From: Pavel Shilovsky <piastry@xxxxxxxxxxx>
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: Pavel Shilovsky <piastry@xxxxxxxxxxx>
---
fs/cifs/file.c | 26 ++++++++++++++++++++++----
1 files changed, 22 insertions(+), 4 deletions(-)
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index f15c30c..da7e3d4 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2421,11 +2421,29 @@ cifs_strict_writev(struct kiocb *iocb, const struct iovec *iov,
struct TCP_Server_Info *server = tcon->ses->server;
int rc = -EACCES;
+#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;
+
+ 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)
--
1.7.1
--
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