ext4: fix error message when rejecting the default hash

Commit 985b67cd8639 ("ext4: filesystems without casefold feature cannot
be mounted with siphash") properly rejects volumes where
s_def_hash_version is set to DX_HASH_SIPHASH, but the check and the
error message should not look into casefold setup - a filesystem should
never have DX_HASH_SIPHASH as the default hash.  Fix it and, since we
are there, move the check to ext4_hash_info_init.

Fixes:985b67cd8639 ("ext4: filesystems without casefold feature cannot
be mounted with siphash")

Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
Link: https://patch.msgid.link/87jzg1en6j.fsf_-_@mailhost.krisman.be
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 481ece3660eb71764549d6ffa201cc9b6da599da..7ac668d4ce83c2187b99b4c4cbfd2e032555a4ce 100644 (file)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2462,6 +2462,7 @@ static inline __le16 ext4_rec_len_to_disk(unsigned len, unsigned blocksize)
 #define DX_HASH_HALF_MD4_UNSIGNED      4
 #define DX_HASH_TEA_UNSIGNED           5
 #define DX_HASH_SIPHASH                        6
+#define DX_HASH_LAST                   DX_HASH_SIPHASH
 
 static inline u32 ext4_chksum(struct ext4_sb_info *sbi, u32 crc,
                              const void *address, unsigned int length)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 58423e6bf3d078ca671ae24206618dbf067283bb..adc5046fe9dd5a29a2aadeb4ab11e5d600175aa1 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3583,13 +3583,6 @@ int ext4_feature_set_ok(struct super_block *sb, int readonly)
                         "mounted without CONFIG_UNICODE");
                return 0;
        }
-       if (EXT4_SB(sb)->s_es->s_def_hash_version == DX_HASH_SIPHASH &&
-           !ext4_has_feature_casefold(sb)) {
-               ext4_msg(sb, KERN_ERR,
-                        "Filesystem without casefold feature cannot be "
-                        "mounted with siphash");
-               return 0;
-       }
 
        if (readonly)
                return 1;
@@ -5095,16 +5088,27 @@ out:
        return ret;
 }
 
-static void ext4_hash_info_init(struct super_block *sb)
+static int ext4_hash_info_init(struct super_block *sb)
 {
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        struct ext4_super_block *es = sbi->s_es;
        unsigned int i;
 
+       sbi->s_def_hash_version = es->s_def_hash_version;
+
+       if (sbi->s_def_hash_version > DX_HASH_LAST) {
+               ext4_msg(sb, KERN_ERR,
+                        "Invalid default hash set in the superblock");
+               return -EINVAL;
+       } else if (sbi->s_def_hash_version == DX_HASH_SIPHASH) {
+               ext4_msg(sb, KERN_ERR,
+                        "SIPHASH is not a valid default hash value");
+               return -EINVAL;
+       }
+
        for (i = 0; i < 4; i++)
                sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]);
 
-       sbi->s_def_hash_version = es->s_def_hash_version;
        if (ext4_has_feature_dir_index(sb)) {
                i = le32_to_cpu(es->s_flags);
                if (i & EXT2_FLAGS_UNSIGNED_HASH)
@@ -5122,6 +5126,7 @@ static void ext4_hash_info_init(struct super_block *sb)
 #endif
                }
        }
+       return 0;
 }
 
 static int ext4_block_group_meta_init(struct super_block *sb, int silent)
@@ -5257,7 +5262,9 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
        if (err)
                goto failed_mount;
 
-       ext4_hash_info_init(sb);
+       err = ext4_hash_info_init(sb);
+       if (err)
+               goto failed_mount;
 
        err = ext4_handle_clustersize(sb);
        if (err)