Author: kib
Date: Fri Nov 11 20:08:45 2016
New Revision: 308552
URL: https://svnweb.freebsd.org/changeset/base/308552
Log:
MFC r308025:
Enable vn_io_fault() deadlock avoidance for msdosfs.
Modified:
stable/10/sys/fs/msdosfs/msdosfs_vfsops.c
stable/10/sys/fs/msdosfs/msdosfs_vnops.c
Directory Properties:
stable/10/ (props changed)
Modified: stable/10/sys/fs/msdosfs/msdosfs_vfsops.c
==============================================================================
--- stable/10/sys/fs/msdosfs/msdosfs_vfsops.c Fri Nov 11 20:06:07 2016
(r308551)
+++ stable/10/sys/fs/msdosfs/msdosfs_vfsops.c Fri Nov 11 20:08:45 2016
(r308552)
@@ -743,7 +743,7 @@ mountmsdosfs(struct vnode *devvp, struct
mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum;
MNT_ILOCK(mp);
mp->mnt_flag |= MNT_LOCAL;
- mp->mnt_kern_flag |= MNTK_USES_BCACHE;
+ mp->mnt_kern_flag |= MNTK_USES_BCACHE | MNTK_NO_IOPF;
MNT_IUNLOCK(mp);
if (pmp->pm_flags & MSDOSFS_LARGEFS)
Modified: stable/10/sys/fs/msdosfs/msdosfs_vnops.c
==============================================================================
--- stable/10/sys/fs/msdosfs/msdosfs_vnops.c Fri Nov 11 20:06:07 2016
(r308551)
+++ stable/10/sys/fs/msdosfs/msdosfs_vnops.c Fri Nov 11 20:08:45 2016
(r308552)
@@ -640,7 +640,7 @@ msdosfs_read(ap)
diff = blsize - bp->b_resid;
if (diff < n)
n = diff;
- error = uiomove(bp->b_data + on, (int) n, uio);
+ error = vn_io_fault_uiomove(bp->b_data + on, (int) n, uio);
brelse(bp);
} while (error == 0 && uio->uio_resid > 0 && n != 0);
if (!isadir && (error == 0 || uio->uio_resid != orig_resid) &&
@@ -776,6 +776,12 @@ msdosfs_write(ap)
* then no need to read data from disk.
*/
bp = getblk(thisvp, bn, pmp->pm_bpcluster, 0, 0, 0);
+ /*
+ * This call to vfs_bio_clrbuf() ensures that
+ * even if vn_io_fault_uiomove() below faults,
+ * garbage from the newly instantiated buffer
+ * is not exposed to the userspace via mmap().
+ */
vfs_bio_clrbuf(bp);
/*
* Do the bmap now, since pcbmap needs buffers
@@ -813,7 +819,7 @@ msdosfs_write(ap)
/*
* Copy the data from user space into the buf header.
*/
- error = uiomove(bp->b_data + croffset, n, uio);
+ error = vn_io_fault_uiomove(bp->b_data + croffset, n, uio);
if (error) {
brelse(bp);
break;
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