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Move the vnode lock into file systems
The vnode lock operations currently work on a rw lock located inside the
vnode. I propose to move this lock into the file system node.
This place is more logical as we lock a file system node and not a vnode.
This becomes clear if we think of a file system where one file system node
is attached to more than one vnode. Ptyfs allowing multiple mounts is such
a candidate.
A diff implemeting this for ufs, lfs and ext2fs is attached.
Comments or objections anyone?
--
Juergen Hannken-Illjes - hannken%eis.cs.tu-bs.de@localhost - TU Braunschweig
(Germany)
Index: sys/ufs/ufs/inode.h
===================================================================
RCS file: /cvsroot/src/sys/ufs/ufs/inode.h,v
retrieving revision 1.56
diff -p -u -4 -r1.56 inode.h
--- sys/ufs/ufs/inode.h 22 Feb 2009 20:28:07 -0000 1.56
+++ sys/ufs/ufs/inode.h 25 Jun 2010 20:43:24 -0000
@@ -91,9 +91,9 @@ struct inode {
#define i_fs inode_u.fs
#define i_lfs inode_u.lfs
#define i_e2fs inode_u.e2fs
- void *i_unused1; /* Unused. */
+ krwlock_t i_lock; /* Inode lock. */
struct dquot *i_dquot[MAXQUOTAS]; /* Dquot structures. */
u_quad_t i_modrev; /* Revision level for NFS lease. */
struct lockf *i_lockf;/* Head of byte-level lock list. */
Index: sys/ufs/ufs/ufs_extern.h
===================================================================
RCS file: /cvsroot/src/sys/ufs/ufs/ufs_extern.h,v
retrieving revision 1.62
diff -p -u -4 -r1.62 ufs_extern.h
--- sys/ufs/ufs/ufs_extern.h 13 Sep 2009 05:17:37 -0000 1.62
+++ sys/ufs/ufs/ufs_extern.h 25 Jun 2010 20:43:24 -0000
@@ -67,11 +67,11 @@ int ufs_create(void *);
int ufs_getattr(void *);
int ufs_inactive(void *);
#define ufs_fcntl genfs_fcntl
#define ufs_ioctl genfs_enoioctl
-#define ufs_islocked genfs_islocked
+int ufs_islocked(void *);
int ufs_link(void *);
-#define ufs_lock genfs_lock
+int ufs_lock(void *);
int ufs_lookup(void *);
int ufs_mkdir(void *);
int ufs_mknod(void *);
#define ufs_mmap genfs_mmap
@@ -88,9 +88,9 @@ int ufs_rmdir(void *);
#define ufs_poll genfs_poll
int ufs_setattr(void *);
int ufs_strategy(void *);
int ufs_symlink(void *);
-#define ufs_unlock genfs_unlock
+int ufs_unlock(void *);
int ufs_whiteout(void *);
int ufsspec_close(void *);
int ufsspec_read(void *);
int ufsspec_write(void *);
Index: sys/ufs/ufs/ufs_ihash.c
===================================================================
RCS file: /cvsroot/src/sys/ufs/ufs/ufs_ihash.c,v
retrieving revision 1.28
diff -p -u -4 -r1.28 ufs_ihash.c
--- sys/ufs/ufs/ufs_ihash.c 5 Nov 2009 08:18:02 -0000 1.28
+++ sys/ufs/ufs/ufs_ihash.c 25 Jun 2010 20:43:24 -0000
@@ -170,9 +170,10 @@ ufs_ihashins(struct inode *ip)
KASSERT(mutex_owned(&ufs_hashlock));
/* lock the inode, then put it on the appropriate hash list */
- vlockmgr(&ip->i_vnode->v_lock, LK_EXCLUSIVE);
+ rw_init(&ip->i_lock);
+ rw_enter(&ip->i_lock, RW_WRITER);
mutex_enter(&ufs_ihash_lock);
ipp = &ihashtbl[INOHASH(ip->i_dev, ip->i_number)];
LIST_INSERT_HEAD(ipp, ip, i_hash);
@@ -187,5 +188,6 @@ ufs_ihashrem(struct inode *ip)
{
mutex_enter(&ufs_ihash_lock);
LIST_REMOVE(ip, i_hash);
mutex_exit(&ufs_ihash_lock);
+ rw_destroy(&ip->i_lock);
}
Index: sys/ufs/ufs/ufs_vnops.c
===================================================================
RCS file: /cvsroot/src/sys/ufs/ufs/ufs_vnops.c,v
retrieving revision 1.183
diff -p -u -4 -r1.183 ufs_vnops.c
--- sys/ufs/ufs/ufs_vnops.c 24 Jun 2010 13:03:20 -0000 1.183
+++ sys/ufs/ufs/ufs_vnops.c 25 Jun 2010 20:43:25 -0000
@@ -2346,4 +2346,66 @@ ufs_gop_markupdate(struct vnode *vp, int
ip->i_flag |= mask;
}
}
+
+/*
+ * Lock the node.
+ */
+int
+ufs_lock(void *v)
+{
+ struct vop_lock_args /* {
+ struct vnode *a_vp;
+ int a_flags;
+ } */ *ap = v;
+ struct inode *ip = VTOI(ap->a_vp);
+ int flags = ap->a_flags;
+ krw_t op;
+
+ KASSERT((flags & ~(LK_EXCLUSIVE | LK_SHARED | LK_NOWAIT)) == 0);
+
+ op = ((flags & LK_EXCLUSIVE) != 0 ? RW_WRITER : RW_READER);
+
+ if ((flags & LK_NOWAIT) != 0)
+ return (rw_tryenter(&ip->i_lock, op) ? 0 : EBUSY);
+
+ rw_enter(&ip->i_lock, op);
+
+ return 0;
+}
+
+/*
+ * Unlock the node.
+ */
+int
+ufs_unlock(void *v)
+{
+ struct vop_unlock_args /* {
+ struct vnode *a_vp;
+ } */ *ap = v;
+ struct inode *ip = VTOI(ap->a_vp);
+
+ rw_exit(&ip->i_lock);
+
+ return 0;
+}
+
+/*
+ * Return whether or not the node is locked.
+ */
+int
+ufs_islocked(void *v)
+{
+ struct vop_islocked_args /* {
+ struct vnode *a_vp;
+ } */ *ap = v;
+ struct inode *ip = VTOI(ap->a_vp);
+
+ if (rw_write_held(&ip->i_lock))
+ return LK_EXCLUSIVE;
+
+ if (rw_read_held(&ip->i_lock))
+ return LK_SHARED;
+
+ return 0;
+}
Index: sys/ufs/lfs/lfs_syscalls.c
===================================================================
RCS file: /cvsroot/src/sys/ufs/lfs/lfs_syscalls.c,v
retrieving revision 1.137
diff -p -u -4 -r1.137 lfs_syscalls.c
--- sys/ufs/lfs/lfs_syscalls.c 24 Jun 2010 13:03:19 -0000 1.137
+++ sys/ufs/lfs/lfs_syscalls.c 25 Jun 2010 20:43:24 -0000
@@ -1136,12 +1136,12 @@ lfs_fastvget(struct mount *mp, ino_t ino
error = copyin(dinp, ip->i_din.ffs1_din, sizeof (struct
ufs1_dinode));
if (error) {
DLOG((DLOG_CLEAN, "lfs_fastvget: dinode copyin failed"
" for ino %d\n", ino));
+ /* Unlock and discard unneeded inode. */
+ rw_exit(&ip->i_lock);
ufs_ihashrem(ip);
- /* Unlock and discard unneeded inode. */
- vlockmgr(&vp->v_lock, LK_RELEASE);
lfs_vunref(vp);
*vpp = NULL;
return (error);
}
@@ -1158,13 +1158,13 @@ lfs_fastvget(struct mount *mp, ino_t ino
/*
* The inode does not contain anything useful, so it
* would be misleading to leave it on its hash chain.
* Iput() will return it to the free list.
+ * Unlock and discard unneeded inode.
*/
+ rw_exit(&ip->i_lock);
ufs_ihashrem(ip);
- /* Unlock and discard unneeded inode. */
- vlockmgr(&vp->v_lock, LK_RELEASE);
lfs_vunref(vp);
brelse(bp, 0);
*vpp = NULL;
return (error);
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