From: Tigran Aivazian Subject: bfs: extra sanity checking and static inode bitmap Strengthen validation of BFS superblock against corruption. Make in-core inode bitmap static part of superblock info structure. Print a warning when mounting a BFS filesystem created with "-N 512" option as only 510 files can be created in the root directory. Make the kernel messages more uniform. Update the 'prefix' passed to bfs_dump_imap() to match the current naming of operations. White space and comments cleanup. Signed-off-by: Tigran Aivazian Reported-by: Tetsuo Handa --- fs/bfs/bfs.h | 11 ++++++- fs/bfs/dir.c | 4 +- fs/bfs/file.c | 2 - fs/bfs/inode.c | 66 ++++++++++++++++++++------------------------ include/uapi/linux/bfs_fs.h | 4 +- 5 files changed, 44 insertions(+), 43 deletions(-) --- include/uapi/linux/bfs_fs.h.0 2018-11-13 19:19:55.941267342 +0000 +++ include/uapi/linux/bfs_fs.h 2018-11-13 19:20:24.101182357 +0000 @@ -1,7 +1,7 @@ /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ /* * include/linux/bfs_fs.h - BFS data structures on disk. - * Copyright (C) 1999 Tigran Aivazian + * Copyright (C) 1999-2018 Tigran Aivazian */ #ifndef _LINUX_BFS_FS_H --- fs/bfs/bfs.h.0 2018-11-13 19:20:40.151161044 +0000 +++ fs/bfs/bfs.h 2018-11-13 19:21:32.929740656 +0000 @@ -1,13 +1,20 @@ /* SPDX-License-Identifier: GPL-2.0 */ /* * fs/bfs/bfs.h - * Copyright (C) 1999 Tigran Aivazian + * Copyright (C) 1999-2018 Tigran Aivazian */ #ifndef _FS_BFS_BFS_H #define _FS_BFS_BFS_H #include +/* In theory BFS supports up to 512 inodes, numbered from 2 (for /) up to 513 inclusive. + In actual fact, attempting to create the 512th inode (i.e. inode No. 513 or file No. 511) + will fail with ENOSPC in bfs_add_entry(): the root directory cannot contain so many entries, counting '..'. + So, mkfs.bfs(8) should really limit its -N option to 511 and not 512. For now, we just print a warning + if a filesystem is mounted with such "impossible to fill up" number of inodes */ +#define BFS_MAX_LASTI 513 + /* * BFS file system in-core superblock info */ @@ -17,7 +24,7 @@ unsigned long si_freei; unsigned long si_lf_eblk; unsigned long si_lasti; - unsigned long *si_imap; + DECLARE_BITMAP(si_imap, BFS_MAX_LASTI+1); struct mutex bfs_lock; }; --- fs/bfs/dir.c.0 2018-11-13 19:29:32.361259272 +0000 +++ fs/bfs/dir.c 2018-11-13 19:30:01.380683858 +0000 @@ -2,8 +2,8 @@ /* * fs/bfs/dir.c * BFS directory operations. - * Copyright (C) 1999,2000 Tigran Aivazian - * Made endianness-clean by Andrew Stribblehill 2005 + * Copyright (C) 1999-2018 Tigran Aivazian + * Made endianness-clean by Andrew Stribblehill 2005 */ #include --- fs/bfs/file.c.0 2018-11-13 19:30:11.760489957 +0000 +++ fs/bfs/file.c 2018-11-13 19:30:27.020214845 +0000 @@ -2,7 +2,7 @@ /* * fs/bfs/file.c * BFS file operations. - * Copyright (C) 1999,2000 Tigran Aivazian + * Copyright (C) 1999-2018 Tigran Aivazian * * Make the file block allocation algorithm understand the size * of the underlying block device. --- fs/bfs/inode.c.0 2018-11-13 19:21:46.089579726 +0000 +++ fs/bfs/inode.c 2018-11-13 19:29:22.521467104 +0000 @@ -1,10 +1,9 @@ /* * fs/bfs/inode.c * BFS superblock and inode operations. - * Copyright (C) 1999-2006 Tigran Aivazian + * Copyright (C) 1999-2018 Tigran Aivazian * From fs/minix, Copyright (C) 1991, 1992 Linus Torvalds. - * - * Made endianness-clean by Andrew Stribblehill , 2005. + * Made endianness-clean by Andrew Stribblehill , 2005. */ #include @@ -118,12 +117,12 @@ { struct bfs_sb_info *info = BFS_SB(inode->i_sb); unsigned int ino = (u16)inode->i_ino; - unsigned long i_sblock; + unsigned long i_sblock; struct bfs_inode *di; struct buffer_head *bh; int err = 0; - dprintf("ino=%08x\n", ino); + dprintf("ino=%08x\n", ino); di = find_inode(inode->i_sb, ino, &bh); if (IS_ERR(di)) @@ -144,7 +143,7 @@ di->i_atime = cpu_to_le32(inode->i_atime.tv_sec); di->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec); di->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec); - i_sblock = BFS_I(inode)->i_sblock; + i_sblock = BFS_I(inode)->i_sblock; di->i_sblock = cpu_to_le32(i_sblock); di->i_eblock = cpu_to_le32(BFS_I(inode)->i_eblock); di->i_eoffset = cpu_to_le32(i_sblock * BFS_BSIZE + inode->i_size - 1); @@ -188,13 +187,13 @@ mark_buffer_dirty(bh); brelse(bh); - if (bi->i_dsk_ino) { + if (bi->i_dsk_ino) { if (bi->i_sblock) info->si_freeb += bi->i_eblock + 1 - bi->i_sblock; info->si_freei++; clear_bit(ino, info->si_imap); - bfs_dump_imap("delete_inode", s); - } + bfs_dump_imap("evict_inode", s); + } /* * If this was the last file, make the previous block @@ -214,7 +213,6 @@ return; mutex_destroy(&info->bfs_lock); - kfree(info->si_imap); kfree(info); s->s_fs_info = NULL; } @@ -311,8 +309,7 @@ else strcat(tmpbuf, "0"); } - printf("BFS-fs: %s: lasti=%08lx <%s>\n", - prefix, BFS_SB(s)->si_lasti, tmpbuf); + printf("%s: lasti=%08lx <%s>\n", prefix, BFS_SB(s)->si_lasti, tmpbuf); free_page((unsigned long)tmpbuf); #endif } @@ -322,7 +319,7 @@ struct buffer_head *bh, *sbh; struct bfs_super_block *bfs_sb; struct inode *inode; - unsigned i, imap_len; + unsigned i; struct bfs_sb_info *info; int ret = -EINVAL; unsigned long i_sblock, i_eblock, i_eoff, s_size; @@ -341,8 +338,7 @@ bfs_sb = (struct bfs_super_block *)sbh->b_data; if (le32_to_cpu(bfs_sb->s_magic) != BFS_MAGIC) { if (!silent) - printf("No BFS filesystem on %s (magic=%08x)\n", - s->s_id, le32_to_cpu(bfs_sb->s_magic)); + printf("No BFS filesystem on %s (magic=%08x)\n", s->s_id, le32_to_cpu(bfs_sb->s_magic)); goto out1; } if (BFS_UNCLEAN(bfs_sb, s) && !silent) @@ -350,18 +346,19 @@ s->s_magic = BFS_MAGIC; - if (le32_to_cpu(bfs_sb->s_start) > le32_to_cpu(bfs_sb->s_end)) { - printf("Superblock is corrupted\n"); + if (le32_to_cpu(bfs_sb->s_start) > le32_to_cpu(bfs_sb->s_end) || + le32_to_cpu(bfs_sb->s_start) < sizeof(struct bfs_super_block) + sizeof(struct bfs_dirent)) { + printf("Superblock is corrupted on %s\n", s->s_id); goto out1; } - info->si_lasti = (le32_to_cpu(bfs_sb->s_start) - BFS_BSIZE) / - sizeof(struct bfs_inode) - + BFS_ROOT_INO - 1; - imap_len = (info->si_lasti / 8) + 1; - info->si_imap = kzalloc(imap_len, GFP_KERNEL); - if (!info->si_imap) + info->si_lasti = (le32_to_cpu(bfs_sb->s_start) - BFS_BSIZE) / sizeof(struct bfs_inode) + BFS_ROOT_INO - 1; + if (info->si_lasti == BFS_MAX_LASTI) + printf("WARNING: filesystem %s was created with 512 inodes, the real maximum is 511, mounting anyway\n", s->s_id); + else if (info->si_lasti > BFS_MAX_LASTI) { + printf("Impossible last inode number %lu > %d on %s\n", info->si_lasti, BFS_MAX_LASTI, s->s_id); goto out1; + } for (i = 0; i < BFS_ROOT_INO; i++) set_bit(i, info->si_imap); @@ -369,26 +366,25 @@ inode = bfs_iget(s, BFS_ROOT_INO); if (IS_ERR(inode)) { ret = PTR_ERR(inode); - goto out2; + goto out1; } s->s_root = d_make_root(inode); if (!s->s_root) { ret = -ENOMEM; - goto out2; + goto out1; } info->si_blocks = (le32_to_cpu(bfs_sb->s_end) + 1) >> BFS_BSIZE_BITS; - info->si_freeb = (le32_to_cpu(bfs_sb->s_end) + 1 - - le32_to_cpu(bfs_sb->s_start)) >> BFS_BSIZE_BITS; + info->si_freeb = (le32_to_cpu(bfs_sb->s_end) + 1 - le32_to_cpu(bfs_sb->s_start)) >> BFS_BSIZE_BITS; info->si_freei = 0; info->si_lf_eblk = 0; /* can we read the last block? */ bh = sb_bread(s, info->si_blocks - 1); if (!bh) { - printf("Last block not available: %lu\n", info->si_blocks - 1); + printf("Last block not available on %s: %lu\n", s->s_id, info->si_blocks - 1); ret = -EIO; - goto out3; + goto out2; } brelse(bh); @@ -422,11 +418,11 @@ (i_eoff != le32_to_cpu(-1) && i_eoff > s_size) || i_sblock * BFS_BSIZE > i_eoff) { - printf("Inode 0x%08x corrupted\n", i); + printf("Inode 0x%08x corrupted on %s\n", i, s->s_id); brelse(bh); ret = -EIO; - goto out3; + goto out2; } if (!di->i_ino) { @@ -442,14 +438,12 @@ } brelse(bh); brelse(sbh); - bfs_dump_imap("read_super", s); + bfs_dump_imap("fill_super", s); return 0; -out3: +out2: dput(s->s_root); s->s_root = NULL; -out2: - kfree(info->si_imap); out1: brelse(sbh); out: @@ -479,7 +473,7 @@ int err = init_inodecache(); if (err) goto out1; - err = register_filesystem(&bfs_fs_type); + err = register_filesystem(&bfs_fs_type); if (err) goto out; return 0; --- include/uapi/linux/bfs_fs.h.0 2018-11-13 19:19:55.941267342 +0000 +++ include/uapi/linux/bfs_fs.h 2018-11-13 19:20:24.101182357 +0000 @@ -1,7 +1,7 @@ /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ /* * include/linux/bfs_fs.h - BFS data structures on disk. - * Copyright (C) 1999 Tigran Aivazian + * Copyright (C) 1999-2018 Tigran Aivazian */ #ifndef _LINUX_BFS_FS_H