Commit 25078105 authored by Pavel Shilovsky's avatar Pavel Shilovsky Committed by Steve French
Browse files

CIFS: Fix cache coherency for read oplock case 



When we have a file opened with read oplock and we are writing a data
to this file, we need to store the data in the cache and then send to
the server to ensure that the next read operation will get a coherent
data.

Also mark it as CONFIG_CIFS_SMB2 because it's more suitable for SMB2
code but can fix some CIFS problems too (when server delays sending
an oplock break after a write request). We can drop this ifdefs
dependence in future.

Signed-off-by: default avatarPavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: default avatarSteve French <sfrench@us.ibm.com>
parent b8c32dbb

fs/cifs/file.c

+23 −4
Original line number Diff line number Diff line
@@ -2461,11 +2461,30 @@ cifs_strict_writev(struct kiocb *iocb, const struct iovec *iov, 
						iocb->ki_filp->private_data;

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



#ifdef CONFIG_CIFS_SMB2

	/*

	 * 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 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;

	}

#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)