1 files changed, 57 insertions, 24 deletions

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index f80c7e612829..c18c5968cd96 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1952,43 +1952,69 @@ failed:
         return 0;
 }
 
-__le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group,
-                            struct ext4_group_desc *gdp)
+static __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group,
+                                   struct ext4_group_desc *gdp)
 {
+        int offset;
         __u16 crc = 0;
+        __le32 le_group = cpu_to_le32(block_group);
 
-        if (sbi->s_es->s_feature_ro_compat &
-            cpu_to_le32(EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
-                int offset = offsetof(struct ext4_group_desc, bg_checksum);
-                __le32 le_group = cpu_to_le32(block_group);
-
-                crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid));
-                crc = crc16(crc, (__u8 *)&le_group, sizeof(le_group));
-                crc = crc16(crc, (__u8 *)gdp, offset);
-                offset += sizeof(gdp->bg_checksum); /* skip checksum */
-                /* for checksum of struct ext4_group_desc do the rest...*/
-                if ((sbi->s_es->s_feature_incompat &
-                     cpu_to_le32(EXT4_FEATURE_INCOMPAT_64BIT)) &&
-                    offset < le16_to_cpu(sbi->s_es->s_desc_size))
-                        crc = crc16(crc, (__u8 *)gdp + offset,
-                                    le16_to_cpu(sbi->s_es->s_desc_size) -
-                                        offset);
+        if ((sbi->s_es->s_feature_ro_compat &
+             cpu_to_le32(EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))) {
+                /* Use new metadata_csum algorithm */
+                __u16 old_csum;
+                __u32 csum32;
+
+                old_csum = gdp->bg_checksum;
+                gdp->bg_checksum = 0;
+                csum32 = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&le_group,
+                                     sizeof(le_group));
+                csum32 = ext4_chksum(sbi, csum32, (__u8 *)gdp,
+                                     sbi->s_desc_size);
+                gdp->bg_checksum = old_csum;
+
+                crc = csum32 & 0xFFFF;
+                goto out;
         }
 
+        /* old crc16 code */
+        offset = offsetof(struct ext4_group_desc, bg_checksum);
+
+        crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid));
+        crc = crc16(crc, (__u8 *)&le_group, sizeof(le_group));
+        crc = crc16(crc, (__u8 *)gdp, offset);
+        offset += sizeof(gdp->bg_checksum); /* skip checksum */
+        /* for checksum of struct ext4_group_desc do the rest...*/
+        if ((sbi->s_es->s_feature_incompat &
+             cpu_to_le32(EXT4_FEATURE_INCOMPAT_64BIT)) &&
+            offset < le16_to_cpu(sbi->s_es->s_desc_size))
+                crc = crc16(crc, (__u8 *)gdp + offset,
+                            le16_to_cpu(sbi->s_es->s_desc_size) -
+                                offset);
+
+out:
         return cpu_to_le16(crc);
 }
 
-int ext4_group_desc_csum_verify(struct ext4_sb_info *sbi, __u32 block_group,
+int ext4_group_desc_csum_verify(struct super_block *sb, __u32 block_group,
                                 struct ext4_group_desc *gdp)
 {
-        if ((sbi->s_es->s_feature_ro_compat &
-             cpu_to_le32(EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) &&
-            (gdp->bg_checksum != ext4_group_desc_csum(sbi, block_group, gdp)))
+        if (ext4_has_group_desc_csum(sb) &&
+            (gdp->bg_checksum != ext4_group_desc_csum(EXT4_SB(sb),
+                                                      block_group, gdp)))
                 return 0;
 
         return 1;
 }
 
+void ext4_group_desc_csum_set(struct super_block *sb, __u32 block_group,
+                              struct ext4_group_desc *gdp)
+{
+        if (!ext4_has_group_desc_csum(sb))
+                return;
+        gdp->bg_checksum = ext4_group_desc_csum(EXT4_SB(sb), block_group, gdp);
+}
+
 /* Called at mount-time, super-block is locked */
 static int ext4_check_descriptors(struct super_block *sb,
                                   ext4_group_t *first_not_zeroed)
@@ -2043,7 +2069,7 @@ static int ext4_check_descriptors(struct super_block *sb,
                         return 0;
                 }
                 ext4_lock_group(sb, i);
-                if (!ext4_group_desc_csum_verify(sbi, i, gdp)) {
+                if (!ext4_group_desc_csum_verify(sb, i, gdp)) {
                         ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
                                  "Checksum for group %u failed (%u!=%u)",
                                  i, le16_to_cpu(ext4_group_desc_csum(sbi, i,
@@ -3069,6 +3095,13 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
                 goto cantfind_ext4;
         sbi->s_kbytes_written = le64_to_cpu(es->s_kbytes_written);
 
+        /* Warn if metadata_csum and gdt_csum are both set. */
+        if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
+                                       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
+            EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
+                ext4_warning(sb, KERN_INFO "metadata_csum and uninit_bg are "
+                             "redundant flags; please run fsck.");
+
         /* Check for a known checksum algorithm */
         if (!ext4_verify_csum_type(sb, es)) {
                 ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
@@ -4400,7 +4433,7 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
                                 struct ext4_group_desc *gdp =
                                         ext4_get_group_desc(sb, g, NULL);
 
-                                if (!ext4_group_desc_csum_verify(sbi, g, gdp)) {
+                                if (!ext4_group_desc_csum_verify(sb, g, gdp)) {
                                         ext4_msg(sb, KERN_ERR,
                "ext4_remount: Checksum for group %u failed (%u!=%u)",
                 g, le16_to_cpu(ext4_group_desc_csum(sbi, g, gdp)),