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-rw-r--r--fs/smb/client/cached_dir.c606
1 files changed, 606 insertions, 0 deletions
diff --git a/fs/smb/client/cached_dir.c b/fs/smb/client/cached_dir.c
new file mode 100644
index 000000000000..bfc964b36c72
--- /dev/null
+++ b/fs/smb/client/cached_dir.c
@@ -0,0 +1,606 @@
+// 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)
+{
+ 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_FIDS) {
+ 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))
+ 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);
+ 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_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);
+
+ 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);
+}
+
+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);
+ 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);
+
+ 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);
+}
generated by cgit (git 2.34.1) at 2024-06-14 10:04:56 +0000