panic ffs_truncate3 (maybe fuse being evil)

[Konstantin Belousov]

On Wed, Feb 03, 2016 at 05:38:50PM +0200, Konstantin Belousov wrote:
> On Tue, Feb 02, 2016 at 06:19:28PM -0500, Rick Macklem wrote:
> > Kostik wrote:
> > > I do think that the IO_UNIT patch fixes some situations where the buffer
> > > can be left on the vnode queue.  I did not found any other places so far.
> 
> Could you, please, try the following explicit buffer relse patch in
> addition to the IO_UNIT patch ? This is as similar to r174973 for IO_EXT
> ffs2_balloc() as I can do.

Please use this version, for several places in the old patch, rollback is
not needed.

diff --git a/sys/ufs/ffs/ffs_balloc.c b/sys/ufs/ffs/ffs_balloc.c
index 8551085..9f15df5 100644
--- a/sys/ufs/ffs/ffs_balloc.c
+++ b/sys/ufs/ffs/ffs_balloc.c
@@ -654,8 +654,16 @@ ffs_balloc_ufs2(struct vnode *vp, off_t startoffset, int size,
 				    ffs_blkpref_ufs2(ip, lbn, (int)lbn,
 				    &dp->di_extb[0]), osize, nsize, flags,
 				    cred, &bp);
-				if (error)
+				if (error != 0) {
+					/* getblk does truncation, if needed */
+					bp = getblk(vp, -1 - lbn, osize, 0, 0,
+					    GB_NOCREAT);
+					if (bp != NULL) {
+						bp->b_xflags |= BX_ALTDATA;
+						brelse(bp);
+					}
 					return (error);
+				}
 				bp->b_xflags |= BX_ALTDATA;
 				if (DOINGSOFTDEP(vp))
 					softdep_setup_allocext(ip, lbn,
@@ -671,8 +679,17 @@ ffs_balloc_ufs2(struct vnode *vp, off_t startoffset, int size,
 			error = ffs_alloc(ip, lbn,
 			   ffs_blkpref_ufs2(ip, lbn, (int)lbn, &dp->di_extb[0]),
 			   nsize, flags, cred, &newb);
-			if (error)
+			if (error != 0) {
+				bp = getblk(vp, -1 - lbn, nsize, 0, 0,
+				    GB_NOCREAT);
+				if (bp != NULL) {
+					bp->b_xflags |= BX_ALTDATA;
+					bp->b_flags |= B_RELBUF | B_INVAL;
+					bp->b_flags &= ~B_ASYNC;
+					brelse(bp);
+				}
 				return (error);
+			}
 			bp = getblk(vp, -1 - lbn, nsize, 0, 0, gbflags);
 			bp->b_blkno = fsbtodb(fs, newb);
 			bp->b_xflags |= BX_ALTDATA;
diff --git a/sys/ufs/ffs/ffs_vnops.c b/sys/ufs/ffs/ffs_vnops.c
index 5a70e5c..ecc3f9b 100644
--- a/sys/ufs/ffs/ffs_vnops.c
+++ b/sys/ufs/ffs/ffs_vnops.c
@@ -1311,7 +1313,8 @@ ffs_close_ea(struct vnode *vp, int commit, struct ucred *cred, struct thread *td
 		/* XXX: I'm not happy about truncating to zero size */
 		if (ip->i_ea_len < dp->di_extsize)
 			error = ffs_truncate(vp, 0, IO_EXT, cred);
-		error = ffs_extwrite(vp, &luio, IO_EXT | IO_SYNC, cred);
+		error = ffs_extwrite(vp, &luio, IO_EXT | IO_SYNC | IO_UNIT,
+		    cred);
 	}
 	if (--ip->i_ea_refs == 0) {
 		free(ip->i_ea_area, M_TEMP);