kernfs: invoke kernfs_unmap_bin_file() directly from __kernfs_remove()
kernfs_unmap_bin_file() is supposed to unmap all memory mappings of
the target file before kernfs_remove() finishes; however, it currently
is being called from kernfs_addrm_finish() and has the same race
problem as the original implementation of deactivation when there are
multiple removers - only the remover which snatches the node to its
addrm_cxt->removed list is guaranteed to wait for its completion
before returning.
It can be fixed by moving kernfs_unmap_bin_file() invocation from
kernfs_addrm_finish() to __kernfs_remove(). The function may be
called multiple times but that shouldn't do any harm.
We end up dropping kernfs_mutex in the removal loop and the node may
be removed inbetween by someone else. kernfs_unlink_sibling() is
updated to test whether the node has already been removed and return
accordingly. __kernfs_remove() in turn performs post-unlinking
cleanup only if it actually unlinked the node.
KERNFS_HAS_MMAP test is moved out of the unmap function into
__kernfs_remove() so that we don't unlock kernfs_mutex unnecessarily.
While at it, drop the now meaningless "bin" qualifier from the
function name.
v2: Rewritten to fit the v2 restructuring of removal path. HAS_MMAP
test relocated.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h
index 57a93f4..e9ec38c 100644
--- a/fs/kernfs/kernfs-internal.h
+++ b/fs/kernfs/kernfs-internal.h
@@ -113,7 +113,7 @@
*/
extern const struct file_operations kernfs_file_fops;
-void kernfs_unmap_bin_file(struct kernfs_node *kn);
+void kernfs_unmap_file(struct kernfs_node *kn);
/*
* symlink.c