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Date:      Thu, 21 Jan 2010 14:33:18 +0000 (UTC)
From:      John Baldwin <jhb@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-7@freebsd.org
Subject:   svn commit: r202750 - in stable/7/sys: cddl/contrib/opensolaris/uts/common/fs/zfs dev/md fs/cd9660 fs/udf kern sys ufs/ffs
Message-ID:  <201001211433.o0LEXIFC054459@svn.freebsd.org>

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Author: jhb
Date: Thu Jan 21 14:33:18 2010
New Revision: 202750
URL: http://svn.freebsd.org/changeset/base/202750

Log:
  MFC 189696,189697:
  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.

Modified:
  stable/7/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_znode.c
  stable/7/sys/dev/md/md.c
  stable/7/sys/fs/cd9660/cd9660_vfsops.c
  stable/7/sys/fs/udf/udf_vfsops.c
  stable/7/sys/kern/vfs_lookup.c
  stable/7/sys/kern/vfs_vnops.c
  stable/7/sys/kern/vnode_if.src
  stable/7/sys/sys/mount.h
  stable/7/sys/ufs/ffs/ffs_vfsops.c
Directory Properties:
  stable/7/sys/   (props changed)
  stable/7/sys/cddl/contrib/opensolaris/   (props changed)
  stable/7/sys/contrib/dev/acpica/   (props changed)
  stable/7/sys/contrib/pf/   (props changed)

Modified: stable/7/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_znode.c
==============================================================================
--- stable/7/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_znode.c	Thu Jan 21 13:31:41 2010	(r202749)
+++ stable/7/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_znode.c	Thu Jan 21 14:33:18 2010	(r202750)
@@ -1520,6 +1520,7 @@ zfs_create_fs(objset_t *os, cred_t *cr, 
 	vnode.v_type = VDIR;
 	vnode.v_data = rootzp;
 	rootzp->z_vnode = &vnode;
+	VN_LOCK_ASHARE(vp);
 
 	bzero(&zfsvfs, sizeof (zfsvfs_t));
 

Modified: stable/7/sys/dev/md/md.c
==============================================================================
--- stable/7/sys/dev/md/md.c	Thu Jan 21 13:31:41 2010	(r202749)
+++ stable/7/sys/dev/md/md.c	Thu Jan 21 14:33:18 2010	(r202750)
@@ -918,12 +918,20 @@ 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, td))) {
-		VOP_UNLOCK(nd.ni_vp, 0, td);
-		(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, td);
+	if (error != 0)
+		goto bad;
+	if (VOP_ISLOCKED(nd.ni_vp, td) != LK_EXCLUSIVE) {
+		vn_lock(nd.ni_vp, LK_UPGRADE | LK_RETRY, td);
+		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, td);
@@ -942,13 +950,15 @@ mdcreate_vnode(struct md_s *sc, struct m
 		sc->vnode = NULL;
 		vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY, td);
 		nd.ni_vp->v_vflag &= ~VV_MD;
-		VOP_UNLOCK(nd.ni_vp, 0, td);
-		(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, td);
+	(void)vn_close(nd.ni_vp, flags, td->td_ucred, td);
+	VFS_UNLOCK_GIANT(vfslocked);
+	return (error);
 }
 
 static int

Modified: stable/7/sys/fs/cd9660/cd9660_vfsops.c
==============================================================================
--- stable/7/sys/fs/cd9660/cd9660_vfsops.c	Thu Jan 21 13:31:41 2010	(r202749)
+++ stable/7/sys/fs/cd9660/cd9660_vfsops.c	Thu Jan 21 14:33:18 2010	(r202750)
@@ -373,7 +373,8 @@ iso_mountfs(devvp, mp, td)
 	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: stable/7/sys/fs/udf/udf_vfsops.c
==============================================================================
--- stable/7/sys/fs/udf/udf_vfsops.c	Thu Jan 21 13:31:41 2010	(r202749)
+++ stable/7/sys/fs/udf/udf_vfsops.c	Thu Jan 21 14:33:18 2010	(r202750)
@@ -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: stable/7/sys/kern/vfs_lookup.c
==============================================================================
--- stable/7/sys/kern/vfs_lookup.c	Thu Jan 21 13:31:41 2010	(r202749)
+++ stable/7/sys/kern/vfs_lookup.c	Thu Jan 21 14:33:18 2010	(r202750)
@@ -322,6 +322,41 @@ 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 (0);
+}
+
 /*
  * Search a pathname.
  * This is a very central and rather complicated routine.
@@ -580,8 +615,7 @@ 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);
@@ -778,8 +812,8 @@ 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, td) != LK_EXCLUSIVE) {
+	if (needs_exclusive_leaf(dp->v_mount, cnp->cn_flags) &&
+	    VOP_ISLOCKED(dp, td) != LK_EXCLUSIVE) {
 		vn_lock(dp, LK_UPGRADE | LK_RETRY, td);
 		if (dp->v_iflag & VI_DOOMED) {
 			error = ENOENT;

Modified: stable/7/sys/kern/vfs_vnops.c
==============================================================================
--- stable/7/sys/kern/vfs_vnops.c	Thu Jan 21 13:31:41 2010	(r202749)
+++ stable/7/sys/kern/vfs_vnops.c	Thu Jan 21 14:33:18 2010	(r202750)
@@ -185,6 +185,8 @@ 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)
@@ -235,7 +237,7 @@ 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);
@@ -280,12 +282,18 @@ 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, td);
+	vn_lock(vp, lock_flags | LK_RETRY, td);
 	if (flags & FWRITE) {
 		VNASSERT(vp->v_writecount > 0, vp, 
 		    ("vn_close: negative writecount"));

Modified: stable/7/sys/kern/vnode_if.src
==============================================================================
--- stable/7/sys/kern/vnode_if.src	Thu Jan 21 13:31:41 2010	(r202749)
+++ stable/7/sys/kern/vnode_if.src	Thu Jan 21 14:33:18 2010	(r202750)
@@ -134,7 +134,7 @@ vop_open {
 };
 
 
-%% close	vp	E E E
+%% close	vp	L L L
 
 vop_close {
 	IN struct vnode *vp;

Modified: stable/7/sys/sys/mount.h
==============================================================================
--- stable/7/sys/sys/mount.h	Thu Jan 21 13:31:41 2010	(r202749)
+++ stable/7/sys/sys/mount.h	Thu Jan 21 14:33:18 2010	(r202750)
@@ -328,6 +328,7 @@ void          __mnt_vnode_markerfree(str
 #define MNTK_SOFTDEP	0x00000004	/* async disabled by softdep */
 #define MNTK_NOINSMNTQ	0x00000008	/* insmntque is not allowed */
 #define	MNTK_REFEXPIRE	0x00000020	/* refcount expiring is happening */
+#define MNTK_EXTENDED_SHARED	0x00000040 /* Allow shared locking for more ops */
 #define	MNTK_SHARED_WRITES	0x00000080 /* Allow shared locking for writes */
 #define MNTK_UNMOUNT	0x01000000	/* unmount in progress */
 #define	MNTK_MWAIT	0x02000000	/* waiting for unmount to finish */
@@ -335,8 +336,8 @@ void          __mnt_vnode_markerfree(str
 #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: stable/7/sys/ufs/ffs/ffs_vfsops.c
==============================================================================
--- stable/7/sys/ufs/ffs/ffs_vfsops.c	Thu Jan 21 13:31:41 2010	(r202749)
+++ stable/7/sys/ufs/ffs/ffs_vfsops.c	Thu Jan 21 14:33:18 2010	(r202750)
@@ -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.
 	 */
-	vp->v_vnlock->lk_flags |= LK_CANRECURSE;
-	vp->v_vnlock->lk_flags &= ~LK_NOSHARE;
+	VN_LOCK_AREC(vp);
 	vp->v_data = ip;
 	vp->v_bufobj.bo_bsize = fs->fs_bsize;
 	ip->i_vnode = vp;
@@ -1518,6 +1518,10 @@ 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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