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Commit 80d6d698 authored by Brian Foster's avatar Brian Foster Committed by Dave Chinner
Browse files

xfs: add log attributes for log lsn and grant head data 



Create log attributes to export the current runtime state of the log to
sysfs. Note that the filesystem should be frozen for consistency across
attributes.

The following per-mount attributes are created: log_head_lsn,
log_tail_lsn, reserve_grant_head and write_grant_head. These represent
the physical log head, tail and reserve and write grant heads
respectively. Attribute values are exported in the following format:

	"cycle:[block,byte]"

... where cycle represents the log cycle and [block,bytes] represents
either the basic block or byte offset of the log, depending on the
attribute.  Log sequence number (LSN) values are encoded in basic blocks
and grant heads are encoded in bytes. All values are in decimal format.

Signed-off-by: default avatarBrian Foster <bfoster@redhat.com>
Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
parent baff4e44

fs/xfs/xfs_sysfs.c

+64 −0
Original line number Diff line number Diff line
@@ -53,7 +53,71 @@ struct kobj_type xfs_mp_ktype = { 


/* xlog */



STATIC ssize_t

log_head_lsn_show(

	char	*buf,

	void	*data)

{

	struct xlog *log = data;

	int cycle;

	int block;



	spin_lock(&log->l_icloglock);

	cycle = log->l_curr_cycle;

	block = log->l_curr_block;

	spin_unlock(&log->l_icloglock);



	return snprintf(buf, PAGE_SIZE, "%d:%d\n", cycle, block);

}

XFS_SYSFS_ATTR_RO(log_head_lsn);



STATIC ssize_t

log_tail_lsn_show(

	char	*buf,

	void	*data)

{

	struct xlog *log = data;

	int cycle;

	int block;



	xlog_crack_atomic_lsn(&log->l_tail_lsn, &cycle, &block);

	return snprintf(buf, PAGE_SIZE, "%d:%d\n", cycle, block);

}

XFS_SYSFS_ATTR_RO(log_tail_lsn);



STATIC ssize_t

reserve_grant_head_show(

	char	*buf,

	void	*data)

{

	struct xlog *log = data;

	int cycle;

	int bytes;



	xlog_crack_grant_head(&log->l_reserve_head.grant, &cycle, &bytes);

	return snprintf(buf, PAGE_SIZE, "%d:%d\n", cycle, bytes);

}

XFS_SYSFS_ATTR_RO(reserve_grant_head);



STATIC ssize_t

write_grant_head_show(

	char	*buf,

	void	*data)

{

	struct xlog *log = data;

	int cycle;

	int bytes;



	xlog_crack_grant_head(&log->l_write_head.grant, &cycle, &bytes);

	return snprintf(buf, PAGE_SIZE, "%d:%d\n", cycle, bytes);

}

XFS_SYSFS_ATTR_RO(write_grant_head);



static struct attribute *xfs_log_attrs[] = {

	ATTR_LIST(log_head_lsn),

	ATTR_LIST(log_tail_lsn),

	ATTR_LIST(reserve_grant_head),

	ATTR_LIST(write_grant_head),

	NULL,

};