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- Do a vn_start_write in vn_close, we may write if this is the last ref

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on an unlinked file.  We can't know if this is the case until after we
   have the lock.
 - Lock the vnode in vn_close, many filesystems had code which was unsafe
   without the lock held, and holding it greatly simplifies vgone().
 - Adjust vn_lock() to check for the VI_DOOMED flag where appropriate.

Sponsored by:	Isilon Systems, Inc.
This commit is contained in:
Jeff Roberson 2005-03-13 11:56:28 +00:00
parent 6703c30bb5
commit 0463dc9ef1
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=143498
1 changed files with 20 additions and 21 deletions
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41
sys/kern/vfs_vnops.c
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@ -288,23 +288,18 @@ vn_close(vp, flags, file_cred, td)
struct ucred *file_cred;
struct thread *td;
{
struct mount *mp;
int error;
VFS_ASSERT_GIANT(vp->v_mount);
vn_start_write(vp, &mp, V_WAIT);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
if (flags & FWRITE)
vp->v_writecount--;
error = VOP_CLOSE(vp, flags, file_cred, td);
/*
* XXX - In certain instances VOP_CLOSE has to do the vrele
* itself. If the vrele has been done, it will return EAGAIN
* to indicate that the vrele should not be done again. When
* this happens, we just return success. The correct thing to
* do would be to have all VOP_CLOSE instances do the vrele.
*/
if (error == EAGAIN)
return (0);
vrele(vp);
vput(vp);
vn_finished_write(mp);
return (error);
}
@ -817,17 +812,11 @@ debug_vn_lock(vp, flags, td, filename, line)
do {
if ((flags & LK_INTERLOCK) == 0)
VI_LOCK(vp);
if ((vp->v_iflag & VI_XLOCK) && vp->v_vxthread != curthread) {
if ((flags & LK_NOWAIT) != 0) {
VI_UNLOCK(vp);
return (ENOENT);
}
vx_waitl(vp);
if ((flags & LK_RETRY) == 0) {
VI_UNLOCK(vp);
return (ENOENT);
}
}
if ((vp->v_iflag & VI_DOOMED) && vp->v_vxthread != td &&
(flags & LK_NOWAIT)) {
VI_UNLOCK(vp);
return (ENOENT);
}
#ifdef DEBUG_LOCKS
vp->filename = filename;
vp->line = line;
@ -838,6 +827,16 @@ debug_vn_lock(vp, flags, td, filename, line)
*/
error = VOP_LOCK(vp, flags | LK_NOPAUSE | LK_INTERLOCK, td);
flags &= ~LK_INTERLOCK;
/*
* Callers specify LK_RETRY if they wish to get dead vnodes.
* If RETRY is not set, we return ENOENT instead.
*/
if (error != 0 && (vp->v_iflag & VI_DOOMED) &&
vp->v_vxthread != td && (flags & LK_RETRY) == 0) {
VOP_UNLOCK(vp, 0, td);
error = ENOENT;
break;
}
} while (flags & LK_RETRY && error != 0);
return (error);
}