Within ufs, the ffs_sync and ffs_fsync functions did not always
check for and/or report I/O errors. The result is that a VFS_SYNC or VOP_FSYNC called with MNT_WAIT could loop infinitely on ufs in the presence of a hard error writing a disk sector or in a filesystem full condition. This patch ensures that I/O errors will always be checked and returned. This patch also ensures that every call to VFS_SYNC or VOP_FSYNC with MNT_WAIT set checks for and takes appropriate action when an error is returned. Sponsored by: DARPA & NAI Labs.
This commit is contained in:
parent
4c40dcd4d7
commit
9ab73fd11a
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=105902
@ -421,8 +421,8 @@ spec_fsync(ap)
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struct vnode *vp = ap->a_vp;
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struct buf *bp;
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struct buf *nbp;
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int s;
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int maxretry = 10000; /* large, arbitrarily chosen */
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int s, error = 0;
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int maxretry = 100; /* large, arbitrarily chosen */
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if (!vn_isdisk(vp, NULL))
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return (0);
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@ -435,6 +435,7 @@ spec_fsync(ap)
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s = splbio();
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TAILQ_FOREACH(bp, &vp->v_dirtyblkhd, b_vnbufs) {
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bp->b_flags &= ~B_SCANNED;
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bp->b_error = 0;
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}
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splx(s);
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@ -481,16 +482,25 @@ spec_fsync(ap)
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PRIBIO + 1, "spfsyn", 0);
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}
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if (!TAILQ_EMPTY(&vp->v_dirtyblkhd)) {
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if (--maxretry != 0) {
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/*
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* If we are unable to write any of these buffers
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* then we fail now rather than trying endlessly
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* to write them out.
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*/
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TAILQ_FOREACH(bp, &vp->v_dirtyblkhd, b_vnbufs)
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if ((error = bp->b_error) == 0)
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continue;
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if (error == 0 && --maxretry >= 0) {
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splx(s);
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goto loop1;
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}
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vprint("spec_fsync: giving up on dirty", vp);
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error = EAGAIN;
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}
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}
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VI_UNLOCK(vp);
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splx(s);
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return (0);
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return (error);
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}
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/*
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@ -3425,7 +3425,7 @@ sync_fsync(ap)
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struct vnode *syncvp = ap->a_vp;
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struct mount *mp = syncvp->v_mount;
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struct thread *td = ap->a_td;
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int asyncflag;
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int error, asyncflag;
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/*
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* We only need to do something if this is a lazy evaluation.
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@ -3456,12 +3456,12 @@ sync_fsync(ap)
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asyncflag = mp->mnt_flag & MNT_ASYNC;
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mp->mnt_flag &= ~MNT_ASYNC;
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vfs_msync(mp, MNT_NOWAIT);
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VFS_SYNC(mp, MNT_LAZY, ap->a_cred, td);
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error = VFS_SYNC(mp, MNT_LAZY, ap->a_cred, td);
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if (asyncflag)
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mp->mnt_flag |= MNT_ASYNC;
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vn_finished_write(mp);
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vfs_unbusy(mp, td);
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return (0);
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return (error);
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}
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/*
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@ -1005,19 +1005,24 @@ vn_finished_write(mp)
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/*
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* Request a filesystem to suspend write operations.
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*/
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void
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int
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vfs_write_suspend(mp)
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struct mount *mp;
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{
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struct thread *td = curthread;
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int error;
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if (mp->mnt_kern_flag & MNTK_SUSPEND)
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return;
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return (0);
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mp->mnt_kern_flag |= MNTK_SUSPEND;
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if (mp->mnt_writeopcount > 0)
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(void) tsleep(&mp->mnt_writeopcount, PUSER - 1, "suspwt", 0);
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VFS_SYNC(mp, MNT_WAIT, td->td_ucred, td);
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if ((error = VFS_SYNC(mp, MNT_WAIT, td->td_ucred, td)) != 0) {
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vfs_write_resume(mp);
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return (error);
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}
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mp->mnt_kern_flag |= MNTK_SUSPENDED;
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return (0);
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}
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/*
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@ -681,7 +681,7 @@ int vfs_object_create(struct vnode *vp, struct thread *td,
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struct ucred *cred);
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void vfs_timestamp(struct timespec *);
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void vfs_write_resume(struct mount *mp);
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void vfs_write_suspend(struct mount *mp);
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int vfs_write_suspend(struct mount *mp);
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int vop_stdbmap(struct vop_bmap_args *);
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int vop_stdgetwritemount(struct vop_getwritemount_args *);
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int vop_stdgetpages(struct vop_getpages_args *);
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@ -307,7 +307,10 @@ ffs_snapshot(mp, snapfile)
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*/
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for (;;) {
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vn_finished_write(wrtmp);
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vfs_write_suspend(vp->v_mount);
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if ((error = vfs_write_suspend(vp->v_mount)) != 0) {
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vn_start_write(NULL, &wrtmp, V_WAIT);
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goto out;
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}
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if (mp->mnt_kern_flag & MNTK_SUSPENDED)
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break;
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vn_start_write(NULL, &wrtmp, V_WAIT);
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@ -184,7 +184,11 @@ ffs_mount(mp, path, data, ndp, td)
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/*
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* Flush any dirty data.
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*/
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VFS_SYNC(mp, MNT_WAIT, td->td_proc->p_ucred, td);
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if ((error = VFS_SYNC(mp, MNT_WAIT,
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td->td_proc->p_ucred, td)) != 0) {
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vn_finished_write(mp);
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return (error);
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}
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/*
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* Check for and optionally get rid of files open
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* for writing.
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@ -1156,7 +1160,7 @@ ffs_sync(mp, waitfor, cred, td)
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if ((error = softdep_flushworklist(ump->um_mountp, &count, td)))
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allerror = error;
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/* Flushed work items may create new vnodes to clean */
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if (count) {
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if (allerror == 0 && count) {
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mtx_lock(&mntvnode_mtx);
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goto loop;
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}
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@ -1172,7 +1176,7 @@ ffs_sync(mp, waitfor, cred, td)
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if ((error = VOP_FSYNC(devvp, cred, waitfor, td)) != 0)
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allerror = error;
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VOP_UNLOCK(devvp, 0, td);
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if (waitfor == MNT_WAIT) {
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if (allerror == 0 && waitfor == MNT_WAIT) {
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mtx_lock(&mntvnode_mtx);
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goto loop;
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}
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