From patchwork Thu Feb 6 05:42:38 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: NeilBrown X-Patchwork-Id: 13962211 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.223.130]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D92B11F60A; Thu, 6 Feb 2025 05:45:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.135.223.130 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738820732; cv=none; b=h/T5ifnH5W4X+sfVknY6XB+P33FJtEF9QAoAn1zbLwBYCDNKtWfqN1gHL/mSOWNOeFstmnne6xUZ3NAwSuS89O51SmhX3Yu4DMlumnhAnyJl1Y2Itg1OHeS6yCZDMbNLK2K13DkZWsz8IBFbeDrvdotLHD9qG4GD8nGGhX67ONY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738820732; c=relaxed/simple; bh=kU7g4vLVsL6JRWzwX+o6lQFbCH2Rq/pjuBZlXLYRV6Y=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=MKnJ8LZjpo3RKYQarf+vVTJFozzNgIGQUVvQmdBMrYCAPLqnXittip2mjSrRp9NmA0JSrn0Jmso18w1rybC7vlp9nKYnuq0HOIaf6wO25Qpaf6L4pDICNXjK53VqymJTrya2vr9OTW1kC1Hf/cdZoEN3JRZ47b836kakVxKZ8I0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=suse.de; spf=pass smtp.mailfrom=suse.de; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b=1/VoARoj; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b=Tl+P9xHT; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b=1/VoARoj; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b=Tl+P9xHT; arc=none smtp.client-ip=195.135.223.130 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=suse.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b="1/VoARoj"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="Tl+P9xHT"; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b="1/VoARoj"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="Tl+P9xHT" Received: from imap1.dmz-prg2.suse.org (imap1.dmz-prg2.suse.org [IPv6:2a07:de40:b281:104:10:150:64:97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 176F521161; Thu, 6 Feb 2025 05:45:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1738820728; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=GAq315uMs7mYDdIfEC74sKx/3hdP2bf4BqcxNrDGOuA=; b=1/VoARojF/fO8rTnWrpcieGYmop/z9zc4DNdvf4oMx6AC+QGhPvzfkTjAJ4M4DGdt4D8Fe iMjkpL2l9vbxvJZw5KFFFW3GTLP8BRKtuk5wYI4O6y36RF/RI2dSfbUKsla5VW40myXT1L dT8+Ri2mN7zom5mzLIkuuRVZWU5RbiY= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1738820728; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=GAq315uMs7mYDdIfEC74sKx/3hdP2bf4BqcxNrDGOuA=; b=Tl+P9xHTn7eOgEV1nXs91JDYpsl82w8Saynpb68phXU2Nu/cqMBbxJplKV5Wi+p3AeY7gi afhZukpSFwNYwnDA== Authentication-Results: smtp-out1.suse.de; dkim=pass header.d=suse.de header.s=susede2_rsa header.b="1/VoARoj"; dkim=pass header.d=suse.de header.s=susede2_ed25519 header.b=Tl+P9xHT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1738820728; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=GAq315uMs7mYDdIfEC74sKx/3hdP2bf4BqcxNrDGOuA=; b=1/VoARojF/fO8rTnWrpcieGYmop/z9zc4DNdvf4oMx6AC+QGhPvzfkTjAJ4M4DGdt4D8Fe iMjkpL2l9vbxvJZw5KFFFW3GTLP8BRKtuk5wYI4O6y36RF/RI2dSfbUKsla5VW40myXT1L dT8+Ri2mN7zom5mzLIkuuRVZWU5RbiY= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1738820728; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=GAq315uMs7mYDdIfEC74sKx/3hdP2bf4BqcxNrDGOuA=; b=Tl+P9xHTn7eOgEV1nXs91JDYpsl82w8Saynpb68phXU2Nu/cqMBbxJplKV5Wi+p3AeY7gi afhZukpSFwNYwnDA== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id 5474013795; Thu, 6 Feb 2025 05:45:25 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id e8KdAnVMpGczBwAAD6G6ig (envelope-from ); Thu, 06 Feb 2025 05:45:25 +0000 From: NeilBrown To: Alexander Viro , Christian Brauner , Jan Kara , Linus Torvalds , Jeff Layton , Dave Chinner Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 01/19] VFS: introduce vfs_mkdir_return() Date: Thu, 6 Feb 2025 16:42:38 +1100 Message-ID: <20250206054504.2950516-2-neilb@suse.de> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20250206054504.2950516-1-neilb@suse.de> References: <20250206054504.2950516-1-neilb@suse.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Rspamd-Queue-Id: 176F521161 X-Spam-Score: -3.01 X-Rspamd-Action: no action X-Spamd-Result: default: False [-3.01 / 50.00]; BAYES_HAM(-3.00)[100.00%]; MID_CONTAINS_FROM(1.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_MISSING_CHARSET(0.50)[]; NEURAL_HAM_SHORT(-0.20)[-1.000]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:dkim,suse.de:mid,suse.de:email]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; MIME_TRACE(0.00)[0:+]; TO_MATCH_ENVRCPT_ALL(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; RCPT_COUNT_SEVEN(0.00)[8]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; FUZZY_BLOCKED(0.00)[rspamd.com]; RCVD_COUNT_TWO(0.00)[2]; RCVD_TLS_ALL(0.00)[]; R_RATELIMIT(0.00)[from(RLewrxuus8mos16izbn)]; DKIM_TRACE(0.00)[suse.de:+] X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Spam-Flag: NO X-Spam-Level: vfs_mkdir() does not guarantee to make the child dentry positive on success. It may leave it negative and then the caller needs to perform a lookup to find the target dentry. This patch introduced vfs_mkdir_return() which performs the lookup if needed so that this code is centralised. This prepares for a new inode operation which will perform mkdir and returns the correct dentry. Signed-off-by: NeilBrown --- fs/cachefiles/namei.c | 7 +--- fs/namei.c | 69 ++++++++++++++++++++++++++++++++++++++++ fs/nfsd/vfs.c | 21 ++---------- fs/overlayfs/dir.c | 33 +------------------ fs/overlayfs/overlayfs.h | 10 +++--- fs/overlayfs/super.c | 2 +- fs/smb/server/vfs.c | 24 +++----------- include/linux/fs.h | 2 ++ 8 files changed, 86 insertions(+), 82 deletions(-) diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c index 7cf59713f0f7..3c866c3b9534 100644 --- a/fs/cachefiles/namei.c +++ b/fs/cachefiles/namei.c @@ -95,7 +95,6 @@ struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, /* search the current directory for the element name */ inode_lock_nested(d_inode(dir), I_MUTEX_PARENT); -retry: ret = cachefiles_inject_read_error(); if (ret == 0) subdir = lookup_one_len(dirname, dir, strlen(dirname)); @@ -130,7 +129,7 @@ struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, goto mkdir_error; ret = cachefiles_inject_write_error(); if (ret == 0) - ret = vfs_mkdir(&nop_mnt_idmap, d_inode(dir), subdir, 0700); + ret = vfs_mkdir_return(&nop_mnt_idmap, d_inode(dir), &subdir, 0700); if (ret < 0) { trace_cachefiles_vfs_error(NULL, d_inode(dir), ret, cachefiles_trace_mkdir_error); @@ -138,10 +137,6 @@ struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, } trace_cachefiles_mkdir(dir, subdir); - if (unlikely(d_unhashed(subdir))) { - cachefiles_put_directory(subdir); - goto retry; - } ASSERT(d_backing_inode(subdir)); _debug("mkdir -> %pd{ino=%lu}", diff --git a/fs/namei.c b/fs/namei.c index 3ab9440c5b93..d98caf36e867 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -4317,6 +4317,75 @@ int vfs_mkdir(struct mnt_idmap *idmap, struct inode *dir, } EXPORT_SYMBOL(vfs_mkdir); +/** + * vfs_mkdir_return - create directory returning correct dentry + * @idmap: idmap of the mount the inode was found from + * @dir: inode of the parent directory + * @dentryp: pointer to dentry of the child directory + * @mode: mode of the child directory + * + * Create a directory. + * + * If the inode has been found through an idmapped mount the idmap of + * the vfsmount must be passed through @idmap. This function will then take + * care to map the inode according to @idmap before checking permissions. + * On non-idmapped mounts or if permission checking is to be performed on the + * raw inode simply pass @nop_mnt_idmap. + * + * The filesystem may not use the dentry that was passed in. In that case + * the passed-in dentry is put and a new one is placed in *@dentryp; + * So on successful return *@dentryp will always be positive. + */ +int vfs_mkdir_return(struct mnt_idmap *idmap, struct inode *dir, + struct dentry **dentryp, umode_t mode) +{ + struct dentry *dentry = *dentryp; + int error; + unsigned max_links = dir->i_sb->s_max_links; + + error = may_create(idmap, dir, dentry); + if (error) + return error; + + if (!dir->i_op->mkdir) + return -EPERM; + + mode = vfs_prepare_mode(idmap, dir, mode, S_IRWXUGO | S_ISVTX, 0); + error = security_inode_mkdir(dir, dentry, mode); + if (error) + return error; + + if (max_links && dir->i_nlink >= max_links) + return -EMLINK; + + error = dir->i_op->mkdir(idmap, dir, dentry, mode); + if (!error) { + fsnotify_mkdir(dir, dentry); + if (unlikely(d_unhashed(dentry))) { + struct dentry *d; + /* Need a "const" pointer. We know d_name is const + * because we hold an exclusive lock on i_rwsem + * in d_parent. + */ + const struct qstr *d_name = (void*)&dentry->d_name; + d = lookup_dcache(d_name, dentry->d_parent, 0); + if (!d) + d = __lookup_slow(d_name, dentry->d_parent, 0); + if (IS_ERR(d)) { + error = PTR_ERR(d); + } else if (unlikely(d_is_negative(d))) { + dput(d); + error = -ENOENT; + } else { + dput(dentry); + *dentryp = d; + } + } + } + return error; +} +EXPORT_SYMBOL(vfs_mkdir_return); + int do_mkdirat(int dfd, struct filename *name, umode_t mode) { struct dentry *dentry; diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 29cb7b812d71..740332413138 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1488,26 +1488,11 @@ nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp, nfsd_check_ignore_resizing(iap); break; case S_IFDIR: - host_err = vfs_mkdir(&nop_mnt_idmap, dirp, dchild, iap->ia_mode); - if (!host_err && unlikely(d_unhashed(dchild))) { - struct dentry *d; - d = lookup_one_len(dchild->d_name.name, - dchild->d_parent, - dchild->d_name.len); - if (IS_ERR(d)) { - host_err = PTR_ERR(d); - break; - } - if (unlikely(d_is_negative(d))) { - dput(d); - err = nfserr_serverfault; - goto out; - } + host_err = vfs_mkdir_return(&nop_mnt_idmap, dirp, &dchild, iap->ia_mode); + if (!host_err && unlikely(dchild != resfhp->fh_dentry)) { dput(resfhp->fh_dentry); - resfhp->fh_dentry = dget(d); + resfhp->fh_dentry = dget(dchild); err = fh_update(resfhp); - dput(dchild); - dchild = d; if (err) goto out; } diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c index c9993ff66fc2..e6c54c6ef0f5 100644 --- a/fs/overlayfs/dir.c +++ b/fs/overlayfs/dir.c @@ -138,37 +138,6 @@ int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct inode *dir, goto out; } -int ovl_mkdir_real(struct ovl_fs *ofs, struct inode *dir, - struct dentry **newdentry, umode_t mode) -{ - int err; - struct dentry *d, *dentry = *newdentry; - - err = ovl_do_mkdir(ofs, dir, dentry, mode); - if (err) - return err; - - if (likely(!d_unhashed(dentry))) - return 0; - - /* - * vfs_mkdir() may succeed and leave the dentry passed - * to it unhashed and negative. If that happens, try to - * lookup a new hashed and positive dentry. - */ - d = ovl_lookup_upper(ofs, dentry->d_name.name, dentry->d_parent, - dentry->d_name.len); - if (IS_ERR(d)) { - pr_warn("failed lookup after mkdir (%pd2, err=%i).\n", - dentry, err); - return PTR_ERR(d); - } - dput(dentry); - *newdentry = d; - - return 0; -} - struct dentry *ovl_create_real(struct ovl_fs *ofs, struct inode *dir, struct dentry *newdentry, struct ovl_cattr *attr) { @@ -191,7 +160,7 @@ struct dentry *ovl_create_real(struct ovl_fs *ofs, struct inode *dir, case S_IFDIR: /* mkdir is special... */ - err = ovl_mkdir_real(ofs, dir, &newdentry, attr->mode); + err = ovl_do_mkdir(ofs, dir, &newdentry, attr->mode); break; case S_IFCHR: diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index 0021e2025020..967870f12482 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -242,11 +242,11 @@ static inline int ovl_do_create(struct ovl_fs *ofs, } static inline int ovl_do_mkdir(struct ovl_fs *ofs, - struct inode *dir, struct dentry *dentry, + struct inode *dir, struct dentry **dentry, umode_t mode) { - int err = vfs_mkdir(ovl_upper_mnt_idmap(ofs), dir, dentry, mode); - pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err); + int err = vfs_mkdir_return(ovl_upper_mnt_idmap(ofs), dir, dentry, mode); + pr_debug("mkdir(%pd2, 0%o) = %i\n", *dentry, mode, err); return err; } @@ -838,8 +838,8 @@ struct ovl_cattr { #define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) }) -int ovl_mkdir_real(struct ovl_fs *ofs, struct inode *dir, - struct dentry **newdentry, umode_t mode); +int ovl_do_mkdir(struct ovl_fs *ofs, struct inode *dir, + struct dentry **newdentry, umode_t mode); struct dentry *ovl_create_real(struct ovl_fs *ofs, struct inode *dir, struct dentry *newdentry, struct ovl_cattr *attr); diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index 86ae6f6da36b..06ca8b01c336 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -327,7 +327,7 @@ static struct dentry *ovl_workdir_create(struct ovl_fs *ofs, goto retry; } - err = ovl_mkdir_real(ofs, dir, &work, attr.ia_mode); + err = ovl_do_mkdir(ofs, dir, &work, attr.ia_mode); if (err) goto out_dput; diff --git a/fs/smb/server/vfs.c b/fs/smb/server/vfs.c index 6890016e1923..4e580bb7baf8 100644 --- a/fs/smb/server/vfs.c +++ b/fs/smb/server/vfs.c @@ -211,7 +211,7 @@ int ksmbd_vfs_mkdir(struct ksmbd_work *work, const char *name, umode_t mode) { struct mnt_idmap *idmap; struct path path; - struct dentry *dentry; + struct dentry *dentry, *d; int err; dentry = ksmbd_vfs_kern_path_create(work, name, @@ -227,27 +227,11 @@ int ksmbd_vfs_mkdir(struct ksmbd_work *work, const char *name, umode_t mode) idmap = mnt_idmap(path.mnt); mode |= S_IFDIR; - err = vfs_mkdir(idmap, d_inode(path.dentry), dentry, mode); - if (!err && d_unhashed(dentry)) { - struct dentry *d; - - d = lookup_one(idmap, dentry->d_name.name, dentry->d_parent, - dentry->d_name.len); - if (IS_ERR(d)) { - err = PTR_ERR(d); - goto out_err; - } - if (unlikely(d_is_negative(d))) { - dput(d); - err = -ENOENT; - goto out_err; - } - + d = dentry; + err = vfs_mkdir_return(idmap, d_inode(path.dentry), &dentry, mode); + if (!err && dentry != d) ksmbd_vfs_inherit_owner(work, d_inode(path.dentry), d_inode(d)); - dput(d); - } -out_err: done_path_create(&path, dentry); if (err) pr_err("mkdir(%s): creation failed (err:%d)\n", name, err); diff --git a/include/linux/fs.h b/include/linux/fs.h index be3ad155ec9f..f81d6bc65fe4 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1971,6 +1971,8 @@ int vfs_create(struct mnt_idmap *, struct inode *, struct dentry *, umode_t, bool); int vfs_mkdir(struct mnt_idmap *, struct inode *, struct dentry *, umode_t); +int vfs_mkdir_return(struct mnt_idmap *, struct inode *, + struct dentry **, umode_t); int vfs_mknod(struct mnt_idmap *, struct inode *, struct dentry *, umode_t, dev_t); int vfs_symlink(struct mnt_idmap *, struct inode *,