Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/fs/afs/dir_silly.c b/fs/afs/dir_silly.c
new file mode 100644
index 0000000..361088a
--- /dev/null
+++ b/fs/afs/dir_silly.c
@@ -0,0 +1,245 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* AFS silly rename handling
+ *
+ * Copyright (C) 2019 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ * - Derived from NFS's sillyrename.
+ */
+
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/fsnotify.h>
+#include "internal.h"
+
+/*
+ * Actually perform the silly rename step.
+ */
+static int afs_do_silly_rename(struct afs_vnode *dvnode, struct afs_vnode *vnode,
+ struct dentry *old, struct dentry *new,
+ struct key *key)
+{
+ struct afs_fs_cursor fc;
+ struct afs_status_cb *scb;
+ int ret = -ERESTARTSYS;
+
+ _enter("%pd,%pd", old, new);
+
+ scb = kzalloc(sizeof(struct afs_status_cb), GFP_KERNEL);
+ if (!scb)
+ return -ENOMEM;
+
+ trace_afs_silly_rename(vnode, false);
+ if (afs_begin_vnode_operation(&fc, dvnode, key, true)) {
+ afs_dataversion_t dir_data_version = dvnode->status.data_version + 1;
+
+ while (afs_select_fileserver(&fc)) {
+ fc.cb_break = afs_calc_vnode_cb_break(dvnode);
+ afs_fs_rename(&fc, old->d_name.name,
+ dvnode, new->d_name.name,
+ scb, scb);
+ }
+
+ afs_vnode_commit_status(&fc, dvnode, fc.cb_break,
+ &dir_data_version, scb);
+ ret = afs_end_vnode_operation(&fc);
+ }
+
+ if (ret == 0) {
+ spin_lock(&old->d_lock);
+ old->d_flags |= DCACHE_NFSFS_RENAMED;
+ spin_unlock(&old->d_lock);
+ if (dvnode->silly_key != key) {
+ key_put(dvnode->silly_key);
+ dvnode->silly_key = key_get(key);
+ }
+
+ if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
+ afs_edit_dir_remove(dvnode, &old->d_name,
+ afs_edit_dir_for_silly_0);
+ if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
+ afs_edit_dir_add(dvnode, &new->d_name,
+ &vnode->fid, afs_edit_dir_for_silly_1);
+ }
+
+ kfree(scb);
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/**
+ * afs_sillyrename - Perform a silly-rename of a dentry
+ *
+ * AFS is stateless and the server doesn't know when the client is holding a
+ * file open. To prevent application problems when a file is unlinked while
+ * it's still open, the client performs a "silly-rename". That is, it renames
+ * the file to a hidden file in the same directory, and only performs the
+ * unlink once the last reference to it is put.
+ *
+ * The final cleanup is done during dentry_iput.
+ */
+int afs_sillyrename(struct afs_vnode *dvnode, struct afs_vnode *vnode,
+ struct dentry *dentry, struct key *key)
+{
+ static unsigned int sillycounter;
+ struct dentry *sdentry = NULL;
+ unsigned char silly[16];
+ int ret = -EBUSY;
+
+ _enter("");
+
+ /* We don't allow a dentry to be silly-renamed twice. */
+ if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
+ return -EBUSY;
+
+ sdentry = NULL;
+ do {
+ int slen;
+
+ dput(sdentry);
+ sillycounter++;
+
+ /* Create a silly name. Note that the ".__afs" prefix is
+ * understood by the salvager and must not be changed.
+ */
+ slen = scnprintf(silly, sizeof(silly), ".__afs%04X", sillycounter);
+ sdentry = lookup_one_len(silly, dentry->d_parent, slen);
+
+ /* N.B. Better to return EBUSY here ... it could be dangerous
+ * to delete the file while it's in use.
+ */
+ if (IS_ERR(sdentry))
+ goto out;
+ } while (!d_is_negative(sdentry));
+
+ ihold(&vnode->vfs_inode);
+
+ ret = afs_do_silly_rename(dvnode, vnode, dentry, sdentry, key);
+ switch (ret) {
+ case 0:
+ /* The rename succeeded. */
+ d_move(dentry, sdentry);
+ break;
+ case -ERESTARTSYS:
+ /* The result of the rename is unknown. Play it safe by forcing
+ * a new lookup.
+ */
+ d_drop(dentry);
+ d_drop(sdentry);
+ }
+
+ iput(&vnode->vfs_inode);
+ dput(sdentry);
+out:
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * Tell the server to remove a sillyrename file.
+ */
+static int afs_do_silly_unlink(struct afs_vnode *dvnode, struct afs_vnode *vnode,
+ struct dentry *dentry, struct key *key)
+{
+ struct afs_fs_cursor fc;
+ struct afs_status_cb *scb;
+ int ret = -ERESTARTSYS;
+
+ _enter("");
+
+ scb = kcalloc(2, sizeof(struct afs_status_cb), GFP_KERNEL);
+ if (!scb)
+ return -ENOMEM;
+
+ trace_afs_silly_rename(vnode, true);
+ if (afs_begin_vnode_operation(&fc, dvnode, key, false)) {
+ afs_dataversion_t dir_data_version = dvnode->status.data_version + 1;
+
+ while (afs_select_fileserver(&fc)) {
+ fc.cb_break = afs_calc_vnode_cb_break(dvnode);
+
+ if (test_bit(AFS_SERVER_FL_IS_YFS, &fc.cbi->server->flags) &&
+ !test_bit(AFS_SERVER_FL_NO_RM2, &fc.cbi->server->flags)) {
+ yfs_fs_remove_file2(&fc, vnode, dentry->d_name.name,
+ &scb[0], &scb[1]);
+ if (fc.ac.error != -ECONNABORTED ||
+ fc.ac.abort_code != RXGEN_OPCODE)
+ continue;
+ set_bit(AFS_SERVER_FL_NO_RM2, &fc.cbi->server->flags);
+ }
+
+ afs_fs_remove(&fc, vnode, dentry->d_name.name, false, &scb[0]);
+ }
+
+ afs_vnode_commit_status(&fc, dvnode, fc.cb_break,
+ &dir_data_version, &scb[0]);
+ ret = afs_end_vnode_operation(&fc);
+ if (ret == 0) {
+ drop_nlink(&vnode->vfs_inode);
+ if (vnode->vfs_inode.i_nlink == 0) {
+ set_bit(AFS_VNODE_DELETED, &vnode->flags);
+ clear_bit(AFS_VNODE_CB_PROMISED, &vnode->flags);
+ }
+ }
+ if (ret == 0 &&
+ test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
+ afs_edit_dir_remove(dvnode, &dentry->d_name,
+ afs_edit_dir_for_unlink);
+ }
+
+ kfree(scb);
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * Remove sillyrename file on iput.
+ */
+int afs_silly_iput(struct dentry *dentry, struct inode *inode)
+{
+ struct afs_vnode *dvnode = AFS_FS_I(d_inode(dentry->d_parent));
+ struct afs_vnode *vnode = AFS_FS_I(inode);
+ struct dentry *alias;
+ int ret;
+
+ DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+
+ _enter("%p{%pd},%llx", dentry, dentry, vnode->fid.vnode);
+
+ down_read(&dvnode->rmdir_lock);
+
+ alias = d_alloc_parallel(dentry->d_parent, &dentry->d_name, &wq);
+ if (IS_ERR(alias)) {
+ up_read(&dvnode->rmdir_lock);
+ return 0;
+ }
+
+ if (!d_in_lookup(alias)) {
+ /* We raced with lookup... See if we need to transfer the
+ * sillyrename information to the aliased dentry.
+ */
+ ret = 0;
+ spin_lock(&alias->d_lock);
+ if (d_really_is_positive(alias) &&
+ !(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
+ alias->d_flags |= DCACHE_NFSFS_RENAMED;
+ ret = 1;
+ }
+ spin_unlock(&alias->d_lock);
+ up_read(&dvnode->rmdir_lock);
+ dput(alias);
+ return ret;
+ }
+
+ /* Stop lock-release from complaining. */
+ spin_lock(&vnode->lock);
+ vnode->lock_state = AFS_VNODE_LOCK_DELETED;
+ trace_afs_flock_ev(vnode, NULL, afs_flock_silly_delete, 0);
+ spin_unlock(&vnode->lock);
+
+ afs_do_silly_unlink(dvnode, vnode, dentry, dvnode->silly_key);
+ up_read(&dvnode->rmdir_lock);
+ d_lookup_done(alias);
+ dput(alias);
+ return 1;
+}