svn commit: r305592 - head/sys/ufs/ffs
Konstantin Belousov
kib at FreeBSD.org
Thu Sep 8 12:01:30 UTC 2016
Author: kib
Date: Thu Sep 8 12:01:28 2016
New Revision: 305592
URL: https://svnweb.freebsd.org/changeset/base/305592
Log:
Partially lift suspension when ffs_reload() finished with cgs and
going to re-read inodes.
Secondary write initiators, e.g. ufs_inactive(), might need to start a
write while owning the vnode lock. Since the suspended state
established by /dev/ufssuspend prevents them from entering
vn_start_secondary_write(), we get deadlock otherwise.
Note that it is arguably not very useful to re-read inodes after
/dev/ufssuspend suspension, because the suspension does not block
readers, and other threads might read existing files in parallel with
suspension owner (for now, only growfs(8)) operations. This
effectively means that suspension owner cannot safely modify existing
inodes, and then there is no sense in re-reading. But keep the code
enabled for now.
Reported and tested by: pho
Reviewed by: mckusick
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Modified:
head/sys/ufs/ffs/ffs_extern.h
head/sys/ufs/ffs/ffs_suspend.c
head/sys/ufs/ffs/ffs_vfsops.c
Modified: head/sys/ufs/ffs/ffs_extern.h
==============================================================================
--- head/sys/ufs/ffs/ffs_extern.h Thu Sep 8 12:00:02 2016 (r305591)
+++ head/sys/ufs/ffs/ffs_extern.h Thu Sep 8 12:01:28 2016 (r305592)
@@ -106,6 +106,9 @@ void ffs_susp_uninitialize(void);
#define FFSV_FORCEINSMQ 0x0001
+#define FFSR_FORCE 0x0001
+#define FFSR_UNSUSPEND 0x0002
+
extern struct vop_vector ffs_vnodeops1;
extern struct vop_vector ffs_fifoops1;
extern struct vop_vector ffs_vnodeops2;
Modified: head/sys/ufs/ffs/ffs_suspend.c
==============================================================================
--- head/sys/ufs/ffs/ffs_suspend.c Thu Sep 8 12:00:02 2016 (r305591)
+++ head/sys/ufs/ffs/ffs_suspend.c Thu Sep 8 12:01:28 2016 (r305592)
@@ -235,7 +235,7 @@ ffs_susp_dtor(void *data)
KASSERT((mp->mnt_kern_flag & MNTK_SUSPEND) != 0,
("MNTK_SUSPEND not set"));
- error = ffs_reload(mp, curthread, 1);
+ error = ffs_reload(mp, curthread, FFSR_FORCE | FFSR_UNSUSPEND);
if (error != 0)
panic("failed to unsuspend writes on %s", fs->fs_fsmnt);
Modified: head/sys/ufs/ffs/ffs_vfsops.c
==============================================================================
--- head/sys/ufs/ffs/ffs_vfsops.c Thu Sep 8 12:00:02 2016 (r305591)
+++ head/sys/ufs/ffs/ffs_vfsops.c Thu Sep 8 12:01:28 2016 (r305592)
@@ -573,11 +573,13 @@ ffs_cmount(struct mntarg *ma, void *data
* 2) re-read superblock from disk.
* 3) re-read summary information from disk.
* 4) invalidate all inactive vnodes.
- * 5) invalidate all cached file data.
- * 6) re-read inode data for all active vnodes.
+ * 5) clear MNTK_SUSPEND2 and MNTK_SUSPENDED flags, allowing secondary
+ * writers, if requested.
+ * 6) invalidate all cached file data.
+ * 7) re-read inode data for all active vnodes.
*/
int
-ffs_reload(struct mount *mp, struct thread *td, int force)
+ffs_reload(struct mount *mp, struct thread *td, int flags)
{
struct vnode *vp, *mvp, *devvp;
struct inode *ip;
@@ -592,7 +594,7 @@ ffs_reload(struct mount *mp, struct thre
ump = VFSTOUFS(mp);
MNT_ILOCK(mp);
- if ((mp->mnt_flag & MNT_RDONLY) == 0 && force == 0) {
+ if ((mp->mnt_flag & MNT_RDONLY) == 0 && (flags & FFSR_FORCE) == 0) {
MNT_IUNLOCK(mp);
return (EINVAL);
}
@@ -682,6 +684,12 @@ ffs_reload(struct mount *mp, struct thre
size = fs->fs_ncg * sizeof(u_int8_t);
fs->fs_contigdirs = (u_int8_t *)space;
bzero(fs->fs_contigdirs, size);
+ if ((flags & FFSR_UNSUSPEND) != 0) {
+ MNT_ILOCK(mp);
+ mp->mnt_kern_flag &= ~(MNTK_SUSPENDED | MNTK_SUSPEND2);
+ wakeup(&mp->mnt_flag);
+ MNT_IUNLOCK(mp);
+ }
loop:
MNT_VNODE_FOREACH_ALL(vp, mp, mvp) {
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