From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f46.google.com (mail-wr1-f46.google.com [209.85.221.46]) (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 C5FA83C7DF1 for ; Tue, 14 Apr 2026 10:07:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.46 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776161254; cv=none; b=FFyDXuGSQGVXsJ/whHbEE504tNpy6CNtlA2WVF+5+IDrYNgs5i7VoX3EU8LQP3ABR6w3CyogaPvV1Umv47kQT4u0UAlc+U8ecUem942gbBvrB6TWXB4yXn5Ee243KI+iANKzMFfXJ8fcgmGMk0PEmRW/Wm66AgAD+q3Gbzy5e+E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776161254; c=relaxed/simple; bh=1uSkaXzm2P0Wj7bPdxog4gc8N/ZNllWGiJvhmN98OSk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=o9yhLgUPEmoBUVfWMteBYn6zoDupnUqjvaPzAVjdUxEcWtVQzKsP8/bt1kL+uJY92V2sFiK+HxUvO9wsn9WdDXRgD0HWxpcus8ckrnj3CcX22C9tjKNP771eGxcsFySpyvCkTq60XR+NOKQBEgltXEMpVfaG3Or8KRcCxhZGXe4= 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=209.85.221.46 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-f46.google.com with SMTP id ffacd0b85a97d-43cf5f6d2eeso258361f8f.0 for ; Tue, 14 Apr 2026 03:07:32 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776161251; x=1776766051; 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=ukvcN/hPEzbhoZ6n0snMbQkF8J76XlbxpRq52+vBCOk=; b=r2fvAzV/HYUstl71F2VATugmJOK7Tc2I5br/SK9qLjgk2w1JATvear9ovid8bx1PzP hISDR8p0D6eM0qpQbSAkvfHr1iogAQ4EzNQ7JA5U/UNOA2R9oh+kQ147jL/GaIuhVive 0CnpW+XpANu64czPoNgKXUUI9/IMwvUngQhH/QjFr0d1at23ijj4rQMClCCR/GinmYRL M2mfgNnvK7DRuDbtrILDWT9XEC4VDHuCZSp+ffBBVhI8HQ6L9X6DOWE2WlEVpAFZabfb Oa6Y0R8hpGD1OFm5FG8OTJvRcrJU+c4rBWPPOzUgIuCYWGQTwEZR2Rug32GsTDzzBsQE zT5g== X-Gm-Message-State: AOJu0YyNRVkn+51t5gCngU5utaVpY846AsiDNC91DU2MB0wJhUF2gpLU tGh2/jYfjg7w3r4zUYpuq9V99DbuFX8IndpqFnq1bZlLp+4DdCOvjIiHAWcRxQTV X-Gm-Gg: AeBDiesigQg4ODtOnXTXlYhxPKU9qj/iZluqtxo+XTSfdJSEnquoXcX5daRMHu9j0ic /K8Fik9gaT0Q4n7W3m7VqaExxo4x+YXh5j12WBjZ8BCNjLjpmgWFgaIwTr1u5gbXe5rWQ7ye/3l W5b9x4OoDlbOVBr67fxxqzx/CaoW962HGk7dY+61liBvqh/pGNVcP6uLPDlSBexAxln5eWWf5OQ oTo+u6iVlafDhNT2tbxaOuvd8nvDYEkctX+r7zSQ2C7QW21VdW2DSackIIf+mye1DflwFBZyEVW mMgHit6RJQ81RlsWmLqH26A071kKo9w/gssTy7JJ8VMyQE+klyQ3B1jtR4hCuwMhgC2Y9ckECFH wJGksbMtVNbXPtrgnPjWNQdaydREjiH5CXDPkNtMHxTTul4fK5NWc600xcSKZeIsEGH1lkd/8LK OsV9roqPymVb9YMXbBiDJ0OfIQRnIq1b/ljXbdKrsD5EQX/rNgQtW04WkI6xtyxjsYPksGiGwzd LI= X-Received: by 2002:a05:600c:c4a2:b0:486:fdc0:4504 with SMTP id 5b1f17b1804b1-488d6864e49mr132033995e9.4.1776161250841; Tue, 14 Apr 2026 03:07:30 -0700 (PDT) Received: from spartian-1.home ([2a01:cb1c:784:2f00:708:2805:7128:7a75]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-488ede1e050sm65870545e9.5.2026.04.14.03.07.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Apr 2026 03:07:30 -0700 (PDT) From: Aurelien DESBRIERES To: linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, willy@infradead.org, djwong@kernel.org, adilger.kernel@dilger.ca, pedro.falcato@gmail.com, xiang@kernel.org, Aurelien DESBRIERES Subject: [PATCH v3 02/12] ftrfs: add superblock operations Date: Tue, 14 Apr 2026 14:07:15 +0200 Message-ID: <20260414120726.5713-3-aurelien@hackers.camp> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260414120726.5713-1-aurelien@hackers.camp> References: <20260413230601.525400-1-aurelien@hackers.camp> <20260414120726.5713-1-aurelien@hackers.camp> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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: Aurelien 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 000000000000..8acc6292124b --- /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