hi.
from man fcntl
EACCES or EAGAIN
Operation is prohibited by locks held by other processes. Or,
operation is prohibited because the file has been memory-mapped
by another process.
a process with file open for writing is essentially holding a lock WRT
allowing a read lease, so i think EAGAIN is the appropriate error.
again from man fcntl
EINVAL For F_DUPFD, arg is negative or is greater than the maximum
allowable value. For F_SETSIG, arg is not an allowable signal
number.
the arguments to the fcntl setlease call are correct, not invalid, so this is
the wrong error.
-->Andy
> Hi,
>
> If one tries to do a fcntl(fd, F_SETLEASE, F_RDLCK) on a file that is open
> for writing, the error returned is always -EAGAIN. This seems like the
> wrong error return for the case where 'fd' points to a file_struct that
> has FMODE_WRITE set. No matter how many times one calls the fcntl on that
> 'fd' it will fail. Therefore, i think the return value should be -EINVAL
> in this case. The patch below implements this behavior. Some more context
> for this issue can be found at: http://lkml.org/lkml/2005/5/2/20. Patch is
> based on a suggestion from Jeff Layton.
>
> thanks,
>
> -Jason
>
> Signed-off-by: Jason Baron <jbaron@xxxxxxxxxx>
>
>
> --- linux-2.6/fs/locks.c.bak 2006-06-13 10:36:58.000000000 -0400
> +++ linux-2.6/fs/locks.c 2006-06-13 10:41:19.000000000 -0400
> @@ -1338,8 +1338,11 @@
> lease = *flp;
>
> error = -EAGAIN;
> - if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0))
> + if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0)) {
> + if (filp->f_mode & FMODE_WRITE)
> + error = -EINVAL;
> goto out;
> + }
> if ((arg == F_WRLCK)
> && ((atomic_read(&dentry->d_count) > 1)
> || (atomic_read(&inode->i_count) > 1)))
> -
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