4.4-stable review patch. If anyone has any objections, please let me know.
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From: Pavel Shilovsky piastryyy@gmail.com
commit 6dfbd84684700cb58b34e8602c01c12f3d2595c8 upstream.
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: Pavel Shilovsky pshilov@microsoft.com Signed-off-by: Steve French stfrench@microsoft.com Reviewed-by: Ronnie Sahlberg lsahlber@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/cifs/file.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)
--- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -2753,14 +2753,16 @@ cifs_strict_writev(struct kiocb *iocb, s * 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; }