Merge tag 'befs-v4.9-rc1' of git://github.com/luisbg/linux-befs

Pull befs fixes from Luis de Bethencourt:
 "I recently took maintainership of the befs file system [0]. This is
  the first time I send you a git pull request, so please let me know if
  all the below is OK.

  Salah Triki and myself have been cleaning the code and fixing a few
  small bugs.

  Sorry I couldn't send this sooner in the merge window, I was waiting
  to have my GPG key signed by kernel members at ELCE in Berlin a few
  days ago."

[0] https://lkml.org/lkml/2016/7/27/502

* tag 'befs-v4.9-rc1' of git://github.com/luisbg/linux-befs: (39 commits)
  befs: befs: fix style issues in datastream.c
  befs: improve documentation in datastream.c
  befs: fix typos in datastream.c
  befs: fix typos in btree.c
  befs: fix style issues in super.c
  befs: fix comment style
  befs: add check for ag_shift in superblock
  befs: dump inode_size superblock information
  befs: remove unnecessary initialization
  befs: fix typo in befs_sb_info
  befs: add flags field to validate superblock state
  befs: fix typo in befs_find_key
  befs: remove unused BEFS_BT_PARMATCH
  fs: befs: remove ret variable
  fs: befs: remove in vain variable assignment
  fs: befs: remove unnecessary *befs_sb variable
  fs: befs: remove useless initialization to zero
  fs: befs: remove in vain variable assignment
  fs: befs: Insert NULL inode to dentry
  fs: befs: Remove useless calls to brelse in befs_find_brun_dblindirect
  ...

fs/befs/befs.h

@@ -43,7 +43,10 @@ struct befs_sb_info {
 	u32 ag_shift;
 	u32 num_ags;
 
-	/* jornal log entry */
+	/* State of the superblock */
+	u32 flags;
+
+	/* Journal log entry */
 	befs_block_run log_blocks;
 	befs_off_t log_start;
 	befs_off_t log_end;
@@ -79,7 +82,7 @@ enum befs_err {
 	BEFS_BT_END,
 	BEFS_BT_EMPTY,
 	BEFS_BT_MATCH,
-	BEFS_BT_PARMATCH,
+	BEFS_BT_OVERFLOW,
 	BEFS_BT_NOT_FOUND
 };
 
@@ -140,18 +143,6 @@ befs_iaddrs_per_block(struct super_block *sb)
 	return BEFS_SB(sb)->block_size / sizeof (befs_disk_inode_addr);
 }
 
-static inline int
-befs_iaddr_is_empty(const befs_inode_addr *iaddr)
-{
-	return (!iaddr->allocation_group) && (!iaddr->start) && (!iaddr->len);
-}
-
-static inline size_t
-befs_brun_size(struct super_block *sb, befs_block_run run)
-{
-	return BEFS_SB(sb)->block_size * run.len;
-}
-
 #include "endian.h"
 
 #endif				/* _LINUX_BEFS_H */

fs/befs/btree.c

@@ -85,7 +85,7 @@ struct befs_btree_node {
 };
 
 /* local constants */
-static const befs_off_t befs_bt_inval = 0xffffffffffffffffULL;
+static const befs_off_t BEFS_BT_INVAL = 0xffffffffffffffffULL;
 
 /* local functions */
 static int befs_btree_seekleaf(struct super_block *sb, const befs_data_stream *ds,
@@ -156,8 +156,6 @@ befs_bt_read_super(struct super_block *sb, const befs_data_stream *ds,
 	sup->max_depth = fs32_to_cpu(sb, od_sup->max_depth);
 	sup->data_type = fs32_to_cpu(sb, od_sup->data_type);
 	sup->root_node_ptr = fs64_to_cpu(sb, od_sup->root_node_ptr);
-	sup->free_node_ptr = fs64_to_cpu(sb, od_sup->free_node_ptr);
-	sup->max_size = fs64_to_cpu(sb, od_sup->max_size);
 
 	brelse(bh);
 	if (sup->magic != BEFS_BTREE_MAGIC) {
@@ -183,8 +181,8 @@ befs_bt_read_super(struct super_block *sb, const befs_data_stream *ds,
  * Calls befs_read_datastream to read in the indicated btree node and
  * makes sure its header fields are in cpu byteorder, byteswapping if
  * necessary.
- * Note: node->bh must be NULL when this function called first
- * time. Don't forget brelse(node->bh) after last call.
+ * Note: node->bh must be NULL when this function is called the first time.
+ * Don't forget brelse(node->bh) after last call.
  *
  * On success, returns BEFS_OK and *@node contains the btree node that
  * starts at @node_off, with the node->head fields in cpu byte order.
@@ -244,7 +242,7 @@ befs_bt_read_node(struct super_block *sb, const befs_data_stream *ds,
  *   Read the superblock and rootnode of the b+tree.
  *   Drill down through the interior nodes using befs_find_key().
  *   Once at the correct leaf node, use befs_find_key() again to get the
- *   actuall value stored with the key.
+ *   actual value stored with the key.
  */
 int
 befs_btree_find(struct super_block *sb, const befs_data_stream *ds,
@@ -283,9 +281,9 @@ befs_btree_find(struct super_block *sb, const befs_data_stream *ds,
 
 	while (!befs_leafnode(this_node)) {
 		res = befs_find_key(sb, this_node, key, &node_off);
-		if (res == BEFS_BT_NOT_FOUND)
+		/* if no key set, try the overflow node */
+		if (res == BEFS_BT_OVERFLOW)
 			node_off = this_node->head.overflow;
-		/* if no match, go to overflow node */
 		if (befs_bt_read_node(sb, ds, this_node, node_off) != BEFS_OK) {
 			befs_error(sb, "befs_btree_find() failed to read "
 				   "node at %llu", node_off);
@@ -293,15 +291,15 @@ befs_btree_find(struct super_block *sb, const befs_data_stream *ds,
 		}
 	}
 
-	/* at the correct leaf node now */
-
+	/* at a leaf node now, check if it is correct */
 	res = befs_find_key(sb, this_node, key, value);
 
 	brelse(this_node->bh);
 	kfree(this_node);
 
 	if (res != BEFS_BT_MATCH) {
-		befs_debug(sb, "<--- %s Key %s not found", __func__, key);
+		befs_error(sb, "<--- %s Key %s not found", __func__, key);
+		befs_debug(sb, "<--- %s ERROR", __func__);
 		*value = 0;
 		return BEFS_BT_NOT_FOUND;
 	}
@@ -324,16 +322,12 @@ befs_btree_find(struct super_block *sb, const befs_data_stream *ds,
  * @findkey: Keystring to search for
  * @value: If key is found, the value stored with the key is put here
  *
- * finds exact match if one exists, and returns BEFS_BT_MATCH
- * If no exact match, finds first key in node that is greater
- * (alphabetically) than the search key and returns BEFS_BT_PARMATCH
- * (for partial match, I guess). Can you think of something better to
- * call it?
- *
- * If no key was a match or greater than the search key, return
- * BEFS_BT_NOT_FOUND.
+ * Finds exact match if one exists, and returns BEFS_BT_MATCH.
+ * If there is no match and node's value array is too small for key, return
+ * BEFS_BT_OVERFLOW.
+ * If no match and node should countain this key, return BEFS_BT_NOT_FOUND.
  *
- * Use binary search instead of a linear.
+ * Uses binary search instead of a linear.
  */
 static int
 befs_find_key(struct super_block *sb, struct befs_btree_node *node,
@@ -348,18 +342,16 @@ befs_find_key(struct super_block *sb, struct befs_btree_node *node,
 
 	befs_debug(sb, "---> %s %s", __func__, findkey);
 
-	*value = 0;
-
 	findkey_len = strlen(findkey);
 
-	/* if node can not contain key, just skeep this node */
+	/* if node can not contain key, just skip this node */
 	last = node->head.all_key_count - 1;
 	thiskey = befs_bt_get_key(sb, node, last, &keylen);
 
 	eq = befs_compare_strings(thiskey, keylen, findkey, findkey_len);
 	if (eq < 0) {
-		befs_debug(sb, "<--- %s %s not found", __func__, findkey);
-		return BEFS_BT_NOT_FOUND;
+		befs_debug(sb, "<--- node can't contain %s", findkey);
+		return BEFS_BT_OVERFLOW;
 	}
 
 	valarray = befs_bt_valarray(node);
@@ -387,12 +379,15 @@ befs_find_key(struct super_block *sb, struct befs_btree_node *node,
 		else
 			first = mid + 1;
 	}
+
+	/* return an existing value so caller can arrive to a leaf node */
 	if (eq < 0)
 		*value = fs64_to_cpu(sb, valarray[mid + 1]);
 	else
 		*value = fs64_to_cpu(sb, valarray[mid]);
-	befs_debug(sb, "<--- %s found %s at %d", __func__, thiskey, mid);
-	return BEFS_BT_PARMATCH;
+	befs_error(sb, "<--- %s %s not found", __func__, findkey);
+	befs_debug(sb, "<--- %s ERROR", __func__);
+	return BEFS_BT_NOT_FOUND;
 }
 
 /**
@@ -405,7 +400,7 @@ befs_find_key(struct super_block *sb, struct befs_btree_node *node,
  * @keysize: Length of the returned key
  * @value: Value stored with the returned key
  *
- * Heres how it works: Key_no is the index of the key/value pair to 
+ * Here's how it works: Key_no is the index of the key/value pair to
  * return in keybuf/value.
  * Bufsize is the size of keybuf (BEFS_NAME_LEN+1 is a good size). Keysize is 
  * the number of characters in the key (just a convenience).
@@ -422,7 +417,7 @@ befs_btree_read(struct super_block *sb, const befs_data_stream *ds,
 {
 	struct befs_btree_node *this_node;
 	befs_btree_super bt_super;
-	befs_off_t node_off = 0;
+	befs_off_t node_off;
 	int cur_key;
 	fs64 *valarray;
 	char *keystart;
@@ -467,7 +462,7 @@ befs_btree_read(struct super_block *sb, const befs_data_stream *ds,
 	while (key_sum + this_node->head.all_key_count <= key_no) {
 
 		/* no more nodes to look in: key_no is too large */
-		if (this_node->head.right == befs_bt_inval) {
+		if (this_node->head.right == BEFS_BT_INVAL) {
 			*keysize = 0;
 			*value = 0;
 			befs_debug(sb,
@@ -541,7 +536,6 @@ befs_btree_read(struct super_block *sb, const befs_data_stream *ds,
  * @node_off: Pointer to offset of current node within datastream. Modified
  * 		by the function.
  *
- *
  * Helper function for btree traverse. Moves the current position to the 
  * start of the first leaf node.
  *
@@ -608,7 +602,7 @@ static int
 befs_leafnode(struct befs_btree_node *node)
 {
 	/* all interior nodes (and only interior nodes) have an overflow node */
-	if (node->head.overflow == befs_bt_inval)
+	if (node->head.overflow == BEFS_BT_INVAL)
 		return 1;
 	else
 		return 0;
@@ -715,7 +709,7 @@ befs_bt_get_key(struct super_block *sb, struct befs_btree_node *node,
  *
  * Returns 0 if @key1 and @key2 are equal.
  * Returns >0 if @key1 is greater.
- * Returns <0 if @key2 is greater..
+ * Returns <0 if @key2 is greater.
  */
 static int
 befs_compare_strings(const void *key1, int keylen1,

fs/befs/debug.c

@@ -169,6 +169,7 @@ befs_dump_super_block(const struct super_block *sb, befs_super_block * sup)
 
 	befs_debug(sb, "  num_blocks %llu", fs64_to_cpu(sb, sup->num_blocks));
 	befs_debug(sb, "  used_blocks %llu", fs64_to_cpu(sb, sup->used_blocks));
+	befs_debug(sb, "  inode_size %u", fs32_to_cpu(sb, sup->inode_size));
 
 	befs_debug(sb, "  magic2 %08x", fs32_to_cpu(sb, sup->magic2));
 	befs_debug(sb, "  blocks_per_ag %u",

fs/befs/io.c

@@ -27,7 +27,7 @@ struct buffer_head *
 befs_bread_iaddr(struct super_block *sb, befs_inode_addr iaddr)
 {
 	struct buffer_head *bh;
-	befs_blocknr_t block = 0;
+	befs_blocknr_t block;
 	struct befs_sb_info *befs_sb = BEFS_SB(sb);
 
 	befs_debug(sb, "---> Enter %s "
@@ -59,27 +59,3 @@ befs_bread_iaddr(struct super_block *sb, befs_inode_addr iaddr)
 	befs_debug(sb, "<--- %s ERROR", __func__);
 	return NULL;
 }
-
-struct buffer_head *
-befs_bread(struct super_block *sb, befs_blocknr_t block)
-{
-	struct buffer_head *bh;
-
-	befs_debug(sb, "---> Enter %s %lu", __func__, (unsigned long)block);
-
-	bh = sb_bread(sb, block);
-
-	if (bh == NULL) {
-		befs_error(sb, "Failed to read block %lu",
-			   (unsigned long)block);
-		goto error;
-	}
-
-	befs_debug(sb, "<--- %s", __func__);
-
-	return bh;
-
-      error:
-	befs_debug(sb, "<--- %s ERROR", __func__);
-	return NULL;
-}

fs/befs/io.h

@@ -5,5 +5,3 @@
 struct buffer_head *befs_bread_iaddr(struct super_block *sb,
 				     befs_inode_addr iaddr);
 
-struct buffer_head *befs_bread(struct super_block *sb, befs_blocknr_t block);
-

fs/befs/linuxvfs.c

@@ -120,7 +120,7 @@ befs_get_block(struct inode *inode, sector_t block,
 	struct super_block *sb = inode->i_sb;
 	befs_data_stream *ds = &BEFS_I(inode)->i_data.ds;
 	befs_block_run run = BAD_IADDR;
-	int res = 0;
+	int res;
 	ulong disk_off;
 
 	befs_debug(sb, "---> befs_get_block() for inode %lu, block %ld",
@@ -179,15 +179,16 @@ befs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
 		kfree(utfname);
 
 	} else {
-		ret = befs_btree_find(sb, ds, dentry->d_name.name, &offset);
+		ret = befs_btree_find(sb, ds, name, &offset);
 	}
 
 	if (ret == BEFS_BT_NOT_FOUND) {
 		befs_debug(sb, "<--- %s %pd not found", __func__, dentry);
+		d_add(dentry, NULL);
 		return ERR_PTR(-ENOENT);
 
 	} else if (ret != BEFS_OK || offset == 0) {
-		befs_warning(sb, "<--- %s Error", __func__);
+		befs_error(sb, "<--- %s Error", __func__);
 		return ERR_PTR(-ENODATA);
 	}
 
@@ -211,56 +212,55 @@ befs_readdir(struct file *file, struct dir_context *ctx)
 	befs_off_t value;
 	int result;
 	size_t keysize;
-	unsigned char d_type;
 	char keybuf[BEFS_NAME_LEN + 1];
 
 	befs_debug(sb, "---> %s name %pD, inode %ld, ctx->pos %lld",
 		  __func__, file, inode->i_ino, ctx->pos);
 
-more:
-	result = befs_btree_read(sb, ds, ctx->pos, BEFS_NAME_LEN + 1,
-				 keybuf, &keysize, &value);
+	while (1) {
+		result = befs_btree_read(sb, ds, ctx->pos, BEFS_NAME_LEN + 1,
+					 keybuf, &keysize, &value);
 
-	if (result == BEFS_ERR) {
-		befs_debug(sb, "<--- %s ERROR", __func__);
-		befs_error(sb, "IO error reading %pD (inode %lu)",
-			   file, inode->i_ino);
-		return -EIO;
-
-	} else if (result == BEFS_BT_END) {
-		befs_debug(sb, "<--- %s END", __func__);
-		return 0;
-
-	} else if (result == BEFS_BT_EMPTY) {
-		befs_debug(sb, "<--- %s Empty directory", __func__);
-		return 0;
-	}
+		if (result == BEFS_ERR) {
+			befs_debug(sb, "<--- %s ERROR", __func__);
+			befs_error(sb, "IO error reading %pD (inode %lu)",
+				   file, inode->i_ino);
+			return -EIO;
 
-	d_type = DT_UNKNOWN;
+		} else if (result == BEFS_BT_END) {
+			befs_debug(sb, "<--- %s END", __func__);
+			return 0;
 
-	/* Convert to NLS */
-	if (BEFS_SB(sb)->nls) {
-		char *nlsname;
-		int nlsnamelen;
-		result =
-		    befs_utf2nls(sb, keybuf, keysize, &nlsname, &nlsnamelen);
-		if (result < 0) {
-			befs_debug(sb, "<--- %s ERROR", __func__);
-			return result;
+		} else if (result == BEFS_BT_EMPTY) {
+			befs_debug(sb, "<--- %s Empty directory", __func__);
+			return 0;
 		}
-		if (!dir_emit(ctx, nlsname, nlsnamelen,
-				 (ino_t) value, d_type)) {
+
+		/* Convert to NLS */
+		if (BEFS_SB(sb)->nls) {
+			char *nlsname;
+			int nlsnamelen;
+
+			result =
+			    befs_utf2nls(sb, keybuf, keysize, &nlsname,
+					 &nlsnamelen);
+			if (result < 0) {
+				befs_debug(sb, "<--- %s ERROR", __func__);
+				return result;
+			}
+			if (!dir_emit(ctx, nlsname, nlsnamelen,
+				      (ino_t) value, DT_UNKNOWN)) {
+				kfree(nlsname);
+				return 0;
+			}
 			kfree(nlsname);
-			return 0;
+		} else {
+			if (!dir_emit(ctx, keybuf, keysize,
+				      (ino_t) value, DT_UNKNOWN))
+				return 0;
 		}
-		kfree(nlsname);
-	} else {
-		if (!dir_emit(ctx, keybuf, keysize,
-				 (ino_t) value, d_type))
-			return 0;
+		ctx->pos++;
 	}
-	ctx->pos++;
-	goto more;
 }
 
 static struct inode *
@@ -299,7 +299,6 @@ static struct inode *befs_iget(struct super_block *sb, unsigned long ino)
 	struct befs_sb_info *befs_sb = BEFS_SB(sb);
 	struct befs_inode_info *befs_ino;
 	struct inode *inode;
-	long ret = -EIO;
 
 	befs_debug(sb, "---> %s inode = %lu", __func__, ino);
 
@@ -318,7 +317,7 @@ static struct inode *befs_iget(struct super_block *sb, unsigned long ino)
 		   befs_ino->i_inode_num.allocation_group,
 		   befs_ino->i_inode_num.start, befs_ino->i_inode_num.len);
 
-	bh = befs_bread(sb, inode->i_ino);
+	bh = sb_bread(sb, inode->i_ino);
 	if (!bh) {
 		befs_error(sb, "unable to read inode block - "
 			   "inode = %lu", inode->i_ino);
@@ -421,7 +420,7 @@ static struct inode *befs_iget(struct super_block *sb, unsigned long ino)
       unacquire_none:
 	iget_failed(inode);
 	befs_debug(sb, "<--- %s - Bad inode", __func__);
-	return ERR_PTR(ret);
+	return ERR_PTR(-EIO);
 }
 
 /* Initialize the inode cache. Called at fs setup.
@@ -436,10 +435,9 @@ befs_init_inodecache(void)
 					      0, (SLAB_RECLAIM_ACCOUNT|
 						SLAB_MEM_SPREAD|SLAB_ACCOUNT),
 					      init_once);
-	if (befs_inode_cachep == NULL) {
-		pr_err("%s: Couldn't initialize inode slabcache\n", __func__);
+	if (befs_inode_cachep == NULL)
 		return -ENOMEM;
-	}
+
 	return 0;
 }
 
@@ -524,8 +522,6 @@ befs_utf2nls(struct super_block *sb, const char *in,
 
 	*out = result = kmalloc(maxlen, GFP_NOFS);
 	if (!*out) {
-		befs_error(sb, "%s cannot allocate memory", __func__);
-		*out_len = 0;
 		return -ENOMEM;
 	}
 
@@ -604,7 +600,6 @@ befs_nls2utf(struct super_block *sb, const char *in,
 
 	*out = result = kmalloc(maxlen, GFP_NOFS);
 	if (!*out) {
-		befs_error(sb, "%s cannot allocate memory", __func__);
 		*out_len = 0;
 		return -ENOMEM;
 	}
@@ -637,10 +632,6 @@ befs_nls2utf(struct super_block *sb, const char *in,
 	return -EILSEQ;
 }
 
-/**
- * Use the
- *
- */
 enum {
 	Opt_uid, Opt_gid, Opt_charset, Opt_debug, Opt_err,
 };
@@ -760,19 +751,19 @@ befs_fill_super(struct super_block *sb, void *data, int silent)
 	long ret = -EINVAL;
 	const unsigned long sb_block = 0;
 	const off_t x86_sb_off = 512;
+	int blocksize;
 
 	save_mount_options(sb, data);
 
 	sb->s_fs_info = kzalloc(sizeof(*befs_sb), GFP_KERNEL);
-	if (sb->s_fs_info == NULL) {
-		pr_err("(%s): Unable to allocate memory for private "
-		       "portion of superblock. Bailing.\n", sb->s_id);
+	if (sb->s_fs_info == NULL)
 		goto unacquire_none;
-	}
+
 	befs_sb = BEFS_SB(sb);
 
 	if (!parse_options((char *) data, &befs_sb->mount_opts)) {
-		befs_error(sb, "cannot parse mount options");
+		if (!silent)
+			befs_error(sb, "cannot parse mount options");
 		goto unacquire_priv_sbp;
 	}
 
@@ -793,10 +784,16 @@ befs_fill_super(struct super_block *sb, void *data, int silent)
 	 * least 1k to get the second 512 bytes of the volume.
 	 * -WD 10-26-01
 	 */ 
-	sb_min_blocksize(sb, 1024);
+	blocksize = sb_min_blocksize(sb, 1024);
+	if (!blocksize) {
+		if (!silent)
+			befs_error(sb, "unable to set blocksize");
+		goto unacquire_priv_sbp;
+	}
 
 	if (!(bh = sb_bread(sb, sb_block))) {
-		befs_error(sb, "unable to read superblock");
+		if (!silent)
+			befs_error(sb, "unable to read superblock");
 		goto unacquire_priv_sbp;
 	}
 
@@ -820,9 +817,9 @@ befs_fill_super(struct super_block *sb, void *data, int silent)
 	brelse(bh);
 
 	if( befs_sb->num_blocks > ~((sector_t)0) ) {
-		befs_error(sb, "blocks count: %llu "
-			"is larger than the host can use",
-			befs_sb->num_blocks);
+		if (!silent)
+			befs_error(sb, "blocks count: %llu is larger than the host can use",
+					befs_sb->num_blocks);
 		goto unacquire_priv_sbp;
 	}
 
@@ -841,7 +838,8 @@ befs_fill_super(struct super_block *sb, void *data, int silent)
 	}
 	sb->s_root = d_make_root(root);
 	if (!sb->s_root) {
-		befs_error(sb, "get root inode failed");
+		if (!silent)
+			befs_error(sb, "get root inode failed");
 		goto unacquire_priv_sbp;
 	}
 
@@ -870,9 +868,9 @@ befs_fill_super(struct super_block *sb, void *data, int silent)
       unacquire_priv_sbp:
 	kfree(befs_sb->mount_opts.iocharset);
 	kfree(sb->s_fs_info);
+	sb->s_fs_info = NULL;
 
       unacquire_none:
-	sb->s_fs_info = NULL;
 	return ret;
 }
 

fs/befs/super.c

@@ -13,24 +13,20 @@
 #include "befs.h"
 #include "super.h"
 
-/**
- * load_befs_sb -- Read from disk and properly byteswap all the fields
+/*
+ * befs_load_sb -- Read from disk and properly byteswap all the fields
  * of the befs superblock
- *
- *
- *
- *
  */
 int
-befs_load_sb(struct super_block *sb, befs_super_block * disk_sb)
+befs_load_sb(struct super_block *sb, befs_super_block *disk_sb)
 {
 	struct befs_sb_info *befs_sb = BEFS_SB(sb);
 
 	/* Check the byte order of the filesystem */
 	if (disk_sb->fs_byte_order == BEFS_BYTEORDER_NATIVE_LE)
-	    befs_sb->byte_order = BEFS_BYTESEX_LE;
+		befs_sb->byte_order = BEFS_BYTESEX_LE;
 	else if (disk_sb->fs_byte_order == BEFS_BYTEORDER_NATIVE_BE)
-	    befs_sb->byte_order = BEFS_BYTESEX_BE;
+		befs_sb->byte_order = BEFS_BYTESEX_BE;
 
 	befs_sb->magic1 = fs32_to_cpu(sb, disk_sb->magic1);
 	befs_sb->magic2 = fs32_to_cpu(sb, disk_sb->magic2);
@@ -45,6 +41,8 @@ befs_load_sb(struct super_block *sb, befs_super_block * disk_sb)
 	befs_sb->ag_shift = fs32_to_cpu(sb, disk_sb->ag_shift);
 	befs_sb->num_ags = fs32_to_cpu(sb, disk_sb->num_ags);
 
+	befs_sb->flags = fs32_to_cpu(sb, disk_sb->flags);
+
 	befs_sb->log_blocks = fsrun_to_cpu(sb, disk_sb->log_blocks);
 	befs_sb->log_start = fs64_to_cpu(sb, disk_sb->log_start);
 	befs_sb->log_end = fs64_to_cpu(sb, disk_sb->log_end);
@@ -84,15 +82,15 @@ befs_check_sb(struct super_block *sb)
 	}
 
 	if (befs_sb->block_size > PAGE_SIZE) {
-		befs_error(sb, "blocksize(%u) cannot be larger"
+		befs_error(sb, "blocksize(%u) cannot be larger "
 			   "than system pagesize(%lu)", befs_sb->block_size,
 			   PAGE_SIZE);
 		return BEFS_ERR;
 	}
 
 	/*
-	   * block_shift and block_size encode the same information
-	   * in different ways as a consistency check.
+	 * block_shift and block_size encode the same information
+	 * in different ways as a consistency check.
 	 */
 
 	if ((1 << befs_sb->block_shift) != befs_sb->block_size) {
@@ -101,10 +99,18 @@ befs_check_sb(struct super_block *sb)
 		return BEFS_ERR;
 	}
 
-	if (befs_sb->log_start != befs_sb->log_end) {
+
+	/* ag_shift also encodes the same information as blocks_per_ag in a
+	 * different way, non-fatal consistency check
+	 */
+	if ((1 << befs_sb->ag_shift) != befs_sb->blocks_per_ag)
+		befs_error(sb, "ag_shift disagrees with blocks_per_ag.");
+
+	if (befs_sb->log_start != befs_sb->log_end ||
+	    befs_sb->flags == BEFS_DIRTY) {
 		befs_error(sb, "Filesystem not clean! There are blocks in the "
-			   "journal. You must boot into BeOS and mount this volume "
-			   "to make it clean.");
+			   "journal. You must boot into BeOS and mount this "
+			   "volume to make it clean.");
 		return BEFS_ERR;
 	}