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CIFS: Fix cache coherency for read oplock case

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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@etersoft.ru>
Signed-off-by: Steve French <sfrench@us.ibm.com>
This commit is contained in:
Pavel Shilovsky 2012-09-19 06:22:45 -07:00 committed by Steve French
parent b8c32dbb0d
commit 25078105fb
1 changed files with 23 additions and 4 deletions
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27
fs/cifs/file.c
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@ -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)