Author: kib
Date: Tue Jan 16 10:58:31 2018
New Revision: 328047
URL: https://svnweb.freebsd.org/changeset/base/328047

Log:
  MFC r327723, r327821:
  Generalize the fix from r322757 and apply it to several more places.

Modified:
  stable/11/sys/ufs/ffs/ffs_softdep.c
Directory Properties:
  stable/11/   (props changed)

Modified: stable/11/sys/ufs/ffs/ffs_softdep.c
==============================================================================
--- stable/11/sys/ufs/ffs/ffs_softdep.c Tue Jan 16 10:56:35 2018        
(r328046)
+++ stable/11/sys/ufs/ffs/ffs_softdep.c Tue Jan 16 10:58:31 2018        
(r328047)
@@ -904,6 +904,7 @@ static      int request_cleanup(struct mount *, int);
 static int softdep_request_cleanup_flush(struct mount *, struct ufsmount *);
 static void schedule_cleanup(struct mount *);
 static void softdep_ast_cleanup_proc(struct thread *);
+static struct ufsmount *softdep_bp_to_mp(struct buf *bp);
 static int process_worklist_item(struct mount *, int, int);
 static void process_removes(struct vnode *);
 static void process_truncates(struct vnode *);
@@ -7245,9 +7246,9 @@ deallocate_dependencies(bp, freeblks, off)
        struct worklist *wk, *wkn;
        struct ufsmount *ump;
 
-       if ((wk = LIST_FIRST(&bp->b_dep)) == NULL)
+       ump = softdep_bp_to_mp(bp);
+       if (ump == NULL)
                goto done;
-       ump = VFSTOUFS(wk->wk_mp);
        ACQUIRE_LOCK(ump);
        LIST_FOREACH_SAFE(wk, &bp->b_dep, wk_list, wkn) {
                switch (wk->wk_type) {
@@ -9972,9 +9973,9 @@ softdep_disk_io_initiation(bp)
                panic("softdep_disk_io_initiation: Writing buffer with "
                    "background write in progress: %p", bp);
 
-       if ((wk = LIST_FIRST(&bp->b_dep)) == NULL)
+       ump = softdep_bp_to_mp(bp);
+       if (ump == NULL)
                return;
-       ump = VFSTOUFS(wk->wk_mp);
 
        marker.wk_type = D_LAST + 1;    /* Not a normal workitem */
        PHOLD(curproc);                 /* Don't swap out kernel stack */
@@ -10974,9 +10975,9 @@ softdep_disk_write_complete(bp)
        struct freeblks *freeblks;
        struct buf *sbp;
 
-       if ((wk = LIST_FIRST(&bp->b_dep)) == NULL)
+       ump = softdep_bp_to_mp(bp);
+       if (ump == NULL)
                return;
-       ump = VFSTOUFS(wk->wk_mp);
 
        /*
         * If an error occurred while doing the write, then the data
@@ -11016,8 +11017,9 @@ softdep_disk_write_complete(bp)
                return;
        }
        LIST_INIT(&reattach);
+
        /*
-        * This lock must not be released anywhere in this code segment.
+        * Ump SU lock must not be released anywhere in this code segment.
         */
        sbp = NULL;
        owk = NULL;
@@ -13885,6 +13887,40 @@ softdep_freework(wkhd)
        FREE_LOCK(ump);
 }
 
+static struct ufsmount *
+softdep_bp_to_mp(bp)
+       struct buf *bp;
+{
+       struct mount *mp;
+       struct vnode *vp;
+
+       if (LIST_EMPTY(&bp->b_dep))
+               return (NULL);
+       vp = bp->b_vp;
+
+       /*
+        * The ump mount point is stable after we get a correct
+        * pointer, since bp is locked and this prevents unmount from
+        * proceeding.  But to get to it, we cannot dereference bp->b_dep
+        * head wk_mp, because we do not yet own SU ump lock and
+        * workitem might be freed while dereferenced.
+        */
+retry:
+       if (vp->v_type == VCHR) {
+               VI_LOCK(vp);
+               mp = vp->v_type == VCHR ? vp->v_rdev->si_mountpt : NULL;
+               VI_UNLOCK(vp);
+               if (mp == NULL)
+                       goto retry;
+       } else if (vp->v_type == VREG || vp->v_type == VDIR ||
+           vp->v_type == VLNK) {
+               mp = vp->v_mount;
+       } else {
+               return (NULL);
+       }
+       return (VFSTOUFS(mp));
+}
+
 /*
  * Function to determine if the buffer has outstanding dependencies
  * that will cause a roll-back if the buffer is written. If wantcount
@@ -13908,36 +13944,12 @@ softdep_count_dependencies(bp, wantcount)
        struct newblk *newblk;
        struct mkdir *mkdir;
        struct diradd *dap;
-       struct vnode *vp;
-       struct mount *mp;
        int i, retval;
 
-       retval = 0;
-       if (LIST_EMPTY(&bp->b_dep))
+       ump = softdep_bp_to_mp(bp);
+       if (ump == NULL)
                return (0);
-       vp = bp->b_vp;
-
-       /*
-        * The ump mount point is stable after we get a correct
-        * pointer, since bp is locked and this prevents unmount from
-        * proceed.  But to get to it, we cannot dereference bp->b_dep
-        * head wk_mp, because we do not yet own SU ump lock and
-        * workitem might be freed while dereferenced.
-        */
-retry:
-       if (vp->v_type == VCHR) {
-               VI_LOCK(vp);
-               mp = vp->v_type == VCHR ? vp->v_rdev->si_mountpt : NULL;
-               VI_UNLOCK(vp);
-               if (mp == NULL)
-                       goto retry;
-       } else if (vp->v_type == VREG) {
-               mp = vp->v_mount;
-       } else {
-               return (0);
-       }
-       ump = VFSTOUFS(mp);
-
+       retval = 0;
        ACQUIRE_LOCK(ump);
        LIST_FOREACH(wk, &bp->b_dep, wk_list) {
                switch (wk->wk_type) {
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