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- Solve a problem where a vput could be called on an outgoing directory

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without Giant held.  Do this by tracking the vfslocked state for
   the directory seperate from the child.  This is only important
   in the case where we cross a mountpoint.

Sponsored by:	Isilon Systems, Inc.
MFC After:	3 days
This commit is contained in:
Jeff Roberson 2006-02-01 09:34:32 +00:00
parent 0ac72424f0
commit 9157b485f0
1 changed files with 13 additions and 5 deletions
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18
sys/kern/vfs_lookup.c
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@ -60,7 +60,7 @@ __FBSDID("$FreeBSD$");
#include <vm/uma.h>
#define NAMEI_DIAGNOSTIC 1
#define NAMEI_DIAGNOSTIC 1
#undef NAMEI_DIAGNOSTIC
/*
@ -352,11 +352,13 @@ lookup(ndp)
struct thread *td = cnp->cn_thread;
int vfslocked;
int tvfslocked;
int dvfslocked;
/*
* Setup: break out flag bits into variables.
*/
vfslocked = (ndp->ni_cnd.cn_flags & GIANTHELD) != 0;
dvfslocked = 0;
ndp->ni_cnd.cn_flags &= ~GIANTHELD;
wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT);
KASSERT(cnp->cn_nameiop == LOOKUP || wantparent,
@ -623,9 +625,8 @@ unionlookup:
if (vfs_busy(mp, 0, 0, td))
continue;
vput(dp);
tvfslocked = VFS_LOCK_GIANT(mp);
VFS_UNLOCK_GIANT(vfslocked);
vfslocked = tvfslocked;
dvfslocked = vfslocked;
vfslocked = VFS_LOCK_GIANT(mp);
VOP_UNLOCK(ndp->ni_dvp, 0, td);
error = VFS_ROOT(mp, cnp->cn_lkflags, &tdp, td);
VOP_LOCK(ndp->ni_dvp, cnp->cn_lkflags | LK_RETRY, td);
@ -687,6 +688,8 @@ nextname:
vput(ndp->ni_dvp);
else
vrele(ndp->ni_dvp);
VFS_UNLOCK_GIANT(dvfslocked);
dvfslocked = 0;
goto dirloop;
}
/*
@ -706,13 +709,17 @@ nextname:
vput(ndp->ni_dvp);
else
vrele(ndp->ni_dvp);
VFS_UNLOCK_GIANT(dvfslocked);
dvfslocked = 0;
} else if ((cnp->cn_flags & LOCKPARENT) == 0 && ndp->ni_dvp != dp)
VOP_UNLOCK(ndp->ni_dvp, 0, td);
if ((cnp->cn_flags & LOCKLEAF) == 0)
VOP_UNLOCK(dp, 0, td);
success:
if (vfslocked)
if (vfslocked && dvfslocked)
VFS_UNLOCK_GIANT(dvfslocked); /* Only need one */
if (vfslocked || dvfslocked)
ndp->ni_cnd.cn_flags |= GIANTHELD;
return (0);
@ -725,6 +732,7 @@ bad:
if (!dpunlocked)
vput(dp);
VFS_UNLOCK_GIANT(vfslocked);
VFS_UNLOCK_GIANT(dvfslocked);
ndp->ni_cnd.cn_flags &= ~GIANTHELD;
ndp->ni_vp = NULL;
return (error);