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Handle a case in kern_openat() when vn_open() change file type from

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DTYPE_VNODE.

Only acquire locks for O_EXLOCK/O_SHLOCK if file type is still vnode,
since we allow for fcntl(2) to process with advisory locks for
DTYPE_VNODE only. Another reason is that all fo_close() routines need to
check and release locks otherwise.

For O_TRUNC, call fo_truncate() instead of truncating the vnode.

Discussed with:	rwatson
MFC after:	2 week
This commit is contained in:
Konstantin Belousov 2010-04-13 08:52:20 +00:00
parent 5478ba7358
commit d5ff273563
1 changed files with 2 additions and 15 deletions
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17
sys/kern/vfs_syscalls.c
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@ -1047,8 +1047,6 @@ kern_openat(struct thread *td, int fd, char *path, enum uio_seg pathseg,
struct filedesc *fdp = p->p_fd;
struct file *fp;
struct vnode *vp;
struct vattr vat;
struct mount *mp;
int cmode;
struct file *nfp;
int type, indx, error;
@ -1141,7 +1139,7 @@ kern_openat(struct thread *td, int fd, char *path, enum uio_seg pathseg,
}
VOP_UNLOCK(vp, 0);
if (flags & (O_EXLOCK | O_SHLOCK)) {
if (fp->f_type == DTYPE_VNODE && (flags & (O_EXLOCK | O_SHLOCK)) != 0) {
lf.l_whence = SEEK_SET;
lf.l_start = 0;
lf.l_len = 0;
@ -1158,18 +1156,7 @@ kern_openat(struct thread *td, int fd, char *path, enum uio_seg pathseg,
atomic_set_int(&fp->f_flag, FHASLOCK);
}
if (flags & O_TRUNC) {
if ((error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0)
goto bad;
VATTR_NULL(&vat);
vat.va_size = 0;
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
#ifdef MAC
error = mac_vnode_check_write(td->td_ucred, fp->f_cred, vp);
if (error == 0)
#endif
error = VOP_SETATTR(vp, &vat, td->td_ucred);
VOP_UNLOCK(vp, 0);
vn_finished_write(mp);
error = fo_truncate(fp, 0, td->td_ucred, td);
if (error)
goto bad;
}