Author: jeff
Date: Mon Jul 4 20:53:55 2011
New Revision: 223770
URL: http://svn.freebsd.org/changeset/base/223770
Log:
- It is impossible to run request_cleanup() while doing a copyonwrite.
This will most likely cause new block allocations which can recurse
into request cleanup.
- While here optimize the ufs locking slightly. We need only acquire and
drop once.
- process_removes() and process_truncates() also is only needed once.
- Attempt to flush each item on the worklist once but do not loop forever
if some can not be completed.
Discussed with: mckusick
Modified:
head/sys/ufs/ffs/ffs_softdep.c
Modified: head/sys/ufs/ffs/ffs_softdep.c
==============================================================================
--- head/sys/ufs/ffs/ffs_softdep.c Mon Jul 4 20:52:23 2011
(r223769)
+++ head/sys/ufs/ffs/ffs_softdep.c Mon Jul 4 20:53:55 2011
(r223770)
@@ -12510,33 +12510,36 @@ softdep_request_cleanup(fs, vp, cred, re
int error;
mp = vp->v_mount;
- ump = VTOI(vp)->i_ump;
+ ump = VFSTOUFS(mp);
mtx_assert(UFS_MTX(ump), MA_OWNED);
if (resource == FLUSH_BLOCKS_WAIT)
stat_cleanup_blkrequests += 1;
else
stat_cleanup_inorequests += 1;
+
/*
* If we are being called because of a process doing a
- * copy-on-write, then it is not safe to update the vnode
- * as we may recurse into the copy-on-write routine.
+ * copy-on-write, then it is not safe to process any
+ * worklist items as we will recurse into the copyonwrite
+ * routine. This will result in an incoherent snapshot.
*/
- if (!(curthread->td_pflags & TDP_COWINPROGRESS)) {
- UFS_UNLOCK(ump);
- error = ffs_update(vp, 1);
+ if (curthread->td_pflags & TDP_COWINPROGRESS)
+ return (0);
+ UFS_UNLOCK(ump);
+ error = ffs_update(vp, 1);
+ if (error != 0) {
UFS_LOCK(ump);
- if (error != 0)
- return (0);
+ return (0);
}
/*
* If we are in need of resources, consider pausing for
* tickdelay to give ourselves some breathing room.
*/
- UFS_UNLOCK(ump);
ACQUIRE_LOCK(&lk);
+ process_removes(vp);
+ process_truncates(vp);
request_cleanup(UFSTOVFS(ump), resource);
FREE_LOCK(&lk);
- UFS_LOCK(ump);
/*
* Now clean up at least as many resources as we will need.
*
@@ -12568,29 +12571,23 @@ softdep_request_cleanup(fs, vp, cred, re
roundup((fs->fs_dsize * fs->fs_minfree / 100) -
fs->fs_cstotal.cs_nffree, fs->fs_frag));
} else {
+ UFS_LOCK(ump);
printf("softdep_request_cleanup: Unknown resource type %d\n",
resource);
return (0);
}
starttime = time_second;
retry:
- while ((resource == FLUSH_BLOCKS_WAIT && ump->softdep_on_worklist > 0 &&
- fs->fs_cstotal.cs_nbfree <= needed) ||
- (resource == FLUSH_INODES_WAIT && fs->fs_pendinginodes > 0 &&
- fs->fs_cstotal.cs_nifree <= needed)) {
- UFS_UNLOCK(ump);
+ if ((resource == FLUSH_BLOCKS_WAIT && ump->softdep_on_worklist > 0 &&
+ fs->fs_cstotal.cs_nbfree <= needed) ||
+ (resource == FLUSH_INODES_WAIT && fs->fs_pendinginodes > 0 &&
+ fs->fs_cstotal.cs_nifree <= needed)) {
ACQUIRE_LOCK(&lk);
- process_removes(vp);
- process_truncates(vp);
if (ump->softdep_on_worklist > 0 &&
- process_worklist_item(UFSTOVFS(ump), 1, LK_NOWAIT) != 0) {
+ process_worklist_item(UFSTOVFS(ump),
+ ump->softdep_on_worklist, LK_NOWAIT) != 0)
stat_worklist_push += 1;
- FREE_LOCK(&lk);
- UFS_LOCK(ump);
- continue;
- }
FREE_LOCK(&lk);
- UFS_LOCK(ump);
}
/*
* If we still need resources and there are no more worklist
@@ -12604,7 +12601,6 @@ retry:
fs->fs_cstotal.cs_nbfree <= needed) ||
(resource == FLUSH_INODES_WAIT && fs->fs_pendinginodes > 0 &&
fs->fs_cstotal.cs_nifree <= needed)) {
- UFS_UNLOCK(ump);
MNT_ILOCK(mp);
MNT_VNODE_FOREACH(lvp, mp, mvp) {
VI_LOCK(lvp);
@@ -12633,7 +12629,6 @@ retry:
VOP_FSYNC(lvp, MNT_NOWAIT, curthread);
VOP_UNLOCK(lvp, 0);
}
- UFS_LOCK(ump);
if (ump->softdep_on_worklist > 0) {
stat_cleanup_retries += 1;
goto retry;
@@ -12642,6 +12637,7 @@ retry:
}
if (time_second - starttime > stat_cleanup_high_delay)
stat_cleanup_high_delay = time_second - starttime;
+ UFS_LOCK(ump);
return (1);
}
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