>this one from -aa fixes fasync too. Please review, thanks.
>
>--- odirect/fs/fcntl.c.~1~ Fri Jul 5 12:20:47 2002
>+++ odirect/fs/fcntl.c Sat Jul 6 18:53:56 2002
>@@ -213,32 +213,29 @@ static int setfl(int fd, struct file * f
> if (!(arg & O_APPEND) && IS_APPEND(inode))
> return -EPERM;
>
>+ /*
>+ * alloc_kiovec() and ->fasync can sleep, so abuse the i_sem
>+ * to serialize against parallel setfl on the same filp,
>+ * to avoid races with ->f_flags and ->f_iobuf.
>+ */
>+ down(&inode->i_sem);
^^^^
> /* Did FASYNC state change? */
> if ((arg ^ filp->f_flags) & FASYNC) {
> if (filp->f_op && filp->f_op->fasync) {
>+ lock_kernel();
> error = filp->f_op->fasync(fd, filp, (arg & FASYNC) !=
> 0);
>+ unlock_kernel();
...
You introduce locking that hasn't been there previously.
To keep things in sync, ioctl.c needs to take i_sem also. In kernel 2.5,
pipe.c needs to move acquisition of i_sem to the surrounding functions.
Patch below. (Trivial documentation update added)
Could somebody please verify this?
Marcus
===== Documentation/filesystems/Locking 1.32 vs edited =====
--- 1.32/Documentation/filesystems/Locking Wed Jul 3 03:22:36 2002
+++ edited/Documentation/filesystems/Locking Thu Jul 11 23:03:52 2002
@@ -343,6 +343,8 @@
->fsync() has i_sem on inode.
+->fasync() has i_sem on inode.
+
--------------------------- dquot_operations -------------------------------
prototypes:
void (*initialize) (struct inode *, short);
===== fs/ioctl.c 1.4 vs edited =====
--- 1.4/fs/ioctl.c Sat May 18 20:50:00 2002
+++ edited/fs/ioctl.c Thu Jul 11 23:49:25 2002
@@ -82,10 +82,13 @@
filp->f_flags &= ~flag;
break;
- case FIOASYNC:
+ case FIOASYNC: {
+ struct inode * inode;
if ((error = get_user(on, (int *)arg)) != 0)
break;
flag = on ? FASYNC : 0;
+ inode = filp->f_dentry->d_inode;
+ down(&inode->i_sem);
/* Did FASYNC state change ? */
if ((flag ^ filp->f_flags) & FASYNC) {
@@ -94,13 +97,16 @@
else error = -ENOTTY;
}
if (error != 0)
- break;
+ goto fioasync_out;
if (on)
filp->f_flags |= FASYNC;
else
filp->f_flags &= ~FASYNC;
+ fioasync_out:
+ up(&inode->i_sem);
break;
+ }
case FIOQSIZE:
if (S_ISDIR(filp->f_dentry->d_inode->i_mode) ||
===== fs/pipe.c 1.14 vs edited =====
--- 1.14/fs/pipe.c Wed Jun 12 03:23:20 2002
+++ edited/fs/pipe.c Thu Jul 11 23:23:58 2002
@@ -329,9 +329,7 @@
struct inode *inode = filp->f_dentry->d_inode;
int retval;
- down(PIPE_SEM(*inode));
retval = fasync_helper(fd, filp, on, PIPE_FASYNC_READERS(*inode));
- up(PIPE_SEM(*inode));
if (retval < 0)
return retval;
@@ -346,9 +344,7 @@
struct inode *inode = filp->f_dentry->d_inode;
int retval;
- down(PIPE_SEM(*inode));
retval = fasync_helper(fd, filp, on, PIPE_FASYNC_WRITERS(*inode));
- up(PIPE_SEM(*inode));
if (retval < 0)
return retval;
@@ -363,15 +359,11 @@
struct inode *inode = filp->f_dentry->d_inode;
int retval;
- down(PIPE_SEM(*inode));
-
retval = fasync_helper(fd, filp, on, PIPE_FASYNC_READERS(*inode));
if (retval >= 0)
retval = fasync_helper(fd, filp, on, PIPE_FASYNC_WRITERS(*inode));
- up(PIPE_SEM(*inode));
-
if (retval < 0)
return retval;
@@ -382,14 +374,18 @@
static int
pipe_read_release(struct inode *inode, struct file *filp)
{
+ down(PIPE_SEM(*inode));
pipe_read_fasync(-1, filp, 0);
+ up(PIPE_SEM(*inode));
return pipe_release(inode, 1, 0);
}
static int
pipe_write_release(struct inode *inode, struct file *filp)
{
+ down(PIPE_SEM(*inode));
pipe_write_fasync(-1, filp, 0);
+ up(PIPE_SEM(*inode));
return pipe_release(inode, 0, 1);
}
@@ -398,7 +394,9 @@
{
int decr, decw;
+ down(PIPE_SEM(*inode));
pipe_rdwr_fasync(-1, filp, 0);
+ up(PIPE_SEM(*inode));
decr = (filp->f_mode & FMODE_READ) != 0;
decw = (filp->f_mode & FMODE_WRITE) != 0;
return pipe_release(inode, decr, decw);
-- Marcus Alanen maalanen@abo.fi - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Mon Jul 15 2002 - 22:00:20 EST