This is a note to let you know that I've just added the patch titled cifs: reduce roundtrips on create/qinfo requests to the 6.1-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: cifs-reduce-roundtrips-on-create-qinfo-requests.patch and it can be found in the queue-6.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From c877ce47e1378dbafa6f1bf84c0c83a05ca8972a Mon Sep 17 00:00:00 2001 From: Paulo Alcantara <pc@xxxxxx> Date: Mon, 12 Dec 2022 23:39:37 -0300 Subject: cifs: reduce roundtrips on create/qinfo requests From: Paulo Alcantara <pc@xxxxxx> commit c877ce47e1378dbafa6f1bf84c0c83a05ca8972a upstream. To work around some Window servers that return STATUS_OBJECT_NAME_INVALID on query infos under DFS namespaces that contain non-ASCII characters, we started checking for -ENOENT on every file open, and if so, then send additional requests to figure out whether it is a DFS link or not. It means that all those requests will be sent to every non-existing file. So, in order to reduce the number of roundtrips, check earlier whether status code is STATUS_OBJECT_NAME_INVALID and tcon supports dfs, and if so, then map -ENOENT to -EREMOTE so mount or automount will take care of chasing the DFS link -- if it isn't an DFS link, then -ENOENT will be returned appropriately. Before patch SMB2 438 Create Request File: ada.test\dfs\foo;GetInfo Request... SMB2 310 Create Response, Error: STATUS_OBJECT_NAME_NOT_FOUND;... SMB2 228 Ioctl Request FSCTL_DFS_GET_REFERRALS, File: \ada.test\dfs\foo SMB2 143 Ioctl Response, Error: STATUS_OBJECT_PATH_NOT_FOUND SMB2 438 Create Request File: ada.test\dfs\foo;GetInfo Request... SMB2 310 Create Response, Error: STATUS_OBJECT_NAME_NOT_FOUND;... SMB2 228 Ioctl Request FSCTL_DFS_GET_REFERRALS, File: \ada.test\dfs\foo SMB2 143 Ioctl Response, Error: STATUS_OBJECT_PATH_NOT_FOUND After patch SMB2 438 Create Request File: ada.test\dfs\foo;GetInfo Request... SMB2 310 Create Response, Error: STATUS_OBJECT_NAME_NOT_FOUND;... SMB2 438 Create Request File: ada.test\dfs\foo;GetInfo Request... SMB2 310 Create Response, Error: STATUS_OBJECT_NAME_NOT_FOUND;... Signed-off-by: Paulo Alcantara (SUSE) <pc@xxxxxx> Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/cifs/connect.c | 16 ---------------- fs/cifs/inode.c | 6 ------ fs/cifs/misc.c | 45 --------------------------------------------- fs/cifs/smb2inode.c | 45 ++++++++++++++++++++++++++++++++------------- fs/cifs/smb2ops.c | 28 ++++++++++++++++++++++++---- 5 files changed, 56 insertions(+), 84 deletions(-) --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -3554,9 +3554,6 @@ static int is_path_remote(struct mount_c struct cifs_tcon *tcon = mnt_ctx->tcon; struct smb3_fs_context *ctx = mnt_ctx->fs_ctx; char *full_path; -#ifdef CONFIG_CIFS_DFS_UPCALL - bool nodfs = cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS; -#endif if (!server->ops->is_path_accessible) return -EOPNOTSUPP; @@ -3573,19 +3570,6 @@ static int is_path_remote(struct mount_c rc = server->ops->is_path_accessible(xid, tcon, cifs_sb, full_path); -#ifdef CONFIG_CIFS_DFS_UPCALL - if (nodfs) { - if (rc == -EREMOTE) - rc = -EOPNOTSUPP; - goto out; - } - - /* path *might* exist with non-ASCII characters in DFS root - * try again with full path (only if nodfs is not set) */ - if (rc == -ENOENT && is_tcon_dfs(tcon)) - rc = cifs_dfs_query_info_nonascii_quirk(xid, tcon, cifs_sb, - full_path); -#endif if (rc != 0 && rc != -EREMOTE) goto out; --- a/fs/cifs/inode.c +++ b/fs/cifs/inode.c @@ -991,12 +991,6 @@ int cifs_get_inode_info(struct inode **i } rc = server->ops->query_path_info(xid, tcon, cifs_sb, full_path, &tmp_data, &adjust_tz, &is_reparse_point); -#ifdef CONFIG_CIFS_DFS_UPCALL - if (rc == -ENOENT && is_tcon_dfs(tcon)) - rc = cifs_dfs_query_info_nonascii_quirk(xid, tcon, - cifs_sb, - full_path); -#endif data = &tmp_data; } --- a/fs/cifs/misc.c +++ b/fs/cifs/misc.c @@ -1314,49 +1314,4 @@ int cifs_update_super_prepath(struct cif cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH; return 0; } - -/** cifs_dfs_query_info_nonascii_quirk - * Handle weird Windows SMB server behaviour. It responds with - * STATUS_OBJECT_NAME_INVALID code to SMB2 QUERY_INFO request - * for "\<server>\<dfsname>\<linkpath>" DFS reference, - * where <dfsname> contains non-ASCII unicode symbols. - * - * Check such DFS reference. - */ -int cifs_dfs_query_info_nonascii_quirk(const unsigned int xid, - struct cifs_tcon *tcon, - struct cifs_sb_info *cifs_sb, - const char *linkpath) -{ - char *treename, *dfspath, sep; - int treenamelen, linkpathlen, rc; - - treename = tcon->tree_name; - /* MS-DFSC: All paths in REQ_GET_DFS_REFERRAL and RESP_GET_DFS_REFERRAL - * messages MUST be encoded with exactly one leading backslash, not two - * leading backslashes. - */ - sep = CIFS_DIR_SEP(cifs_sb); - if (treename[0] == sep && treename[1] == sep) - treename++; - linkpathlen = strlen(linkpath); - treenamelen = strnlen(treename, MAX_TREE_SIZE + 1); - dfspath = kzalloc(treenamelen + linkpathlen + 1, GFP_KERNEL); - if (!dfspath) - return -ENOMEM; - if (treenamelen) - memcpy(dfspath, treename, treenamelen); - memcpy(dfspath + treenamelen, linkpath, linkpathlen); - rc = dfs_cache_find(xid, tcon->ses, cifs_sb->local_nls, - cifs_remap(cifs_sb), dfspath, NULL, NULL); - if (rc == 0) { - cifs_dbg(FYI, "DFS ref '%s' is found, emulate -EREMOTE\n", - dfspath); - rc = -EREMOTE; - } else { - cifs_dbg(FYI, "%s: dfs_cache_find returned %d\n", __func__, rc); - } - kfree(dfspath); - return rc; -} #endif --- a/fs/cifs/smb2inode.c +++ b/fs/cifs/smb2inode.c @@ -540,22 +540,41 @@ int smb2_query_path_info(const unsigned rc = smb2_compound_op(xid, tcon, cifs_sb, full_path, FILE_READ_ATTRIBUTES, FILE_OPEN, create_options, ACL_NO_MODE, data, SMB2_OP_QUERY_INFO, cfile, err_iov, err_buftype); - if (rc == -EOPNOTSUPP) { - if (err_iov[0].iov_base && err_buftype[0] != CIFS_NO_BUFFER && - ((struct smb2_hdr *)err_iov[0].iov_base)->Command == SMB2_CREATE && - ((struct smb2_hdr *)err_iov[0].iov_base)->Status == STATUS_STOPPED_ON_SYMLINK) { - rc = smb2_parse_symlink_response(cifs_sb, err_iov, &data->symlink_target); + if (rc) { + struct smb2_hdr *hdr = err_iov[0].iov_base; + + if (unlikely(!hdr || err_buftype[0] == CIFS_NO_BUFFER)) + goto out; + if (rc == -EOPNOTSUPP && hdr->Command == SMB2_CREATE && + hdr->Status == STATUS_STOPPED_ON_SYMLINK) { + rc = smb2_parse_symlink_response(cifs_sb, err_iov, + &data->symlink_target); if (rc) goto out; - } - *reparse = true; - create_options |= OPEN_REPARSE_POINT; - /* Failed on a symbolic link - query a reparse point info */ - cifs_get_readable_path(tcon, full_path, &cfile); - rc = smb2_compound_op(xid, tcon, cifs_sb, full_path, FILE_READ_ATTRIBUTES, - FILE_OPEN, create_options, ACL_NO_MODE, data, - SMB2_OP_QUERY_INFO, cfile, NULL, NULL); + *reparse = true; + create_options |= OPEN_REPARSE_POINT; + + /* Failed on a symbolic link - query a reparse point info */ + cifs_get_readable_path(tcon, full_path, &cfile); + rc = smb2_compound_op(xid, tcon, cifs_sb, full_path, + FILE_READ_ATTRIBUTES, FILE_OPEN, + create_options, ACL_NO_MODE, data, + SMB2_OP_QUERY_INFO, cfile, NULL, NULL); + goto out; + } else if (rc != -EREMOTE && IS_ENABLED(CONFIG_CIFS_DFS_UPCALL) && + hdr->Status == STATUS_OBJECT_NAME_INVALID) { + /* + * Handle weird Windows SMB server behaviour. It responds with + * STATUS_OBJECT_NAME_INVALID code to SMB2 QUERY_INFO request + * for "\<server>\<dfsname>\<linkpath>" DFS reference, + * where <dfsname> contains non-ASCII unicode symbols. + */ + rc = -EREMOTE; + } + if (rc == -EREMOTE && IS_ENABLED(CONFIG_CIFS_DFS_UPCALL) && cifs_sb && + (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS)) + rc = -EOPNOTSUPP; } out: --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -797,7 +797,9 @@ smb2_is_path_accessible(const unsigned i int rc; __le16 *utf16_path; __u8 oplock = SMB2_OPLOCK_LEVEL_NONE; + int err_buftype = CIFS_NO_BUFFER; struct cifs_open_parms oparms; + struct kvec err_iov = {}; struct cifs_fid fid; struct cached_fid *cfid; @@ -821,14 +823,32 @@ smb2_is_path_accessible(const unsigned i oparms.fid = &fid; oparms.reconnect = false; - rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL, NULL, - NULL); + rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL, + &err_iov, &err_buftype); if (rc) { - kfree(utf16_path); - return rc; + struct smb2_hdr *hdr = err_iov.iov_base; + + if (unlikely(!hdr || err_buftype == CIFS_NO_BUFFER)) + goto out; + /* + * Handle weird Windows SMB server behaviour. It responds with + * STATUS_OBJECT_NAME_INVALID code to SMB2 QUERY_INFO request + * for "\<server>\<dfsname>\<linkpath>" DFS reference, + * where <dfsname> contains non-ASCII unicode symbols. + */ + if (rc != -EREMOTE && IS_ENABLED(CONFIG_CIFS_DFS_UPCALL) && + hdr->Status == STATUS_OBJECT_NAME_INVALID) + rc = -EREMOTE; + if (rc == -EREMOTE && IS_ENABLED(CONFIG_CIFS_DFS_UPCALL) && cifs_sb && + (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS)) + rc = -EOPNOTSUPP; + goto out; } rc = SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid); + +out: + free_rsp_buf(err_buftype, err_iov.iov_base); kfree(utf16_path); return rc; } Patches currently in stable-queue which might be from pc@xxxxxx are queue-6.1/cifs-fix-race-in-assemble_neg_contexts.patch queue-6.1/cifs-reduce-roundtrips-on-create-qinfo-requests.patch queue-6.1/cifs-do-not-include-page-data-when-checking-signature.patch