Merge tag 'jfs-6.5' of github.com:kleikamp/linux-shaggy

Pull jfs updates from David Kleikamp:
"Minor bug fixes and cleanups"

* tag 'jfs-6.5' of github.com:kleikamp/linux-shaggy:
FS: JFS: Check for read-only mounted filesystem in txBegin
FS: JFS: Fix null-ptr-deref Read in txBegin
fs: jfs: Fix UBSAN: array-index-out-of-bounds in dbAllocDmapLev
fs: jfs: (trivial) Fix typo in dbInitTree function
jfs: jfs_dmap: Validate db_l2nbperpage while mounting

fs/jfs/jfs_dmap.c

···
 	dbmp_le = (struct dbmap_disk *) mp->data;
 	bmp->db_mapsize = le64_to_cpu(dbmp_le->dn_mapsize);
 	bmp->db_nfree = le64_to_cpu(dbmp_le->dn_nfree);
+
 	bmp->db_l2nbperpage = le32_to_cpu(dbmp_le->dn_l2nbperpage);
+	if (bmp->db_l2nbperpage > L2PSIZE - L2MINBLOCKSIZE) {
+		err = -EINVAL;
+		goto err_release_metapage;
+	}
+
 	bmp->db_numag = le32_to_cpu(dbmp_le->dn_numag);
 	if (!bmp->db_numag) {
 		err = -EINVAL;
···
 	 */
 	if (dbFindLeaf((dmtree_t *) & dp->tree, l2nb, &leafidx))
 		return -ENOSPC;
+
+	if (leafidx < 0)
+		return -EIO;
 
 	/* determine the block number within the file system corresponding
 	 * to the leaf at which free space was found.
···
 	l2max = le32_to_cpu(dtp->l2nleafs) + dtp->budmin;
 
 	/*
-	 * configure the leaf levevl into binary buddy system
+	 * configure the leaf level into binary buddy system
 	 *
 	 * Try to combine buddies starting with a buddy size of 1
 	 * (i.e. two leaves). At a buddy size of 1 two buddy leaves

fs/jfs/jfs_filsys.h

···
 #define NUM_INODE_PER_IAG	INOSPERIAG
 
 #define MINBLOCKSIZE		512
+#define L2MINBLOCKSIZE		9
 #define MAXBLOCKSIZE		4096
+#define L2MAXBLOCKSIZE		12
 #define	MAXFILESIZE		((s64)1 << 52)
 
 #define JFS_LINK_MAX		0xffffffff

fs/jfs/jfs_txnmgr.c

···
 	jfs_info("txBegin: flag = 0x%x", flag);
 	log = JFS_SBI(sb)->log;
 
+	if (!log) {
+		jfs_error(sb, "read-only filesystem\n");
+		return 0;
+	}
+
 	TXN_LOCK();
 
 	INCREMENT(TxStat.txBegin);

fs/jfs/namei.c

···
 	if (rc)
 		goto out;
 
+	if (isReadOnly(ip)) {
+		jfs_error(ip->i_sb, "read-only filesystem\n");
+		return -EROFS;
+	}
+
 	tid = txBegin(ip->i_sb, 0);
 
 	mutex_lock_nested(&JFS_IP(dir)->commit_mutex, COMMIT_MUTEX_PARENT);