cifs: ensure that we always do cifsFileInfo_get under the spinlock
The readpages bug is a regression that was introduced in 6993f74a5.
This also fixes a couple of similar bugs in the uncached read and write
codepaths.
Also, prevent this sort of thing in the future by having cifsFileInfo_get
take the spinlock itself, and adding a _locked variant for use in places
that are already holding the lock. The _put code has always done that
so this makes for a less confusing interface.
Cc: <stable@vger.kernel.org> # 3.5.x
Reviewed-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 07e9d41..9154192 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -284,6 +284,15 @@
static void cifs_del_lock_waiters(struct cifsLockInfo *lock);
+struct cifsFileInfo *
+cifsFileInfo_get(struct cifsFileInfo *cifs_file)
+{
+ spin_lock(&cifs_file_list_lock);
+ cifsFileInfo_get_locked(cifs_file);
+ spin_unlock(&cifs_file_list_lock);
+ return cifs_file;
+}
+
/*
* Release a reference on the file private data. This may involve closing
* the filehandle out on the server. Must be called without holding
@@ -1562,7 +1571,7 @@
if (!open_file->invalidHandle) {
/* found a good file */
/* lock it so it will not be closed on us */
- cifsFileInfo_get(open_file);
+ cifsFileInfo_get_locked(open_file);
spin_unlock(&cifs_file_list_lock);
return open_file;
} /* else might as well continue, and look for
@@ -1614,7 +1623,7 @@
if (OPEN_FMODE(open_file->f_flags) & FMODE_WRITE) {
if (!open_file->invalidHandle) {
/* found a good writable file */
- cifsFileInfo_get(open_file);
+ cifsFileInfo_get_locked(open_file);
spin_unlock(&cifs_file_list_lock);
return open_file;
} else {
@@ -1631,7 +1640,7 @@
if (inv_file) {
any_available = false;
- cifsFileInfo_get(inv_file);
+ cifsFileInfo_get_locked(inv_file);
}
spin_unlock(&cifs_file_list_lock);
@@ -3082,8 +3091,6 @@
break;
}
- spin_lock(&cifs_file_list_lock);
- spin_unlock(&cifs_file_list_lock);
rdata->cfile = cifsFileInfo_get(open_file);
rdata->mapping = mapping;
rdata->offset = offset;