| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Functions to handle the cached directory entries |
| * |
| * Copyright (c) 2022, Ronnie Sahlberg <lsahlber@redhat.com> |
| */ |
| |
| #include <linux/namei.h> |
| #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 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->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); |
| 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; |
| |
| if (tcon == NULL || tcon->cfids == NULL || tcon->nohandlecache || |
| is_smb1_server(tcon->ses->server) || (dir_cache_timeout == 0)) |
| return -EOPNOTSUPP; |
| |
| ses = tcon->ses; |
| server = ses->server; |
| cfids = tcon->cfids; |
| |
| if (!server->ops->new_lease_key) |
| return -EIO; |
| |
| if (cifs_sb->root == NULL) |
| return -ENOENT; |
| |
| 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; |
| } |
| /* |
| * At this point we either have a lease already and we can just |
| * return it. If not we are guaranteed to be the only thread accessing |
| * this cfid. |
| */ |
| if (cfid->has_lease) { |
| *ret_cfid = cfid; |
| kfree(utf16_path); |
| return 0; |
| } |
| |
| /* |
| * 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); |
| kfree(utf16_path); |
| return rc; |
| } |
| |
| /* |
| * 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, |
| .disposition = FILE_OPEN, |
| .fid = pfid, |
| }; |
| |
| 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]); |
| |
| 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->tcon = tcon; |
| cfid->is_open = true; |
| |
| 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) |
| goto oshr_free; |
| |
| smb2_parse_contexts(server, o_rsp, |
| &oparms.fid->epoch, |
| oparms.fid->lease_key, &oplock, |
| NULL, NULL); |
| if (!(oplock & SMB2_LEASE_READ_CACHING_HE)) |
| 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)) |
| 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; |
| |
| if (!npath[0]) |
| dentry = dget(cifs_sb->root); |
| else { |
| dentry = path_to_dentry(cifs_sb, npath); |
| if (IS_ERR(dentry)) { |
| rc = -ENOENT; |
| goto oshr_free; |
| } |
| } |
| cfid->dentry = dentry; |
| cfid->time = jiffies; |
| cfid->has_lease = true; |
| |
| oshr_free: |
| kfree(utf16_path); |
| 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); |
| spin_lock(&cfids->cfid_list_lock); |
| if (rc && !cfid->has_lease) { |
| if (cfid->on_list) { |
| list_del(&cfid->entry); |
| cfid->on_list = false; |
| cfids->num_entries--; |
| } |
| rc = -ENOENT; |
| } |
| spin_unlock(&cfids->cfid_list_lock); |
| if (!rc && !cfid->has_lease) { |
| /* |
| * We are guaranteed to have two references at this point. |
| * One for the caller and one for a potential lease. |
| * Release the Lease-ref so that the directory will be closed |
| * when the caller closes the cached handle. |
| */ |
| kref_put(&cfid->refcount, smb2_close_cached_fid); |
| } |
| if (rc) { |
| if (cfid->is_open) |
| SMB2_close(0, cfid->tcon, cfid->fid.persistent_fid, |
| cfid->fid.volatile_fid); |
| free_cached_dir(cfid); |
| cfid = NULL; |
| } |
| |
| if (rc == 0) { |
| *ret_cfid = cfid; |
| atomic_inc(&tcon->num_remote_opens); |
| } |
| |
| 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 -ENOENT; |
| |
| 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 root 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); |
| |
| 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) { |
| SMB2_close(0, cfid->tcon, cfid->fid.persistent_fid, |
| cfid->fid.volatile_fid); |
| atomic_dec(&cfid->tcon->num_remote_opens); |
| } |
| |
| 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; |
| |
| 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; |
| list_for_each_entry(cfid, &cfids->entries, entry) { |
| dput(cfid->dentry); |
| cfid->dentry = NULL; |
| } |
| } |
| } |
| |
| /* |
| * 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; |
| LIST_HEAD(entry); |
| |
| if (cfids == NULL) |
| return; |
| |
| spin_lock(&cfids->cfid_list_lock); |
| list_for_each_entry_safe(cfid, q, &cfids->entries, entry) { |
| list_move(&cfid->entry, &entry); |
| cfids->num_entries--; |
| cfid->is_open = false; |
| cfid->on_list = false; |
| /* To prevent race with smb2_cached_lease_break() */ |
| kref_get(&cfid->refcount); |
| } |
| spin_unlock(&cfids->cfid_list_lock); |
| |
| list_for_each_entry_safe(cfid, q, &entry, entry) { |
| list_del(&cfid->entry); |
| cancel_work_sync(&cfid->lease_break); |
| if (cfid->has_lease) { |
| /* |
| * We lease was never cancelled from the server so we |
| * need to drop the reference. |
| */ |
| spin_lock(&cfids->cfid_list_lock); |
| cfid->has_lease = false; |
| spin_unlock(&cfids->cfid_list_lock); |
| kref_put(&cfid->refcount, smb2_close_cached_fid); |
| } |
| /* Drop the extra reference opened above*/ |
| kref_put(&cfid->refcount, smb2_close_cached_fid); |
| } |
| } |
| |
| static void |
| smb2_cached_lease_break(struct work_struct *work) |
| { |
| struct cached_fid *cfid = container_of(work, |
| struct cached_fid, lease_break); |
| |
| spin_lock(&cfid->cfids->cfid_list_lock); |
| cfid->has_lease = false; |
| spin_unlock(&cfid->cfids->cfid_list_lock); |
| kref_put(&cfid->refcount, smb2_close_cached_fid); |
| } |
| |
| 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->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--; |
| |
| queue_work(cifsiod_wq, |
| &cfid->lease_break); |
| 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->lease_break, smb2_cached_lease_break); |
| 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; |
| |
| 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 int |
| cifs_cfids_laundromat_thread(void *p) |
| { |
| struct cached_fids *cfids = p; |
| struct cached_fid *cfid, *q; |
| struct list_head entry; |
| |
| while (!kthread_should_stop()) { |
| ssleep(1); |
| INIT_LIST_HEAD(&entry); |
| if (kthread_should_stop()) |
| return 0; |
| spin_lock(&cfids->cfid_list_lock); |
| list_for_each_entry_safe(cfid, q, &cfids->entries, entry) { |
| if (time_after(jiffies, cfid->time + HZ * dir_cache_timeout)) { |
| list_del(&cfid->entry); |
| list_add(&cfid->entry, &entry); |
| cfids->num_entries--; |
| } |
| } |
| spin_unlock(&cfids->cfid_list_lock); |
| |
| list_for_each_entry_safe(cfid, q, &entry, entry) { |
| cfid->on_list = false; |
| list_del(&cfid->entry); |
| /* |
| * Cancel, and wait for the work to finish in |
| * case we are racing with it. |
| */ |
| cancel_work_sync(&cfid->lease_break); |
| if (cfid->has_lease) { |
| /* |
| * We lease has not yet been cancelled from |
| * the server so we need to drop the reference. |
| */ |
| spin_lock(&cfids->cfid_list_lock); |
| cfid->has_lease = false; |
| spin_unlock(&cfids->cfid_list_lock); |
| kref_put(&cfid->refcount, smb2_close_cached_fid); |
| } |
| } |
| } |
| |
| return 0; |
| } |
| |
| |
| 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); |
| |
| /* |
| * since we're in a cifs function already, we know that |
| * this will succeed. No need for try_module_get(). |
| */ |
| __module_get(THIS_MODULE); |
| cfids->laundromat = kthread_run(cifs_cfids_laundromat_thread, |
| cfids, "cifsd-cfid-laundromat"); |
| if (IS_ERR(cfids->laundromat)) { |
| cifs_dbg(VFS, "Failed to start cfids laundromat thread.\n"); |
| kfree(cfids); |
| module_put(THIS_MODULE); |
| return NULL; |
| } |
| 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; |
| |
| if (cfids->laundromat) { |
| kthread_stop(cfids->laundromat); |
| cfids->laundromat = NULL; |
| module_put(THIS_MODULE); |
| } |
| |
| 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); |
| } |
| 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); |
| } |