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Commit 6dfbd846 authored by Pavel Shilovsky's avatar Pavel Shilovsky Committed by Steve French
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CIFS: Fix read after write for files with read caching 



When we have a READ lease for a file and have just issued a write
operation to the server we need to purge the cache and set oplock/lease
level to NONE to avoid reading stale data. Currently we do that
only if a write operation succedeed thus not covering cases when
a request was sent to the server but a negative error code was
returned later for some other reasons (e.g. -EIOCBQUEUED or -EINTR).
Fix this by turning off caching regardless of the error code being
returned.

The patches fixes generic tests 075 and 112 from the xfs-tests.

Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
Reviewed-by: default avatarRonnie Sahlberg <lsahlber@redhat.com>
parent 96281b9e

fs/cifs/file.c

+7 −5
Original line number Diff line number Diff line
@@ -3096,14 +3096,16 @@ cifs_strict_writev(struct kiocb *iocb, struct iov_iter *from) 
	 * these pages but not on the region from pos to ppos+len-1.

	 */

	written = cifs_user_writev(iocb, from);

	if (written > 0 && CIFS_CACHE_READ(cinode)) {

	if (CIFS_CACHE_READ(cinode)) {

		/*

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

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

		 * an old data.

		 * We have read level caching and we have just sent a write

		 * request to the server thus making data in the cache stale.

		 * Zap the cache and set oplock/lease level to NONE to avoid

		 * reading stale data from the cache. All subsequent read

		 * operations will read new data from the server.

		 */

		cifs_zap_mapping(inode);

		cifs_dbg(FYI, "Set no oplock for inode=%p after a write operation\n",

		cifs_dbg(FYI, "Set Oplock/Lease to NONE for inode=%p after write\n",

			 inode);

		cinode->oplock = 0;

	}