Author: jhb
Date: Wed Mar 11 14:13:47 2009
New Revision: 189696
URL: http://svn.freebsd.org/changeset/base/189696
Log:
Add a new internal mount flag (MNTK_EXTENDED_SHARED) to indicate that a
filesystem supports additional operations using shared vnode locks.
Currently this is used to enable shared locks for open() and close() of
read-only file descriptors.
- When an ISOPEN namei() request is performed with LOCKSHARED, use a
shared vnode lock for the leaf vnode only if the mount point has the
extended shared flag set.
- Set LOCKSHARED in vn_open_cred() for requests that specify O_RDONLY but
not O_CREAT.
- Use a shared vnode lock around VOP_CLOSE() if the file was opened with
O_RDONLY and the mountpoint has the extended shared flag set.
- Adjust md(4) to upgrade the vnode lock on the vnode it gets back from
vn_open() since it now may only have a shared vnode lock.
- Don't enable shared vnode locks on FIFO vnodes in ZFS and UFS since
FIFO's require exclusive vnode locks for their open() and close()
routines. (My recent MPSAFE patches for UDF and cd9660 already included
this change.)
- Enable extended shared operations on UFS, cd9660, and UDF.
Submitted by: ups
Reviewed by: pjd (ZFS bits)
MFC after: 1 month
Modified:
head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_znode.c
head/sys/dev/md/md.c
head/sys/fs/cd9660/cd9660_vfsops.c
head/sys/fs/udf/udf_vfsops.c
head/sys/kern/vfs_lookup.c
head/sys/kern/vfs_vnops.c
head/sys/kern/vnode_if.src
head/sys/sys/mount.h
head/sys/ufs/ffs/ffs_vfsops.c
Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_znode.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_znode.c Wed Mar
11 13:15:42 2009 (r189695)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_znode.c Wed Mar
11 14:13:47 2009 (r189696)
@@ -153,7 +153,6 @@ zfs_znode_cache_constructor(void *buf, v
zp->z_vnode = vp;
vp->v_data = (caddr_t)zp;
VN_LOCK_AREC(vp);
- VN_LOCK_ASHARE(vp);
list_link_init(&zp->z_link_node);
@@ -610,6 +609,8 @@ zfs_znode_alloc(zfsvfs_t *zfsvfs, dmu_bu
vp->v_op = &zfs_fifoops;
break;
}
+ if (vp->v_type != VFIFO)
+ VN_LOCK_ASHARE(vp);
mutex_enter(&zfsvfs->z_znodes_lock);
list_insert_tail(&zfsvfs->z_all_znodes, zp);
@@ -1491,6 +1492,7 @@ zfs_create_fs(objset_t *os, cred_t *cr,
vp = ZTOV(rootzp);
vp->v_type = VDIR;
+ VN_LOCK_ASHARE(vp);
bzero(&zfsvfs, sizeof (zfsvfs_t));
Modified: head/sys/dev/md/md.c
==============================================================================
--- head/sys/dev/md/md.c Wed Mar 11 13:15:42 2009 (r189695)
+++ head/sys/dev/md/md.c Wed Mar 11 14:13:47 2009 (r189696)
@@ -924,12 +924,20 @@ mdcreate_vnode(struct md_s *sc, struct m
return (error);
vfslocked = NDHASGIANT(&nd);
NDFREE(&nd, NDF_ONLY_PNBUF);
- if (nd.ni_vp->v_type != VREG ||
- (error = VOP_GETATTR(nd.ni_vp, &vattr, td->td_ucred))) {
- VOP_UNLOCK(nd.ni_vp, 0);
- (void)vn_close(nd.ni_vp, flags, td->td_ucred, td);
- VFS_UNLOCK_GIANT(vfslocked);
- return (error ? error : EINVAL);
+ if (nd.ni_vp->v_type != VREG) {
+ error = EINVAL;
+ goto bad;
+ }
+ error = VOP_GETATTR(nd.ni_vp, &vattr, td->td_ucred);
+ if (error != 0)
+ goto bad;
+ if (VOP_ISLOCKED(nd.ni_vp) != LK_EXCLUSIVE) {
+ vn_lock(nd.ni_vp, LK_UPGRADE | LK_RETRY);
+ if (nd.ni_vp->v_iflag & VI_DOOMED) {
+ /* Forced unmount. */
+ error = EBADF;
+ goto bad;
+ }
}
nd.ni_vp->v_vflag |= VV_MD;
VOP_UNLOCK(nd.ni_vp, 0);
@@ -948,13 +956,15 @@ mdcreate_vnode(struct md_s *sc, struct m
sc->vnode = NULL;
vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY);
nd.ni_vp->v_vflag &= ~VV_MD;
- VOP_UNLOCK(nd.ni_vp, 0);
- (void)vn_close(nd.ni_vp, flags, td->td_ucred, td);
- VFS_UNLOCK_GIANT(vfslocked);
- return (error);
+ goto bad;
}
VFS_UNLOCK_GIANT(vfslocked);
return (0);
+bad:
+ VOP_UNLOCK(nd.ni_vp, 0);
+ (void)vn_close(nd.ni_vp, flags, td->td_ucred, td);
+ VFS_UNLOCK_GIANT(vfslocked);
+ return (error);
}
static int
Modified: head/sys/fs/cd9660/cd9660_vfsops.c
==============================================================================
--- head/sys/fs/cd9660/cd9660_vfsops.c Wed Mar 11 13:15:42 2009
(r189695)
+++ head/sys/fs/cd9660/cd9660_vfsops.c Wed Mar 11 14:13:47 2009
(r189696)
@@ -371,7 +371,8 @@ iso_mountfs(devvp, mp)
mp->mnt_maxsymlinklen = 0;
MNT_ILOCK(mp);
mp->mnt_flag |= MNT_LOCAL;
- mp->mnt_kern_flag |= MNTK_MPSAFE | MNTK_LOOKUP_SHARED;
+ mp->mnt_kern_flag |= MNTK_MPSAFE | MNTK_LOOKUP_SHARED |
+ MNTK_EXTENDED_SHARED;
MNT_IUNLOCK(mp);
isomp->im_mountp = mp;
isomp->im_dev = dev;
Modified: head/sys/fs/udf/udf_vfsops.c
==============================================================================
--- head/sys/fs/udf/udf_vfsops.c Wed Mar 11 13:15:42 2009
(r189695)
+++ head/sys/fs/udf/udf_vfsops.c Wed Mar 11 14:13:47 2009
(r189696)
@@ -353,7 +353,8 @@ udf_mountfs(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_MPSAFE | MNTK_LOOKUP_SHARED;
+ mp->mnt_kern_flag |= MNTK_MPSAFE | MNTK_LOOKUP_SHARED |
+ MNTK_EXTENDED_SHARED;
MNT_IUNLOCK(mp);
udfmp->im_mountp = mp;
udfmp->im_dev = dev;
Modified: head/sys/kern/vfs_lookup.c
==============================================================================
--- head/sys/kern/vfs_lookup.c Wed Mar 11 13:15:42 2009 (r189695)
+++ head/sys/kern/vfs_lookup.c Wed Mar 11 14:13:47 2009 (r189696)
@@ -353,6 +353,41 @@ compute_cn_lkflags(struct mount *mp, int
return (lkflags);
}
+static __inline int
+needs_exclusive_leaf(struct mount *mp, int flags)
+{
+
+ /*
+ * Intermediate nodes can use shared locks, we only need to
+ * force an exclusive lock for leaf nodes.
+ */
+ if ((flags & (ISLASTCN | LOCKLEAF)) != (ISLASTCN | LOCKLEAF))
+ return (0);
+
+ /* Always use exclusive locks if LOCKSHARED isn't set. */
+ if (!(flags & LOCKSHARED))
+ return (1);
+
+ /*
+ * For lookups during open(), if the mount point supports
+ * extended shared operations, then use a shared lock for the
+ * leaf node, otherwise use an exclusive lock.
+ */
+ if (flags & ISOPEN) {
+ if (mp != NULL &&
+ (mp->mnt_kern_flag & MNTK_EXTENDED_SHARED))
+ return (0);
+ else
+ return (1);
+ }
+
+ /*
+ * Lookup requests outside of open() that specify LOCKSHARED
+ * only need a shared lock on the leaf vnode.
+ */
+ return (1);
+}
+
/*
* Search a pathname.
* This is a very central and rather complicated routine.
@@ -610,8 +645,7 @@ unionlookup:
* If we're looking up the last component and we need an exclusive
* lock, adjust our lkflags.
*/
- if ((cnp->cn_flags & (ISLASTCN|LOCKSHARED|LOCKLEAF)) ==
- (ISLASTCN|LOCKLEAF))
+ if (needs_exclusive_leaf(dp->v_mount, cnp->cn_flags))
cnp->cn_lkflags = LK_EXCLUSIVE;
#ifdef NAMEI_DIAGNOSTIC
vprint("lookup in", dp);
@@ -811,8 +845,8 @@ success:
* Because of lookup_shared we may have the vnode shared locked, but
* the caller may want it to be exclusively locked.
*/
- if ((cnp->cn_flags & (ISLASTCN | LOCKSHARED | LOCKLEAF)) ==
- (ISLASTCN | LOCKLEAF) && VOP_ISLOCKED(dp) != LK_EXCLUSIVE) {
+ if (needs_exclusive_leaf(dp->v_mount, cnp->cn_flags) &&
+ VOP_ISLOCKED(dp) != LK_EXCLUSIVE) {
vn_lock(dp, LK_UPGRADE | LK_RETRY);
if (dp->v_iflag & VI_DOOMED) {
error = ENOENT;
Modified: head/sys/kern/vfs_vnops.c
==============================================================================
--- head/sys/kern/vfs_vnops.c Wed Mar 11 13:15:42 2009 (r189695)
+++ head/sys/kern/vfs_vnops.c Wed Mar 11 14:13:47 2009 (r189696)
@@ -188,6 +188,8 @@ restart:
ndp->ni_cnd.cn_flags = ISOPEN |
((fmode & O_NOFOLLOW) ? NOFOLLOW : FOLLOW) |
LOCKLEAF | MPSAFE | AUDITVNODE1;
+ if (!(fmode & FWRITE))
+ ndp->ni_cnd.cn_flags |= LOCKSHARED;
if ((error = namei(ndp)) != 0)
return (error);
if (!mpsafe)
@@ -240,7 +242,7 @@ restart:
if (fmode & FWRITE)
vp->v_writecount++;
*flagp = fmode;
- ASSERT_VOP_ELOCKED(vp, "vn_open_cred");
+ ASSERT_VOP_LOCKED(vp, "vn_open_cred");
if (!mpsafe)
VFS_UNLOCK_GIANT(vfslocked);
return (0);
@@ -285,12 +287,18 @@ vn_close(vp, flags, file_cred, td)
struct thread *td;
{
struct mount *mp;
- int error;
+ int error, lock_flags;
+
+ if (!(flags & FWRITE) && vp->v_mount != NULL &&
+ vp->v_mount->mnt_kern_flag & MNTK_EXTENDED_SHARED)
+ lock_flags = LK_SHARED;
+ else
+ lock_flags = LK_EXCLUSIVE;
VFS_ASSERT_GIANT(vp->v_mount);
vn_start_write(vp, &mp, V_WAIT);
- vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
+ vn_lock(vp, lock_flags | LK_RETRY);
if (flags & FWRITE) {
VNASSERT(vp->v_writecount > 0, vp,
("vn_close: negative writecount"));
Modified: head/sys/kern/vnode_if.src
==============================================================================
--- head/sys/kern/vnode_if.src Wed Mar 11 13:15:42 2009 (r189695)
+++ head/sys/kern/vnode_if.src Wed Mar 11 14:13:47 2009 (r189696)
@@ -133,7 +133,7 @@ vop_open {
};
-%% close vp E E E
+%% close vp L L L
vop_close {
IN struct vnode *vp;
Modified: head/sys/sys/mount.h
==============================================================================
--- head/sys/sys/mount.h Wed Mar 11 13:15:42 2009 (r189695)
+++ head/sys/sys/mount.h Wed Mar 11 14:13:47 2009 (r189696)
@@ -324,14 +324,15 @@ void __mnt_vnode_markerfree(str
#define MNTK_NOINSMNTQ 0x00000008 /* insmntque is not allowed */
#define MNTK_DRAINING 0x00000010 /* lock draining is happening */
#define MNTK_REFEXPIRE 0x00000020 /* refcount expiring is
happening */
+#define MNTK_EXTENDED_SHARED 0x00000040 /* Allow shared locking for more ops
*/
#define MNTK_UNMOUNT 0x01000000 /* unmount in progress */
#define MNTK_MWAIT 0x02000000 /* waiting for unmount to
finish */
#define MNTK_SUSPEND 0x08000000 /* request write suspension */
#define MNTK_SUSPEND2 0x04000000 /* block secondary writes */
#define MNTK_SUSPENDED 0x10000000 /* write operations are
suspended */
#define MNTK_MPSAFE 0x20000000 /* Filesystem is MPSAFE. */
-#define MNTK_NOKNOTE 0x80000000 /* Don't send KNOTEs from VOP
hooks */
#define MNTK_LOOKUP_SHARED 0x40000000 /* FS supports shared lock lookups */
+#define MNTK_NOKNOTE 0x80000000 /* Don't send KNOTEs from VOP
hooks */
/*
* Sysctl CTL_VFS definitions.
Modified: head/sys/ufs/ffs/ffs_vfsops.c
==============================================================================
--- head/sys/ufs/ffs/ffs_vfsops.c Wed Mar 11 13:15:42 2009
(r189695)
+++ head/sys/ufs/ffs/ffs_vfsops.c Wed Mar 11 14:13:47 2009
(r189696)
@@ -883,7 +883,8 @@ ffs_mountfs(devvp, mp, td)
* Initialize filesystem stat information in mount struct.
*/
MNT_ILOCK(mp);
- mp->mnt_kern_flag |= MNTK_MPSAFE | MNTK_LOOKUP_SHARED;
+ mp->mnt_kern_flag |= MNTK_MPSAFE | MNTK_LOOKUP_SHARED |
+ MNTK_EXTENDED_SHARED;
MNT_IUNLOCK(mp);
#ifdef UFS_EXTATTR
#ifdef UFS_EXTATTR_AUTOSTART
@@ -1440,10 +1441,9 @@ ffs_vgetf(mp, ino, flags, vpp, ffs_flags
return (error);
}
/*
- * FFS supports recursive and shared locking.
+ * FFS supports recursive locking.
*/
VN_LOCK_AREC(vp);
- VN_LOCK_ASHARE(vp);
vp->v_data = ip;
vp->v_bufobj.bo_bsize = fs->fs_bsize;
ip->i_vnode = vp;
@@ -1516,6 +1516,10 @@ ffs_vgetf(mp, ino, flags, vpp, ffs_flags
/*
* Finish inode initialization.
*/
+ if (vp->v_type != VFIFO) {
+ /* FFS supports shared locking for all files except fifos. */
+ VN_LOCK_ASHARE(vp);
+ }
/*
* Set up a generation number for this inode if it does not
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