Re: [PATCH] add blockconsole version 1.1

From: Borislav Petkov
Date: Mon Jul 16 2012 - 08:46:20 EST

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On Fri, Jul 13, 2012 at 12:20:09PM -0400, JÃrn Engel wrote:

[ â ]

> diff --git a/Documentation/block/blockconsole/bcon_tail b/Documentation/block/blockconsole/bcon_tail
> new file mode 100755
> index 0000000..950bfd1
> --- /dev/null
> +++ b/Documentation/block/blockconsole/bcon_tail
> @@ -0,0 +1,52 @@
> +#!/bin/bash
> +
> +TAIL_LEN=16
> +TEMPLATE=/tmp/bcon_template
> +BUF=/tmp/bcon_buf
> +
> +end_of_log() {
> + DEV=$1
> + UUID=`head -c40 $DEV|tail -c8`
> + LOGFILE=/var/log/bcon.$UUID
> + SECTORS=`hdparm -g $DEV|grep sectors|sed 's/.*sectors = $[0-9]*$.*/\1/'`
> + #MSIZE=`expr $SECTORS / 2048`
> + dd if=$DEV iflag=direct bs=512 2>/dev/null|head -c50 > $TEMPLATE
> + #START, MIDDLE and END are in sectors
> + START=0
> + MIDDLE=$SECTORS
> + END=$SECTORS
> + while true; do
> + MIDDLE=`expr $ \( $END + $START $ / 4096 \) \* 2048`
> + if [ $MIDDLE -eq $START ]; then
> + break
> + fi
> + dd if=$DEV iflag=direct bs=512 count=1 skip=$MIDDLE 2>/dev/null|head -c50 > $BUF
> + if diff -q $BUF $TEMPLATE > /dev/null; then
> + START=$MIDDLE
> + else
> + END=$MIDDLE
> + fi
> + done
> + #switch to megabytes
> + END=`expr $END / 2048`
> + START=`expr $START / 2048`
> + if [ $START -lt $TAIL_LEN ]; then
> + START=0
> + else
> + START=`expr $START - $TAIL_LEN + 1`
> + fi
> + LEN=`expr $END - $START`
> + dd if=$DEV iflag=direct bs=1M count=$LEN skip=$START >$LOGFILE 2>/dev/null
> + echo $LOGFILE
> +}
> +
> +# HEADER contains a newline, so the funny quoting is necessary
> +HEADER='
> +Linux blockconsole version 1.1'
> +CANDIDATES=`lsscsi |sed 's|.*/dev|/dev|'`

You probably want to check lsscsi presence on the system, wasn't
installed by default on my debian testing image, for example. See diff
at the end of this mail.

> +
> +for DEV in $CANDIDATES; do
> + if [ "`head -c32 $DEV`" == "$HEADER" ]; then
> + end_of_log $DEV
> + fi
> +done
> diff --git a/Documentation/block/blockconsole/mkblockconsole b/Documentation/block/blockconsole/mkblockconsole
> new file mode 100755
> index 0000000..d9514e7
> --- /dev/null
> +++ b/Documentation/block/blockconsole/mkblockconsole
> @@ -0,0 +1,24 @@
> +#!/bin/sh
> +
> +if [ ! $# -eq 1 ]; then
> + echo "Usage: mkblockconsole <dev>"

echo "Usage: $0 <dev>"

in case the name of the script changes.

> + exit 1
> +elif mount|fgrep -q $1; then
> + echo Device appears to be mounted - aborting
> + exit 1
> +else
> + dd if=/dev/zero bs=1M count=1 > $1
> + # The funky formatting is actually needed!
> + UUID=`head -c4 /dev/urandom |hexdump -e '/4 "%08x"'`
> + echo > /tmp/$UUID
> + echo 'Linux blockconsole version 1.1' >> /tmp/$UUID
> + echo "$UUID" >> /tmp/$UUID
> + echo 00000000 >> /tmp/$UUID
> + echo 00000000 >> /tmp/$UUID
> + for i in `seq 452`; do echo -n " " >> /tmp/$UUID; done
> + echo >> /tmp/$UUID
> + cat /tmp/$UUID > $1
> + rm /tmp/$UUID
> + sync
> + exit 0
> +fi
> diff --git a/block/partitions/Makefile b/block/partitions/Makefile
> index 03af8ea..bf26d4a 100644
> --- a/block/partitions/Makefile
> +++ b/block/partitions/Makefile
> @@ -18,3 +18,4 @@ obj-$(CONFIG_IBM_PARTITION) += ibm.o
> obj-$(CONFIG_EFI_PARTITION) += efi.o
> obj-$(CONFIG_KARMA_PARTITION) += karma.o
> obj-$(CONFIG_SYSV68_PARTITION) += sysv68.o
> +obj-$(CONFIG_BLOCKCONSOLE) += blockconsole.o
> diff --git a/block/partitions/blockconsole.c b/block/partitions/blockconsole.c
> new file mode 100644
> index 0000000..79796a8
> --- /dev/null
> +++ b/block/partitions/blockconsole.c
> @@ -0,0 +1,22 @@
> +#include <linux/blockconsole.h>
> +
> +#include "check.h"
> +
> +int blockconsole_partition(struct parsed_partitions *state)
> +{
> + Sector sect;
> + void *data;
> + int err = 0;
> +
> + data = read_part_sector(state, 0, &sect);
> + if (!data)
> + return -EIO;
> + if (!bcon_magic_present(data))
> + goto out;
> +
> + bcon_add(state->name);
> + err = 1;
> +out:
> + put_dev_sector(sect);
> + return err;
> +}
> diff --git a/block/partitions/check.c b/block/partitions/check.c
> index bc90867..8de99fa 100644
> --- a/block/partitions/check.c
> +++ b/block/partitions/check.c
> @@ -36,11 +36,15 @@
>
> int warn_no_part = 1; /*This is ugly: should make genhd removable media aware*/
>
> +int blockconsole_partition(struct parsed_partitions *state);
> static int (*check_part[])(struct parsed_partitions *) = {
> /*
> * Probe partition formats with tables at disk address 0
> * that also have an ADFS boot block at 0xdc0.
> */
> +#ifdef CONFIG_BLOCKCONSOLE
> + blockconsole_partition,
> +#endif
> #ifdef CONFIG_ACORN_PARTITION_ICS
> adfspart_check_ICS,
> #endif
> diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
> index a796407..637c952 100644
> --- a/drivers/block/Kconfig
> +++ b/drivers/block/Kconfig
> @@ -555,4 +555,10 @@ config BLK_DEV_RBD
>
> If unsure, say N.
>
> +config BLOCKCONSOLE
> + bool "Block device console logging support"
> + help
> + This enables logging to block devices.
> + See <file:Documentation/block/blockconsole.txt> for details.
> +
> endif # BLK_DEV
> diff --git a/drivers/block/Makefile b/drivers/block/Makefile
> index 5b79505..1eb7f902 100644
> --- a/drivers/block/Makefile
> +++ b/drivers/block/Makefile
> @@ -41,5 +41,6 @@ obj-$(CONFIG_XEN_BLKDEV_BACKEND) += xen-blkback/
> obj-$(CONFIG_BLK_DEV_DRBD) += drbd/
> obj-$(CONFIG_BLK_DEV_RBD) += rbd.o
> obj-$(CONFIG_BLK_DEV_PCIESSD_MTIP32XX) += mtip32xx/
> +obj-$(CONFIG_BLOCKCONSOLE) += blockconsole.o
>
> swim_mod-y := swim.o swim_asm.o
> diff --git a/drivers/block/blockconsole.c b/drivers/block/blockconsole.c
> new file mode 100644
> index 0000000..d13203f
> --- /dev/null
> +++ b/drivers/block/blockconsole.c
> @@ -0,0 +1,606 @@
> +#include <linux/bio.h>
> +#include <linux/blockconsole.h>
> +#include <linux/console.h>
> +#include <linux/fs.h>
> +#include <linux/kthread.h>
> +#include <linux/mm.h>
> +#include <linux/mount.h>
> +#include <linux/random.h>
> +#include <linux/slab.h>
> +#include <linux/string.h>
> +#include <linux/workqueue.h>
> +
> +#define BLOCKCONSOLE_MAGIC_OLD "\nLinux blockconsole version 1.0\n"

blockconsole is not yet upstream, you probably want to get rid of the
_OLD handling completely?

> +#define BLOCKCONSOLE_MAGIC "\nLinux blockconsole version 1.1\n"
> +#define BCON_UUID_OFS (32)
> +#define BCON_ROUND_OFS (41)
> +#define BCON_TILE_OFS (50)
> +#define BCON_HEADERSIZE (50)
> +#define BCON_LONG_HEADERSIZE (59) /* with tile index */
> +
> +#define PAGE_COUNT (256)
> +#define SECTOR_COUNT (PAGE_COUNT * (PAGE_SIZE >> 9))
> +#define CACHE_PAGE_MASK (PAGE_COUNT - 1)
> +#define CACHE_SECTOR_MASK (SECTOR_COUNT - 1)
> +#define CACHE_SIZE (PAGE_COUNT << PAGE_SHIFT)
> +#define CACHE_MASK (CACHE_SIZE - 1)
> +#define SECTOR_SHIFT (9)
> +#define SECTOR_SIZE (1 << SECTOR_SHIFT)
> +#define SECTOR_MASK (~(SECTOR_SIZE-1))
> +#define PG_SECTOR_MASK ((PAGE_SIZE >> 9) - 1)
> +
> +struct bcon_bio {
> + struct bio bio;
> + struct bio_vec bvec;
> + void *sector;
> + int in_flight;
> +};
> +
> +struct blockconsole {
> + char devname[32];
> + struct spinlock end_io_lock;
> + struct timer_list pad_timer;
> + int error_count;
> + struct kref kref;

Another build failure missing

#include <linux/kref.h>

drivers/block/blockconsole.c:44:14: error: field âkrefâ has incomplete type
drivers/block/blockconsole.c: In function âbcon_getâ:
drivers/block/blockconsole.c:63:2: error: implicit declaration of function âkref_getâ [-Werror=implicit-function-declaration]
drivers/block/blockconsole.c: In function âbcon_releaseâ:
drivers/block/blockconsole.c:68:28: warning: initialization from incompatible pointer type [enabled by default]
drivers/block/blockconsole.c:68:28: warning: (near initialization for âbcâ) [enabled by default]
drivers/block/blockconsole.c: In function âbcon_putâ:
drivers/block/blockconsole.c:79:2: error: implicit declaration of function âkref_putâ [-Werror=implicit-function-declaration]
drivers/block/blockconsole.c: In function âbcon_createâ:
drivers/block/blockconsole.c:499:2: error: implicit declaration of function âkref_initâ [-Werror=implicit-function-declaration]
cc1: some warnings being treated as errors

make[2]: *** [drivers/block/blockconsole.o] Error 1
make[1]: *** [drivers/block] Error 2
make[1]: *** Waiting for unfinished jobs....
make: *** [drivers] Error 2
make: *** Waiting for unfinished jobs....

Below's a diff of what I did here to make this work, feel free to take
anything from it.

With the include added, it builds fine. Then I took an usb stick and I
did:

$ ./mkblockconsole /dev/sdc

<reboot>

$ ./bcon_tail

which created a file called /var/log/bcon.32ea1561.

Doing a

$ less /var/log/bcon.32ea1561
Linux blockconsole version 1.1
32ea1561
00000000
00000000

^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@
^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@
^@^@^@^@^@^@
...

gives a lot of zeros, right up to the first megabyte, to be exact after which
the log starts:

$ hexdump -C /var/log/bcon.32ea1561

00000000 0a 4c 69 6e 75 78 20 62 6c 6f 63 6b 63 6f 6e 73 |.Linux blockcons|
00000010 6f 6c 65 20 76 65 72 73 69 6f 6e 20 31 2e 31 0a |ole version 1.1.|
00000020 33 32 65 61 31 35 36 31 0a 30 30 30 30 30 30 30 |32ea1561.0000000|
00000030 30 0a 30 30 30 30 30 30 30 30 0a 20 20 20 20 20 |0.00000000. |
00000040 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
*
000001f0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 0a | .|
00000200 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
00100000 0a 4c 69 6e 75 78 20 62 6c 6f 63 6b 63 6f 6e 73 |.Linux blockcons|
00100010 6f 6c 65 20 76 65 72 73 69 6f 6e 20 31 2e 31 0a |ole version 1.1.|
00100020 33 32 65 61 31 35 36 31 0a 30 30 30 30 30 30 30 |32ea1561.0000000|
00100030 30 0a 30 30 30 30 30 30 30 31 0a 5b 20 20 20 20 |0.00000001.[ |
00100040 30 2e 30 30 30 30 30 30 5d 20 49 6e 69 74 69 61 |0.000000] Initia|
00100050 6c 69 7a 69 6e 67 20 63 67 72 6f 75 70 20 73 75 |lizing cgroup su|
....

So I can read the log by doing

$ strings /var/log/bcon.32ea1561 | less

So why is that first megabyte full of zeros there?

Other than that, it works like a charm and I like the idea that no
kernel cmdline args are needed.

Also, you might want to add a step-by-step fast howto to the docs with
concrete steps like the above so that people can try this out faster.

Thanks.

--
diff --git a/Documentation/block/blockconsole/bcon_tail b/Documentation/block/blockconsole/bcon_tail
index 950bfd1..e415b6f 100755
--- a/Documentation/block/blockconsole/bcon_tail
+++ b/Documentation/block/blockconsole/bcon_tail
@@ -4,6 +4,12 @@ TAIL_LEN=16
TEMPLATE=/tmp/bcon_template
BUF=/tmp/bcon_buf

+if [ -z "$(which lsscsi)" ];
+then
+ echo "You need to install the lsscsi package on your distro."
+ exit 1
+fi
+
end_of_log() {
DEV=$1
UUID=`head -c40 $DEV|tail -c8`
diff --git a/Documentation/block/blockconsole/mkblockconsole b/Documentation/block/blockconsole/mkblockconsole
index d9514e7..05c4ad8 100755
--- a/Documentation/block/blockconsole/mkblockconsole
+++ b/Documentation/block/blockconsole/mkblockconsole
@@ -1,7 +1,7 @@
#!/bin/sh

if [ ! $# -eq 1 ]; then
- echo "Usage: mkblockconsole <dev>"
+ echo "Usage: $0 <dev>"
exit 1
elif mount|fgrep -q $1; then
echo Device appears to be mounted - aborting
diff --git a/drivers/block/blockconsole.c b/drivers/block/blockconsole.c
index d13203f..b4e995d 100644
--- a/drivers/block/blockconsole.c
+++ b/drivers/block/blockconsole.c
@@ -9,6 +9,7 @@
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/workqueue.h>
+#include <linux/kref.h>

#define BLOCKCONSOLE_MAGIC_OLD "\nLinux blockconsole version 1.0\n"
#define BLOCKCONSOLE_MAGIC "\nLinux blockconsole version 1.1\n"

--
Regards/Gruss,
Boris.
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Next message: Guennadi Liakhovetski: "Re: [PATCH 5/7 v2] dma: sh: use an integer slave ID to improve APIcompatibility"
Previous message: Thierry Reding: "Re: Adding support for configuring polarity in PWM framework."
Next in thread: JÃrn Engel: "Re: [PATCH] add blockconsole version 1.1"
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