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.

Link: http://lkml.kernel.org/r/CAK+_RLkFZMduoQF36wZFd3zLi-6ZutWKsydjeHFNdtRvZZEb4w@mail.gmail.com
Signed-off-by: Tigran Aivazian <aivazian.tigran@gmail.com>
Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/bfs/bfs.h b/fs/bfs/bfs.h
index 67aef3b..606f937 100644 (file)
--- a/fs/bfs/bfs.h
+++ b/fs/bfs/bfs.h
@@ -1,13 +1,20 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 /*
  *     fs/bfs/bfs.h
- *     Copyright (C) 1999 Tigran Aivazian <tigran@veritas.com>
+ *     Copyright (C) 1999-2018 Tigran Aivazian <aivazian.tigran@gmail.com>
  */
 #ifndef _FS_BFS_BFS_H
 #define _FS_BFS_BFS_H
 
 #include <linux/bfs_fs.h>
 
+/* 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 @@ struct bfs_sb_info {
        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;
 };
 

diff --git a/fs/bfs/dir.c b/fs/bfs/dir.c
index f32f21c..d8dfe3a 100644 (file)
--- a/fs/bfs/dir.c
+++ b/fs/bfs/dir.c
@@ -2,8 +2,8 @@
 /*
  *     fs/bfs/dir.c
  *     BFS directory operations.
- *     Copyright (C) 1999,2000  Tigran Aivazian <tigran@veritas.com>
- *      Made endianness-clean by Andrew Stribblehill <ads@wompom.org> 2005
+ *     Copyright (C) 1999-2018  Tigran Aivazian <aivazian.tigran@gmail.com>
+ *  Made endianness-clean by Andrew Stribblehill <ads@wompom.org> 2005
  */
 
 #include <linux/time.h>

diff --git a/fs/bfs/file.c b/fs/bfs/file.c
index 1476cdd..0dceefc 100644 (file)
--- a/fs/bfs/file.c
+++ b/fs/bfs/file.c
@@ -2,7 +2,7 @@
 /*
  *     fs/bfs/file.c
  *     BFS file operations.
- *     Copyright (C) 1999,2000 Tigran Aivazian <tigran@veritas.com>
+ *     Copyright (C) 1999-2018 Tigran Aivazian <aivazian.tigran@gmail.com>
  *
  *     Make the file block allocation algorithm understand the size
  *     of the underlying block device.

diff --git a/fs/bfs/inode.c b/fs/bfs/inode.c
index d81c148..d136b2a 100644 (file)
--- a/fs/bfs/inode.c
+++ b/fs/bfs/inode.c
@@ -1,10 +1,9 @@
 /*
  *     fs/bfs/inode.c
  *     BFS superblock and inode operations.
- *     Copyright (C) 1999-2006 Tigran Aivazian <aivazian.tigran@gmail.com>
+ *     Copyright (C) 1999-2018 Tigran Aivazian <aivazian.tigran@gmail.com>
  *     From fs/minix, Copyright (C) 1991, 1992 Linus Torvalds.
- *
- *      Made endianness-clean by Andrew Stribblehill <ads@wompom.org>, 2005.
+ *     Made endianness-clean by Andrew Stribblehill <ads@wompom.org>, 2005.
  */
 
 #include <linux/module.h>
@@ -118,12 +117,12 @@ static int bfs_write_inode(struct inode *inode, struct writeback_control *wbc)
 {
        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 @@ static int bfs_write_inode(struct inode *inode, struct writeback_control *wbc)
        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 @@ static void bfs_evict_inode(struct inode *inode)
        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 @@ static void bfs_put_super(struct super_block *s)
                return;
 
        mutex_destroy(&info->bfs_lock);
-       kfree(info->si_imap);
        kfree(info);
        s->s_fs_info = NULL;
 }
@@ -311,8 +309,7 @@ void bfs_dump_imap(const char *prefix, struct super_block *s)
                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 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent)
        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 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent)
        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)
@@ -351,18 +347,16 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent)
        s->s_magic = BFS_MAGIC;
 
        if (le32_to_cpu(bfs_sb->s_start) > le32_to_cpu(bfs_sb->s_end) ||
-           le32_to_cpu(bfs_sb->s_start) < BFS_BSIZE) {
-               printf("Superblock is corrupted\n");
+           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 | __GFP_NOWARN);
-       if (!info->si_imap) {
-               printf("Cannot allocate %u bytes\n", imap_len);
+       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++)
@@ -372,26 +366,25 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent)
        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);
 
@@ -425,11 +418,11 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent)
                        (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) {
@@ -445,14 +438,12 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent)
        }
        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:
@@ -482,7 +473,7 @@ static int __init init_bfs_fs(void)
        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;

diff --git a/include/uapi/linux/bfs_fs.h b/include/uapi/linux/bfs_fs.h
index 940b047..08f6b49 100644 (file)
--- a/include/uapi/linux/bfs_fs.h
+++ b/include/uapi/linux/bfs_fs.h
@@ -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 <tigran@veritas.com>
+ *     Copyright (C) 1999-2018 Tigran Aivazian <aivazian.tigran@gmail.com>
  */
 
 #ifndef _LINUX_BFS_FS_H