Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

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 000000000..5a132c1e6
--- /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_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);
+
+	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);
+}