On Thu, Jan 31, 2019 at 04:26:45PM -0500, Ted Unangst wrote:
> Instead, we note that the write failed and mark a flag in the vnode. Future
> calls to fsync will then return EIO when this flag is set. We clear the flag
> when the vnode is released.
Sounds reasonable.
OK bluhm@
> Index: kern/vfs_bio.c
> ===================================================================
> RCS file: /home/cvs/src/sys/kern/vfs_bio.c,v
> retrieving revision 1.187
> diff -u -p -r1.187 vfs_bio.c
> --- kern/vfs_bio.c 21 Nov 2018 16:14:43 -0000 1.187
> +++ kern/vfs_bio.c 31 Jan 2019 21:19:36 -0000
> @@ -867,6 +867,11 @@ brelse(struct buf *bp)
> /* If it's not cacheable, or an error, mark it invalid. */
> if (ISSET(bp->b_flags, (B_NOCACHE|B_ERROR)))
> SET(bp->b_flags, B_INVAL);
> + /* If it's a write error, also mark the vnode as damaged. */
> + if (ISSET(bp->b_flags, B_ERROR) && !ISSET(bp->b_flags, B_READ)) {
> + if (bp->b_vp && bp->b_vp->v_type == VREG)
> + SET(bp->b_vp->v_bioflag, VBIOERROR);
> + }
>
> if (ISSET(bp->b_flags, B_INVAL)) {
> /*
> Index: kern/vfs_subr.c
> ===================================================================
> RCS file: /home/cvs/src/sys/kern/vfs_subr.c,v
> retrieving revision 1.285
> diff -u -p -r1.285 vfs_subr.c
> --- kern/vfs_subr.c 21 Jan 2019 18:09:21 -0000 1.285
> +++ kern/vfs_subr.c 31 Jan 2019 21:09:22 -0000
> @@ -712,6 +712,7 @@ vputonfreelist(struct vnode *vp)
> #endif
>
> vp->v_bioflag |= VBIOONFREELIST;
> + vp->v_bioflag &= ~VBIOERROR;
>
> if (vp->v_holdcnt > 0)
> lst = &vnode_hold_list;
> Index: kern/vfs_vops.c
> ===================================================================
> RCS file: /home/cvs/src/sys/kern/vfs_vops.c,v
> retrieving revision 1.19
> diff -u -p -r1.19 vfs_vops.c
> --- kern/vfs_vops.c 21 Jun 2018 14:17:23 -0000 1.19
> +++ kern/vfs_vops.c 31 Jan 2019 21:04:43 -0000
> @@ -336,7 +336,7 @@ int
> VOP_FSYNC(struct vnode *vp, struct ucred *cred, int waitfor,
> struct proc *p)
> {
> - int r;
> + int r, s;
> struct vop_fsync_args a;
> a.a_vp = vp;
> a.a_cred = cred;
> @@ -351,6 +351,10 @@ VOP_FSYNC(struct vnode *vp, struct ucred
> vp->v_inflight++;
> r = (vp->v_op->vop_fsync)(&a);
> vp->v_inflight--;
> + s = splbio();
> + if (r == 0 && vp->v_bioflag & VBIOERROR)
> + r = EIO;
> + splx(s);
> return r;
> }
>
> Index: sys/vnode.h
> ===================================================================
> RCS file: /home/cvs/src/sys/sys/vnode.h,v
> retrieving revision 1.149
> diff -u -p -r1.149 vnode.h
> --- sys/vnode.h 23 Dec 2018 10:46:51 -0000 1.149
> +++ sys/vnode.h 31 Jan 2019 20:52:37 -0000
> @@ -149,6 +149,7 @@ struct vnode {
> #define VBIOWAIT 0x0001 /* waiting for output to complete */
> #define VBIOONSYNCLIST 0x0002 /* Vnode is on syncer worklist */
> #define VBIOONFREELIST 0x0004 /* Vnode is on a free list */
> +#define VBIOERROR 0x0008 /* A write failed */
>
> /*
> * Vnode attributes. A field value of VNOVAL represents a field whose value
