Date: Fri, 27 Mar 2015 13:55:56 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r280760 - head/sys/ufs/ffs Message-ID: <201503271355.t2RDtuLt071068@svn.freebsd.org>
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Author: kib Date: Fri Mar 27 13:55:56 2015 New Revision: 280760 URL: https://svnweb.freebsd.org/changeset/base/280760 Log: Fix the hand after the immediate reboot when the following command sequence is performed on UFS SU+J rootfs: cp -Rp /sbin/init /sbin/init.old mv -f /sbin/init.old /sbin/init Hang occurs on the rootfs unmount. There are two issues: 1. Removed init binary, which is still mapped, creates a reference to the removed vnode. The inodeblock for such vnode must have active inodedep, which is (eventually) linked through the unlinked list. This means that ffs_sync(MNT_SUSPEND) cannot succeed, because number of softdep workitems for the mp is always > 0. FFS is suspended during unmount, so unmount just hangs. 2. As noted above, the inodedep is linked eventually. It is not linked until the superblock is written. But at the vfs_unmountall() time, when the rootfs is unmounted, the call is made to ffs_unmount()->ffs_sync() before vflush(), and ffs_sync() only calls ffs_sbupdate() after all workitems are flushed. It is masked for normal system operations, because syncer works in parallel and eventually flushes superblock. Syncer is stopped when rootfs unmounted, so ffs_sync() must do sb update on its own. Correct the issues listed above. For MNT_SUSPEND, count the number of linked unlinked inodedeps (this is not a typo) and substract the count of such workitems from the total. For the second issue, the ffs_sbupdate() is called right after device sync in ffs_sync() loop. There is third problem, occuring with both SU and SU+J. The softdep_waitidle() loop, which waits for softdep_flush() thread to clear the worklist, only waits 20ms max. It seems that the 1 tick, specified for msleep(9), was a typo. Add fsync(devvp, MNT_WAIT) call to softdep_waitidle(), which seems to significantly help the softdep thread, and change the MNT_LAZY update at the reboot time to MNT_WAIT for similar reasons. Note that userspace cannot create more work while devvp is flushed, since the mount point is always suspended before the call to softdep_waitidle() in unmount or remount path. PR: 195458 In collaboration with: gjb, pho Reviewed by: mckusick Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Modified: head/sys/ufs/ffs/ffs_softdep.c head/sys/ufs/ffs/ffs_vfsops.c Modified: head/sys/ufs/ffs/ffs_softdep.c ============================================================================== --- head/sys/ufs/ffs/ffs_softdep.c Fri Mar 27 13:26:59 2015 (r280759) +++ head/sys/ufs/ffs/ffs_softdep.c Fri Mar 27 13:55:56 2015 (r280760) @@ -1885,8 +1885,8 @@ softdep_flushworklist(oldmnt, countp, td struct thread *td; { struct vnode *devvp; - int count, error = 0; struct ufsmount *ump; + int count, error; /* * Alternately flush the block device associated with the mount @@ -1895,6 +1895,7 @@ softdep_flushworklist(oldmnt, countp, td * are found. */ *countp = 0; + error = 0; ump = VFSTOUFS(oldmnt); devvp = ump->um_devvp; while ((count = softdep_process_worklist(oldmnt, 1)) > 0) { @@ -1902,37 +1903,47 @@ softdep_flushworklist(oldmnt, countp, td vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY); error = VOP_FSYNC(devvp, MNT_WAIT, td); VOP_UNLOCK(devvp, 0); - if (error) + if (error != 0) break; } return (error); } +#define SU_WAITIDLE_RETRIES 20 static int softdep_waitidle(struct mount *mp, int flags __unused) { struct ufsmount *ump; - int error; - int i; + struct vnode *devvp; + struct thread *td; + int error, i; ump = VFSTOUFS(mp); + devvp = ump->um_devvp; + td = curthread; + error = 0; ACQUIRE_LOCK(ump); - for (i = 0; i < 10 && ump->softdep_deps; i++) { + for (i = 0; i < SU_WAITIDLE_RETRIES && ump->softdep_deps != 0; i++) { ump->softdep_req = 1; KASSERT((flags & FORCECLOSE) == 0 || ump->softdep_on_worklist == 0, ("softdep_waitidle: work added after flush")); - msleep(&ump->softdep_deps, LOCK_PTR(ump), PVM, "softdeps", 1); + msleep(&ump->softdep_deps, LOCK_PTR(ump), PVM | PDROP, + "softdeps", 10 * hz); + vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY); + error = VOP_FSYNC(devvp, MNT_WAIT, td); + VOP_UNLOCK(devvp, 0); + if (error != 0) + break; + ACQUIRE_LOCK(ump); } ump->softdep_req = 0; - FREE_LOCK(ump); - error = 0; - if (i == 10) { + if (i == SU_WAITIDLE_RETRIES && error == 0 && ump->softdep_deps != 0) { error = EBUSY; printf("softdep_waitidle: Failed to flush worklist for %p\n", mp); } - + FREE_LOCK(ump); return (error); } @@ -7637,17 +7648,13 @@ check_inode_unwritten(inodedep) return (1); } -/* - * Try to free an inodedep structure. Return 1 if it could be freed. - */ static int -free_inodedep(inodedep) +check_inodedep_free(inodedep) struct inodedep *inodedep; { LOCK_OWNED(VFSTOUFS(inodedep->id_list.wk_mp)); - if ((inodedep->id_state & (ONWORKLIST | UNLINKED)) != 0 || - (inodedep->id_state & ALLCOMPLETE) != ALLCOMPLETE || + if ((inodedep->id_state & ALLCOMPLETE) != ALLCOMPLETE || !LIST_EMPTY(&inodedep->id_dirremhd) || !LIST_EMPTY(&inodedep->id_pendinghd) || !LIST_EMPTY(&inodedep->id_bufwait) || @@ -7662,6 +7669,21 @@ free_inodedep(inodedep) inodedep->id_nlinkdelta != 0 || inodedep->id_savedino1 != NULL) return (0); + return (1); +} + +/* + * Try to free an inodedep structure. Return 1 if it could be freed. + */ +static int +free_inodedep(inodedep) + struct inodedep *inodedep; +{ + + LOCK_OWNED(VFSTOUFS(inodedep->id_list.wk_mp)); + if ((inodedep->id_state & (ONWORKLIST | UNLINKED)) != 0 || + !check_inodedep_free(inodedep)) + return (0); if (inodedep->id_state & ONDEPLIST) LIST_REMOVE(inodedep, id_deps); LIST_REMOVE(inodedep, id_hash); @@ -13846,7 +13868,8 @@ softdep_check_suspend(struct mount *mp, { struct bufobj *bo; struct ufsmount *ump; - int error; + struct inodedep *inodedep; + int error, unlinked; bo = &devvp->v_bufobj; ASSERT_BO_WLOCKED(bo); @@ -13907,6 +13930,20 @@ softdep_check_suspend(struct mount *mp, break; } + unlinked = 0; + if (MOUNTEDSUJ(mp)) { + for (inodedep = TAILQ_FIRST(&ump->softdep_unlinked); + inodedep != NULL; + inodedep = TAILQ_NEXT(inodedep, id_unlinked)) { + if ((inodedep->id_state & (UNLINKED | UNLINKLINKS | + UNLINKONLIST)) != (UNLINKED | UNLINKLINKS | + UNLINKONLIST) || + !check_inodedep_free(inodedep)) + continue; + unlinked++; + } + } + /* * Reasons for needing more work before suspend: * - Dirty buffers on devvp. @@ -13916,8 +13953,8 @@ softdep_check_suspend(struct mount *mp, error = 0; if (bo->bo_numoutput > 0 || bo->bo_dirty.bv_cnt > 0 || - softdep_depcnt != 0 || - ump->softdep_deps != 0 || + softdep_depcnt != unlinked || + ump->softdep_deps != unlinked || softdep_accdepcnt != ump->softdep_accdeps || secondary_writes != 0 || mp->mnt_secondary_writes != 0 || Modified: head/sys/ufs/ffs/ffs_vfsops.c ============================================================================== --- head/sys/ufs/ffs/ffs_vfsops.c Fri Mar 27 13:26:59 2015 (r280759) +++ head/sys/ufs/ffs/ffs_vfsops.c Fri Mar 27 13:55:56 2015 (r280760) @@ -1502,8 +1502,11 @@ ffs_sync(mp, waitfor) if (fs->fs_fmod != 0 && fs->fs_ronly != 0 && ump->um_fsckpid == 0) panic("%s: ffs_sync: modification on read-only filesystem", fs->fs_fsmnt); - if (waitfor == MNT_LAZY) - return (ffs_sync_lazy(mp)); + if (waitfor == MNT_LAZY) { + if (!rebooting) + return (ffs_sync_lazy(mp)); + waitfor = MNT_NOWAIT; + } /* * Write back each (modified) inode. @@ -1560,7 +1563,7 @@ loop: /* * Force stale filesystem control information to be flushed. */ - if (waitfor == MNT_WAIT) { + if (waitfor == MNT_WAIT || rebooting) { if ((error = softdep_flushworklist(ump->um_mountp, &count, td))) allerror = error; /* Flushed work items may create new vnodes to clean */ @@ -1577,9 +1580,12 @@ loop: if (bo->bo_numoutput > 0 || bo->bo_dirty.bv_cnt > 0) { BO_UNLOCK(bo); vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY); - if ((error = VOP_FSYNC(devvp, waitfor, td)) != 0) - allerror = error; + error = VOP_FSYNC(devvp, waitfor, td); VOP_UNLOCK(devvp, 0); + if (MOUNTEDSOFTDEP(mp) && (error == 0 || error == EAGAIN)) + error = ffs_sbupdate(ump, waitfor, 0); + if (error != 0) + allerror = error; if (allerror == 0 && waitfor == MNT_WAIT) goto loop; } else if (suspend != 0) {
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