From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f47.google.com (mail-wr1-f47.google.com [209.85.221.47]) (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 1663E3C4552 for ; Mon, 13 Apr 2026 12:24:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.47 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776083058; cv=none; b=bjwXCIS0JHEIugkbWqNUG3zRsnqQZ53iSgi4GmUFDGVCUquIHe52NQC0I4ufBQEX3vWmYQVa/JE7KaSu+sj3UhuWXBOcg9GzToW0Dfad214iSYY7eiaFs8U95d68ZcdenOnZcvEFa8F9cAnYK34oAtGG0iEg+8cdhtNXFPhBO0k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776083058; c=relaxed/simple; bh=yiXDPjYkO81D1LyoV9hGUo5Orc17aNP1k5Gp61/ee1Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=rb29auXzZ9Iv2IS2D564A6Opc61Dj5uIk8368m7PqqTilePqaP+v5lhZXWl0KC+m1c9OonEkfBNdEOtnjedsWoFpnVpFPBS1LvsWeuZeeywuZmskrO6MouWHwWpmb+cYPm5KZ9+o5tr6cpUI/fISiUcwDlLqGqm+/Gxb9evDFTg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=hackers.camp; spf=pass smtp.mailfrom=gmail.com; arc=none smtp.client-ip=209.85.221.47 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=hackers.camp Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-wr1-f47.google.com with SMTP id ffacd0b85a97d-43d6f57062fso145062f8f.1 for ; Mon, 13 Apr 2026 05:24:16 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776083055; x=1776687855; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=5gEXSZ+uScr7KRUr40EnRlVlFvf/yGJPhJ4k6WJeHh8=; b=CV/dIXY4TXT20OOmjyevZ2v+VMlsrxF45BS9SFz0lLa1K1kQ6IDg1W1zqltA1nAii+ rCS+Uep+uUNKGOoQXu9MCqTmCLN46WVzcQlbCcJxTuv/s5SQ4eXDGUI2gwNaIGlSZ68X tomOtatf8Z38WF6K18S1Hxp1zMM5Xo0sOc9EnFL95w3wpQTahkc8OuFX/z+7NMn7PzkT wA5O0lMIy7NuIobpgd/GeZZew6IT7MCgs9Rg1m8WyesNRmfkeYd6sl7GajtB/v5h3rIB ZvFOORfwtQ+KLWWt+dJ3+4qIFw2CJnEQb0RFRlm6nXdNDyrX/Wybepb6u33C3VN9A0M9 Ox8Q== X-Gm-Message-State: AOJu0Yyz8eFmRZWjCa7VKyUgqT5vdQ4zORiWA6wr0+UrLKnz5y7ez21m xSXP560PsrSU/OeMEbL/b7M8TyUzBWf1pcI+T/5W364MnayRKnRNhLU5 X-Gm-Gg: AeBDietm+1D/dxRfymSFBU0/Kg0oSmK2Legont9xs2QgZqLd0w0DPVfiv/VdVknBzH8 0KSO37keXBtBO623LfRHNyP+J8U6yv5oQyZ10YAIMi8iesHDBC/9q7oRYp+DtosVX2jzZrft4Kl 3l83I4lFpDUuiURJljrKtxiSftKz6tsAl5FIMHuPO7lN5Pz9a2BRfRcg++Qm+BcsX+QOPtMBSOw OT+Mn2QxHuhDph0sQGvdVzbsLPyspdTS9tvem5VLEglhSfWTQqbprfor9rK8WoS8ad9Efd02XTU vL/I6EEXzqDm+pqpRSVJ4YZhVPpjWXIyHZf2apIiy86ooKHcf7/DF/Wb260WeSxkVLhwXYAVh+I pYDD+Qq9Ht4zJFOAkRGIgdJiMw3Lu5VfFeiMOxNvJczB/K/lh5i0XDPyKbMj3J3NHilwpg7KBle m51MvgRwLcMsjTucOB8cAWOya5lznjs0l59j8sE3ofRI3eihYQgo3TuMzcdcqyDk69UQ== X-Received: by 2002:a05:600c:1c06:b0:485:c456:5e4f with SMTP id 5b1f17b1804b1-488d7e21466mr98392275e9.0.1776083055395; Mon, 13 Apr 2026 05:24:15 -0700 (PDT) Received: from spartian-1.home ([2a01:cb1c:784:2f00:708:2805:7128:7a75]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-488d532ed4dsm278260915e9.4.2026.04.13.05.24.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 13 Apr 2026 05:24:14 -0700 (PDT) From: Aurelien DESBRIERES To: linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk, brauner@kernel.org, aurelien@hackers.camp Subject: [RFC PATCH 02/10] ftrfs: add superblock operations Date: Mon, 13 Apr 2026 16:23:48 +0200 Message-ID: <20260413142357.515792-3-aurelien@hackers.camp> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260413142357.515792-1-aurelien@hackers.camp> References: <20260413142357.515792-1-aurelien@hackers.camp> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Aurélien DESBRIERES Implement VFS superblock operations for FTRFS: - ftrfs_fill_super(): read and validate on-disk superblock (magic, CRC32), allocate ftrfs_sb_info, read root inode, initialize in-memory free block bitmap - ftrfs_put_super(): release bitmap and buffer heads on unmount - ftrfs_statfs(): report filesystem statistics - ftrfs_write_inode(): persist inode to disk via namei.c - ftrfs_init_fs_context() / ftrfs_get_tree(): kernel 5.15+ mount API - ftrfs_free_inode(): kernel 5.9+ inode freeing API Module init/exit registers ftrfs as a filesystem type and allocates a dedicated slab cache for ftrfs_inode_info objects. Signed-off-by: Aurélien DESBRIERES --- fs/ftrfs/super.c | 274 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 274 insertions(+) create mode 100644 fs/ftrfs/super.c diff --git a/fs/ftrfs/super.c b/fs/ftrfs/super.c new file mode 100644 index 000000000..8acc62921 --- /dev/null +++ b/fs/ftrfs/super.c @@ -0,0 +1,274 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * FTRFS — Superblock operations + * Author: roastercode - Aurelien DESBRIERES + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include "ftrfs.h" + +/* Inode cache (slab allocator) */ +static struct kmem_cache *ftrfs_inode_cachep; + +/* + * alloc_inode — allocate a new inode with ftrfs_inode_info embedded + */ +static struct inode *ftrfs_alloc_inode(struct super_block *sb) +{ + struct ftrfs_inode_info *fi; + + fi = kmem_cache_alloc(ftrfs_inode_cachep, GFP_KERNEL); + if (!fi) + return NULL; + + memset(fi->i_direct, 0, sizeof(fi->i_direct)); + fi->i_indirect = 0; + fi->i_dindirect = 0; + fi->i_flags = 0; + + return &fi->vfs_inode; +} + +/* + * free_inode — return inode to slab cache (kernel 5.9+ uses free_inode) + */ +static void ftrfs_free_inode(struct inode *inode) +{ + kmem_cache_free(ftrfs_inode_cachep, FTRFS_I(inode)); +} + +/* + * statfs — filesystem statistics + */ +static int ftrfs_statfs(struct dentry *dentry, struct kstatfs *buf) +{ + struct super_block *sb = dentry->d_sb; + struct ftrfs_sb_info *sbi = FTRFS_SB(sb); + + buf->f_type = FTRFS_MAGIC; + buf->f_bsize = sb->s_blocksize; + buf->f_blocks = le64_to_cpu(sbi->s_ftrfs_sb->s_block_count); + buf->f_bfree = sbi->s_free_blocks; + buf->f_bavail = sbi->s_free_blocks; + buf->f_files = le64_to_cpu(sbi->s_ftrfs_sb->s_inode_count); + buf->f_ffree = sbi->s_free_inodes; + buf->f_namelen = FTRFS_MAX_FILENAME; + + return 0; +} + +/* + * put_super — release superblock resources + */ +static void ftrfs_put_super(struct super_block *sb) +{ + struct ftrfs_sb_info *sbi = FTRFS_SB(sb); + + if (sbi) { + ftrfs_destroy_bitmap(sb); + brelse(sbi->s_sbh); + kfree(sbi->s_ftrfs_sb); + kfree(sbi); + sb->s_fs_info = NULL; + } +} + +static const struct super_operations ftrfs_super_ops = { + .alloc_inode = ftrfs_alloc_inode, + .free_inode = ftrfs_free_inode, + .put_super = ftrfs_put_super, + .write_inode = ftrfs_write_inode, + .statfs = ftrfs_statfs, +}; + +/* + * ftrfs_fill_super — read superblock from disk and initialize VFS sb + */ +int ftrfs_fill_super(struct super_block *sb, struct fs_context *fc) +{ + struct ftrfs_sb_info *sbi; + struct ftrfs_super_block *fsb; + struct buffer_head *bh; + struct inode *root_inode; + __u32 crc; + int ret = -EINVAL; + + /* Set block size */ + if (!sb_set_blocksize(sb, FTRFS_BLOCK_SIZE)) { + errorf(fc, "ftrfs: unable to set block size %d", FTRFS_BLOCK_SIZE); + return -EINVAL; + } + + /* Read block 0 — superblock */ + bh = sb_bread(sb, 0); + if (!bh) { + errorf(fc, "ftrfs: unable to read superblock"); + return -EIO; + } + + fsb = (struct ftrfs_super_block *)bh->b_data; + + /* Verify magic */ + if (le32_to_cpu(fsb->s_magic) != FTRFS_MAGIC) { + errorf(fc, "ftrfs: bad magic 0x%08x (expected 0x%08x)", + le32_to_cpu(fsb->s_magic), FTRFS_MAGIC); + goto out_brelse; + } + + /* Verify CRC32 of superblock (excluding the crc32 field itself) */ + crc = ftrfs_crc32(fsb, offsetof(struct ftrfs_super_block, s_crc32)); + if (crc != le32_to_cpu(fsb->s_crc32)) { + errorf(fc, "ftrfs: superblock CRC32 mismatch (got 0x%08x, expected 0x%08x)", + crc, le32_to_cpu(fsb->s_crc32)); + goto out_brelse; + } + + /* Allocate in-memory sb info */ + sbi = kzalloc(sizeof(*sbi), GFP_KERNEL); + if (!sbi) { + ret = -ENOMEM; + goto out_brelse; + } + + sbi->s_ftrfs_sb = kzalloc(sizeof(*sbi->s_ftrfs_sb), GFP_KERNEL); + if (!sbi->s_ftrfs_sb) { + ret = -ENOMEM; + goto out_free_sbi; + } + + memcpy(sbi->s_ftrfs_sb, fsb, sizeof(*fsb)); + sbi->s_sbh = bh; + sbi->s_free_blocks = le64_to_cpu(fsb->s_free_blocks); + sbi->s_free_inodes = le64_to_cpu(fsb->s_free_inodes); + spin_lock_init(&sbi->s_lock); + + sb->s_fs_info = sbi; + sb->s_magic = FTRFS_MAGIC; + sb->s_op = &ftrfs_super_ops; + sb->s_maxbytes = MAX_LFS_FILESIZE; + + /* Read root inode (inode 1) */ + root_inode = ftrfs_iget(sb, 1); + if (IS_ERR(root_inode)) { + ret = PTR_ERR(root_inode); + pr_err("ftrfs: failed to read root inode: %d\n", ret); + goto out_free_fsb; + } + + sb->s_root = d_make_root(root_inode); + if (!sb->s_root) { + ret = -ENOMEM; + goto out_free_fsb; + } + + if (ftrfs_setup_bitmap(sb)) { + ret = -ENOMEM; + goto out_free_fsb; + } + + pr_info("ftrfs: mounted (blocks=%llu free=%lu inodes=%llu)\n", + le64_to_cpu(fsb->s_block_count), + sbi->s_free_blocks, + le64_to_cpu(fsb->s_inode_count)); + + return 0; + +out_free_fsb: + kfree(sbi->s_ftrfs_sb); +out_free_sbi: + kfree(sbi); + sb->s_fs_info = NULL; +out_brelse: + brelse(bh); + return ret; +} + +/* + * fs_context ops — kernel 5.15+ mount API + */ +static int ftrfs_get_tree(struct fs_context *fc) +{ + return get_tree_bdev(fc, ftrfs_fill_super); +} + +static const struct fs_context_operations ftrfs_context_ops = { + .get_tree = ftrfs_get_tree, +}; + +static int ftrfs_init_fs_context(struct fs_context *fc) +{ + fc->ops = &ftrfs_context_ops; + return 0; +} + +static struct file_system_type ftrfs_fs_type = { + .owner = THIS_MODULE, + .name = "ftrfs", + .init_fs_context = ftrfs_init_fs_context, + .kill_sb = kill_block_super, + .fs_flags = FS_REQUIRES_DEV, +}; + +/* + * Inode cache constructor + */ +static void ftrfs_inode_init_once(void *obj) +{ + struct ftrfs_inode_info *fi = obj; + + inode_init_once(&fi->vfs_inode); +} + +/* + * Module init / exit + */ +static int __init ftrfs_init(void) +{ + int ret; + + ftrfs_inode_cachep = kmem_cache_create( + "ftrfs_inode_cache", + sizeof(struct ftrfs_inode_info), + 0, + SLAB_RECLAIM_ACCOUNT | SLAB_ACCOUNT, + ftrfs_inode_init_once); + + if (!ftrfs_inode_cachep) { + pr_err("ftrfs: failed to create inode cache\n"); + return -ENOMEM; + } + + ret = register_filesystem(&ftrfs_fs_type); + if (ret) { + pr_err("ftrfs: failed to register filesystem: %d\n", ret); + kmem_cache_destroy(ftrfs_inode_cachep); + return ret; + } + + pr_info("ftrfs: module loaded (FTRFS Fault-Tolerant Radiation-Robust FS)\n"); + return 0; +} + +static void __exit ftrfs_exit(void) +{ + unregister_filesystem(&ftrfs_fs_type); + rcu_barrier(); + kmem_cache_destroy(ftrfs_inode_cachep); + pr_info("ftrfs: module unloaded\n"); +} + +module_init(ftrfs_init); +module_exit(ftrfs_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("roastercode - Aurelien DESBRIERES "); +MODULE_DESCRIPTION("FTRFS: Fault-Tolerant Radiation-Robust Filesystem"); +MODULE_VERSION("0.1.0"); +MODULE_ALIAS_FS("ftrfs"); -- 2.52.0