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169b803397
the victim might've been rmdir'ed just before the lock_rename();
unlike the normal callers, we do not look the source up after the
parents are locked - we know it beforehand and just recheck that it's
still the child of what used to be its parent. Unfortunately,
the check is too weak - we don't spot a dead directory since its
->d_parent is unchanged, dentry is positive, etc. So we sail all
the way to ->rename(), with hosting filesystems _not_ expecting
to be asked renaming an rmdir'ed subdirectory.
The fix is easy, fortunately - the lock on parent is sufficient for
making IS_DEADDIR() on child safe.
Cc: stable@vger.kernel.org
Fixes: 9ae326a690
(CacheFiles: A cache that backs onto a mounted filesystem)
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1030 lines
26 KiB
C
1030 lines
26 KiB
C
/* CacheFiles path walking and related routines
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*
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* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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*/
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/file.h>
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#include <linux/fs.h>
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#include <linux/fsnotify.h>
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#include <linux/quotaops.h>
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#include <linux/xattr.h>
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#include <linux/mount.h>
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#include <linux/namei.h>
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#include <linux/security.h>
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#include <linux/slab.h>
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#include <linux/xattr.h>
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#include "internal.h"
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#define CACHEFILES_KEYBUF_SIZE 512
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/*
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* dump debugging info about an object
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*/
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static noinline
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void __cachefiles_printk_object(struct cachefiles_object *object,
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const char *prefix)
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{
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struct fscache_cookie *cookie;
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const u8 *k;
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unsigned loop;
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pr_err("%sobject: OBJ%x\n", prefix, object->fscache.debug_id);
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pr_err("%sobjstate=%s fl=%lx wbusy=%x ev=%lx[%lx]\n",
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prefix, object->fscache.state->name,
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object->fscache.flags, work_busy(&object->fscache.work),
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object->fscache.events, object->fscache.event_mask);
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pr_err("%sops=%u inp=%u exc=%u\n",
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prefix, object->fscache.n_ops, object->fscache.n_in_progress,
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object->fscache.n_exclusive);
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pr_err("%sparent=%p\n",
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prefix, object->fscache.parent);
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spin_lock(&object->fscache.lock);
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cookie = object->fscache.cookie;
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if (cookie) {
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pr_err("%scookie=%p [pr=%p nd=%p fl=%lx]\n",
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prefix,
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object->fscache.cookie,
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object->fscache.cookie->parent,
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object->fscache.cookie->netfs_data,
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object->fscache.cookie->flags);
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pr_err("%skey=[%u] '", prefix, cookie->key_len);
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k = (cookie->key_len <= sizeof(cookie->inline_key)) ?
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cookie->inline_key : cookie->key;
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for (loop = 0; loop < cookie->key_len; loop++)
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pr_cont("%02x", k[loop]);
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pr_cont("'\n");
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} else {
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pr_err("%scookie=NULL\n", prefix);
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}
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spin_unlock(&object->fscache.lock);
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}
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/*
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* dump debugging info about a pair of objects
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*/
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static noinline void cachefiles_printk_object(struct cachefiles_object *object,
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struct cachefiles_object *xobject)
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{
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if (object)
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__cachefiles_printk_object(object, "");
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if (xobject)
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__cachefiles_printk_object(xobject, "x");
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}
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/*
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* mark the owner of a dentry, if there is one, to indicate that that dentry
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* has been preemptively deleted
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* - the caller must hold the i_mutex on the dentry's parent as required to
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* call vfs_unlink(), vfs_rmdir() or vfs_rename()
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*/
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static void cachefiles_mark_object_buried(struct cachefiles_cache *cache,
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struct dentry *dentry,
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enum fscache_why_object_killed why)
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{
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struct cachefiles_object *object;
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struct rb_node *p;
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_enter(",'%pd'", dentry);
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write_lock(&cache->active_lock);
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p = cache->active_nodes.rb_node;
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while (p) {
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object = rb_entry(p, struct cachefiles_object, active_node);
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if (object->dentry > dentry)
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p = p->rb_left;
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else if (object->dentry < dentry)
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p = p->rb_right;
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else
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goto found_dentry;
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}
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write_unlock(&cache->active_lock);
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trace_cachefiles_mark_buried(NULL, dentry, why);
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_leave(" [no owner]");
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return;
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/* found the dentry for */
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found_dentry:
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kdebug("preemptive burial: OBJ%x [%s] %p",
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object->fscache.debug_id,
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object->fscache.state->name,
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dentry);
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trace_cachefiles_mark_buried(object, dentry, why);
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if (fscache_object_is_live(&object->fscache)) {
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pr_err("\n");
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pr_err("Error: Can't preemptively bury live object\n");
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cachefiles_printk_object(object, NULL);
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} else {
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if (why != FSCACHE_OBJECT_IS_STALE)
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fscache_object_mark_killed(&object->fscache, why);
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}
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write_unlock(&cache->active_lock);
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_leave(" [owner marked]");
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}
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/*
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* record the fact that an object is now active
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*/
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static int cachefiles_mark_object_active(struct cachefiles_cache *cache,
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struct cachefiles_object *object)
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{
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struct cachefiles_object *xobject;
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struct rb_node **_p, *_parent = NULL;
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struct dentry *dentry;
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_enter(",%p", object);
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try_again:
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write_lock(&cache->active_lock);
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dentry = object->dentry;
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trace_cachefiles_mark_active(object, dentry);
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if (test_and_set_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) {
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pr_err("Error: Object already active\n");
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cachefiles_printk_object(object, NULL);
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BUG();
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}
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_p = &cache->active_nodes.rb_node;
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while (*_p) {
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_parent = *_p;
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xobject = rb_entry(_parent,
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struct cachefiles_object, active_node);
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ASSERT(xobject != object);
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if (xobject->dentry > dentry)
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_p = &(*_p)->rb_left;
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else if (xobject->dentry < dentry)
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_p = &(*_p)->rb_right;
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else
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goto wait_for_old_object;
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}
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rb_link_node(&object->active_node, _parent, _p);
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rb_insert_color(&object->active_node, &cache->active_nodes);
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write_unlock(&cache->active_lock);
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_leave(" = 0");
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return 0;
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/* an old object from a previous incarnation is hogging the slot - we
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* need to wait for it to be destroyed */
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wait_for_old_object:
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trace_cachefiles_wait_active(object, dentry, xobject);
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clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags);
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if (fscache_object_is_live(&xobject->fscache)) {
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pr_err("\n");
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pr_err("Error: Unexpected object collision\n");
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cachefiles_printk_object(object, xobject);
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}
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atomic_inc(&xobject->usage);
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write_unlock(&cache->active_lock);
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if (test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) {
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wait_queue_head_t *wq;
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signed long timeout = 60 * HZ;
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wait_queue_entry_t wait;
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bool requeue;
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/* if the object we're waiting for is queued for processing,
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* then just put ourselves on the queue behind it */
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if (work_pending(&xobject->fscache.work)) {
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_debug("queue OBJ%x behind OBJ%x immediately",
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object->fscache.debug_id,
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xobject->fscache.debug_id);
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goto requeue;
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}
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/* otherwise we sleep until either the object we're waiting for
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* is done, or the fscache_object is congested */
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wq = bit_waitqueue(&xobject->flags, CACHEFILES_OBJECT_ACTIVE);
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init_wait(&wait);
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requeue = false;
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do {
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prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
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if (!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags))
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break;
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requeue = fscache_object_sleep_till_congested(&timeout);
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} while (timeout > 0 && !requeue);
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finish_wait(wq, &wait);
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if (requeue &&
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test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) {
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_debug("queue OBJ%x behind OBJ%x after wait",
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object->fscache.debug_id,
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xobject->fscache.debug_id);
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goto requeue;
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}
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if (timeout <= 0) {
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pr_err("\n");
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pr_err("Error: Overlong wait for old active object to go away\n");
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cachefiles_printk_object(object, xobject);
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goto requeue;
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}
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}
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ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags));
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cache->cache.ops->put_object(&xobject->fscache, cachefiles_obj_put_wait_retry);
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goto try_again;
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requeue:
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cache->cache.ops->put_object(&xobject->fscache, cachefiles_obj_put_wait_timeo);
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_leave(" = -ETIMEDOUT");
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return -ETIMEDOUT;
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}
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/*
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* Mark an object as being inactive.
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*/
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void cachefiles_mark_object_inactive(struct cachefiles_cache *cache,
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struct cachefiles_object *object,
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blkcnt_t i_blocks)
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{
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struct dentry *dentry = object->dentry;
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struct inode *inode = d_backing_inode(dentry);
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trace_cachefiles_mark_inactive(object, dentry, inode);
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write_lock(&cache->active_lock);
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rb_erase(&object->active_node, &cache->active_nodes);
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clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags);
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write_unlock(&cache->active_lock);
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wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE);
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/* This object can now be culled, so we need to let the daemon know
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* that there is something it can remove if it needs to.
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*/
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atomic_long_add(i_blocks, &cache->b_released);
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if (atomic_inc_return(&cache->f_released))
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cachefiles_state_changed(cache);
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}
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/*
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* delete an object representation from the cache
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* - file backed objects are unlinked
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* - directory backed objects are stuffed into the graveyard for userspace to
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* delete
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* - unlocks the directory mutex
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*/
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static int cachefiles_bury_object(struct cachefiles_cache *cache,
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struct cachefiles_object *object,
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struct dentry *dir,
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struct dentry *rep,
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bool preemptive,
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enum fscache_why_object_killed why)
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{
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struct dentry *grave, *trap;
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struct path path, path_to_graveyard;
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char nbuffer[8 + 8 + 1];
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int ret;
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_enter(",'%pd','%pd'", dir, rep);
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_debug("remove %p from %p", rep, dir);
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/* non-directories can just be unlinked */
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if (!d_is_dir(rep)) {
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_debug("unlink stale object");
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path.mnt = cache->mnt;
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path.dentry = dir;
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ret = security_path_unlink(&path, rep);
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if (ret < 0) {
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cachefiles_io_error(cache, "Unlink security error");
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} else {
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trace_cachefiles_unlink(object, rep, why);
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ret = vfs_unlink(d_inode(dir), rep, NULL);
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if (preemptive)
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cachefiles_mark_object_buried(cache, rep, why);
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}
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inode_unlock(d_inode(dir));
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if (ret == -EIO)
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cachefiles_io_error(cache, "Unlink failed");
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_leave(" = %d", ret);
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return ret;
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}
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/* directories have to be moved to the graveyard */
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_debug("move stale object to graveyard");
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inode_unlock(d_inode(dir));
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try_again:
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/* first step is to make up a grave dentry in the graveyard */
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sprintf(nbuffer, "%08x%08x",
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(uint32_t) get_seconds(),
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(uint32_t) atomic_inc_return(&cache->gravecounter));
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/* do the multiway lock magic */
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trap = lock_rename(cache->graveyard, dir);
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/* do some checks before getting the grave dentry */
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if (rep->d_parent != dir || IS_DEADDIR(d_inode(rep))) {
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/* the entry was probably culled when we dropped the parent dir
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* lock */
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unlock_rename(cache->graveyard, dir);
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_leave(" = 0 [culled?]");
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return 0;
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}
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if (!d_can_lookup(cache->graveyard)) {
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unlock_rename(cache->graveyard, dir);
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cachefiles_io_error(cache, "Graveyard no longer a directory");
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return -EIO;
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}
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if (trap == rep) {
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unlock_rename(cache->graveyard, dir);
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cachefiles_io_error(cache, "May not make directory loop");
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return -EIO;
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}
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if (d_mountpoint(rep)) {
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unlock_rename(cache->graveyard, dir);
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cachefiles_io_error(cache, "Mountpoint in cache");
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return -EIO;
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}
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grave = lookup_one_len(nbuffer, cache->graveyard, strlen(nbuffer));
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if (IS_ERR(grave)) {
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unlock_rename(cache->graveyard, dir);
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if (PTR_ERR(grave) == -ENOMEM) {
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_leave(" = -ENOMEM");
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return -ENOMEM;
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}
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cachefiles_io_error(cache, "Lookup error %ld",
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PTR_ERR(grave));
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return -EIO;
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}
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if (d_is_positive(grave)) {
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unlock_rename(cache->graveyard, dir);
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dput(grave);
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grave = NULL;
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cond_resched();
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goto try_again;
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}
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if (d_mountpoint(grave)) {
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unlock_rename(cache->graveyard, dir);
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dput(grave);
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cachefiles_io_error(cache, "Mountpoint in graveyard");
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return -EIO;
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}
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/* target should not be an ancestor of source */
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if (trap == grave) {
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unlock_rename(cache->graveyard, dir);
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dput(grave);
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cachefiles_io_error(cache, "May not make directory loop");
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return -EIO;
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}
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/* attempt the rename */
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path.mnt = cache->mnt;
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path.dentry = dir;
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path_to_graveyard.mnt = cache->mnt;
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path_to_graveyard.dentry = cache->graveyard;
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ret = security_path_rename(&path, rep, &path_to_graveyard, grave, 0);
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if (ret < 0) {
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cachefiles_io_error(cache, "Rename security error %d", ret);
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} else {
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trace_cachefiles_rename(object, rep, grave, why);
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ret = vfs_rename(d_inode(dir), rep,
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d_inode(cache->graveyard), grave, NULL, 0);
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if (ret != 0 && ret != -ENOMEM)
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cachefiles_io_error(cache,
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"Rename failed with error %d", ret);
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|
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if (preemptive)
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cachefiles_mark_object_buried(cache, rep, why);
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}
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unlock_rename(cache->graveyard, dir);
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dput(grave);
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_leave(" = 0");
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return 0;
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}
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|
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/*
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* delete an object representation from the cache
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*/
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int cachefiles_delete_object(struct cachefiles_cache *cache,
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struct cachefiles_object *object)
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{
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struct dentry *dir;
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int ret;
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|
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_enter(",OBJ%x{%p}", object->fscache.debug_id, object->dentry);
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|
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ASSERT(object->dentry);
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ASSERT(d_backing_inode(object->dentry));
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ASSERT(object->dentry->d_parent);
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|
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dir = dget_parent(object->dentry);
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|
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inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
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|
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if (test_bit(FSCACHE_OBJECT_KILLED_BY_CACHE, &object->fscache.flags)) {
|
|
/* object allocation for the same key preemptively deleted this
|
|
* object's file so that it could create its own file */
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_debug("object preemptively buried");
|
|
inode_unlock(d_inode(dir));
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ret = 0;
|
|
} else {
|
|
/* we need to check that our parent is _still_ our parent - it
|
|
* may have been renamed */
|
|
if (dir == object->dentry->d_parent) {
|
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ret = cachefiles_bury_object(cache, object, dir,
|
|
object->dentry, false,
|
|
FSCACHE_OBJECT_WAS_RETIRED);
|
|
} else {
|
|
/* it got moved, presumably by cachefilesd culling it,
|
|
* so it's no longer in the key path and we can ignore
|
|
* it */
|
|
inode_unlock(d_inode(dir));
|
|
ret = 0;
|
|
}
|
|
}
|
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|
|
dput(dir);
|
|
_leave(" = %d", ret);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* walk from the parent object to the child object through the backing
|
|
* filesystem, creating directories as we go
|
|
*/
|
|
int cachefiles_walk_to_object(struct cachefiles_object *parent,
|
|
struct cachefiles_object *object,
|
|
const char *key,
|
|
struct cachefiles_xattr *auxdata)
|
|
{
|
|
struct cachefiles_cache *cache;
|
|
struct dentry *dir, *next = NULL;
|
|
struct inode *inode;
|
|
struct path path;
|
|
unsigned long start;
|
|
const char *name;
|
|
int ret, nlen;
|
|
|
|
_enter("OBJ%x{%p},OBJ%x,%s,",
|
|
parent->fscache.debug_id, parent->dentry,
|
|
object->fscache.debug_id, key);
|
|
|
|
cache = container_of(parent->fscache.cache,
|
|
struct cachefiles_cache, cache);
|
|
path.mnt = cache->mnt;
|
|
|
|
ASSERT(parent->dentry);
|
|
ASSERT(d_backing_inode(parent->dentry));
|
|
|
|
if (!(d_is_dir(parent->dentry))) {
|
|
// TODO: convert file to dir
|
|
_leave("looking up in none directory");
|
|
return -ENOBUFS;
|
|
}
|
|
|
|
dir = dget(parent->dentry);
|
|
|
|
advance:
|
|
/* attempt to transit the first directory component */
|
|
name = key;
|
|
nlen = strlen(key);
|
|
|
|
/* key ends in a double NUL */
|
|
key = key + nlen + 1;
|
|
if (!*key)
|
|
key = NULL;
|
|
|
|
lookup_again:
|
|
/* search the current directory for the element name */
|
|
_debug("lookup '%s'", name);
|
|
|
|
inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
|
|
|
|
start = jiffies;
|
|
next = lookup_one_len(name, dir, nlen);
|
|
cachefiles_hist(cachefiles_lookup_histogram, start);
|
|
if (IS_ERR(next)) {
|
|
trace_cachefiles_lookup(object, next, NULL);
|
|
goto lookup_error;
|
|
}
|
|
|
|
inode = d_backing_inode(next);
|
|
trace_cachefiles_lookup(object, next, inode);
|
|
_debug("next -> %p %s", next, inode ? "positive" : "negative");
|
|
|
|
if (!key)
|
|
object->new = !inode;
|
|
|
|
/* if this element of the path doesn't exist, then the lookup phase
|
|
* failed, and we can release any readers in the certain knowledge that
|
|
* there's nothing for them to actually read */
|
|
if (d_is_negative(next))
|
|
fscache_object_lookup_negative(&object->fscache);
|
|
|
|
/* we need to create the object if it's negative */
|
|
if (key || object->type == FSCACHE_COOKIE_TYPE_INDEX) {
|
|
/* index objects and intervening tree levels must be subdirs */
|
|
if (d_is_negative(next)) {
|
|
ret = cachefiles_has_space(cache, 1, 0);
|
|
if (ret < 0)
|
|
goto no_space_error;
|
|
|
|
path.dentry = dir;
|
|
ret = security_path_mkdir(&path, next, 0);
|
|
if (ret < 0)
|
|
goto create_error;
|
|
start = jiffies;
|
|
ret = vfs_mkdir(d_inode(dir), next, 0);
|
|
cachefiles_hist(cachefiles_mkdir_histogram, start);
|
|
if (!key)
|
|
trace_cachefiles_mkdir(object, next, ret);
|
|
if (ret < 0)
|
|
goto create_error;
|
|
|
|
if (unlikely(d_unhashed(next))) {
|
|
dput(next);
|
|
inode_unlock(d_inode(dir));
|
|
goto lookup_again;
|
|
}
|
|
ASSERT(d_backing_inode(next));
|
|
|
|
_debug("mkdir -> %p{%p{ino=%lu}}",
|
|
next, d_backing_inode(next), d_backing_inode(next)->i_ino);
|
|
|
|
} else if (!d_can_lookup(next)) {
|
|
pr_err("inode %lu is not a directory\n",
|
|
d_backing_inode(next)->i_ino);
|
|
ret = -ENOBUFS;
|
|
goto error;
|
|
}
|
|
|
|
} else {
|
|
/* non-index objects start out life as files */
|
|
if (d_is_negative(next)) {
|
|
ret = cachefiles_has_space(cache, 1, 0);
|
|
if (ret < 0)
|
|
goto no_space_error;
|
|
|
|
path.dentry = dir;
|
|
ret = security_path_mknod(&path, next, S_IFREG, 0);
|
|
if (ret < 0)
|
|
goto create_error;
|
|
start = jiffies;
|
|
ret = vfs_create(d_inode(dir), next, S_IFREG, true);
|
|
cachefiles_hist(cachefiles_create_histogram, start);
|
|
trace_cachefiles_create(object, next, ret);
|
|
if (ret < 0)
|
|
goto create_error;
|
|
|
|
ASSERT(d_backing_inode(next));
|
|
|
|
_debug("create -> %p{%p{ino=%lu}}",
|
|
next, d_backing_inode(next), d_backing_inode(next)->i_ino);
|
|
|
|
} else if (!d_can_lookup(next) &&
|
|
!d_is_reg(next)
|
|
) {
|
|
pr_err("inode %lu is not a file or directory\n",
|
|
d_backing_inode(next)->i_ino);
|
|
ret = -ENOBUFS;
|
|
goto error;
|
|
}
|
|
}
|
|
|
|
/* process the next component */
|
|
if (key) {
|
|
_debug("advance");
|
|
inode_unlock(d_inode(dir));
|
|
dput(dir);
|
|
dir = next;
|
|
next = NULL;
|
|
goto advance;
|
|
}
|
|
|
|
/* we've found the object we were looking for */
|
|
object->dentry = next;
|
|
|
|
/* if we've found that the terminal object exists, then we need to
|
|
* check its attributes and delete it if it's out of date */
|
|
if (!object->new) {
|
|
_debug("validate '%pd'", next);
|
|
|
|
ret = cachefiles_check_object_xattr(object, auxdata);
|
|
if (ret == -ESTALE) {
|
|
/* delete the object (the deleter drops the directory
|
|
* mutex) */
|
|
object->dentry = NULL;
|
|
|
|
ret = cachefiles_bury_object(cache, object, dir, next,
|
|
true,
|
|
FSCACHE_OBJECT_IS_STALE);
|
|
dput(next);
|
|
next = NULL;
|
|
|
|
if (ret < 0)
|
|
goto delete_error;
|
|
|
|
_debug("redo lookup");
|
|
fscache_object_retrying_stale(&object->fscache);
|
|
goto lookup_again;
|
|
}
|
|
}
|
|
|
|
/* note that we're now using this object */
|
|
ret = cachefiles_mark_object_active(cache, object);
|
|
|
|
inode_unlock(d_inode(dir));
|
|
dput(dir);
|
|
dir = NULL;
|
|
|
|
if (ret == -ETIMEDOUT)
|
|
goto mark_active_timed_out;
|
|
|
|
_debug("=== OBTAINED_OBJECT ===");
|
|
|
|
if (object->new) {
|
|
/* attach data to a newly constructed terminal object */
|
|
ret = cachefiles_set_object_xattr(object, auxdata);
|
|
if (ret < 0)
|
|
goto check_error;
|
|
} else {
|
|
/* always update the atime on an object we've just looked up
|
|
* (this is used to keep track of culling, and atimes are only
|
|
* updated by read, write and readdir but not lookup or
|
|
* open) */
|
|
path.dentry = next;
|
|
touch_atime(&path);
|
|
}
|
|
|
|
/* open a file interface onto a data file */
|
|
if (object->type != FSCACHE_COOKIE_TYPE_INDEX) {
|
|
if (d_is_reg(object->dentry)) {
|
|
const struct address_space_operations *aops;
|
|
|
|
ret = -EPERM;
|
|
aops = d_backing_inode(object->dentry)->i_mapping->a_ops;
|
|
if (!aops->bmap)
|
|
goto check_error;
|
|
if (object->dentry->d_sb->s_blocksize > PAGE_SIZE)
|
|
goto check_error;
|
|
|
|
object->backer = object->dentry;
|
|
} else {
|
|
BUG(); // TODO: open file in data-class subdir
|
|
}
|
|
}
|
|
|
|
object->new = 0;
|
|
fscache_obtained_object(&object->fscache);
|
|
|
|
_leave(" = 0 [%lu]", d_backing_inode(object->dentry)->i_ino);
|
|
return 0;
|
|
|
|
no_space_error:
|
|
fscache_object_mark_killed(&object->fscache, FSCACHE_OBJECT_NO_SPACE);
|
|
create_error:
|
|
_debug("create error %d", ret);
|
|
if (ret == -EIO)
|
|
cachefiles_io_error(cache, "Create/mkdir failed");
|
|
goto error;
|
|
|
|
mark_active_timed_out:
|
|
_debug("mark active timed out");
|
|
goto release_dentry;
|
|
|
|
check_error:
|
|
_debug("check error %d", ret);
|
|
cachefiles_mark_object_inactive(
|
|
cache, object, d_backing_inode(object->dentry)->i_blocks);
|
|
release_dentry:
|
|
dput(object->dentry);
|
|
object->dentry = NULL;
|
|
goto error_out;
|
|
|
|
delete_error:
|
|
_debug("delete error %d", ret);
|
|
goto error_out2;
|
|
|
|
lookup_error:
|
|
_debug("lookup error %ld", PTR_ERR(next));
|
|
ret = PTR_ERR(next);
|
|
if (ret == -EIO)
|
|
cachefiles_io_error(cache, "Lookup failed");
|
|
next = NULL;
|
|
error:
|
|
inode_unlock(d_inode(dir));
|
|
dput(next);
|
|
error_out2:
|
|
dput(dir);
|
|
error_out:
|
|
_leave(" = error %d", -ret);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* get a subdirectory
|
|
*/
|
|
struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
|
|
struct dentry *dir,
|
|
const char *dirname)
|
|
{
|
|
struct dentry *subdir;
|
|
unsigned long start;
|
|
struct path path;
|
|
int ret;
|
|
|
|
_enter(",,%s", dirname);
|
|
|
|
/* search the current directory for the element name */
|
|
inode_lock(d_inode(dir));
|
|
|
|
retry:
|
|
start = jiffies;
|
|
subdir = lookup_one_len(dirname, dir, strlen(dirname));
|
|
cachefiles_hist(cachefiles_lookup_histogram, start);
|
|
if (IS_ERR(subdir)) {
|
|
if (PTR_ERR(subdir) == -ENOMEM)
|
|
goto nomem_d_alloc;
|
|
goto lookup_error;
|
|
}
|
|
|
|
_debug("subdir -> %p %s",
|
|
subdir, d_backing_inode(subdir) ? "positive" : "negative");
|
|
|
|
/* we need to create the subdir if it doesn't exist yet */
|
|
if (d_is_negative(subdir)) {
|
|
ret = cachefiles_has_space(cache, 1, 0);
|
|
if (ret < 0)
|
|
goto mkdir_error;
|
|
|
|
_debug("attempt mkdir");
|
|
|
|
path.mnt = cache->mnt;
|
|
path.dentry = dir;
|
|
ret = security_path_mkdir(&path, subdir, 0700);
|
|
if (ret < 0)
|
|
goto mkdir_error;
|
|
ret = vfs_mkdir(d_inode(dir), subdir, 0700);
|
|
if (ret < 0)
|
|
goto mkdir_error;
|
|
|
|
if (unlikely(d_unhashed(subdir))) {
|
|
dput(subdir);
|
|
goto retry;
|
|
}
|
|
ASSERT(d_backing_inode(subdir));
|
|
|
|
_debug("mkdir -> %p{%p{ino=%lu}}",
|
|
subdir,
|
|
d_backing_inode(subdir),
|
|
d_backing_inode(subdir)->i_ino);
|
|
}
|
|
|
|
inode_unlock(d_inode(dir));
|
|
|
|
/* we need to make sure the subdir is a directory */
|
|
ASSERT(d_backing_inode(subdir));
|
|
|
|
if (!d_can_lookup(subdir)) {
|
|
pr_err("%s is not a directory\n", dirname);
|
|
ret = -EIO;
|
|
goto check_error;
|
|
}
|
|
|
|
ret = -EPERM;
|
|
if (!(d_backing_inode(subdir)->i_opflags & IOP_XATTR) ||
|
|
!d_backing_inode(subdir)->i_op->lookup ||
|
|
!d_backing_inode(subdir)->i_op->mkdir ||
|
|
!d_backing_inode(subdir)->i_op->create ||
|
|
!d_backing_inode(subdir)->i_op->rename ||
|
|
!d_backing_inode(subdir)->i_op->rmdir ||
|
|
!d_backing_inode(subdir)->i_op->unlink)
|
|
goto check_error;
|
|
|
|
_leave(" = [%lu]", d_backing_inode(subdir)->i_ino);
|
|
return subdir;
|
|
|
|
check_error:
|
|
dput(subdir);
|
|
_leave(" = %d [check]", ret);
|
|
return ERR_PTR(ret);
|
|
|
|
mkdir_error:
|
|
inode_unlock(d_inode(dir));
|
|
dput(subdir);
|
|
pr_err("mkdir %s failed with error %d\n", dirname, ret);
|
|
return ERR_PTR(ret);
|
|
|
|
lookup_error:
|
|
inode_unlock(d_inode(dir));
|
|
ret = PTR_ERR(subdir);
|
|
pr_err("Lookup %s failed with error %d\n", dirname, ret);
|
|
return ERR_PTR(ret);
|
|
|
|
nomem_d_alloc:
|
|
inode_unlock(d_inode(dir));
|
|
_leave(" = -ENOMEM");
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
/*
|
|
* find out if an object is in use or not
|
|
* - if finds object and it's not in use:
|
|
* - returns a pointer to the object and a reference on it
|
|
* - returns with the directory locked
|
|
*/
|
|
static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache,
|
|
struct dentry *dir,
|
|
char *filename)
|
|
{
|
|
struct cachefiles_object *object;
|
|
struct rb_node *_n;
|
|
struct dentry *victim;
|
|
unsigned long start;
|
|
int ret;
|
|
|
|
//_enter(",%pd/,%s",
|
|
// dir, filename);
|
|
|
|
/* look up the victim */
|
|
inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
|
|
|
|
start = jiffies;
|
|
victim = lookup_one_len(filename, dir, strlen(filename));
|
|
cachefiles_hist(cachefiles_lookup_histogram, start);
|
|
if (IS_ERR(victim))
|
|
goto lookup_error;
|
|
|
|
//_debug("victim -> %p %s",
|
|
// victim, d_backing_inode(victim) ? "positive" : "negative");
|
|
|
|
/* if the object is no longer there then we probably retired the object
|
|
* at the netfs's request whilst the cull was in progress
|
|
*/
|
|
if (d_is_negative(victim)) {
|
|
inode_unlock(d_inode(dir));
|
|
dput(victim);
|
|
_leave(" = -ENOENT [absent]");
|
|
return ERR_PTR(-ENOENT);
|
|
}
|
|
|
|
/* check to see if we're using this object */
|
|
read_lock(&cache->active_lock);
|
|
|
|
_n = cache->active_nodes.rb_node;
|
|
|
|
while (_n) {
|
|
object = rb_entry(_n, struct cachefiles_object, active_node);
|
|
|
|
if (object->dentry > victim)
|
|
_n = _n->rb_left;
|
|
else if (object->dentry < victim)
|
|
_n = _n->rb_right;
|
|
else
|
|
goto object_in_use;
|
|
}
|
|
|
|
read_unlock(&cache->active_lock);
|
|
|
|
//_leave(" = %p", victim);
|
|
return victim;
|
|
|
|
object_in_use:
|
|
read_unlock(&cache->active_lock);
|
|
inode_unlock(d_inode(dir));
|
|
dput(victim);
|
|
//_leave(" = -EBUSY [in use]");
|
|
return ERR_PTR(-EBUSY);
|
|
|
|
lookup_error:
|
|
inode_unlock(d_inode(dir));
|
|
ret = PTR_ERR(victim);
|
|
if (ret == -ENOENT) {
|
|
/* file or dir now absent - probably retired by netfs */
|
|
_leave(" = -ESTALE [absent]");
|
|
return ERR_PTR(-ESTALE);
|
|
}
|
|
|
|
if (ret == -EIO) {
|
|
cachefiles_io_error(cache, "Lookup failed");
|
|
} else if (ret != -ENOMEM) {
|
|
pr_err("Internal error: %d\n", ret);
|
|
ret = -EIO;
|
|
}
|
|
|
|
_leave(" = %d", ret);
|
|
return ERR_PTR(ret);
|
|
}
|
|
|
|
/*
|
|
* cull an object if it's not in use
|
|
* - called only by cache manager daemon
|
|
*/
|
|
int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
|
|
char *filename)
|
|
{
|
|
struct dentry *victim;
|
|
int ret;
|
|
|
|
_enter(",%pd/,%s", dir, filename);
|
|
|
|
victim = cachefiles_check_active(cache, dir, filename);
|
|
if (IS_ERR(victim))
|
|
return PTR_ERR(victim);
|
|
|
|
_debug("victim -> %p %s",
|
|
victim, d_backing_inode(victim) ? "positive" : "negative");
|
|
|
|
/* okay... the victim is not being used so we can cull it
|
|
* - start by marking it as stale
|
|
*/
|
|
_debug("victim is cullable");
|
|
|
|
ret = cachefiles_remove_object_xattr(cache, victim);
|
|
if (ret < 0)
|
|
goto error_unlock;
|
|
|
|
/* actually remove the victim (drops the dir mutex) */
|
|
_debug("bury");
|
|
|
|
ret = cachefiles_bury_object(cache, NULL, dir, victim, false,
|
|
FSCACHE_OBJECT_WAS_CULLED);
|
|
if (ret < 0)
|
|
goto error;
|
|
|
|
dput(victim);
|
|
_leave(" = 0");
|
|
return 0;
|
|
|
|
error_unlock:
|
|
inode_unlock(d_inode(dir));
|
|
error:
|
|
dput(victim);
|
|
if (ret == -ENOENT) {
|
|
/* file or dir now absent - probably retired by netfs */
|
|
_leave(" = -ESTALE [absent]");
|
|
return -ESTALE;
|
|
}
|
|
|
|
if (ret != -ENOMEM) {
|
|
pr_err("Internal error: %d\n", ret);
|
|
ret = -EIO;
|
|
}
|
|
|
|
_leave(" = %d", ret);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* find out if an object is in use or not
|
|
* - called only by cache manager daemon
|
|
* - returns -EBUSY or 0 to indicate whether an object is in use or not
|
|
*/
|
|
int cachefiles_check_in_use(struct cachefiles_cache *cache, struct dentry *dir,
|
|
char *filename)
|
|
{
|
|
struct dentry *victim;
|
|
|
|
//_enter(",%pd/,%s",
|
|
// dir, filename);
|
|
|
|
victim = cachefiles_check_active(cache, dir, filename);
|
|
if (IS_ERR(victim))
|
|
return PTR_ERR(victim);
|
|
|
|
inode_unlock(d_inode(dir));
|
|
dput(victim);
|
|
//_leave(" = 0");
|
|
return 0;
|
|
}
|