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CIFS: Fix write after setting a read lock for read oplock files 

If we have a read oplock and set a read lock in it, we can't write to the
locked area - so, filemap_fdatawrite may fail with a no information for a
userspace application even if we request a write to non-locked area. Fix
this by writing directly to the server and then breaking oplock level from
level2 to None.

Also remove CONFIG_CIFS_SMB2 ifdefs because it's suitable for both CIFS
and SMB2 protocols.

Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
This commit is contained in:
Pavel Shilovsky 2012-12-21 15:07:52 +04:00 committed by Steve French
parent ca8aa29c60
commit 88cf75aaaf
1 changed files with 20 additions and 28 deletions
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48
fs/cifs/file.c
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@ -2505,42 +2505,34 @@ cifs_strict_writev(struct kiocb *iocb, const struct iovec *iov,
struct cifsFileInfo *cfile = (struct cifsFileInfo *)
iocb->ki_filp->private_data;
struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
ssize_t written;
#ifdef CONFIG_CIFS_SMB2
/*
* 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;
if (cinode->clientCanCacheAll) {
if (cap_unix(tcon->ses) &&
(CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability))
&& ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0))
return generic_file_aio_write(iocb, iov, nr_segs, pos);
return cifs_writev(iocb, iov, nr_segs, pos);
}
#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)
return cifs_user_writev(iocb, iov, nr_segs, pos);
if (cap_unix(tcon->ses) &&
(CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability)) &&
((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0))
return generic_file_aio_write(iocb, iov, nr_segs, pos);
return cifs_writev(iocb, iov, nr_segs, pos);
written = cifs_user_writev(iocb, iov, nr_segs, pos);
if (written > 0 && cinode->clientCanCacheRead) {
/*
* Windows 7 server can delay breaking level2 oplock if a write
* request comes - break it on the client to prevent reading
* an old data.
*/
cifs_invalidate_mapping(inode);
cFYI(1, "Set no oplock for inode=%p after a write operation",
inode);
cinode->clientCanCacheRead = false;
}
return written;
}
static struct cifs_readdata *