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-rw-r--r--fs/afs/dir_silly.c282
1 files changed, 282 insertions, 0 deletions
diff --git a/fs/afs/dir_silly.c b/fs/afs/dir_silly.c
new file mode 100644
index 000000000..bb5807e87
--- /dev/null
+++ b/fs/afs/dir_silly.c
@@ -0,0 +1,282 @@
+// 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"
+
+static void afs_silly_rename_success(struct afs_operation *op)
+{
+ _enter("op=%08x", op->debug_id);
+
+ afs_check_dir_conflict(op, &op->file[0]);
+ afs_vnode_commit_status(op, &op->file[0]);
+}
+
+static void afs_silly_rename_edit_dir(struct afs_operation *op)
+{
+ struct afs_vnode_param *dvp = &op->file[0];
+ struct afs_vnode *dvnode = dvp->vnode;
+ struct afs_vnode *vnode = AFS_FS_I(d_inode(op->dentry));
+ struct dentry *old = op->dentry;
+ struct dentry *new = op->dentry_2;
+
+ spin_lock(&old->d_lock);
+ old->d_flags |= DCACHE_NFSFS_RENAMED;
+ spin_unlock(&old->d_lock);
+ if (dvnode->silly_key != op->key) {
+ key_put(dvnode->silly_key);
+ dvnode->silly_key = key_get(op->key);
+ }
+
+ down_write(&dvnode->validate_lock);
+ if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags) &&
+ dvnode->status.data_version == dvp->dv_before + dvp->dv_delta) {
+ afs_edit_dir_remove(dvnode, &old->d_name,
+ afs_edit_dir_for_silly_0);
+ afs_edit_dir_add(dvnode, &new->d_name,
+ &vnode->fid, afs_edit_dir_for_silly_1);
+ }
+ up_write(&dvnode->validate_lock);
+}
+
+static const struct afs_operation_ops afs_silly_rename_operation = {
+ .issue_afs_rpc = afs_fs_rename,
+ .issue_yfs_rpc = yfs_fs_rename,
+ .success = afs_silly_rename_success,
+ .edit_dir = afs_silly_rename_edit_dir,
+};
+
+/*
+ * 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_operation *op;
+
+ _enter("%pd,%pd", old, new);
+
+ op = afs_alloc_operation(key, dvnode->volume);
+ if (IS_ERR(op))
+ return PTR_ERR(op);
+
+ afs_op_set_vnode(op, 0, dvnode);
+ afs_op_set_vnode(op, 1, dvnode);
+ op->file[0].dv_delta = 1;
+ op->file[1].dv_delta = 1;
+ op->file[0].modification = true;
+ op->file[1].modification = true;
+ op->file[0].update_ctime = true;
+ op->file[1].update_ctime = true;
+
+ op->dentry = old;
+ op->dentry_2 = new;
+ op->ops = &afs_silly_rename_operation;
+
+ trace_afs_silly_rename(vnode, false);
+ return afs_do_sync_operation(op);
+}
+
+/*
+ * Perform 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->netfs.inode);
+
+ ret = afs_do_silly_rename(dvnode, vnode, dentry, sdentry, key);
+ switch (ret) {
+ case 0:
+ /* The rename succeeded. */
+ set_bit(AFS_VNODE_SILLY_DELETED, &vnode->flags);
+ 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->netfs.inode);
+ dput(sdentry);
+out:
+ _leave(" = %d", ret);
+ return ret;
+}
+
+static void afs_silly_unlink_success(struct afs_operation *op)
+{
+ _enter("op=%08x", op->debug_id);
+ afs_check_dir_conflict(op, &op->file[0]);
+ afs_vnode_commit_status(op, &op->file[0]);
+ afs_vnode_commit_status(op, &op->file[1]);
+ afs_update_dentry_version(op, &op->file[0], op->dentry);
+}
+
+static void afs_silly_unlink_edit_dir(struct afs_operation *op)
+{
+ struct afs_vnode_param *dvp = &op->file[0];
+ struct afs_vnode *dvnode = dvp->vnode;
+
+ _enter("op=%08x", op->debug_id);
+ down_write(&dvnode->validate_lock);
+ if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags) &&
+ dvnode->status.data_version == dvp->dv_before + dvp->dv_delta)
+ afs_edit_dir_remove(dvnode, &op->dentry->d_name,
+ afs_edit_dir_for_unlink);
+ up_write(&dvnode->validate_lock);
+}
+
+static const struct afs_operation_ops afs_silly_unlink_operation = {
+ .issue_afs_rpc = afs_fs_remove_file,
+ .issue_yfs_rpc = yfs_fs_remove_file,
+ .success = afs_silly_unlink_success,
+ .aborted = afs_check_for_remote_deletion,
+ .edit_dir = afs_silly_unlink_edit_dir,
+};
+
+/*
+ * 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_operation *op;
+
+ _enter("");
+
+ op = afs_alloc_operation(NULL, dvnode->volume);
+ if (IS_ERR(op))
+ return PTR_ERR(op);
+
+ afs_op_set_vnode(op, 0, dvnode);
+ afs_op_set_vnode(op, 1, vnode);
+ op->file[0].dv_delta = 1;
+ op->file[0].modification = true;
+ op->file[0].update_ctime = true;
+ op->file[1].op_unlinked = true;
+ op->file[1].update_ctime = true;
+
+ op->dentry = dentry;
+ op->ops = &afs_silly_unlink_operation;
+
+ trace_afs_silly_rename(vnode, true);
+ afs_begin_vnode_operation(op);
+ afs_wait_for_operation(op);
+
+ /* If there was a conflict with a third party, check the status of the
+ * unlinked vnode.
+ */
+ if (op->error == 0 && (op->flags & AFS_OPERATION_DIR_CONFLICT)) {
+ op->file[1].update_ctime = false;
+ op->fetch_status.which = 1;
+ op->ops = &afs_fetch_status_operation;
+ afs_begin_vnode_operation(op);
+ afs_wait_for_operation(op);
+ }
+
+ return afs_put_operation(op);
+}
+
+/*
+ * 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;
+}