d/freebsd-nq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Fix autofs triggering problem. Assume you have an NFS server,

Browse Source 
192.168.1.1, with share "share". This commit fixes a problem
where "mkdir /net/192.168.1.1/share/meh" would return spurious
error instead of creating the directory if the target filesystem
wasn't mounted yet; subsequent attempts would work correctly.

The failure scenario is kind of complicated to explain, but it all
boils down to calling VOP_MKDIR() for the target filesystem (NFS)
with wrong dvp - the autofs vnode instead of the filesystem root
mounted over it.

Reviewed by:	kib@
MFC after:	1 month
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D5442
This commit is contained in:
Edward Tomasz Napierala 2016-03-12 07:54:42 +00:00
parent 6d3eca246c
commit 213ed83855
3 changed files with 26 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
sys/fs/autofs/autofs_vnops.c
View File

@ -214,7 +214,7 @@ autofs_lookup(struct vop_lookup_args *ap)
struct autofs_mount *amp;
struct autofs_node *anp, *child;
struct componentname *cnp;
int error, lock_flags;
int error;
dvp = ap->a_dvp;
vpp = ap->a_vpp;
@ -257,23 +257,13 @@ autofs_lookup(struct vop_lookup_args *ap)
return (error);
if (newvp != NULL) {
error = VOP_LOOKUP(newvp, ap->a_vpp, ap->a_cnp);
/*
* Instead of figuring out whether our vnode should
* be locked or not given the error and cnp flags,
* just "copy" the lock status from vnode returned
* by mounted filesystem's VOP_LOOKUP(). Get rid
* of that new vnode afterwards.
* The target filesystem got automounted.
* Let the lookup(9) go around with the same
* path component.
*/
lock_flags = VOP_ISLOCKED(newvp);
if (lock_flags == 0) {
VOP_UNLOCK(dvp, 0);
vrele(newvp);
} else {
vput(newvp);
}
return (error);
vput(newvp);
return (ERELOOKUP);
}
}

19
sys/kern/vfs_lookup.c
View File

@ -495,6 +495,7 @@ lookup(struct nameidata *ndp)
int rdonly; /* lookup read-only flag bit */
int error = 0;
int dpunlocked = 0; /* dp has already been unlocked */
int relookup = 0; /* do not consume the path component */
struct componentname *cnp = &ndp->ni_cnd;
int lkflags_save;
int ni_dvp_unlocked;
@ -745,6 +746,14 @@ lookup(struct nameidata *ndp)
goto unionlookup;
}
if (error == ERELOOKUP) {
vref(dp);
ndp->ni_vp = dp;
error = 0;
relookup = 1;
goto good;
}
if (error != EJUSTRETURN)
goto bad;
/*
@ -777,6 +786,8 @@ lookup(struct nameidata *ndp)
goto success;
} else
cnp->cn_lkflags = lkflags_save;
good:
#ifdef NAMEI_DIAGNOSTIC
printf("found\n");
#endif
@ -856,6 +867,14 @@ lookup(struct nameidata *ndp)
*/
KASSERT((cnp->cn_flags & ISLASTCN) || *ndp->ni_next == '/',
("lookup: invalid path state."));
if (relookup) {
relookup = 0;
if (ndp->ni_dvp != dp)
vput(ndp->ni_dvp);
else
vrele(ndp->ni_dvp);
goto dirloop;
}
if (*ndp->ni_next == '/') {
cnp->cn_nameptr = ndp->ni_next;
while (*cnp->cn_nameptr == '/') {

1
sys/sys/errno.h
View File

@ -190,6 +190,7 @@ __END_DECLS
#define EJUSTRETURN (-2) /* don't modify regs, just return */
#define ENOIOCTL (-3) /* ioctl not handled by this layer */
#define EDIRIOCTL (-4) /* do direct ioctl in GEOM */
#define ERELOOKUP (-5) /* retry the directory lookup */
#endif
#endif