This patch virtualizes & untangles the bioops operations vector.
Background:
The bioops operation vector is a list of OO-like operations which can
be performed on struct buf. They are used by the softupdates code
to handle dependencies.
Ideally struct buf should have had a real OO like operations vector
like vnodes have it, and struct bioops is the first step towards that.
One of the reasons we should have OO-like struct buf, is that as
long as bwrite(bp) "knows" that the buffer is backed by a disk
device, we cannot use the UFS layer on top of a storage manager
which isn't based on disk-devices: When UFS modifies a directory
inode, it will call bwrite(bp) on the buffer with the data. This
would not work if the backing were based on malloc(9) or anonymous
swap-backed VM objects for instance.
In other words: this is the main reason why we don't have a decent
tmpfs in FreeBSD.
Instead of just assuming that it works on a disk, bwrite(bp) should
do a "bp->b_ops->bwrite(bp)" so that each buffer could have its own
private idea of how to write itself, depending on what backing it has.
So in order to move bioops closer to become a bp->b_ops, this patch
takes two entries out of bioops: the "sync" and the "fsync" items
and virtualizes the rest of the elements a bit.
The "sync" item is called only from the syncer, and is a call to the
softupdates code to do what it needs to do for periodic syncing.
The real way of doing that would be to have an event-handler for this
since other code could need to be part of the sync trafic, raid5
private parity caches could be one example. I have not done this
yet, since currently softupdates is the only client.
The fsync item really doesn't belong in the fsync system call, it
belongs in ffs_fsync, and has been moved there.
To give the right behaviour when SOFTUPDATES is not compiled in,
stubs for both of these functions have been added to ffs_softdep_stub.c
Finally all the checks to see if the bioops vector is populated
has been centralized in in-line functions in <sys/buf.h> thereby
paving the road for the global bioops to become bp->b_ops.
Comments, reviews, tests please
Poul-Henning
Index: contrib/softupdates/ffs_softdep.c
===================================================================
RCS file: /home/ncvs/src/sys/contrib/softupdates/ffs_softdep.c,v
retrieving revision 1.64
diff -u -r1.64 ffs_softdep.c
--- contrib/softupdates/ffs_softdep.c 2000/05/26 02:01:59 1.64
+++ contrib/softupdates/ffs_softdep.c 2000/06/14 19:26:46
@@ -222,8 +222,6 @@
softdep_disk_io_initiation, /* io_start */
softdep_disk_write_complete, /* io_complete */
softdep_deallocate_dependencies, /* io_deallocate */
- softdep_fsync, /* io_fsync */
- softdep_process_worklist, /* io_sync */
softdep_move_dependencies, /* io_movedeps */
softdep_count_dependencies, /* io_countdeps */
};
Index: kern/vfs_bio.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/vfs_bio.c,v
retrieving revision 1.258
diff -u -r1.258 vfs_bio.c
--- kern/vfs_bio.c 2000/05/26 02:04:39 1.258
+++ kern/vfs_bio.c 2000/06/14 19:00:56
@@ -616,8 +616,8 @@
newbp->b_flags &= ~B_INVAL;
/* move over the dependencies */
- if (LIST_FIRST(&bp->b_dep) != NULL && bioops.io_movedeps)
- (*bioops.io_movedeps)(bp, newbp);
+ if (LIST_FIRST(&bp->b_dep) != NULL)
+ buf_movedeps(bp, newbp);
/*
* Initiate write on the copy, release the original to
@@ -673,10 +673,10 @@
/*
* Process dependencies then return any unfinished ones.
*/
- if (LIST_FIRST(&bp->b_dep) != NULL && bioops.io_complete)
- (*bioops.io_complete)(bp);
- if (LIST_FIRST(&bp->b_dep) != NULL && bioops.io_movedeps)
- (*bioops.io_movedeps)(bp, origbp);
+ if (LIST_FIRST(&bp->b_dep) != NULL)
+ buf_complete(bp);
+ if (LIST_FIRST(&bp->b_dep) != NULL)
+ buf_movedeps(bp, origbp);
/*
* Clear the BX_BKGRDINPROG flag in the original buffer
* and awaken it if it is waiting for the write to complete.
@@ -939,8 +939,8 @@
* cache the buffer.
*/
bp->b_flags |= B_INVAL;
- if (LIST_FIRST(&bp->b_dep) != NULL && bioops.io_deallocate)
- (*bioops.io_deallocate)(bp);
+ if (LIST_FIRST(&bp->b_dep) != NULL)
+ buf_deallocate(bp);
if (bp->b_flags & B_DELWRI) {
--numdirtybuffers;
numdirtywakeup();
@@ -1570,8 +1570,8 @@
crfree(bp->b_wcred);
bp->b_wcred = NOCRED;
}
- if (LIST_FIRST(&bp->b_dep) != NULL && bioops.io_deallocate)
- (*bioops.io_deallocate)(bp);
+ if (LIST_FIRST(&bp->b_dep) != NULL)
+ buf_deallocate(bp);
if (bp->b_xflags & BX_BKGRDINPROG)
panic("losing buffer 3");
LIST_REMOVE(bp, b_hash);
@@ -1848,9 +1848,8 @@
break;
}
if (LIST_FIRST(&bp->b_dep) != NULL &&
- bioops.io_countdeps &&
(bp->b_flags & B_DEFERRED) == 0 &&
- (*bioops.io_countdeps)(bp, 0)) {
+ buf_countdeps(bp, 0)) {
TAILQ_REMOVE(&bufqueues[QUEUE_DIRTY],
bp, b_freelist);
TAILQ_INSERT_TAIL(&bufqueues[QUEUE_DIRTY],
@@ -2664,8 +2663,8 @@
splx(s);
return;
}
- if (LIST_FIRST(&bp->b_dep) != NULL && bioops.io_complete)
- (*bioops.io_complete)(bp);
+ if (LIST_FIRST(&bp->b_dep) != NULL)
+ buf_complete(bp);
if (bp->b_flags & B_VMIO) {
int i, resid;
Index: kern/vfs_cluster.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/vfs_cluster.c,v
retrieving revision 1.98
diff -u -r1.98 vfs_cluster.c
--- kern/vfs_cluster.c 2000/05/05 09:58:25 1.98
+++ kern/vfs_cluster.c 2000/06/14 19:01:13
@@ -805,9 +805,8 @@
splx(s);
} /* end of code for non-first buffers only */
/* check for latent dependencies to be handled */
- if ((LIST_FIRST(&tbp->b_dep)) != NULL &&
- bioops.io_start)
- (*bioops.io_start)(tbp);
+ if ((LIST_FIRST(&tbp->b_dep)) != NULL)
+ buf_start(tbp);
/*
* If the IO is via the VM then we do some
* special VM hackery. (yuck)
Index: kern/vfs_subr.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/vfs_subr.c,v
retrieving revision 1.257
diff -u -r1.257 vfs_subr.c
--- kern/vfs_subr.c 2000/05/26 02:04:39 1.257
+++ kern/vfs_subr.c 2000/06/14 19:56:33
@@ -1029,8 +1029,7 @@
/*
* Do soft update processing.
*/
- if (bioops.io_sync)
- (*bioops.io_sync)(NULL);
+ softdep_process_worklist(NULL);
/*
* The variable rushjob allows the kernel to speed up the
Index: kern/vfs_syscalls.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/vfs_syscalls.c,v
retrieving revision 1.153
diff -u -r1.153 vfs_syscalls.c
--- kern/vfs_syscalls.c 2000/05/05 09:58:27 1.153
+++ kern/vfs_syscalls.c 2000/06/14 19:38:24
@@ -2545,10 +2545,7 @@
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
if (vp->v_object)
vm_object_page_clean(vp->v_object, 0, 0, 0);
- if ((error = VOP_FSYNC(vp, fp->f_cred, MNT_WAIT, p)) == 0 &&
- vp->v_mount && (vp->v_mount->mnt_flag & MNT_SOFTDEP) &&
- bioops.io_fsync)
- error = (*bioops.io_fsync)(vp);
+ error = VOP_FSYNC(vp, fp->f_cred, MNT_WAIT, p);
VOP_UNLOCK(vp, 0, p);
return (error);
}
Index: miscfs/devfs/devfs_vnops.c
===================================================================
RCS file: /home/ncvs/src/sys/miscfs/devfs/devfs_vnops.c,v
retrieving revision 1.96
diff -u -r1.96 devfs_vnops.c
--- miscfs/devfs/devfs_vnops.c 2000/05/05 09:58:29 1.96
+++ miscfs/devfs/devfs_vnops.c 2000/06/14 19:02:35
@@ -1570,9 +1570,8 @@
return error;
- if ((bp->b_iocmd == BIO_WRITE) &&
- (LIST_FIRST(&bp->b_dep)) != NULL && bioops.io_start)
- (*bioops.io_start)(bp);
+ if ((bp->b_iocmd == BIO_WRITE) && (LIST_FIRST(&bp->b_dep)) != NULL)
+ buf_start(bp);
switch (vp->v_type) {
case VCHR:
(*vp->v_rdev->si_devsw->d_strategy)(&bp->b_io);
Index: miscfs/specfs/spec_vnops.c
===================================================================
RCS file: /home/ncvs/src/sys/miscfs/specfs/spec_vnops.c,v
retrieving revision 1.138
diff -u -r1.138 spec_vnops.c
--- miscfs/specfs/spec_vnops.c 2000/06/12 10:20:18 1.138
+++ miscfs/specfs/spec_vnops.c 2000/06/14 19:02:49
@@ -417,9 +417,8 @@
struct mount *mp;
bp = ap->a_bp;
- if ((bp->b_iocmd == BIO_WRITE) &&
- (LIST_FIRST(&bp->b_dep)) != NULL && bioops.io_start)
- (*bioops.io_start)(bp);
+ if ((bp->b_iocmd == BIO_WRITE) && (LIST_FIRST(&bp->b_dep)) != NULL)
+ buf_start(bp);
/*
* Collect statistics on synchronous and asynchronous read
Index: sys/buf.h
===================================================================
RCS file: /home/ncvs/src/sys/sys/buf.h,v
retrieving revision 1.103
diff -u -r1.103 buf.h
--- sys/buf.h 2000/05/26 02:06:53 1.103
+++ sys/buf.h 2000/06/14 19:26:59
@@ -64,8 +64,6 @@
void (*io_start) __P((struct buf *));
void (*io_complete) __P((struct buf *));
void (*io_deallocate) __P((struct buf *));
- int (*io_fsync) __P((struct vnode *));
- int (*io_sync) __P((struct mount *));
void (*io_movedeps) __P((struct buf *, struct buf *));
int (*io_countdeps) __P((struct buf *, int));
} bioops;
@@ -405,6 +403,43 @@
#define BUF_WRITE(bp) VOP_BWRITE((bp)->b_vp, (bp))
#define BUF_STRATEGY(bp) VOP_STRATEGY((bp)->b_vp, (bp))
+
+static __inline void
+buf_start(struct buf *bp)
+{
+ if (bioops.io_start)
+ (*bioops.io_start)(bp);
+}
+
+static __inline void
+buf_complete(struct buf *bp)
+{
+ if (bioops.io_complete)
+ (*bioops.io_complete)(bp);
+}
+
+static __inline void
+buf_deallocate(struct buf *bp)
+{
+ if (bioops.io_deallocate)
+ (*bioops.io_deallocate)(bp);
+}
+
+static __inline void
+buf_movedeps(struct buf *bp, struct buf *bp2)
+{
+ if (bioops.io_movedeps)
+ (*bioops.io_movedeps)(bp, bp2);
+}
+
+static __inline int
+buf_countdeps(struct buf *bp, int i)
+{
+ if (bioops.io_countdeps)
+ return ((*bioops.io_countdeps)(bp, i));
+ else
+ return (0);
+}
#endif /* _KERNEL */
Index: sys/mount.h
===================================================================
RCS file: /home/ncvs/src/sys/sys/mount.h,v
retrieving revision 1.91
diff -u -r1.91 mount.h
--- sys/mount.h 2000/05/26 02:06:55 1.91
+++ sys/mount.h 2000/06/14 19:58:22
@@ -447,6 +447,7 @@
int vfs_stdextattrctl __P((struct mount *mp, int cmd, const char *attrname,
caddr_t arg, struct proc *p));
+void softdep_process_worklist __P((struct mount *));
#else /* !_KERNEL */
#include <sys/cdefs.h>
Index: ufs/ffs/ffs_softdep_stub.c
===================================================================
RCS file: /home/ncvs/src/sys/ufs/ffs/ffs_softdep_stub.c,v
retrieving revision 1.8
diff -u -r1.8 ffs_softdep_stub.c
--- ufs/ffs/ffs_softdep_stub.c 2000/04/19 14:58:25 1.8
+++ ufs/ffs/ffs_softdep_stub.c 2000/06/14 19:33:11
@@ -254,4 +254,20 @@
return (0);
}
+
+int
+softdep_fsync(vp)
+ struct vnode *vp; /* the "in_core" copy of the inode */
+{
+
+ return (0);
+}
+
+int
+softdep_process_worklist(matchmnt)
+ struct mount *matchmnt;
+{
+ return (0);
+}
+
#endif /* SOFTUPDATES not configured in */
Index: ufs/ffs/ffs_vnops.c
===================================================================
RCS file: /home/ncvs/src/sys/ufs/ffs/ffs_vnops.c,v
retrieving revision 1.66
diff -u -r1.66 ffs_vnops.c
--- ufs/ffs/ffs_vnops.c 2000/05/05 09:59:05 1.66
+++ ufs/ffs/ffs_vnops.c 2000/06/14 19:38:13
@@ -175,7 +175,7 @@
continue;
if (!wait && LIST_FIRST(&bp->b_dep) != NULL &&
(bp->b_flags & B_DEFERRED) == 0 &&
- bioops.io_countdeps && (*bioops.io_countdeps)(bp, 0)) {
+ buf_countdeps(bp, 0)) {
bp->b_flags |= B_DEFERRED;
continue;
}
@@ -278,5 +278,8 @@
}
}
splx(s);
- return (UFS_UPDATE(vp, wait));
+ error = UFS_UPDATE(vp, wait);
+ if (error == 0 && vp->v_mount && (vp->v_mount->mnt_flag & MNT_SOFTDEP))
+ error = softdep_fsync(vp);
+ return (error);
}
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
[EMAIL PROTECTED] | TCP/IP since RFC 956
FreeBSD coreteam member | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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