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In the mknod(), mkfifo(), link(), symlink() and undelete() syscalls,

Browse Source 
use vrele() instead of vput() on the parent directory vnode returned
by namei() in the case where it is equal to the target vnode. This
handles namei()'s somewhat strange (but documented) behaviour of
not locking either vnode when the two vnodes are equal and LOCKPARENT
but not LOCKLEAF is specified.

Note that since a vnode double-unlock is not currently fatal, these
coding errors were effectively harmless.

Spotted by:	Juergen Hannken-Illjes <hannken@eis.cs.tu-bs.de>
Reviewed by:	mckusick
This commit is contained in:
iedowse 2003-08-05 00:26:51 +00:00
parent c5cc3acad0
commit 7bf5fa9caf
2 changed files with 46 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
sys/kern/vfs_extattr.c
View File

@ -907,8 +907,13 @@ kern_mknod(struct thread *td, char *path, enum uio_seg pathseg, int mode,
return (error);
vp = nd.ni_vp;
if (vp != NULL) {
NDFREE(&nd, NDF_ONLY_PNBUF);
vrele(vp);
error = EEXIST;
if (vp == nd.ni_dvp)
vrele(nd.ni_dvp);
else
vput(nd.ni_dvp);
return (EEXIST);
} else {
VATTR_NULL(&vattr);
FILEDESC_LOCK(td->td_proc->p_fd);
@ -1005,7 +1010,10 @@ kern_mkfifo(struct thread *td, char *path, enum uio_seg pathseg, int mode)
if (nd.ni_vp != NULL) {
NDFREE(&nd, NDF_ONLY_PNBUF);
vrele(nd.ni_vp);
vput(nd.ni_dvp);
if (nd.ni_vp == nd.ni_dvp)
vrele(nd.ni_dvp);
else
vput(nd.ni_dvp);
return (EEXIST);
}
if (vn_start_write(nd.ni_dvp, &mp, V_NOWAIT) != 0) {
@ -1087,6 +1095,10 @@ kern_link(struct thread *td, char *path, char *link, enum uio_seg segflg)
if ((error = namei(&nd)) == 0) {
if (nd.ni_vp != NULL) {
vrele(nd.ni_vp);
if (nd.ni_dvp == nd.ni_vp)
vrele(nd.ni_dvp);
else
vput(nd.ni_dvp);
error = EEXIST;
} else if ((error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td))
== 0) {
@ -1099,9 +1111,9 @@ kern_link(struct thread *td, char *path, char *link, enum uio_seg segflg)
#endif
error = VOP_LINK(nd.ni_dvp, vp, &nd.ni_cnd);
VOP_UNLOCK(vp, 0, td);
vput(nd.ni_dvp);
}
NDFREE(&nd, NDF_ONLY_PNBUF);
vput(nd.ni_dvp);
}
vrele(vp);
vn_finished_write(mp);
@ -1156,7 +1168,10 @@ kern_symlink(struct thread *td, char *path, char *link, enum uio_seg segflg)
if (nd.ni_vp) {
NDFREE(&nd, NDF_ONLY_PNBUF);
vrele(nd.ni_vp);
vput(nd.ni_dvp);
if (nd.ni_vp == nd.ni_dvp)
vrele(nd.ni_dvp);
else
vput(nd.ni_dvp);
error = EEXIST;
goto out;
}
@ -1223,7 +1238,10 @@ undelete(td, uap)
NDFREE(&nd, NDF_ONLY_PNBUF);
if (nd.ni_vp)
vrele(nd.ni_vp);
vput(nd.ni_dvp);
if (nd.ni_vp == nd.ni_dvp)
vrele(nd.ni_dvp);
else
vput(nd.ni_dvp);
return (EEXIST);
}
if (vn_start_write(nd.ni_dvp, &mp, V_NOWAIT) != 0) {

28
sys/kern/vfs_syscalls.c
View File

@ -907,8 +907,13 @@ kern_mknod(struct thread *td, char *path, enum uio_seg pathseg, int mode,
return (error);
vp = nd.ni_vp;
if (vp != NULL) {
NDFREE(&nd, NDF_ONLY_PNBUF);
vrele(vp);
error = EEXIST;
if (vp == nd.ni_dvp)
vrele(nd.ni_dvp);
else
vput(nd.ni_dvp);
return (EEXIST);
} else {
VATTR_NULL(&vattr);
FILEDESC_LOCK(td->td_proc->p_fd);
@ -1005,7 +1010,10 @@ kern_mkfifo(struct thread *td, char *path, enum uio_seg pathseg, int mode)
if (nd.ni_vp != NULL) {
NDFREE(&nd, NDF_ONLY_PNBUF);
vrele(nd.ni_vp);
vput(nd.ni_dvp);
if (nd.ni_vp == nd.ni_dvp)
vrele(nd.ni_dvp);
else
vput(nd.ni_dvp);
return (EEXIST);
}
if (vn_start_write(nd.ni_dvp, &mp, V_NOWAIT) != 0) {
@ -1087,6 +1095,10 @@ kern_link(struct thread *td, char *path, char *link, enum uio_seg segflg)
if ((error = namei(&nd)) == 0) {
if (nd.ni_vp != NULL) {
vrele(nd.ni_vp);
if (nd.ni_dvp == nd.ni_vp)
vrele(nd.ni_dvp);
else
vput(nd.ni_dvp);
error = EEXIST;
} else if ((error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td))
== 0) {
@ -1099,9 +1111,9 @@ kern_link(struct thread *td, char *path, char *link, enum uio_seg segflg)
#endif
error = VOP_LINK(nd.ni_dvp, vp, &nd.ni_cnd);
VOP_UNLOCK(vp, 0, td);
vput(nd.ni_dvp);
}
NDFREE(&nd, NDF_ONLY_PNBUF);
vput(nd.ni_dvp);
}
vrele(vp);
vn_finished_write(mp);
@ -1156,7 +1168,10 @@ kern_symlink(struct thread *td, char *path, char *link, enum uio_seg segflg)
if (nd.ni_vp) {
NDFREE(&nd, NDF_ONLY_PNBUF);
vrele(nd.ni_vp);
vput(nd.ni_dvp);
if (nd.ni_vp == nd.ni_dvp)
vrele(nd.ni_dvp);
else
vput(nd.ni_dvp);
error = EEXIST;
goto out;
}
@ -1223,7 +1238,10 @@ undelete(td, uap)
NDFREE(&nd, NDF_ONLY_PNBUF);
if (nd.ni_vp)
vrele(nd.ni_vp);
vput(nd.ni_dvp);
if (nd.ni_vp == nd.ni_dvp)
vrele(nd.ni_dvp);
else
vput(nd.ni_dvp);
return (EEXIST);
}
if (vn_start_write(nd.ni_dvp, &mp, V_NOWAIT) != 0) {