From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from zeniv.linux.org.uk (zeniv.linux.org.uk [62.89.141.173]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A7F303469F2; Tue, 11 Nov 2025 06:55:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.89.141.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762844131; cv=none; b=Cw4lx582u6hD728EbbemCQ0RJ06wOUalLvcjVTs5TCeD7SmCA2JxhatxpRrO+2cXtxC+qRpsuWQI2ZJ6I0x74w1ohmamPBylcy+2M4BdF36Vej3eHu/G5QUm1XmqlxPR4lDgYL7MpcOKjfdIwTma7hAv+0BQ7VwZcefJONqvWU4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762844131; c=relaxed/simple; bh=jwkFEDrwvTGDwUNpjVB1S2cW3gao1k8zeHmkQ0uUtHs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XQ6+iXZfhOavDL++hgTwuBXEHE7h4xCmnOffnD0wScLtlD5gf1WRhHEp9dvY8zU9mt/HGO42ZzhX0Ii0T8N6e+ZYWyKnrJYDDnRCY8xAKBEIKycrjwjG9S5NrXxAeaQFstj6WBqz5RK5QpuzIqSkZx4bIq4MEB5ey2KRJW0ho88= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk; spf=none smtp.mailfrom=ftp.linux.org.uk; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b=hM6msKPS; arc=none smtp.client-ip=62.89.141.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=ftp.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b="hM6msKPS" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linux.org.uk; s=zeniv-20220401; h=Sender:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description; bh=Swq0voO+aKDUTzOh35qGY7dyE9PZZpqvfSqrFdp+4zM=; b=hM6msKPSIkdjC0WuzKYvaQi8y8 SMuoUsmVVskXl3viTWYdFMHDSs8cfuh8pOhMNc5KX4MsBtLI1gAxDkLn1mZ/iWpVkcIQJV0ThCVZ7 22fj9roVqJ4E9onmNfDu4LvkO58PJBbm9Hz02mcX43J/Lo/SwpbUieAaCU2FrVmktHXwyF5uszsU7 O3VsQ5TYfXnLP4aVqxvjJyrTyrP6WhsIjlAUGUHmQ2uT32yLmdkhwpy0mttsq3V733OXEC2Xl/nww 0zp3NYPnTyNY12tOtir+MEyRwQDaZSghmv619Rpla3YEUAQnn/G3sSXKhTygu/EatNxfEEtcgC6Wn d0e4bw0Q==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vIiHi-0000000BwxV-2gUL; Tue, 11 Nov 2025 06:55:22 +0000 From: Al Viro To: linux-fsdevel@vger.kernel.org Cc: torvalds@linux-foundation.org, brauner@kernel.org, jack@suse.cz, raven@themaw.net, miklos@szeredi.hu, neil@brown.name, a.hindborg@kernel.org, linux-mm@kvack.org, linux-efi@vger.kernel.org, ocfs2-devel@lists.linux.dev, kees@kernel.org, rostedt@goodmis.org, gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, paul@paul-moore.com, casey@schaufler-ca.com, linuxppc-dev@lists.ozlabs.org, john.johansen@canonical.com, selinux@vger.kernel.org, borntraeger@linux.ibm.com, bpf@vger.kernel.org Subject: [PATCH v3 08/50] convert ramfs and tmpfs Date: Tue, 11 Nov 2025 06:54:37 +0000 Message-ID: <20251111065520.2847791-9-viro@zeniv.linux.org.uk> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20251111065520.2847791-1-viro@zeniv.linux.org.uk> References: <20251111065520.2847791-1-viro@zeniv.linux.org.uk> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: Al Viro Quite a bit is already done by infrastructure changes (simple_link(), simple_unlink()) - all that is left is replacing d_instantiate() + pinning dget() (in ->symlink() and ->mknod()) with d_make_persistent(), and, in case of shmem, using simple_unlink() and simple_link() in ->unlink() and ->link() resp., instead of open-coding those there. Since d_make_persistent() accepts (and hashes) unhashed ones, shmem situation gets simpler - we no longer care whether ->lookup() has hashed the sucker. With that done, we don't need kill_litter_super() for these filesystems anymore - by the umount time all remaining dentries will be marked persistent and kill_litter_super() will boil down to call of kill_anon_super(). The same goes for devtmpfs and rootfs - they are handled by ramfs or by shmem, depending upon config. NB: strictly speaking, both devtmpfs and rootfs ought to use ramfs_kill_sb() if they end up using ramfs; that's a separate story and the only impact of "just use kill_{litter,anon}_super()" is that we fail to free their sb->s_fs_info... on reboot. That's orthogonal to the changes in this series - kill_litter_super() is identical to kill_anon_super() for those at this point. Signed-off-by: Al Viro --- drivers/base/devtmpfs.c | 2 +- fs/ramfs/inode.c | 8 +++----- init/do_mounts.c | 2 +- mm/shmem.c | 38 ++++++++------------------------------ 4 files changed, 13 insertions(+), 37 deletions(-) diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c index 9d4e46ad8352..a63b0ff0c432 100644 --- a/drivers/base/devtmpfs.c +++ b/drivers/base/devtmpfs.c @@ -70,7 +70,7 @@ static struct file_system_type internal_fs_type = { #else .init_fs_context = ramfs_init_fs_context, #endif - .kill_sb = kill_litter_super, + .kill_sb = kill_anon_super, }; /* Simply take a ref on the existing mount */ diff --git a/fs/ramfs/inode.c b/fs/ramfs/inode.c index 41f9995da7ca..505d10a0cb36 100644 --- a/fs/ramfs/inode.c +++ b/fs/ramfs/inode.c @@ -110,8 +110,7 @@ ramfs_mknod(struct mnt_idmap *idmap, struct inode *dir, goto out; } - d_instantiate(dentry, inode); - dget(dentry); /* Extra count - pin the dentry in core */ + d_make_persistent(dentry, inode); error = 0; inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir)); } @@ -154,8 +153,7 @@ static int ramfs_symlink(struct mnt_idmap *idmap, struct inode *dir, error = page_symlink(inode, symname, l); if (!error) { - d_instantiate(dentry, inode); - dget(dentry); + d_make_persistent(dentry, inode); inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir)); } else @@ -313,7 +311,7 @@ int ramfs_init_fs_context(struct fs_context *fc) void ramfs_kill_sb(struct super_block *sb) { kfree(sb->s_fs_info); - kill_litter_super(sb); + kill_anon_super(sb); } static struct file_system_type ramfs_fs_type = { diff --git a/init/do_mounts.c b/init/do_mounts.c index 6af29da8889e..810878fb55b6 100644 --- a/init/do_mounts.c +++ b/init/do_mounts.c @@ -507,7 +507,7 @@ static int rootfs_init_fs_context(struct fs_context *fc) struct file_system_type rootfs_fs_type = { .name = "rootfs", .init_fs_context = rootfs_init_fs_context, - .kill_sb = kill_litter_super, + .kill_sb = kill_anon_super, }; void __init init_rootfs(void) diff --git a/mm/shmem.c b/mm/shmem.c index b9081b817d28..a38f71519813 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -3858,12 +3858,7 @@ shmem_mknod(struct mnt_idmap *idmap, struct inode *dir, inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir)); inode_inc_iversion(dir); - if (IS_ENABLED(CONFIG_UNICODE) && IS_CASEFOLDED(dir)) - d_add(dentry, inode); - else - d_instantiate(dentry, inode); - - dget(dentry); /* Extra count - pin the dentry in core */ + d_make_persistent(dentry, inode); return error; out_iput: @@ -3924,7 +3919,7 @@ static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) { struct inode *inode = d_inode(old_dentry); - int ret = 0; + int ret; /* * No ordinary (disk based) filesystem counts links as inodes; @@ -3936,29 +3931,19 @@ static int shmem_link(struct dentry *old_dentry, struct inode *dir, if (inode->i_nlink) { ret = shmem_reserve_inode(inode->i_sb, NULL); if (ret) - goto out; + return ret; } ret = simple_offset_add(shmem_get_offset_ctx(dir), dentry); if (ret) { if (inode->i_nlink) shmem_free_inode(inode->i_sb, 0); - goto out; + return ret; } dir->i_size += BOGO_DIRENT_SIZE; - inode_set_mtime_to_ts(dir, - inode_set_ctime_to_ts(dir, inode_set_ctime_current(inode))); inode_inc_iversion(dir); - inc_nlink(inode); - ihold(inode); /* New dentry reference */ - dget(dentry); /* Extra pinning count for the created dentry */ - if (IS_ENABLED(CONFIG_UNICODE) && IS_CASEFOLDED(dir)) - d_add(dentry, inode); - else - d_instantiate(dentry, inode); -out: - return ret; + return simple_link(old_dentry, dir, dentry); } static int shmem_unlink(struct inode *dir, struct dentry *dentry) @@ -3971,11 +3956,8 @@ static int shmem_unlink(struct inode *dir, struct dentry *dentry) simple_offset_remove(shmem_get_offset_ctx(dir), dentry); dir->i_size -= BOGO_DIRENT_SIZE; - inode_set_mtime_to_ts(dir, - inode_set_ctime_to_ts(dir, inode_set_ctime_current(inode))); inode_inc_iversion(dir); - drop_nlink(inode); - dput(dentry); /* Undo the count from "create" - does all the work */ + simple_unlink(dir, dentry); /* * For now, VFS can't deal with case-insensitive negative dentries, so @@ -4130,11 +4112,7 @@ static int shmem_symlink(struct mnt_idmap *idmap, struct inode *dir, dir->i_size += BOGO_DIRENT_SIZE; inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir)); inode_inc_iversion(dir); - if (IS_ENABLED(CONFIG_UNICODE) && IS_CASEFOLDED(dir)) - d_add(dentry, inode); - else - d_instantiate(dentry, inode); - dget(dentry); + d_make_persistent(dentry, inode); return 0; out_remove_offset: @@ -5334,7 +5312,7 @@ static struct file_system_type shmem_fs_type = { #ifdef CONFIG_TMPFS .parameters = shmem_fs_parameters, #endif - .kill_sb = kill_litter_super, + .kill_sb = kill_anon_super, .fs_flags = FS_USERNS_MOUNT | FS_ALLOW_IDMAP | FS_MGTIME, }; -- 2.47.3