nilfs2: reject incompatible filesystem

This forces nilfs to check compatibility of feature flags so as to
reject a filesystem with unknown features when it mounts or remounts
the filesystem.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

1 files changed, 20 insertions, 0 deletions

diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c
index f2efc8c5be7f..da67b560f3c3 100644
--- a/fs/nilfs2/the_nilfs.c
+++ b/fs/nilfs2/the_nilfs.c
@@ -385,11 +385,23 @@ int load_nilfs(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi)
                 goto skip_recovery;
 
         if (s_flags & MS_RDONLY) {
+                __u64 features;
+
                 if (nilfs_test_opt(sbi, NORECOVERY)) {
                         printk(KERN_INFO "NILFS: norecovery option specified. "
                                "skipping roll-forward recovery\n");
                         goto skip_recovery;
                 }
+                features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
+                        ~NILFS_FEATURE_COMPAT_RO_SUPP;
+                if (features) {
+                        printk(KERN_ERR "NILFS: couldn't proceed with "
+                               "recovery because of unsupported optional "
+                               "features (%llx)\n",
+                               (unsigned long long)features);
+                        err = -EROFS;
+                        goto failed_unload;
+                }
                 if (really_read_only) {
                         printk(KERN_ERR "NILFS: write access "
                                "unavailable, cannot proceed.\n");
@@ -644,6 +656,10 @@ int init_nilfs(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi, char *data)
                 if (err)
                         goto out;
 
+                err = nilfs_check_feature_compatibility(sb, sbp);
+                if (err)
+                        goto out;
+
                 blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
                 if (sb->s_blocksize != blocksize &&
                     !sb_set_blocksize(sb, blocksize)) {
@@ -669,6 +685,10 @@ int init_nilfs(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi, char *data)
         if (err)
                 goto failed_sbh;
 
+        err = nilfs_check_feature_compatibility(sb, sbp);
+        if (err)
+                goto failed_sbh;
+
         blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
         if (sb->s_blocksize != blocksize) {
                 int hw_blocksize = bdev_logical_block_size(sb->s_bdev);