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Commit d0deef5b authored by Shawn Du's avatar Shawn Du Committed by Ingo Molnar
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blktrace: support per-partition tracing 

Though one can specify '-d /dev/sda1' when using blktrace, it still
traces the whole sda.

To support per-partition tracing, when we start tracing, we initialize
bt->start_lba and bt->end_lba to the start and end sector of that
partition.

Note some actions are per device, thus we don't filter 0-sector events.

The original patch and discussion can be found here:
	http://marc.info/?l=linux-btrace&m=122949374214540&w=2



Signed-off-by: default avatarShawn Du <duyuyang@gmail.com>
Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Acked-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
LKML-Reference: <49E42620.4050701@cn.fujitsu.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 9cfe06f8

block/compat_ioctl.c

+1 −1
Original line number Diff line number Diff line
@@ -568,7 +568,7 @@ static int compat_blk_trace_setup(struct block_device *bdev, char __user *arg) 
	memcpy(&buts.name, &cbuts.name, 32);



	mutex_lock(&bdev->bd_mutex);

	ret = do_blk_trace_setup(q, b, bdev->bd_dev, &buts);

	ret = do_blk_trace_setup(q, b, bdev->bd_dev, bdev, &buts);

	mutex_unlock(&bdev->bd_mutex);

	if (ret)

		return ret;

drivers/scsi/sg.c

+1 −0
Original line number Diff line number Diff line
@@ -1065,6 +1065,7 @@ sg_ioctl(struct inode *inode, struct file *filp, 
		return blk_trace_setup(sdp->device->request_queue,

				       sdp->disk->disk_name,

				       MKDEV(SCSI_GENERIC_MAJOR, sdp->index),

				       NULL,

				       (char *)arg);

	case BLKTRACESTART:

		return blk_trace_startstop(sdp->device->request_queue, 1);

include/linux/blktrace_api.h

+13 −11
Original line number Diff line number Diff line
@@ -165,8 +165,9 @@ struct blk_trace { 


extern int blk_trace_ioctl(struct block_device *, unsigned, char __user *);

extern void blk_trace_shutdown(struct request_queue *);

extern int do_blk_trace_setup(struct request_queue *q,

	char *name, dev_t dev, struct blk_user_trace_setup *buts);

extern int do_blk_trace_setup(struct request_queue *q, char *name,

			      dev_t dev, struct block_device *bdev,

			      struct blk_user_trace_setup *buts);

extern void __trace_note_message(struct blk_trace *, const char *fmt, ...);



/**
@@ -193,6 +194,7 @@ extern void __trace_note_message(struct blk_trace *, const char *fmt, ...); 
extern void blk_add_driver_data(struct request_queue *q, struct request *rq,

				void *data, size_t len);

extern int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,

			   struct block_device *bdev,

			   char __user *arg);

extern int blk_trace_startstop(struct request_queue *q, int start);

extern int blk_trace_remove(struct request_queue *q);
@@ -202,13 +204,13 @@ extern struct attribute_group blk_trace_attr_group; 
#else /* !CONFIG_BLK_DEV_IO_TRACE */

# define blk_trace_ioctl(bdev, cmd, arg)		(-ENOTTY)

# define blk_trace_shutdown(q)				do { } while (0)

#define do_blk_trace_setup(q, name, dev, buts)	(-ENOTTY)

# define do_blk_trace_setup(q, name, dev, bdev, buts)	(-ENOTTY)

# define blk_add_driver_data(q, rq, data, len)		do {} while (0)

#define blk_trace_setup(q, name, dev, arg)	(-ENOTTY)

# define blk_trace_setup(q, name, dev, bdev, arg)	(-ENOTTY)

# define blk_trace_startstop(q, start)			(-ENOTTY)

# define blk_trace_remove(q)				(-ENOTTY)

# define blk_add_trace_msg(q, fmt, ...)			do { } while (0)



#endif /* CONFIG_BLK_DEV_IO_TRACE */



#endif /* __KERNEL__ */

#endif

kernel/trace/blktrace.c

+21 −8
Original line number Diff line number Diff line
@@ -147,7 +147,7 @@ static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector, 
{

	if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)

		return 1;

	if (sector < bt->start_lba || sector > bt->end_lba)

	if (sector && (sector < bt->start_lba || sector > bt->end_lba))

		return 1;

	if (bt->pid && pid != bt->pid)

		return 1;
@@ -192,7 +192,7 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, 
	what |= MASK_TC_BIT(rw, DISCARD);



	pid = tsk->pid;

	if (unlikely(act_log_check(bt, what, sector, pid)))

	if (act_log_check(bt, what, sector, pid))

		return;

	cpu = raw_smp_processor_id();
@@ -407,11 +407,13 @@ static struct rchan_callbacks blk_relay_callbacks = { 
 * Setup everything required to start tracing

 */

int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,

		       struct block_device *bdev,

		       struct blk_user_trace_setup *buts)

{

	struct blk_trace *old_bt, *bt = NULL;

	struct dentry *dir = NULL;

	int ret, i;

	struct hd_struct *part = NULL;



	if (!buts->buf_size || !buts->buf_nr)

		return -EINVAL;
@@ -480,10 +482,20 @@ int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 
	if (!bt->act_mask)

		bt->act_mask = (u16) -1;



	if (bdev)

		part = bdev->bd_part;



	if (part) {

		bt->start_lba = part->start_sect;

		bt->end_lba = part->start_sect + part->nr_sects;

	} else

		bt->end_lba = -1ULL;



	/* overwrite with user settings */

	if (buts->start_lba)

		bt->start_lba = buts->start_lba;

	if (buts->end_lba)

		bt->end_lba = buts->end_lba;

	if (!bt->end_lba)

		bt->end_lba = -1ULL;



	bt->pid = buts->pid;

	bt->trace_state = Blktrace_setup;
@@ -505,6 +517,7 @@ int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 
}



int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,

		    struct block_device *bdev,

		    char __user *arg)

{

	struct blk_user_trace_setup buts;
@@ -514,7 +527,7 @@ int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 
	if (ret)

		return -EFAULT;



	ret = do_blk_trace_setup(q, name, dev, &buts);

	ret = do_blk_trace_setup(q, name, dev, bdev, &buts);

	if (ret)

		return ret;
@@ -582,7 +595,7 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) 
	switch (cmd) {

	case BLKTRACESETUP:

		bdevname(bdev, b);

		ret = blk_trace_setup(q, b, bdev->bd_dev, arg);

		ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);

		break;

	case BLKTRACESTART:

		start = 1;