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Don't go to a whole lot of extra work to handle the race where the new

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file descriptor is closed out from under us in kern_open().  This race
is already handled and the file will be closed when kern_open() does an
fdrop just before returning.
This commit is contained in:
John Baldwin 2007-04-02 13:40:38 +00:00
parent 8427171a34
commit ebb3c22c16
1 changed files with 2 additions and 25 deletions
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27
sys/kern/vfs_syscalls.c
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@ -1024,31 +1024,8 @@ kern_open(struct thread *td, char *path, enum uio_seg pathseg, int flags,
NDFREE(&nd, NDF_ONLY_PNBUF);
vp = nd.ni_vp;
/*
* There should be 2 references on the file, one from the descriptor
* table, and one for us.
*
* Handle the case where someone closed the file (via its file
* descriptor) while we were blocked. The end result should look
* like opening the file succeeded but it was immediately closed.
* We call vn_close() manually because we haven't yet hooked up
* the various 'struct file' fields.
*/
FILEDESC_LOCK(fdp);
FILEDESC_LOCK_FAST(fdp);
FILE_LOCK(fp);
if (fp->f_count == 1) {
mp = vp->v_mount;
KASSERT(fdp->fd_ofiles[indx] != fp,
("Open file descriptor lost all refs"));
FILE_UNLOCK(fp);
FILEDESC_UNLOCK(fdp);
VOP_UNLOCK(vp, 0, td);
vn_close(vp, flags & FMASK, fp->f_cred, td);
VFS_UNLOCK_GIANT(vfslocked);
fdrop(fp, td);
td->td_retval[0] = indx;
return (0);
}
fp->f_vnode = vp;
if (fp->f_data == NULL)
fp->f_data = vp;
@ -1058,7 +1035,7 @@ kern_open(struct thread *td, char *path, enum uio_seg pathseg, int flags,
fp->f_seqcount = 1;
fp->f_type = (vp->v_type == VFIFO ? DTYPE_FIFO : DTYPE_VNODE);
FILE_UNLOCK(fp);
FILEDESC_UNLOCK(fdp);
FILEDESC_UNLOCK_FAST(fdp);
VOP_UNLOCK(vp, 0, td);
if (flags & (O_EXLOCK | O_SHLOCK)) {