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>

1 files changed, 28 insertions, 37 deletions

diff --git a/fs/bfs/inode.c b/fs/bfs/inode.c
index d81c148682e7..d136b2aaafb3 100644
--- 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;