Fixes to the BFS filesystem driver

I found a few bugs in the BFS driver.  Detailed description of the bugs as
well as the steps to reproduce the errors are given in the kernel bugzilla.
 Please follow these links for more information:

http://bugzilla.kernel.org/show_bug.cgi?id=9363
http://bugzilla.kernel.org/show_bug.cgi?id=9364
http://bugzilla.kernel.org/show_bug.cgi?id=9365
http://bugzilla.kernel.org/show_bug.cgi?id=9366

This patch fixes the bugs described above.  Besides, the patch introduces
coding style changes to make the BFS driver conform to the requirements
specified for Linux kernel code.  Finally, I made a few cosmetic changes
such as removal of trivial debug output.

Also, the patch removes the fields `si_lf_ioff' and `si_lf_sblk' of the
in-core superblock structure.  These fields are initialized but never
actually used.

If you are wondering why I need BFS, here is the answer: I am using this
driver in the context of Linux kernel classes I am teaching in the Moscow
State University and in the International Institute of Information
Technology in Pune, India.

Signed-off-by: Dmitri Vorobiev <dmitri.vorobiev@gmail.com>
Cc: Tigran Aivazian <tigran@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 64 insertions, 63 deletions

diff --git a/fs/bfs/inode.c b/fs/bfs/inode.c
index 7bd9c2b..294c41b 100644
--- a/fs/bfs/inode.c
+++ b/fs/bfs/inode.c
@@ -30,25 +30,26 @@ MODULE_LICENSE("GPL");
 #define dprintf(x...)
 #endif
 
-void dump_imap(const char *prefix, struct super_block * s);
+void dump_imap(const char *prefix, struct super_block *s);
 
-static void bfs_read_inode(struct inode * inode)
+static void bfs_read_inode(struct inode *inode)
 {
 	unsigned long ino = inode->i_ino;
-	struct bfs_inode * di;
-	struct buffer_head * bh;
+	struct bfs_inode *di;
+	struct buffer_head *bh;
 	int block, off;
 
-	if (ino < BFS_ROOT_INO || ino > BFS_SB(inode->i_sb)->si_lasti) {
+	if ((ino < BFS_ROOT_INO) || (ino > BFS_SB(inode->i_sb)->si_lasti)) {
 		printf("Bad inode number %s:%08lx\n", inode->i_sb->s_id, ino);
 		make_bad_inode(inode);
 		return;
 	}
 
-	block = (ino - BFS_ROOT_INO)/BFS_INODES_PER_BLOCK + 1;
+	block = (ino - BFS_ROOT_INO) / BFS_INODES_PER_BLOCK + 1;
 	bh = sb_bread(inode->i_sb, block);
 	if (!bh) {
-		printf("Unable to read inode %s:%08lx\n", inode->i_sb->s_id, ino);
+		printf("Unable to read inode %s:%08lx\n", inode->i_sb->s_id,
+									ino);
 		make_bad_inode(inode);
 		return;
 	}
@@ -56,7 +57,7 @@ static void bfs_read_inode(struct inode * inode)
 	off = (ino - BFS_ROOT_INO) % BFS_INODES_PER_BLOCK;
 	di = (struct bfs_inode *)bh->b_data + off;
 
-	inode->i_mode = 0x0000FFFF &  le32_to_cpu(di->i_mode);
+	inode->i_mode = 0x0000FFFF & le32_to_cpu(di->i_mode);
 	if (le32_to_cpu(di->i_vtype) == BFS_VDIR) {
 		inode->i_mode |= S_IFDIR;
 		inode->i_op = &bfs_dir_inops;
@@ -70,48 +71,48 @@ static void bfs_read_inode(struct inode * inode)
 
 	BFS_I(inode)->i_sblock =  le32_to_cpu(di->i_sblock);
 	BFS_I(inode)->i_eblock =  le32_to_cpu(di->i_eblock);
+	BFS_I(inode)->i_dsk_ino = le16_to_cpu(di->i_ino);
 	inode->i_uid =  le32_to_cpu(di->i_uid);
 	inode->i_gid =  le32_to_cpu(di->i_gid);
 	inode->i_nlink =  le32_to_cpu(di->i_nlink);
 	inode->i_size = BFS_FILESIZE(di);
 	inode->i_blocks = BFS_FILEBLOCKS(di);
-        if (inode->i_size || inode->i_blocks) dprintf("Registered inode with %lld size, %ld blocks\n", inode->i_size, inode->i_blocks);
 	inode->i_atime.tv_sec =  le32_to_cpu(di->i_atime);
 	inode->i_mtime.tv_sec =  le32_to_cpu(di->i_mtime);
 	inode->i_ctime.tv_sec =  le32_to_cpu(di->i_ctime);
 	inode->i_atime.tv_nsec = 0;
 	inode->i_mtime.tv_nsec = 0;
 	inode->i_ctime.tv_nsec = 0;
-	BFS_I(inode)->i_dsk_ino = le16_to_cpu(di->i_ino); /* can be 0 so we store a copy */
 
 	brelse(bh);
 }
 
-static int bfs_write_inode(struct inode * inode, int unused)
+static int bfs_write_inode(struct inode *inode, int unused)
 {
 	unsigned int ino = (u16)inode->i_ino;
         unsigned long i_sblock;
-	struct bfs_inode * di;
-	struct buffer_head * bh;
+	struct bfs_inode *di;
+	struct buffer_head *bh;
 	int block, off;
 
         dprintf("ino=%08x\n", ino);
 
-	if (ino < BFS_ROOT_INO || ino > BFS_SB(inode->i_sb)->si_lasti) {
+	if ((ino < BFS_ROOT_INO) || (ino > BFS_SB(inode->i_sb)->si_lasti)) {
 		printf("Bad inode number %s:%08x\n", inode->i_sb->s_id, ino);
 		return -EIO;
 	}
 
 	lock_kernel();
-	block = (ino - BFS_ROOT_INO)/BFS_INODES_PER_BLOCK + 1;
+	block = (ino - BFS_ROOT_INO) / BFS_INODES_PER_BLOCK + 1;
 	bh = sb_bread(inode->i_sb, block);
 	if (!bh) {
-		printf("Unable to read inode %s:%08x\n", inode->i_sb->s_id, ino);
+		printf("Unable to read inode %s:%08x\n",
+				inode->i_sb->s_id, ino);
 		unlock_kernel();
 		return -EIO;
 	}
 
-	off = (ino - BFS_ROOT_INO)%BFS_INODES_PER_BLOCK;
+	off = (ino - BFS_ROOT_INO) % BFS_INODES_PER_BLOCK;
 	di = (struct bfs_inode *)bh->b_data + off;
 
 	if (ino == BFS_ROOT_INO)
@@ -133,27 +134,26 @@ static int bfs_write_inode(struct inode * inode, int unused)
 	di->i_eoffset = cpu_to_le32(i_sblock * BFS_BSIZE + inode->i_size - 1);
 
 	mark_buffer_dirty(bh);
-        dprintf("Written ino=%d into %d:%d\n",le16_to_cpu(di->i_ino),block,off);
 	brelse(bh);
 	unlock_kernel();
 	return 0;
 }
 
-static void bfs_delete_inode(struct inode * inode)
+static void bfs_delete_inode(struct inode *inode)
 {
 	unsigned long ino = inode->i_ino;
-	struct bfs_inode * di;
-	struct buffer_head * bh;
+	struct bfs_inode *di;
+	struct buffer_head *bh;
 	int block, off;
-	struct super_block * s = inode->i_sb;
-	struct bfs_sb_info * info = BFS_SB(s);
-	struct bfs_inode_info * bi = BFS_I(inode);
+	struct super_block *s = inode->i_sb;
+	struct bfs_sb_info *info = BFS_SB(s);
+	struct bfs_inode_info *bi = BFS_I(inode);
 
 	dprintf("ino=%08lx\n", ino);
 
 	truncate_inode_pages(&inode->i_data, 0);
 
-	if (ino < BFS_ROOT_INO || ino > info->si_lasti) {
+	if ((ino < BFS_ROOT_INO) || (ino > info->si_lasti)) {
 		printf("invalid ino=%08lx\n", ino);
 		return;
 	}
@@ -162,31 +162,35 @@ static void bfs_delete_inode(struct inode * inode)
 	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
 	lock_kernel();
 	mark_inode_dirty(inode);
-	block = (ino - BFS_ROOT_INO)/BFS_INODES_PER_BLOCK + 1;
+
+	block = (ino - BFS_ROOT_INO) / BFS_INODES_PER_BLOCK + 1;
 	bh = sb_bread(s, block);
 	if (!bh) {
-		printf("Unable to read inode %s:%08lx\n", inode->i_sb->s_id, ino);
+		printf("Unable to read inode %s:%08lx\n",
+					inode->i_sb->s_id, ino);
 		unlock_kernel();
 		return;
 	}
-	off = (ino - BFS_ROOT_INO)%BFS_INODES_PER_BLOCK;
-	di = (struct bfs_inode *) bh->b_data + off;
+	off = (ino - BFS_ROOT_INO) % BFS_INODES_PER_BLOCK;
+	di = (struct bfs_inode *)bh->b_data + off;
+	memset((void *)di, 0, sizeof(struct bfs_inode));
+	mark_buffer_dirty(bh);
+	brelse(bh);
+
         if (bi->i_dsk_ino) {
-		info->si_freeb += 1 + bi->i_eblock - bi->i_sblock;
+		info->si_freeb += BFS_FILEBLOCKS(bi);
 		info->si_freei++;
 		clear_bit(ino, info->si_imap);
 		dump_imap("delete_inode", s);
         }
-	di->i_ino = 0;
-	di->i_sblock = 0;
-	mark_buffer_dirty(bh);
-	brelse(bh);
 
-	/* if this was the last file, make the previous 
-	   block "last files last block" even if there is no real file there,
-	   saves us 1 gap */
-	if (info->si_lf_eblk == BFS_I(inode)->i_eblock) {
-		info->si_lf_eblk = BFS_I(inode)->i_sblock - 1;
+	/*
+	 * If this was the last file, make the previous block
+	 * "last block of the last file" even if there is no
+	 * real file there, saves us 1 gap.
+	 */
+	if (info->si_lf_eblk == bi->i_eblock) {
+		info->si_lf_eblk = bi->i_sblock - 1;
 		mark_buffer_dirty(info->si_sbh);
 	}
 	unlock_kernel();
@@ -228,7 +232,7 @@ static void bfs_write_super(struct super_block *s)
 	unlock_kernel();
 }
 
-static struct kmem_cache * bfs_inode_cachep;
+static struct kmem_cache *bfs_inode_cachep;
 
 static struct inode *bfs_alloc_inode(struct super_block *sb)
 {
@@ -279,7 +283,7 @@ static const struct super_operations bfs_sops = {
 	.statfs		= bfs_statfs,
 };
 
-void dump_imap(const char *prefix, struct super_block * s)
+void dump_imap(const char *prefix, struct super_block *s)
 {
 #ifdef DEBUG
 	int i;
@@ -287,25 +291,26 @@ void dump_imap(const char *prefix, struct super_block * s)
 
 	if (!tmpbuf)
 		return;
-	for (i=BFS_SB(s)->si_lasti; i>=0; i--) {
-		if (i > PAGE_SIZE-100) break;
+	for (i = BFS_SB(s)->si_lasti; i >= 0; i--) {
+		if (i > PAGE_SIZE - 100) break;
 		if (test_bit(i, BFS_SB(s)->si_imap))
 			strcat(tmpbuf, "1");
 		else
 			strcat(tmpbuf, "0");
 	}
-	printk(KERN_ERR "BFS-fs: %s: lasti=%08lx <%s>\n", prefix, BFS_SB(s)->si_lasti, tmpbuf);
+	printf("BFS-fs: %s: lasti=%08lx <%s>\n",
+				prefix, BFS_SB(s)->si_lasti, tmpbuf);
 	free_page((unsigned long)tmpbuf);
 #endif
 }
 
 static int bfs_fill_super(struct super_block *s, void *data, int silent)
 {
-	struct buffer_head * bh;
-	struct bfs_super_block * bfs_sb;
-	struct inode * inode;
+	struct buffer_head *bh;
+	struct bfs_super_block *bfs_sb;
+	struct inode *inode;
 	unsigned i, imap_len;
-	struct bfs_sb_info * info;
+	struct bfs_sb_info *info;
 
 	info = kzalloc(sizeof(*info), GFP_KERNEL);
 	if (!info)
@@ -329,14 +334,14 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent)
 
 	s->s_magic = BFS_MAGIC;
 	info->si_sbh = bh;
-	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_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)
 		goto out;
-	for (i=0; i<BFS_ROOT_INO; i++) 
+	for (i = 0; i < BFS_ROOT_INO; i++)
 		set_bit(i, info->si_imap);
 
 	s->s_op = &bfs_sops;
@@ -352,16 +357,15 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent)
 		goto out;
 	}
 
-	info->si_blocks = (le32_to_cpu(bfs_sb->s_end) + 1)>>BFS_BSIZE_BITS; /* for statfs(2) */
-	info->si_freeb = (le32_to_cpu(bfs_sb->s_end) + 1 -  le32_to_cpu(bfs_sb->s_start))>>BFS_BSIZE_BITS;
+	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_freei = 0;
 	info->si_lf_eblk = 0;
-	info->si_lf_sblk = 0;
-	info->si_lf_ioff = 0;
 	bh = NULL;
-	for (i=BFS_ROOT_INO; i<=info->si_lasti; i++) {
+	for (i = BFS_ROOT_INO; i <= info->si_lasti; i++) {
 		struct bfs_inode *di;
-		int block = (i - BFS_ROOT_INO)/BFS_INODES_PER_BLOCK + 1;
+		int block = (i - BFS_ROOT_INO) / BFS_INODES_PER_BLOCK + 1;
 		int off = (i - BFS_ROOT_INO) % BFS_INODES_PER_BLOCK;
 		unsigned long sblock, eblock;
 
@@ -384,11 +388,8 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent)
 
 		sblock =  le32_to_cpu(di->i_sblock);
 		eblock =  le32_to_cpu(di->i_eblock);
-		if (eblock > info->si_lf_eblk) {
+		if (eblock > info->si_lf_eblk)
 			info->si_lf_eblk = eblock;
-			info->si_lf_sblk = sblock;
-			info->si_lf_ioff = BFS_INO2OFF(i);
-		}
 	}
 	brelse(bh);
 	if (!(s->s_flags & MS_RDONLY)) {