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Commit 88cf75aa authored by Pavel Shilovsky's avatar Pavel Shilovsky Committed by Steve French
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CIFS: Fix write after setting a read lock for read oplock files 



If we have a read oplock and set a read lock in it, we can't write to the
locked area - so, filemap_fdatawrite may fail with a no information for a
userspace application even if we request a write to non-locked area. Fix
this by writing directly to the server and then breaking oplock level from
level2 to None.

Also remove CONFIG_CIFS_SMB2 ifdefs because it's suitable for both CIFS
and SMB2 protocols.

Signed-off-by: default avatarPavel Shilovsky <piastry@etersoft.ru>
Reviewed-by: default avatarJeff Layton <jlayton@redhat.com>
Signed-off-by: default avatarSteve French <smfrench@gmail.com>
parent ca8aa29c

fs/cifs/file.c

+20 −28
Original line number Diff line number Diff line
@@ -2505,42 +2505,34 @@ cifs_strict_writev(struct kiocb *iocb, const struct iovec *iov, 
	struct cifsFileInfo *cfile = (struct cifsFileInfo *)

						iocb->ki_filp->private_data;

	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);



#ifdef CONFIG_CIFS_SMB2

	/*

	 * If we have an oplock for read and want to write a data to the file

	 * we need to store it in the page cache and then push it to the server

	 * to be sure the next read will get a valid data.

	 */

	if (!cinode->clientCanCacheAll && cinode->clientCanCacheRead) {

	ssize_t written;

		int rc;



		written = generic_file_aio_write(iocb, iov, nr_segs, pos);

		rc = filemap_fdatawrite(inode->i_mapping);

		if (rc)

			return (ssize_t)rc;



		return written;

	if (cinode->clientCanCacheAll) {

		if (cap_unix(tcon->ses) &&

		(CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability))

		    && ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0))

			return generic_file_aio_write(iocb, iov, nr_segs, pos);

		return cifs_writev(iocb, iov, nr_segs, pos);

	}

#endif



	/*

	 * For non-oplocked files in strict cache mode we need to write the data

	 * to the server exactly from the pos to pos+len-1 rather than flush all

	 * affected pages because it may cause a error with mandatory locks on

	 * these pages but not on the region from pos to ppos+len-1.

	 */



	if (!cinode->clientCanCacheAll)

		return cifs_user_writev(iocb, iov, nr_segs, pos);



	if (cap_unix(tcon->ses) &&

	    (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability)) &&

	    ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0))

		return generic_file_aio_write(iocb, iov, nr_segs, pos);



	return cifs_writev(iocb, iov, nr_segs, pos);

	written = cifs_user_writev(iocb, iov, nr_segs, pos);

	if (written > 0 && cinode->clientCanCacheRead) {

		/*

		 * Windows 7 server can delay breaking level2 oplock if a write

		 * request comes - break it on the client to prevent reading

		 * an old data.

		 */

		cifs_invalidate_mapping(inode);

		cFYI(1, "Set no oplock for inode=%p after a write operation",

		     inode);

		cinode->clientCanCacheRead = false;

	}

	return written;

}



static struct cifs_readdata *