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vfs: simplify error handling in namei

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The logic is reorganised so that there is one exit point prior to the
lookup loop. This is an intermediate step to making audit logging
functions use found vnode instead of translating ni_dirfd on their own.

ni_startdir validation is removed. The only in-tree consumer is nfs
which already makes sure it is a directory.

Reviewed by:	kib
This commit is contained in:
Mateusz Guzik 2015-07-09 16:32:58 +00:00
parent 56844a6203
commit d177f49f6f
1 changed files with 20 additions and 29 deletions
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49
sys/kern/vfs_lookup.c
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@ -158,7 +158,7 @@ namei(struct nameidata *ndp)
struct vnode *dp; /* the directory we are searching */
struct iovec aiov; /* uio for reading symbolic links */
struct uio auio;
int error, linklen;
int error, linklen, startdir_used;
struct componentname *cnp = &ndp->ni_cnd;
struct thread *td = cnp->cn_thread;
struct proc *p = td->td_proc;
@ -169,6 +169,8 @@ namei(struct nameidata *ndp)
("namei: nameiop contaminated with flags"));
KASSERT((cnp->cn_flags & OPMASK) == 0,
("namei: flags contaminated with nameiops"));
MPASS(ndp->ni_startdir == NULL || ndp->ni_startdir->v_type == VDIR ||
ndp->ni_startdir->v_type == VBAD);
if (!lookup_shared)
cnp->cn_flags &= ~LOCKSHARED;
fdp = p->p_fd;
@ -242,23 +244,19 @@ namei(struct nameidata *ndp)
if (cnp->cn_flags & AUDITVNODE2)
AUDIT_ARG_UPATH2(td, ndp->ni_dirfd, cnp->cn_pnbuf);
startdir_used = 0;
dp = NULL;
cnp->cn_nameptr = cnp->cn_pnbuf;
if (cnp->cn_pnbuf[0] == '/') {
error = namei_handle_root(ndp, &dp);
FILEDESC_SUNLOCK(fdp);
if (error != 0) {
vrele(ndp->ni_rootdir);
if (ndp->ni_startdir != NULL)
vrele(ndp->ni_startdir);
namei_cleanup_cnp(cnp);
return (error);
}
} else {
if (ndp->ni_startdir != NULL) {
dp = ndp->ni_startdir;
error = 0;
} else if (ndp->ni_dirfd != AT_FDCWD) {
startdir_used = 1;
} else if (ndp->ni_dirfd == AT_FDCWD) {
dp = fdp->fd_cdir;
VREF(dp);
} else {
cap_rights_t rights;
rights = ndp->ni_rightsneeded;
@ -285,25 +283,18 @@ namei(struct nameidata *ndp)
}
#endif
}
if (error != 0 || dp != NULL) {
FILEDESC_SUNLOCK(fdp);
if (error == 0 && dp->v_type != VDIR) {
vrele(dp);
error = ENOTDIR;
}
}
if (error) {
vrele(ndp->ni_rootdir);
namei_cleanup_cnp(cnp);
return (error);
}
if (error == 0 && dp->v_type != VDIR)
error = ENOTDIR;
}
if (dp == NULL) {
dp = fdp->fd_cdir;
VREF(dp);
FILEDESC_SUNLOCK(fdp);
if (ndp->ni_startdir != NULL)
vrele(ndp->ni_startdir);
FILEDESC_SUNLOCK(fdp);
if (ndp->ni_startdir != NULL && !startdir_used)
vrele(ndp->ni_startdir);
if (error != 0) {
if (dp != NULL)
vrele(dp);
vrele(ndp->ni_rootdir);
namei_cleanup_cnp(cnp);
return (error);
}
SDT_PROBE(vfs, namei, lookup, entry, dp, cnp->cn_pnbuf,
cnp->cn_flags, 0, 0);