NFS: use generic_write_checks() to sanity check direct writes

 Replace ad hoc write parameter sanity checking in nfs_file_direct_write()
 with a call to generic_write_checks().  This should make the proper checks
 modulo the O_LARGEFILE flag, and should catch NFSv2-specific limitations by
 virtue of i_sb->s_maxbytes.

 Test plan:
 Posix compliance testing with both NFSv2 and NFSv3.

 Signed-off-by: Chuck Lever <cel@netapp.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index ae2be07..f69d95a 100644 (file)
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -660,10 +660,10 @@ nfs_file_direct_read(struct kiocb *iocb, char __user *buf, size_t count, loff_t
                .iov_len = count,
        };
 
-       dprintk("nfs: direct read(%s/%s, %lu@%lu)\n",
+       dprintk("nfs: direct read(%s/%s, %lu@%Ld)\n",
                file->f_dentry->d_parent->d_name.name,
                file->f_dentry->d_name.name,
-               (unsigned long) count, (unsigned long) pos);
+               (unsigned long) count, (long long) pos);
 
        if (!is_sync_kiocb(iocb))
                goto out;
@@ -716,9 +716,7 @@ out:
 ssize_t
 nfs_file_direct_write(struct kiocb *iocb, const char __user *buf, size_t count, loff_t pos)
 {
-       ssize_t retval = -EINVAL;
-       loff_t *ppos = &iocb->ki_pos;
-       unsigned long limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
+       ssize_t retval;
        struct file *file = iocb->ki_filp;
        struct nfs_open_context *ctx =
                        (struct nfs_open_context *) file->private_data;
@@ -726,35 +724,32 @@ nfs_file_direct_write(struct kiocb *iocb, const char __user *buf, size_t count,
        struct inode *inode = mapping->host;
        struct iovec iov = {
                .iov_base = (char __user *)buf,
-               .iov_len = count,
        };
 
-       dfprintk(VFS, "nfs: direct write(%s/%s(%ld), %lu@%lu)\n",
+       dfprintk(VFS, "nfs: direct write(%s/%s, %lu@%Ld)\n",
                file->f_dentry->d_parent->d_name.name,
-               file->f_dentry->d_name.name, inode->i_ino,
-               (unsigned long) count, (unsigned long) pos);
+               file->f_dentry->d_name.name,
+               (unsigned long) count, (long long) pos);
 
+       retval = -EINVAL;
        if (!is_sync_kiocb(iocb))
                goto out;
-       if (count < 0)
-               goto out;
-        if (pos < 0)
+
+       retval = generic_write_checks(file, &pos, &count, 0);
+       if (retval)
                goto out;
-       retval = -EFAULT;
-       if (!access_ok(VERIFY_READ, iov.iov_base, iov.iov_len))
+
+       retval = -EINVAL;
+       if ((ssize_t) count < 0)
                goto out;
-       retval = -EFBIG;
-       if (limit != RLIM_INFINITY) {
-               if (pos >= limit) {
-                       send_sig(SIGXFSZ, current, 0);
-                       goto out;
-               }
-               if (count > limit - (unsigned long) pos)
-                       count = limit - (unsigned long) pos;
-       }
        retval = 0;
        if (!count)
                goto out;
+       iov.iov_len = count,
+
+       retval = -EFAULT;
+       if (!access_ok(VERIFY_READ, iov.iov_base, iov.iov_len))
+               goto out;
 
        retval = nfs_sync_mapping(mapping);
        if (retval)
@@ -764,7 +759,7 @@ nfs_file_direct_write(struct kiocb *iocb, const char __user *buf, size_t count,
        if (mapping->nrpages)
                invalidate_inode_pages2(mapping);
        if (retval > 0)
-               *ppos = pos + retval;
+               iocb->ki_pos = pos + retval;
 
 out:
        return retval;