cifs: have find_writeable_file prefer filehandles opened by same task
When the CIFS client goes to write out pages, it needs to pick a
filehandle to write to. find_writeable_file however just picks the
first filehandle that it finds. This can cause problems when a lock
is issued against a particular filehandle and we pick a different
filehandle to write to.
This patch tries to avert this situation by having find_writable_file
prefer filehandles that have a pid that matches the current task.
This seems to fix lock test 11 from the connectathon test suite when
run against a windows server.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index cbefe1f..d39e852 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -1065,6 +1065,7 @@
struct cifsFileInfo *find_writable_file(struct cifsInodeInfo *cifs_inode)
{
struct cifsFileInfo *open_file;
+ bool any_available = false;
int rc;
/* Having a null inode here (because mapping->host was set to zero by
@@ -1080,8 +1081,10 @@
read_lock(&GlobalSMBSeslock);
refind_writable:
list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
- if (open_file->closePend)
+ if (open_file->closePend ||
+ (!any_available && open_file->pid != current->tgid))
continue;
+
if (open_file->pfile &&
((open_file->pfile->f_flags & O_RDWR) ||
(open_file->pfile->f_flags & O_WRONLY))) {
@@ -1131,6 +1134,11 @@
of the loop here. */
}
}
+ /* couldn't find useable FH with same pid, try any available */
+ if (!any_available) {
+ any_available = true;
+ goto refind_writable;
+ }
read_unlock(&GlobalSMBSeslock);
return NULL;
}