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Add functions syncer_suspend() and syncer_resume(), which are supposed

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to be called before suspension and after resume, correspondingly.  The
syncer_suspend() ensures that all filesystems dirty data and metadata
are saved to the permanent storage, and stops kernel threads which
might modify filesystems.  The syncer_resume() restores stopped
threads.

For now, only syncer is stopped.  This is needed, because each sync
loop causes superblock updates for UFS.

Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
This commit is contained in:
Konstantin Belousov 2014-12-08 16:48:57 +00:00
parent 904ed548bb
commit a25100c539
2 changed files with 24 additions and 1 deletions
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22
sys/kern/vfs_subr.c
View File

@ -1773,6 +1773,8 @@ sync_vnode(struct synclist *slp, struct bufobj **bo, struct thread *td)
return (0);
}
static int first_printf = 1;
/*
* System filesystem synchronizer daemon.
*/
@ -1791,7 +1793,6 @@ sched_sync(void)
last_work_seen = 0;
syncer_final_iter = 0;
first_printf = 1;
syncer_state = SYNCER_RUNNING;
starttime = time_uptime;
td->td_pflags |= TDP_NORUNNINGBUF;
@ -1955,6 +1956,25 @@ syncer_shutdown(void *arg, int howto)
kproc_shutdown(arg, howto);
}
void
syncer_suspend(void)
{
syncer_shutdown(updateproc, 0);
}
void
syncer_resume(void)
{
mtx_lock(&sync_mtx);
first_printf = 1;
syncer_state = SYNCER_RUNNING;
mtx_unlock(&sync_mtx);
cv_broadcast(&sync_wakeup);
kproc_resume(updateproc);
}
/*
* Reassign a buffer from one vnode to another.
* Used to assign file specific control information

3
sys/sys/mount.h
View File

@ -917,6 +917,9 @@ vfs_uninit_t vfs_stduninit;
vfs_extattrctl_t vfs_stdextattrctl;
vfs_sysctl_t vfs_stdsysctl;
void syncer_suspend(void);
void syncer_resume(void);
#else /* !_KERNEL */
#include <sys/cdefs.h>