// SPDX-License-Identifier: GPL-2.0 /* * Functions to handle the cached directory entries * * Copyright (c) 2022, Ronnie Sahlberg */ #include #include "cifsglob.h" #include "cifsproto.h" #include "cifs_debug.h" #include "smb2proto.h" #include "cached_dir.h" static struct cached_fid *init_cached_dir(const char *path); static void free_cached_dir(struct cached_fid *cfid); static void smb2_close_cached_fid(struct kref *ref); static void cfids_laundromat_worker(struct work_struct *work); struct cached_dir_dentry { struct list_head entry; struct dentry *dentry; }; static struct cached_fid *find_or_create_cached_dir(struct cached_fids *cfids, const char *path, bool lookup_only, __u32 max_cached_dirs) { struct cached_fid *cfid; spin_lock(&cfids->cfid_list_lock); list_for_each_entry(cfid, &cfids->entries, entry) { if (!strcmp(cfid->path, path)) { /* * If it doesn't have a lease it is either not yet * fully cached or it may be in the process of * being deleted due to a lease break. */ if (!cfid->time || !cfid->has_lease) { spin_unlock(&cfids->cfid_list_lock); return NULL; } kref_get(&cfid->refcount); spin_unlock(&cfids->cfid_list_lock); return cfid; } } if (lookup_only) { spin_unlock(&cfids->cfid_list_lock); return NULL; } if (cfids->num_entries >= max_cached_dirs) { spin_unlock(&cfids->cfid_list_lock); return NULL; } cfid = init_cached_dir(path); if (cfid == NULL) { spin_unlock(&cfids->cfid_list_lock); return NULL; } cfid->cfids = cfids; cfids->num_entries++; list_add(&cfid->entry, &cfids->entries); cfid->on_list = true; kref_get(&cfid->refcount); /* * Set @cfid->has_lease to true during construction so that the lease * reference can be put in cached_dir_lease_break() due to a potential * lease break right after the request is sent or while @cfid is still * being cached, or if a reconnection is triggered during construction. * Concurrent processes won't be to use it yet due to @cfid->time being * zero. */ cfid->has_lease = true; spin_unlock(&cfids->cfid_list_lock); return cfid; } static struct dentry * path_to_dentry(struct cifs_sb_info *cifs_sb, const char *path) { struct dentry *dentry; const char *s, *p; char sep; sep = CIFS_DIR_SEP(cifs_sb); dentry = dget(cifs_sb->root); s = path; do { struct inode *dir = d_inode(dentry); struct dentry *child; if (!S_ISDIR(dir->i_mode)) { dput(dentry); dentry = ERR_PTR(-ENOTDIR); break; } /* skip separators */ while (*s == sep) s++; if (!*s) break; p = s++; /* next separator */ while (*s && *s != sep) s++; child = lookup_positive_unlocked(p, dentry, s - p); dput(dentry); dentry = child; } while (!IS_ERR(dentry)); return dentry; } static const char *path_no_prefix(struct cifs_sb_info *cifs_sb, const char *path) { size_t len = 0; if (!*path) return path; if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) && cifs_sb->prepath) { len = strlen(cifs_sb->prepath) + 1; if (unlikely(len > strlen(path))) return ERR_PTR(-EINVAL); } return path + len; } /* * Open the and cache a directory handle. * If error then *cfid is not initialized. */ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon, const char *path, struct cifs_sb_info *cifs_sb, bool lookup_only, struct cached_fid **ret_cfid) { struct cifs_ses *ses; struct TCP_Server_Info *server; struct cifs_open_parms oparms; struct smb2_create_rsp *o_rsp = NULL; struct smb2_query_info_rsp *qi_rsp = NULL; int resp_buftype[2]; struct smb_rqst rqst[2]; struct kvec rsp_iov[2]; struct kvec open_iov[SMB2_CREATE_IOV_SIZE]; struct kvec qi_iov[1]; int rc, flags = 0; __le16 *utf16_path = NULL; u8 oplock = SMB2_OPLOCK_LEVEL_II; struct cifs_fid *pfid; struct dentry *dentry = NULL; struct cached_fid *cfid; struct cached_fids *cfids; const char *npath; int retries = 0, cur_sleep = 1; if (cifs_sb->root == NULL) return -ENOENT; if (tcon == NULL) return -EOPNOTSUPP; ses = tcon->ses; cfids = tcon->cfids; if (cfids == NULL) return -EOPNOTSUPP; replay_again: /* reinitialize for possible replay */ flags = 0; oplock = SMB2_OPLOCK_LEVEL_II; server = cifs_pick_channel(ses); if (!server->ops->new_lease_key) return -EIO; utf16_path = cifs_convert_path_to_utf16(path, cifs_sb); if (!utf16_path) return -ENOMEM; cfid = find_or_create_cached_dir(cfids, path, lookup_only, tcon->max_cached_dirs); if (cfid == NULL) { kfree(utf16_path); return -ENOENT; } /* * Return cached fid if it is valid (has a lease and has a time). * Otherwise, it is either a new entry or laundromat worker removed it * from @cfids->entries. Caller will put last reference if the latter. */ spin_lock(&cfids->cfid_list_lock); if (cfid->has_lease && cfid->time) { spin_unlock(&cfids->cfid_list_lock); *ret_cfid = cfid; kfree(utf16_path); return 0; } spin_unlock(&cfids->cfid_list_lock); /* * Skip any prefix paths in @path as lookup_positive_unlocked() ends up * calling ->lookup() which already adds those through * build_path_from_dentry(). Also, do it earlier as we might reconnect * below when trying to send compounded request and then potentially * having a different prefix path (e.g. after DFS failover). */ npath = path_no_prefix(cifs_sb, path); if (IS_ERR(npath)) { rc = PTR_ERR(npath); goto out; } if (!npath[0]) { dentry = dget(cifs_sb->root); } else { dentry = path_to_dentry(cifs_sb, npath); if (IS_ERR(dentry)) { rc = -ENOENT; goto out; } } cfid->dentry = dentry; cfid->tcon = tcon; /* * We do not hold the lock for the open because in case * SMB2_open needs to reconnect. * This is safe because no other thread will be able to get a ref * to the cfid until we have finished opening the file and (possibly) * acquired a lease. */ if (smb3_encryption_required(tcon)) flags |= CIFS_TRANSFORM_REQ; pfid = &cfid->fid; server->ops->new_lease_key(pfid); memset(rqst, 0, sizeof(rqst)); resp_buftype[0] = resp_buftype[1] = CIFS_NO_BUFFER; memset(rsp_iov, 0, sizeof(rsp_iov)); /* Open */ memset(&open_iov, 0, sizeof(open_iov)); rqst[0].rq_iov = open_iov; rqst[0].rq_nvec = SMB2_CREATE_IOV_SIZE; oparms = (struct cifs_open_parms) { .tcon = tcon, .path = path, .create_options = cifs_create_options(cifs_sb, CREATE_NOT_FILE), .desired_access = FILE_READ_DATA | FILE_READ_ATTRIBUTES | FILE_READ_EA, .disposition = FILE_OPEN, .fid = pfid, .replay = !!(retries), }; rc = SMB2_open_init(tcon, server, &rqst[0], &oplock, &oparms, utf16_path); if (rc) goto oshr_free; smb2_set_next_command(tcon, &rqst[0]); memset(&qi_iov, 0, sizeof(qi_iov)); rqst[1].rq_iov = qi_iov; rqst[1].rq_nvec = 1; rc = SMB2_query_info_init(tcon, server, &rqst[1], COMPOUND_FID, COMPOUND_FID, FILE_ALL_INFORMATION, SMB2_O_INFO_FILE, 0, sizeof(struct smb2_file_all_info) + PATH_MAX * 2, 0, NULL); if (rc) goto oshr_free; smb2_set_related(&rqst[1]); if (retries) { smb2_set_replay(server, &rqst[0]); smb2_set_replay(server, &rqst[1]); } rc = compound_send_recv(xid, ses, server, flags, 2, rqst, resp_buftype, rsp_iov); if (rc) { if (rc == -EREMCHG) { tcon->need_reconnect = true; pr_warn_once("server share %s deleted\n", tcon->tree_name); } goto oshr_free; } cfid->is_open = true; spin_lock(&cfids->cfid_list_lock); o_rsp = (struct smb2_create_rsp *)rsp_iov[0].iov_base; oparms.fid->persistent_fid = o_rsp->PersistentFileId; oparms.fid->volatile_fid = o_rsp->VolatileFileId; #ifdef CONFIG_CIFS_DEBUG2 oparms.fid->mid = le64_to_cpu(o_rsp->hdr.MessageId); #endif /* CIFS_DEBUG2 */ if (o_rsp->OplockLevel != SMB2_OPLOCK_LEVEL_LEASE) { spin_unlock(&cfids->cfid_list_lock); rc = -EINVAL; goto oshr_free; } rc = smb2_parse_contexts(server, rsp_iov, &oparms.fid->epoch, oparms.fid->lease_key, &oplock, NULL, NULL); if (rc) { spin_unlock(&cfids->cfid_list_lock); goto oshr_free; } rc = -EINVAL; if (!(oplock & SMB2_LEASE_READ_CACHING_HE)) { spin_unlock(&cfids->cfid_list_lock); goto oshr_free; } qi_rsp = (struct smb2_query_info_rsp *)rsp_iov[1].iov_base; if (le32_to_cpu(qi_rsp->OutputBufferLength) < sizeof(struct smb2_file_all_info)) { spin_unlock(&cfids->cfid_list_lock); goto oshr_free; } if (!smb2_validate_and_copy_iov( le16_to_cpu(qi_rsp->OutputBufferOffset), sizeof(struct smb2_file_all_info), &rsp_iov[1], sizeof(struct smb2_file_all_info), (char *)&cfid->file_all_info)) cfid->file_all_info_is_valid = true; cfid->time = jiffies; spin_unlock(&cfids->cfid_list_lock); /* At this point the directory handle is fully cached */ rc = 0; oshr_free: SMB2_open_free(&rqst[0]); SMB2_query_info_free(&rqst[1]); free_rsp_buf(resp_buftype[0], rsp_iov[0].iov_base); free_rsp_buf(resp_buftype[1], rsp_iov[1].iov_base); out: if (rc) { spin_lock(&cfids->cfid_list_lock); if (cfid->on_list) { list_del(&cfid->entry); cfid->on_list = false; cfids->num_entries--; } if (cfid->has_lease) { /* * We are guaranteed to have two references at this * point. One for the caller and one for a potential * lease. Release one here, and the second below. */ cfid->has_lease = false; kref_put(&cfid->refcount, smb2_close_cached_fid); } spin_unlock(&cfids->cfid_list_lock); kref_put(&cfid->refcount, smb2_close_cached_fid); } else { *ret_cfid = cfid; atomic_inc(&tcon->num_remote_opens); } kfree(utf16_path); if (is_replayable_error(rc) && smb2_should_replay(tcon, &retries, &cur_sleep)) goto replay_again; return rc; } int open_cached_dir_by_dentry(struct cifs_tcon *tcon, struct dentry *dentry, struct cached_fid **ret_cfid) { struct cached_fid *cfid; struct cached_fids *cfids = tcon->cfids; if (cfids == NULL) return -EOPNOTSUPP; spin_lock(&cfids->cfid_list_lock); list_for_each_entry(cfid, &cfids->entries, entry) { if (dentry && cfid->dentry == dentry) { cifs_dbg(FYI, "found a cached file handle by dentry\n"); kref_get(&cfid->refcount); *ret_cfid = cfid; spin_unlock(&cfids->cfid_list_lock); return 0; } } spin_unlock(&cfids->cfid_list_lock); return -ENOENT; } static void smb2_close_cached_fid(struct kref *ref) { struct cached_fid *cfid = container_of(ref, struct cached_fid, refcount); int rc; spin_lock(&cfid->cfids->cfid_list_lock); if (cfid->on_list) { list_del(&cfid->entry); cfid->on_list = false; cfid->cfids->num_entries--; } spin_unlock(&cfid->cfids->cfid_list_lock); dput(cfid->dentry); cfid->dentry = NULL; if (cfid->is_open) { rc = SMB2_close(0, cfid->tcon, cfid->fid.persistent_fid, cfid->fid.volatile_fid); if (rc) /* should we retry on -EBUSY or -EAGAIN? */ cifs_dbg(VFS, "close cached dir rc %d\n", rc); } free_cached_dir(cfid); } void drop_cached_dir_by_name(const unsigned int xid, struct cifs_tcon *tcon, const char *name, struct cifs_sb_info *cifs_sb) { struct cached_fid *cfid = NULL; int rc; rc = open_cached_dir(xid, tcon, name, cifs_sb, true, &cfid); if (rc) { cifs_dbg(FYI, "no cached dir found for rmdir(%s)\n", name); return; } spin_lock(&cfid->cfids->cfid_list_lock); if (cfid->has_lease) { cfid->has_lease = false; kref_put(&cfid->refcount, smb2_close_cached_fid); } spin_unlock(&cfid->cfids->cfid_list_lock); close_cached_dir(cfid); } void close_cached_dir(struct cached_fid *cfid) { kref_put(&cfid->refcount, smb2_close_cached_fid); } /* * Called from cifs_kill_sb when we unmount a share */ void close_all_cached_dirs(struct cifs_sb_info *cifs_sb) { struct rb_root *root = &cifs_sb->tlink_tree; struct rb_node *node; struct cached_fid *cfid; struct cifs_tcon *tcon; struct tcon_link *tlink; struct cached_fids *cfids; struct cached_dir_dentry *tmp_list, *q; LIST_HEAD(entry); spin_lock(&cifs_sb->tlink_tree_lock); for (node = rb_first(root); node; node = rb_next(node)) { tlink = rb_entry(node, struct tcon_link, tl_rbnode); tcon = tlink_tcon(tlink); if (IS_ERR(tcon)) continue; cfids = tcon->cfids; if (cfids == NULL) continue; spin_lock(&cfids->cfid_list_lock); list_for_each_entry(cfid, &cfids->entries, entry) { tmp_list = kmalloc(sizeof(*tmp_list), GFP_ATOMIC); if (tmp_list == NULL) break; spin_lock(&cfid->fid_lock); tmp_list->dentry = cfid->dentry; cfid->dentry = NULL; spin_unlock(&cfid->fid_lock); list_add_tail(&tmp_list->entry, &entry); } spin_unlock(&cfids->cfid_list_lock); } spin_unlock(&cifs_sb->tlink_tree_lock); list_for_each_entry_safe(tmp_list, q, &entry, entry) { list_del(&tmp_list->entry); dput(tmp_list->dentry); kfree(tmp_list); } /* Flush any pending work that will drop dentries */ flush_workqueue(cfid_put_wq); } /* * Invalidate all cached dirs when a TCON has been reset * due to a session loss. */ void invalidate_all_cached_dirs(struct cifs_tcon *tcon) { struct cached_fids *cfids = tcon->cfids; struct cached_fid *cfid, *q; if (cfids == NULL) return; /* * Mark all the cfids as closed, and move them to the cfids->dying list. * They'll be cleaned up later by cfids_invalidation_worker. Take * a reference to each cfid during this process. */ spin_lock(&cfids->cfid_list_lock); list_for_each_entry_safe(cfid, q, &cfids->entries, entry) { list_move(&cfid->entry, &cfids->dying); cfids->num_entries--; cfid->is_open = false; cfid->on_list = false; if (cfid->has_lease) { /* * The lease was never cancelled from the server, * so steal that reference. */ cfid->has_lease = false; } else kref_get(&cfid->refcount); } /* * Queue dropping of the dentries once locks have been dropped */ if (!list_empty(&cfids->dying)) queue_work(cfid_put_wq, &cfids->invalidation_work); spin_unlock(&cfids->cfid_list_lock); } static void cached_dir_offload_close(struct work_struct *work) { struct cached_fid *cfid = container_of(work, struct cached_fid, close_work); struct cifs_tcon *tcon = cfid->tcon; WARN_ON(cfid->on_list); kref_put(&cfid->refcount, smb2_close_cached_fid); cifs_put_tcon(tcon, netfs_trace_tcon_ref_put_cached_close); } /* * Release the cached directory's dentry, and then queue work to drop cached * directory itself (closing on server if needed). * * Must be called with a reference to the cached_fid and a reference to the * tcon. */ static void cached_dir_put_work(struct work_struct *work) { struct cached_fid *cfid = container_of(work, struct cached_fid, put_work); struct dentry *dentry; spin_lock(&cfid->fid_lock); dentry = cfid->dentry; cfid->dentry = NULL; spin_unlock(&cfid->fid_lock); dput(dentry); queue_work(serverclose_wq, &cfid->close_work); } int cached_dir_lease_break(struct cifs_tcon *tcon, __u8 lease_key[16]) { struct cached_fids *cfids = tcon->cfids; struct cached_fid *cfid; if (cfids == NULL) return false; spin_lock(&cfids->cfid_list_lock); list_for_each_entry(cfid, &cfids->entries, entry) { if (cfid->has_lease && !memcmp(lease_key, cfid->fid.lease_key, SMB2_LEASE_KEY_SIZE)) { cfid->has_lease = false; cfid->time = 0; /* * We found a lease remove it from the list * so no threads can access it. */ list_del(&cfid->entry); cfid->on_list = false; cfids->num_entries--; ++tcon->tc_count; trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count, netfs_trace_tcon_ref_get_cached_lease_break); queue_work(cfid_put_wq, &cfid->put_work); spin_unlock(&cfids->cfid_list_lock); return true; } } spin_unlock(&cfids->cfid_list_lock); return false; } static struct cached_fid *init_cached_dir(const char *path) { struct cached_fid *cfid; cfid = kzalloc(sizeof(*cfid), GFP_ATOMIC); if (!cfid) return NULL; cfid->path = kstrdup(path, GFP_ATOMIC); if (!cfid->path) { kfree(cfid); return NULL; } INIT_WORK(&cfid->close_work, cached_dir_offload_close); INIT_WORK(&cfid->put_work, cached_dir_put_work); INIT_LIST_HEAD(&cfid->entry); INIT_LIST_HEAD(&cfid->dirents.entries); mutex_init(&cfid->dirents.de_mutex); spin_lock_init(&cfid->fid_lock); kref_init(&cfid->refcount); return cfid; } static void free_cached_dir(struct cached_fid *cfid) { struct cached_dirent *dirent, *q; WARN_ON(work_pending(&cfid->close_work)); WARN_ON(work_pending(&cfid->put_work)); dput(cfid->dentry); cfid->dentry = NULL; /* * Delete all cached dirent names */ list_for_each_entry_safe(dirent, q, &cfid->dirents.entries, entry) { list_del(&dirent->entry); kfree(dirent->name); kfree(dirent); } kfree(cfid->path); cfid->path = NULL; kfree(cfid); } static void cfids_invalidation_worker(struct work_struct *work) { struct cached_fids *cfids = container_of(work, struct cached_fids, invalidation_work); struct cached_fid *cfid, *q; LIST_HEAD(entry); spin_lock(&cfids->cfid_list_lock); /* move cfids->dying to the local list */ list_cut_before(&entry, &cfids->dying, &cfids->dying); spin_unlock(&cfids->cfid_list_lock); list_for_each_entry_safe(cfid, q, &entry, entry) { list_del(&cfid->entry); /* Drop the ref-count acquired in invalidate_all_cached_dirs */ kref_put(&cfid->refcount, smb2_close_cached_fid); } } static void cfids_laundromat_worker(struct work_struct *work) { struct cached_fids *cfids; struct cached_fid *cfid, *q; struct dentry *dentry; LIST_HEAD(entry); cfids = container_of(work, struct cached_fids, laundromat_work.work); spin_lock(&cfids->cfid_list_lock); list_for_each_entry_safe(cfid, q, &cfids->entries, entry) { if (cfid->time && time_after(jiffies, cfid->time + HZ * dir_cache_timeout)) { cfid->on_list = false; list_move(&cfid->entry, &entry); cfids->num_entries--; if (cfid->has_lease) { /* * Our lease has not yet been cancelled from the * server. Steal that reference. */ cfid->has_lease = false; } else kref_get(&cfid->refcount); } } spin_unlock(&cfids->cfid_list_lock); list_for_each_entry_safe(cfid, q, &entry, entry) { list_del(&cfid->entry); spin_lock(&cfid->fid_lock); dentry = cfid->dentry; cfid->dentry = NULL; spin_unlock(&cfid->fid_lock); dput(dentry); if (cfid->is_open) { spin_lock(&cifs_tcp_ses_lock); ++cfid->tcon->tc_count; trace_smb3_tcon_ref(cfid->tcon->debug_id, cfid->tcon->tc_count, netfs_trace_tcon_ref_get_cached_laundromat); spin_unlock(&cifs_tcp_ses_lock); queue_work(serverclose_wq, &cfid->close_work); } else /* * Drop the ref-count from above, either the lease-ref (if there * was one) or the extra one acquired. */ kref_put(&cfid->refcount, smb2_close_cached_fid); } queue_delayed_work(cfid_put_wq, &cfids->laundromat_work, dir_cache_timeout * HZ); } struct cached_fids *init_cached_dirs(void) { struct cached_fids *cfids; cfids = kzalloc(sizeof(*cfids), GFP_KERNEL); if (!cfids) return NULL; spin_lock_init(&cfids->cfid_list_lock); INIT_LIST_HEAD(&cfids->entries); INIT_LIST_HEAD(&cfids->dying); INIT_WORK(&cfids->invalidation_work, cfids_invalidation_worker); INIT_DELAYED_WORK(&cfids->laundromat_work, cfids_laundromat_worker); queue_delayed_work(cfid_put_wq, &cfids->laundromat_work, dir_cache_timeout * HZ); return cfids; } /* * Called from tconInfoFree when we are tearing down the tcon. * There are no active users or open files/directories at this point. */ void free_cached_dirs(struct cached_fids *cfids) { struct cached_fid *cfid, *q; LIST_HEAD(entry); if (cfids == NULL) return; cancel_delayed_work_sync(&cfids->laundromat_work); cancel_work_sync(&cfids->invalidation_work); spin_lock(&cfids->cfid_list_lock); list_for_each_entry_safe(cfid, q, &cfids->entries, entry) { cfid->on_list = false; cfid->is_open = false; list_move(&cfid->entry, &entry); } list_for_each_entry_safe(cfid, q, &cfids->dying, entry) { cfid->on_list = false; cfid->is_open = false; list_move(&cfid->entry, &entry); } spin_unlock(&cfids->cfid_list_lock); list_for_each_entry_safe(cfid, q, &entry, entry) { list_del(&cfid->entry); free_cached_dir(cfid); } kfree(cfids); }