This inserts sanity check that refuses to mount a filesystem with
unsupported block size.

Previously, kernel code of nilfs was looking only limitation of
devices though mkfs.nilfs2 limits the range of block sizes; there was
no check that prevents rec_len overflow with larger block sizes.

With this change, block sizes larger than 64KB or smaller than 1KB
will get rejected explicitly by kernel.

Signed-off-by: Ryusuke Konishi <[email protected]>
---
 fs/nilfs2/the_nilfs.c     |    9 ++++++++-
 include/linux/nilfs2_fs.h |    6 ++++++
 2 files changed, 14 insertions(+), 1 deletions(-)

diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c
index da67b56..37de1f0 100644
--- a/fs/nilfs2/the_nilfs.c
+++ b/fs/nilfs2/the_nilfs.c
@@ -671,7 +671,7 @@ int init_nilfs(struct the_nilfs *nilfs, struct 
nilfs_sb_info *sbi, char *data)
                goto out;
        }
 
-       blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
+       blocksize = sb_min_blocksize(sb, NILFS_MIN_BLOCK_SIZE);
        if (!blocksize) {
                printk(KERN_ERR "NILFS: unable to set blocksize\n");
                err = -EINVAL;
@@ -690,6 +690,13 @@ int init_nilfs(struct the_nilfs *nilfs, struct 
nilfs_sb_info *sbi, char *data)
                goto failed_sbh;
 
        blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
+       if (blocksize < NILFS_MIN_BLOCK_SIZE ||
+           blocksize > NILFS_MAX_BLOCK_SIZE) {
+               printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
+                      "filesystem blocksize %d\n", blocksize);
+               err = -EINVAL;
+               goto failed_sbh;
+       }
        if (sb->s_blocksize != blocksize) {
                int hw_blocksize = bdev_logical_block_size(sb->s_bdev);
 
diff --git a/include/linux/nilfs2_fs.h b/include/linux/nilfs2_fs.h
index 970828a..f5487b6 100644
--- a/include/linux/nilfs2_fs.h
+++ b/include/linux/nilfs2_fs.h
@@ -287,6 +287,12 @@ struct nilfs_super_block {
 #define NILFS_NAME_LEN 255
 
 /*
+ * Block size limitations
+ */
+#define NILFS_MIN_BLOCK_SIZE           1024
+#define NILFS_MAX_BLOCK_SIZE           65536
+
+/*
  * The new version of the directory entry.  Since V0 structures are
  * stored in intel byte order, and the name_len field could never be
  * bigger than 255 chars, it's safe to reclaim the extra byte for the
-- 
1.6.6.2

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