> written to backing store file.
> 
> Signed-off-by: Mark Harvey <markh794 at gmail.com>
> ---
>  usr/bs_ssc.c |   23 +++++++++++++++++++++--
>  1 files changed, 21 insertions(+), 2 deletions(-)
> 
> diff --git a/usr/bs_ssc.c b/usr/bs_ssc.c
> index ce5c3bf..b2ad7c7 100644
> --- a/usr/bs_ssc.c
> +++ b/usr/bs_ssc.c
> @@ -40,6 +40,12 @@
>  #include "ssc.h"
>  #include "libssc.h"
>  
> +#define SENSE_FILEMARK	0x80
> +#define SENSE_EOM	0x40
> +#define SENSE_ILI	0X20
> +
> +static uint64_t media_capacity;

Hmm, the global media_capacity value doesn't look correct? If you have
multiple virtual tape devices, what happens?

Why can't we do something like this?


diff --git a/usr/bs_ssc.c b/usr/bs_ssc.c
index c0d5b59..8e57c1c 100644
--- a/usr/bs_ssc.c
+++ b/usr/bs_ssc.c
@@ -40,6 +40,10 @@
 #include "ssc.h"
 #include "libssc.h"
 
+#define SENSE_FILEMARK	0x80
+#define SENSE_EOM	0x40
+#define SENSE_ILI	0X20
+
 static void ssc_sense_data_build(struct scsi_cmd *cmd, uint8_t key,
 				 uint16_t asc, uint8_t *info, int info_len)
 {
@@ -109,6 +113,12 @@ static int resp_rewind(struct scsi_lu *lu)
 	return skip_next_header(lu);
 }
 
+static unsigned long current_size(struct scsi_cmd *cmd)
+{
+	struct ssc_info *ssc = dtype_priv(cmd->dev);
+	return ssc->c_blk.curr;
+}
+
 static int append_blk(struct scsi_cmd *cmd, uint8_t *data,
 		      int size, int orig_sz, int type)
 {
@@ -184,8 +194,6 @@ static int append_blk(struct scsi_cmd *cmd, uint8_t *data,
 	return SAM_STAT_GOOD;
 }
 
-#define SENSE_FILEMARK 0x80
-
 static int space_filemark_reverse(struct scsi_cmd *cmd, int32_t count)
 {
 	struct ssc_info *ssc = dtype_priv(cmd->dev);
@@ -515,6 +523,14 @@ static void tape_rdwr_request(struct scsi_cmd *cmd)
 			count, length, ret, (fixed) ? "Yes" : "No",
 			block_length);
 
+		/* Check for end of media */
+		if (current_size(cmd) > ssc->mam.max_capacity) {
+			sense_data_build(cmd, NO_SENSE|SENSE_EOM,
+						NO_ADDITIONAL_SENSE);
+			result = SAM_STAT_CHECK_CONDITION;
+			break;
+		}
+
 		if (ret != length) {
 			sense_data_build(cmd, MEDIUM_ERROR, ASC_WRITE_ERROR);
 			result = SAM_STAT_CHECK_CONDITION;

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