diff options
Diffstat (limited to 'fs/cachefiles/namei.c')
| -rw-r--r-- | fs/cachefiles/namei.c | 1223 |
1 files changed, 526 insertions, 697 deletions
diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c index a9aca5ab5970..9bd692870617 100644 --- a/fs/cachefiles/namei.c +++ b/fs/cachefiles/namei.c @@ -1,295 +1,268 @@ // SPDX-License-Identifier: GPL-2.0-or-later /* CacheFiles path walking and related routines * - * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) */ -#include <linux/module.h> -#include <linux/sched.h> -#include <linux/file.h> #include <linux/fs.h> -#include <linux/fsnotify.h> -#include <linux/quotaops.h> -#include <linux/xattr.h> -#include <linux/mount.h> #include <linux/namei.h> -#include <linux/security.h> -#include <linux/slab.h> #include "internal.h" -#define CACHEFILES_KEYBUF_SIZE 512 - /* - * dump debugging info about an object + * Mark the backing file as being a cache file if it's not already in use. The + * mark tells the culling request command that it's not allowed to cull the + * file or directory. The caller must hold the inode lock. */ -static noinline -void __cachefiles_printk_object(struct cachefiles_object *object, - const char *prefix) +static bool __cachefiles_mark_inode_in_use(struct cachefiles_object *object, + struct dentry *dentry) { - struct fscache_cookie *cookie; - const u8 *k; - unsigned loop; - - pr_err("%sobject: OBJ%x\n", prefix, object->fscache.debug_id); - pr_err("%sobjstate=%s fl=%lx wbusy=%x ev=%lx[%lx]\n", - prefix, object->fscache.state->name, - object->fscache.flags, work_busy(&object->fscache.work), - object->fscache.events, object->fscache.event_mask); - pr_err("%sops=%u inp=%u exc=%u\n", - prefix, object->fscache.n_ops, object->fscache.n_in_progress, - object->fscache.n_exclusive); - pr_err("%sparent=%x\n", - prefix, object->fscache.parent ? object->fscache.parent->debug_id : 0); - - spin_lock(&object->fscache.lock); - cookie = object->fscache.cookie; - if (cookie) { - pr_err("%scookie=%x [pr=%x nd=%p fl=%lx]\n", - prefix, - cookie->debug_id, - cookie->parent ? cookie->parent->debug_id : 0, - cookie->netfs_data, - cookie->flags); - pr_err("%skey=[%u] '", prefix, cookie->key_len); - k = (cookie->key_len <= sizeof(cookie->inline_key)) ? - cookie->inline_key : cookie->key; - for (loop = 0; loop < cookie->key_len; loop++) - pr_cont("%02x", k[loop]); - pr_cont("'\n"); + struct inode *inode = d_backing_inode(dentry); + bool can_use = false; + + if (!(inode->i_flags & S_KERNEL_FILE)) { + inode->i_flags |= S_KERNEL_FILE; + trace_cachefiles_mark_active(object, inode); + can_use = true; } else { - pr_err("%scookie=NULL\n", prefix); + pr_notice("cachefiles: Inode already in use: %pd\n", dentry); } - spin_unlock(&object->fscache.lock); + + return can_use; } -/* - * dump debugging info about a pair of objects - */ -static noinline void cachefiles_printk_object(struct cachefiles_object *object, - struct cachefiles_object *xobject) +static bool cachefiles_mark_inode_in_use(struct cachefiles_object *object, + struct dentry *dentry) { - if (object) - __cachefiles_printk_object(object, ""); - if (xobject) - __cachefiles_printk_object(xobject, "x"); + struct inode *inode = d_backing_inode(dentry); + bool can_use; + + inode_lock(inode); + can_use = __cachefiles_mark_inode_in_use(object, dentry); + inode_unlock(inode); + return can_use; } /* - * mark the owner of a dentry, if there is one, to indicate that that dentry - * has been preemptively deleted - * - the caller must hold the i_mutex on the dentry's parent as required to - * call vfs_unlink(), vfs_rmdir() or vfs_rename() + * Unmark a backing inode. The caller must hold the inode lock. */ -static void cachefiles_mark_object_buried(struct cachefiles_cache *cache, - struct dentry *dentry, - enum fscache_why_object_killed why) +static void __cachefiles_unmark_inode_in_use(struct cachefiles_object *object, + struct dentry *dentry) { - struct cachefiles_object *object; - struct rb_node *p; - - _enter(",'%pd'", dentry); + struct inode *inode = d_backing_inode(dentry); - write_lock(&cache->active_lock); + inode->i_flags &= ~S_KERNEL_FILE; + trace_cachefiles_mark_inactive(object, inode); +} - p = cache->active_nodes.rb_node; - while (p) { - object = rb_entry(p, struct cachefiles_object, active_node); - if (object->dentry > dentry) - p = p->rb_left; - else if (object->dentry < dentry) - p = p->rb_right; - else - goto found_dentry; +/* + * Unmark a backing inode and tell cachefilesd that there's something that can + * be culled. + */ +void cachefiles_unmark_inode_in_use(struct cachefiles_object *object, + struct file *file) +{ + struct cachefiles_cache *cache = object->volume->cache; + struct inode *inode = file_inode(file); + + if (inode) { + inode_lock(inode); + __cachefiles_unmark_inode_in_use(object, file->f_path.dentry); + inode_unlock(inode); + + if (!test_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags)) { + atomic_long_add(inode->i_blocks, &cache->b_released); + if (atomic_inc_return(&cache->f_released)) + cachefiles_state_changed(cache); + } } +} - write_unlock(&cache->active_lock); - trace_cachefiles_mark_buried(NULL, dentry, why); - _leave(" [no owner]"); - return; +/* + * get a subdirectory + */ +struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, + struct dentry *dir, + const char *dirname, + bool *_is_new) +{ + struct dentry *subdir; + struct path path; + int ret; - /* found the dentry for */ -found_dentry: - kdebug("preemptive burial: OBJ%x [%s] %pd", - object->fscache.debug_id, - object->fscache.state->name, - dentry); + _enter(",,%s", dirname); - trace_cachefiles_mark_buried(object, dentry, why); + /* search the current directory for the element name */ + inode_lock_nested(d_inode(dir), I_MUTEX_PARENT); - if (fscache_object_is_live(&object->fscache)) { - pr_err("\n"); - pr_err("Error: Can't preemptively bury live object\n"); - cachefiles_printk_object(object, NULL); - } else { - if (why != FSCACHE_OBJECT_IS_STALE) - fscache_object_mark_killed(&object->fscache, why); +retry: + ret = cachefiles_inject_read_error(); + if (ret == 0) + subdir = lookup_one_len(dirname, dir, strlen(dirname)); + else + subdir = ERR_PTR(ret); + if (IS_ERR(subdir)) { + trace_cachefiles_vfs_error(NULL, d_backing_inode(dir), + PTR_ERR(subdir), + cachefiles_trace_lookup_error); + if (PTR_ERR(subdir) == -ENOMEM) + goto nomem_d_alloc; + goto lookup_error; } - write_unlock(&cache->active_lock); - _leave(" [owner marked]"); -} + _debug("subdir -> %pd %s", + subdir, d_backing_inode(subdir) ? "positive" : "negative"); -/* - * record the fact that an object is now active - */ -static int cachefiles_mark_object_active(struct cachefiles_cache *cache, - struct cachefiles_object *object) -{ - struct cachefiles_object *xobject; - struct rb_node **_p, *_parent = NULL; - struct dentry *dentry; + /* we need to create the subdir if it doesn't exist yet */ + if (d_is_negative(subdir)) { + ret = cachefiles_has_space(cache, 1, 0, + cachefiles_has_space_for_create); + if (ret < 0) + goto mkdir_error; - _enter(",%x", object->fscache.debug_id); + _debug("attempt mkdir"); -try_again: - write_lock(&cache->active_lock); + path.mnt = cache->mnt; + path.dentry = dir; + ret = security_path_mkdir(&path, subdir, 0700); + if (ret < 0) + goto mkdir_error; + ret = cachefiles_inject_write_error(); + if (ret == 0) + ret = vfs_mkdir(&init_user_ns, d_inode(dir), subdir, 0700); + if (ret < 0) { + trace_cachefiles_vfs_error(NULL, d_inode(dir), ret, + cachefiles_trace_mkdir_error); + goto mkdir_error; + } - dentry = object->dentry; - trace_cachefiles_mark_active(object, dentry); + if (unlikely(d_unhashed(subdir))) { + cachefiles_put_directory(subdir); + goto retry; + } + ASSERT(d_backing_inode(subdir)); - if (test_and_set_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) { - pr_err("Error: Object already active\n"); - cachefiles_printk_object(object, NULL); - BUG(); + _debug("mkdir -> %pd{ino=%lu}", + subdir, d_backing_inode(subdir)->i_ino); + if (_is_new) + *_is_new = true; } - _p = &cache->active_nodes.rb_node; - while (*_p) { - _parent = *_p; - xobject = rb_entry(_parent, - struct cachefiles_object, active_node); + /* Tell rmdir() it's not allowed to delete the subdir */ + inode_lock(d_inode(subdir)); + inode_unlock(d_inode(dir)); - ASSERT(xobject != object); + if (!__cachefiles_mark_inode_in_use(NULL, subdir)) + goto mark_error; - if (xobject->dentry > dentry) - _p = &(*_p)->rb_left; - else if (xobject->dentry < dentry) - _p = &(*_p)->rb_right; - else - goto wait_for_old_object; - } + inode_unlock(d_inode(subdir)); - rb_link_node(&object->active_node, _parent, _p); - rb_insert_color(&object->active_node, &cache->active_nodes); + /* we need to make sure the subdir is a directory */ + ASSERT(d_backing_inode(subdir)); - write_unlock(&cache->active_lock); - _leave(" = 0"); - return 0; + if (!d_can_lookup(subdir)) { + pr_err("%s is not a directory\n", dirname); + ret = -EIO; + goto check_error; + } - /* an old object from a previous incarnation is hogging the slot - we - * need to wait for it to be destroyed */ -wait_for_old_object: - trace_cachefiles_wait_active(object, dentry, xobject); - clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags); - - if (fscache_object_is_live(&xobject->fscache)) { - pr_err("\n"); - pr_err("Error: Unexpected object collision\n"); - cachefiles_printk_object(object, xobject); - } - atomic_inc(&xobject->usage); - write_unlock(&cache->active_lock); - - if (test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) { - wait_queue_head_t *wq; - - signed long timeout = 60 * HZ; - wait_queue_entry_t wait; - bool requeue; - - /* if the object we're waiting for is queued for processing, - * then just put ourselves on the queue behind it */ - if (work_pending(&xobject->fscache.work)) { - _debug("queue OBJ%x behind OBJ%x immediately", - object->fscache.debug_id, - xobject->fscache.debug_id); - goto requeue; - } + 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->rename || + !d_backing_inode(subdir)->i_op->rmdir || + !d_backing_inode(subdir)->i_op->unlink) + goto check_error; - /* otherwise we sleep until either the object we're waiting for - * is done, or the fscache_object is congested */ - wq = bit_waitqueue(&xobject->flags, CACHEFILES_OBJECT_ACTIVE); - init_wait(&wait); - requeue = false; - do { - prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); - if (!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) - break; - - requeue = fscache_object_sleep_till_congested(&timeout); - } while (timeout > 0 && !requeue); - finish_wait(wq, &wait); - - if (requeue && - test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) { - _debug("queue OBJ%x behind OBJ%x after wait", - object->fscache.debug_id, - xobject->fscache.debug_id); - goto requeue; - } + _leave(" = [%lu]", d_backing_inode(subdir)->i_ino); + return subdir; - if (timeout <= 0) { - pr_err("\n"); - pr_err("Error: Overlong wait for old active object to go away\n"); - cachefiles_printk_object(object, xobject); - goto requeue; - } - } +check_error: + cachefiles_put_directory(subdir); + _leave(" = %d [check]", ret); + return ERR_PTR(ret); - ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)); +mark_error: + inode_unlock(d_inode(subdir)); + dput(subdir); + return ERR_PTR(-EBUSY); - cache->cache.ops->put_object(&xobject->fscache, - (enum fscache_obj_ref_trace)cachefiles_obj_put_wait_retry); - goto try_again; +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); -requeue: - cache->cache.ops->put_object(&xobject->fscache, - (enum fscache_obj_ref_trace)cachefiles_obj_put_wait_timeo); - _leave(" = -ETIMEDOUT"); - return -ETIMEDOUT; +nomem_d_alloc: + inode_unlock(d_inode(dir)); + _leave(" = -ENOMEM"); + return ERR_PTR(-ENOMEM); } /* - * Mark an object as being inactive. + * Put a subdirectory. */ -void cachefiles_mark_object_inactive(struct cachefiles_cache *cache, - struct cachefiles_object *object, - blkcnt_t i_blocks) +void cachefiles_put_directory(struct dentry *dir) { - struct dentry *dentry = object->dentry; - struct inode *inode = d_backing_inode(dentry); - - trace_cachefiles_mark_inactive(object, dentry, inode); + if (dir) { + inode_lock(dir->d_inode); + __cachefiles_unmark_inode_in_use(NULL, dir); + inode_unlock(dir->d_inode); + dput(dir); + } +} - write_lock(&cache->active_lock); - rb_erase(&object->active_node, &cache->active_nodes); - clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags); - write_unlock(&cache->active_lock); +/* + * Remove a regular file from the cache. + */ +static int cachefiles_unlink(struct cachefiles_cache *cache, + struct cachefiles_object *object, + struct dentry *dir, struct dentry *dentry, + enum fscache_why_object_killed why) +{ + struct path path = { + .mnt = cache->mnt, + .dentry = dir, + }; + int ret; - wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE); + trace_cachefiles_unlink(object, dentry, why); + ret = security_path_unlink(&path, dentry); + if (ret < 0) { + cachefiles_io_error(cache, "Unlink security error"); + return ret; + } - /* This object can now be culled, so we need to let the daemon know - * that there is something it can remove if it needs to. - */ - atomic_long_add(i_blocks, &cache->b_released); - if (atomic_inc_return(&cache->f_released)) - cachefiles_state_changed(cache); + ret = cachefiles_inject_remove_error(); + if (ret == 0) { + ret = vfs_unlink(&init_user_ns, d_backing_inode(dir), dentry, NULL); + if (ret == -EIO) + cachefiles_io_error(cache, "Unlink failed"); + } + if (ret != 0) + trace_cachefiles_vfs_error(object, d_backing_inode(dir), ret, + cachefiles_trace_unlink_error); + return ret; } /* - * delete an object representation from the cache - * - file backed objects are unlinked - * - directory backed objects are stuffed into the graveyard for userspace to + * Delete an object representation from the cache + * - File backed objects are unlinked + * - Directory backed objects are stuffed into the graveyard for userspace to * delete - * - unlocks the directory mutex */ -static int cachefiles_bury_object(struct cachefiles_cache *cache, - struct cachefiles_object *object, - struct dentry *dir, - struct dentry *rep, - bool preemptive, - enum fscache_why_object_killed why) +int cachefiles_bury_object(struct cachefiles_cache *cache, + struct cachefiles_object *object, + struct dentry *dir, + struct dentry *rep, + enum fscache_why_object_killed why) { struct dentry *grave, *trap; struct path path, path_to_graveyard; @@ -298,29 +271,21 @@ static int cachefiles_bury_object(struct cachefiles_cache *cache, _enter(",'%pd','%pd'", dir, rep); + if (rep->d_parent != dir) { + inode_unlock(d_inode(dir)); + _leave(" = -ESTALE"); + return -ESTALE; + } + /* non-directories can just be unlinked */ if (!d_is_dir(rep)) { - _debug("unlink stale object"); - - path.mnt = cache->mnt; - path.dentry = dir; - ret = security_path_unlink(&path, rep); - if (ret < 0) { - cachefiles_io_error(cache, "Unlink security error"); - } else { - trace_cachefiles_unlink(object, rep, why); - ret = vfs_unlink(&init_user_ns, d_inode(dir), rep, - NULL); - - if (preemptive) - cachefiles_mark_object_buried(cache, rep, why); - } + dget(rep); /* Stop the dentry being negated if it's only pinned + * by a file struct. + */ + ret = cachefiles_unlink(cache, object, dir, rep, why); + dput(rep); inode_unlock(d_inode(dir)); - - if (ret == -EIO) - cachefiles_io_error(cache, "Unlink failed"); - _leave(" = %d", ret); return ret; } @@ -368,14 +333,16 @@ try_again: grave = lookup_one_len(nbuffer, cache->graveyard, strlen(nbuffer)); if (IS_ERR(grave)) { unlock_rename(cache->graveyard, dir); + trace_cachefiles_vfs_error(object, d_inode(cache->graveyard), + PTR_ERR(grave), + cachefiles_trace_lookup_error); if (PTR_ERR(grave) == -ENOMEM) { _leave(" = -ENOMEM"); return -ENOMEM; } - cachefiles_io_error(cache, "Lookup error %ld", - PTR_ERR(grave)); + cachefiles_io_error(cache, "Lookup error %ld", PTR_ERR(grave)); return -EIO; } @@ -420,15 +387,18 @@ try_again: .new_dentry = grave, }; trace_cachefiles_rename(object, rep, grave, why); - ret = vfs_rename(&rd); + ret = cachefiles_inject_read_error(); + if (ret == 0) + ret = vfs_rename(&rd); + if (ret != 0) + trace_cachefiles_vfs_error(object, d_inode(dir), ret, + cachefiles_trace_rename_error); if (ret != 0 && ret != -ENOMEM) cachefiles_io_error(cache, "Rename failed with error %d", ret); - - if (preemptive) - cachefiles_mark_object_buried(cache, rep, why); } + __cachefiles_unmark_inode_in_use(object, rep); unlock_rename(cache->graveyard, dir); dput(grave); _leave(" = 0"); @@ -436,493 +406,358 @@ try_again: } /* - * delete an object representation from the cache + * Delete a cache file. */ -int cachefiles_delete_object(struct cachefiles_cache *cache, - struct cachefiles_object *object) +int cachefiles_delete_object(struct cachefiles_object *object, + enum fscache_why_object_killed why) { - struct dentry *dir; + struct cachefiles_volume *volume = object->volume; + struct dentry *dentry = object->file->f_path.dentry; + struct dentry *fan = volume->fanout[(u8)object->cookie->key_hash]; int ret; - _enter(",OBJ%x{%pd}", object->fscache.debug_id, object->dentry); - - ASSERT(object->dentry); - ASSERT(d_backing_inode(object->dentry)); - ASSERT(object->dentry->d_parent); + _enter(",OBJ%x{%pD}", object->debug_id, object->file); - dir = dget_parent(object->dentry); + /* Stop the dentry being negated if it's only pinned by a file struct. */ + dget(dentry); - inode_lock_nested(d_inode(dir), I_MUTEX_PARENT); - - 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 */ - _debug("object preemptively buried"); - inode_unlock(d_inode(dir)); - 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) { - 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; - } - } - - dput(dir); - _leave(" = %d", ret); + inode_lock_nested(d_backing_inode(fan), I_MUTEX_PARENT); + ret = cachefiles_unlink(volume->cache, object, fan, dentry, why); + inode_unlock(d_backing_inode(fan)); + dput(dentry); return ret; } /* - * walk from the parent object to the child object through the backing - * filesystem, creating directories as we go + * Create a temporary file and leave it unattached and un-xattr'd until the + * time comes to discard the object from memory. */ -int cachefiles_walk_to_object(struct cachefiles_object *parent, - struct cachefiles_object *object, - const char *key, - struct cachefiles_xattr *auxdata) +struct file *cachefiles_create_tmpfile(struct cachefiles_object *object) { - struct cachefiles_cache *cache; - struct dentry *dir, *next = NULL; - struct inode *inode; + struct cachefiles_volume *volume = object->volume; + struct cachefiles_cache *cache = volume->cache; + const struct cred *saved_cred; + struct dentry *fan = volume->fanout[(u8)object->cookie->key_hash]; + struct file *file; struct path path; - const char *name; - int ret, nlen; - - _enter("OBJ%x{%pd},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); + uint64_t ni_size = object->cookie->object_size; + long ret; - next = lookup_one_len(name, dir, nlen); - if (IS_ERR(next)) { - trace_cachefiles_lookup(object, next, NULL); - goto lookup_error; - } + ni_size = round_up(ni_size, CACHEFILES_DIO_BLOCK_SIZE); - inode = d_backing_inode(next); - trace_cachefiles_lookup(object, next, inode); - _debug("next -> %pd %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; - ret = vfs_mkdir(&init_user_ns, d_inode(dir), next, 0); - 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 -> %pd{ino=%lu}", - 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; - } + cachefiles_begin_secure(cache, &saved_cred); - } 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; - ret = vfs_create(&init_user_ns, d_inode(dir), next, - S_IFREG, true); - trace_cachefiles_create(object, next, ret); - if (ret < 0) - goto create_error; - - ASSERT(d_backing_inode(next)); - - _debug("create -> %pd{ino=%lu}", - 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; + path.mnt = cache->mnt; + ret = cachefiles_inject_write_error(); + if (ret == 0) + path.dentry = vfs_tmpfile(&init_user_ns, fan, S_IFREG, O_RDWR); + else + path.dentry = ERR_PTR(ret); + if (IS_ERR(path.dentry)) { + trace_cachefiles_vfs_error(object, d_inode(fan), PTR_ERR(path.dentry), + cachefiles_trace_tmpfile_error); + if (PTR_ERR(path.dentry) == -EIO) + cachefiles_io_error_obj(object, "Failed to create tmpfile"); + file = ERR_CAST(path.dentry); + goto out; + } + + trace_cachefiles_tmpfile(object, d_backing_inode(path.dentry)); + + if (!cachefiles_mark_inode_in_use(object, path.dentry)) { + file = ERR_PTR(-EBUSY); + goto out_dput; + } + + if (ni_size > 0) { + trace_cachefiles_trunc(object, d_backing_inode(path.dentry), 0, ni_size, + cachefiles_trunc_expand_tmpfile); + ret = cachefiles_inject_write_error(); + if (ret == 0) + ret = vfs_truncate(&path, ni_size); + if (ret < 0) { + trace_cachefiles_vfs_error( + object, d_backing_inode(path.dentry), ret, + cachefiles_trace_trunc_error); + file = ERR_PTR(ret); + goto out_dput; } } - /* process the next component */ - if (key) { - _debug("advance"); - inode_unlock(d_inode(dir)); - dput(dir); - dir = next; - next = NULL; - goto advance; + file = open_with_fake_path(&path, O_RDWR | O_LARGEFILE | O_DIRECT, + d_backing_inode(path.dentry), cache->cache_cred); + if (IS_ERR(file)) { + trace_cachefiles_vfs_error(object, d_backing_inode(path.dentry), + PTR_ERR(file), + cachefiles_trace_open_error); + goto out_dput; + } + if (unlikely(!file->f_op->read_iter) || + unlikely(!file->f_op->write_iter)) { + fput(file); + pr_notice("Cache does not support read_iter and write_iter\n"); + file = ERR_PTR(-EINVAL); } - /* 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; +out_dput: + dput(path.dentry); +out: + cachefiles_end_secure(cache, saved_cred); + return file; +} - ret = cachefiles_bury_object(cache, object, dir, next, - true, - FSCACHE_OBJECT_IS_STALE); - dput(next); - next = NULL; +/* + * Create a new file. + */ +static bool cachefiles_create_file(struct cachefiles_object *object) +{ + struct file *file; + int ret; - if (ret < 0) - goto delete_error; + ret = cachefiles_has_space(object->volume->cache, 1, 0, + cachefiles_has_space_for_create); + if (ret < 0) + return false; - _debug("redo lookup"); - fscache_object_retrying_stale(&object->fscache); - goto lookup_again; - } - } + file = cachefiles_create_tmpfile(object); + if (IS_ERR(file)) + return false; - /* note that we're now using this object */ - ret = cachefiles_mark_object_active(cache, object); + set_bit(FSCACHE_COOKIE_NEEDS_UPDATE, &object->cookie->flags); + set_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags); + _debug("create -> %pD{ino=%lu}", file, file_inode(file)->i_ino); + object->file = file; + return true; +} - inode_unlock(d_inode(dir)); - dput(dir); - dir = NULL; +/* + * Open an existing file, checking its attributes and replacing it if it is + * stale. + */ +static bool cachefiles_open_file(struct cachefiles_object *object, + struct dentry *dentry) +{ + struct cachefiles_cache *cache = object->volume->cache; + struct file *file; + struct path path; + int ret; - if (ret == -ETIMEDOUT) - goto mark_active_timed_out; + _enter("%pd", dentry); - _debug("=== OBTAINED_OBJECT ==="); + if (!cachefiles_mark_inode_in_use(object, dentry)) + return false; - 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 - } + /* We need to open a file interface onto a data file now as we can't do + * it on demand because writeback called from do_exit() sees + * current->fs == NULL - which breaks d_path() called from ext4 open. + */ + path.mnt = cache->mnt; + path.dentry = dentry; + file = open_with_fake_path(&path, O_RDWR | O_LARGEFILE | O_DIRECT, + d_backing_inode(dentry), cache->cache_cred); + if (IS_ERR(file)) { + trace_cachefiles_vfs_error(object, d_backing_inode(dentry), + PTR_ERR(file), + cachefiles_trace_open_error); + goto error; } - 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; + if (unlikely(!file->f_op->read_iter) || + unlikely(!file->f_op->write_iter)) { + pr_notice("Cache does not support read_iter and write_iter\n"); + goto error_fput; + } + _debug("file -> %pd positive", dentry); -mark_active_timed_out: - _debug("mark active timed out"); - goto release_dentry; + ret = cachefiles_check_auxdata(object, file); + if (ret < 0) + goto check_failed; -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; + object->file = file; -lookup_error: - _debug("lookup error %ld", PTR_ERR(next)); - ret = PTR_ERR(next); - if (ret == -EIO) - cachefiles_io_error(cache, "Lookup failed"); - next = NULL; + /* 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). + */ + touch_atime(&file->f_path); + dput(dentry); + return true; + +check_failed: + fscache_cookie_lookup_negative(object->cookie); + cachefiles_unmark_inode_in_use(object, file); + if (ret == -ESTALE) { + fput(file); + dput(dentry); + return cachefiles_create_file(object); + } +error_fput: + fput(file); error: - inode_unlock(d_inode(dir)); - dput(next); -error_out2: - dput(dir); -error_out: - _leave(" = error %d", -ret); - return ret; + dput(dentry); + return false; } /* - * get a subdirectory + * walk from the parent object to the child object through the backing + * filesystem, creating directories as we go */ -struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, - struct dentry *dir, - const char *dirname) +bool cachefiles_look_up_object(struct cachefiles_object *object) { - struct dentry *subdir; - struct path path; + struct cachefiles_volume *volume = object->volume; + struct dentry *dentry, *fan = volume->fanout[(u8)object->cookie->key_hash]; int ret; - _enter(",,%s", dirname); - - /* search the current directory for the element name */ - inode_lock(d_inode(dir)); - -retry: - subdir = lookup_one_len(dirname, dir, strlen(dirname)); - if (IS_ERR(subdir)) { - if (PTR_ERR(subdir) == -ENOMEM) - goto nomem_d_alloc; - goto lookup_error; + _enter("OBJ%x,%s,", object->debug_id, object->d_name); + + /* Look up path "cache/vol/fanout/file". */ + ret = cachefiles_inject_read_error(); + if (ret == 0) + dentry = lookup_positive_unlocked(object->d_name, fan, + object->d_name_len); + else + dentry = ERR_PTR(ret); + trace_cachefiles_lookup(object, dentry); + if (IS_ERR(dentry)) { + if (dentry == ERR_PTR(-ENOENT)) + goto new_file; + if (dentry == ERR_PTR(-EIO)) + cachefiles_io_error_obj(object, "Lookup failed"); + return false; + } + + if (!d_is_reg(dentry)) { + pr_err("%pd is not a file\n", dentry); + inode_lock_nested(d_inode(fan), I_MUTEX_PARENT); + ret = cachefiles_bury_object(volume->cache, object, fan, dentry, + FSCACHE_OBJECT_IS_WEIRD); + dput(dentry); + if (ret < 0) + return false; + goto new_file; } - _debug("subdir -> %pd %s", - subdir, d_backing_inode(subdir) ? "positive" : "negative"); + if (!cachefiles_open_file(object, dentry)) + return false; - /* 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; + _leave(" = t [%lu]", file_inode(object->file)->i_ino); + return true; - _debug("attempt mkdir"); +new_file: + fscache_cookie_lookup_negative(object->cookie); + return cachefiles_create_file(object); +} - path.mnt = cache->mnt; - path.dentry = dir; - ret = security_path_mkdir(&path, subdir, 0700); - if (ret < 0) - goto mkdir_error; - ret = vfs_mkdir(&init_user_ns, d_inode(dir), subdir, 0700); - if (ret < 0) - goto mkdir_error; +/* + * Attempt to link a temporary file into its rightful place in the cache. + */ +bool cachefiles_commit_tmpfile(struct cachefiles_cache *cache, + struct cachefiles_object *object) +{ + struct cachefiles_volume *volume = object->volume; + struct dentry *dentry, *fan = volume->fanout[(u8)object->cookie->key_hash]; + bool success = false; + int ret; - if (unlikely(d_unhashed(subdir))) { - dput(subdir); - goto retry; + _enter(",%pD", object->file); + + inode_lock_nested(d_inode(fan), I_MUTEX_PARENT); + ret = cachefiles_inject_read_error(); + if (ret == 0) + dentry = lookup_one_len(object->d_name, fan, object->d_name_len); + else + dentry = ERR_PTR(ret); + if (IS_ERR(dentry)) { + trace_cachefiles_vfs_error(object, d_inode(fan), PTR_ERR(dentry), + cachefiles_trace_lookup_error); + _debug("lookup fail %ld", PTR_ERR(dentry)); + goto out_unlock; + } + + if (!d_is_negative(dentry)) { + if (d_backing_inode(dentry) == file_inode(object->file)) { + success = true; + goto out_dput; } - ASSERT(d_backing_inode(subdir)); - _debug("mkdir -> %pd{ino=%lu}", - 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)); + ret = cachefiles_unlink(volume->cache, object, fan, dentry, + FSCACHE_OBJECT_IS_STALE); + if (ret < 0) + goto out_dput; - if (!d_can_lookup(subdir)) { - pr_err("%s is not a directory\n", dirname); - ret = -EIO; - goto check_error; + dput(dentry); + ret = cachefiles_inject_read_error(); + if (ret == 0) + dentry = lookup_one_len(object->d_name, fan, object->d_name_len); + else + dentry = ERR_PTR(ret); + if (IS_ERR(dentry)) { + trace_cachefiles_vfs_error(object, d_inode(fan), PTR_ERR(dentry), + cachefiles_trace_lookup_error); + _debug("lookup fail %ld", PTR_ERR(dentry)); + goto out_unlock; + } } - 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); + ret = cachefiles_inject_read_error(); + if (ret == 0) + ret = vfs_link(object->file->f_path.dentry, &init_user_ns, + d_inode(fan), dentry, NULL); + if (ret < 0) { + trace_cachefiles_vfs_error(object, d_inode(fan), ret, + cachefiles_trace_link_error); + _debug("link fail %d", ret); + } else { + trace_cachefiles_link(object, file_inode(object->file)); + spin_lock(&object->lock); + /* TODO: Do we want to switch the file pointer to the new dentry? */ + clear_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags); + spin_unlock(&object->lock); + success = true; + } + +out_dput: + dput(dentry); +out_unlock: + inode_unlock(d_inode(fan)); + _leave(" = %u", success); + return success; } /* - * 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 + * Look up an inode to be checked or culled. Return -EBUSY if the inode is + * marked in use. */ -static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache, - struct dentry *dir, - char *filename) +static struct dentry *cachefiles_lookup_for_cull(struct cachefiles_cache *cache, + struct dentry *dir, + char *filename) { - struct cachefiles_object *object; - struct rb_node *_n; struct dentry *victim; - int ret; - - //_enter(",%pd/,%s", - // dir, filename); + int ret = -ENOENT; - /* look up the victim */ inode_lock_nested(d_inode(dir), I_MUTEX_PARENT); victim = lookup_one_len(filename, dir, strlen(filename)); if (IS_ERR(victim)) goto lookup_error; - - //_debug("victim -> %pd %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(" = %pd", victim); + if (d_is_negative(victim)) + goto lookup_put; + if (d_inode(victim)->i_flags & S_KERNEL_FILE) + goto lookup_busy; return victim; -object_in_use: - read_unlock(&cache->active_lock); +lookup_busy: + ret = -EBUSY; +lookup_put: inode_unlock(d_inode(dir)); dput(victim); - //_leave(" = -EBUSY [in use]"); - return ERR_PTR(-EBUSY); + return ERR_PTR(ret); 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 == -ENOENT) + return ERR_PTR(-ESTALE); /* Probably got retired by the netfs */ if (ret == -EIO) { cachefiles_io_error(cache, "Lookup failed"); @@ -931,46 +766,46 @@ lookup_error: ret = -EIO; } - _leave(" = %d", ret); return ERR_PTR(ret); } /* - * cull an object if it's not in use + * 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; + struct inode *inode; int ret; _enter(",%pd/,%s", dir, filename); - victim = cachefiles_check_active(cache, dir, filename); + victim = cachefiles_lookup_for_cull(cache, dir, filename); if (IS_ERR(victim)) return PTR_ERR(victim); - _debug("victim -> %pd %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); + /* check to see if someone is using this object */ + inode = d_inode(victim); + inode_lock(inode); + if (inode->i_flags & S_KERNEL_FILE) { + ret = -EBUSY; + } else { + /* Stop the cache from picking it back up */ + inode->i_flags |= S_KERNEL_FILE; + ret = 0; + } + inode_unlock(inode); 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, + ret = cachefiles_bury_object(cache, NULL, dir, victim, FSCACHE_OBJECT_WAS_CULLED); if (ret < 0) goto error; + fscache_count_culled(); dput(victim); _leave(" = 0"); return 0; @@ -979,11 +814,8 @@ 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 == -ENOENT) + return -ESTALE; /* Probably got retired by the netfs */ if (ret != -ENOMEM) { pr_err("Internal error: %d\n", ret); @@ -995,7 +827,7 @@ error: } /* - * find out if an object is in use or not + * 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 */ @@ -1003,16 +835,13 @@ int cachefiles_check_in_use(struct cachefiles_cache *cache, struct dentry *dir, char *filename) { struct dentry *victim; + int ret = 0; - //_enter(",%pd/,%s", - // dir, filename); - - victim = cachefiles_check_active(cache, dir, filename); + victim = cachefiles_lookup_for_cull(cache, dir, filename); if (IS_ERR(victim)) return PTR_ERR(victim); inode_unlock(d_inode(dir)); dput(victim); - //_leave(" = 0"); - return 0; + return ret; } |