ext4: make block group checksums use metadata_csum algorithm

metadata_csum supersedes uninit_bg.  Convert the ROCOMPAT uninit_bg
flag check to a helper function that covers both, and make the
checksum calculation algorithm use either crc16 or the metadata_csum
chosen algorithm depending on which flag is set.  Print a warning if
we try to mount a filesystem with both feature flags set.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 0a64e4d..5745d53 100644 (file)
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -168,7 +168,7 @@ void ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
 
        /* If checksum is bad mark all blocks used to prevent allocation
         * essentially implementing a per-group read-only flag. */
-       if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) {
+       if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) {
                ext4_error(sb, "Checksum bad for group %u", block_group);
                ext4_free_group_clusters_set(sb, gdp, 0);
                ext4_free_inodes_set(sb, gdp, 0);
@@ -214,7 +214,7 @@ void ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
                             sb->s_blocksize * 8, bh->b_data);
        ext4_block_bitmap_csum_set(sb, block_group, gdp, bh,
                                   EXT4_BLOCKS_PER_GROUP(sb) / 8);
-       gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp);
+       ext4_group_desc_csum_set(sb, block_group, gdp);
 }
 
 /* Return the number of free blocks in a block group.  It is used when

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 57d7c35..84e76bb 100644 (file)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2114,10 +2114,10 @@ extern void ext4_used_dirs_set(struct super_block *sb,
                                struct ext4_group_desc *bg, __u32 count);
 extern void ext4_itable_unused_set(struct super_block *sb,
                                   struct ext4_group_desc *bg, __u32 count);
-extern __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 group,
-                                  struct ext4_group_desc *gdp);
-extern int ext4_group_desc_csum_verify(struct ext4_sb_info *sbi, __u32 group,
+extern int ext4_group_desc_csum_verify(struct super_block *sb, __u32 group,
                                       struct ext4_group_desc *gdp);
+extern void ext4_group_desc_csum_set(struct super_block *sb, __u32 group,
+                                    struct ext4_group_desc *gdp);
 
 static inline int ext4_has_group_desc_csum(struct super_block *sb)
 {

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index a6383fc..a044a9b 100644 (file)
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -70,13 +70,11 @@ static unsigned ext4_init_inode_bitmap(struct super_block *sb,
                                       ext4_group_t block_group,
                                       struct ext4_group_desc *gdp)
 {
-       struct ext4_sb_info *sbi = EXT4_SB(sb);
-
        J_ASSERT_BH(bh, buffer_locked(bh));
 
        /* If checksum is bad mark all blocks and inodes use to prevent
         * allocation, essentially implementing a per-group read-only flag. */
-       if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) {
+       if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) {
                ext4_error(sb, "Checksum bad for group %u", block_group);
                ext4_free_group_clusters_set(sb, gdp, 0);
                ext4_free_inodes_set(sb, gdp, 0);
@@ -92,7 +90,7 @@ static unsigned ext4_init_inode_bitmap(struct super_block *sb,
                        bh->b_data);
        ext4_inode_bitmap_csum_set(sb, block_group, gdp, bh,
                                   EXT4_INODES_PER_GROUP(sb) / 8);
-       gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp);
+       ext4_group_desc_csum_set(sb, block_group, gdp);
 
        return EXT4_INODES_PER_GROUP(sb);
 }
@@ -298,7 +296,7 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
        }
        ext4_inode_bitmap_csum_set(sb, block_group, gdp, bitmap_bh,
                                   EXT4_INODES_PER_GROUP(sb) / 8);
-       gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp);
+       ext4_group_desc_csum_set(sb, block_group, gdp);
        ext4_unlock_group(sb, block_group);
 
        percpu_counter_inc(&sbi->s_freeinodes_counter);
@@ -731,7 +729,7 @@ repeat_in_this_group:
 
 got:
        /* We may have to initialize the block bitmap if it isn't already */
-       if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM) &&
+       if (ext4_has_group_desc_csum(sb) &&
            gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
                struct buffer_head *block_bitmap_bh;
 
@@ -757,8 +755,7 @@ got:
                                                   block_bitmap_bh,
                                                   EXT4_BLOCKS_PER_GROUP(sb) /
                                                   8);
-                       gdp->bg_checksum = ext4_group_desc_csum(sbi, group,
-                                                               gdp);
+                       ext4_group_desc_csum_set(sb, group, gdp);
                }
                ext4_unlock_group(sb, group);
 
@@ -811,7 +808,7 @@ got:
        if (ext4_has_group_desc_csum(sb)) {
                ext4_inode_bitmap_csum_set(sb, group, gdp, inode_bitmap_bh,
                                           EXT4_INODES_PER_GROUP(sb) / 8);
-               gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
+               ext4_group_desc_csum_set(sb, group, gdp);
                ext4_unlock_group(sb, group);
        }
 
@@ -1181,7 +1178,7 @@ int ext4_init_inode_table(struct super_block *sb, ext4_group_t group,
 skip_zeroout:
        ext4_lock_group(sb, group);
        gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_ZEROED);
-       gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
+       ext4_group_desc_csum_set(sb, group, gdp);
        ext4_unlock_group(sb, group);
 
        BUFFER_TRACE(group_desc_bh,

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 16a6735..7bccdf3 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3584,8 +3584,7 @@ make_io:
                                b = table;
                        end = b + EXT4_SB(sb)->s_inode_readahead_blks;
                        num = EXT4_INODES_PER_GROUP(sb);
-                       if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
-                                      EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
+                       if (ext4_has_group_desc_csum(sb))
                                num -= ext4_itable_unused_count(sb, gdp);
                        table += num / inodes_per_block;
                        if (end > table)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 95a388f..ccb9c2f 100644 (file)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2799,7 +2799,7 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
        ext4_free_group_clusters_set(sb, gdp, len);
        ext4_block_bitmap_csum_set(sb, ac->ac_b_ex.fe_group, gdp, bitmap_bh,
                                   EXT4_BLOCKS_PER_GROUP(sb) / 8);
-       gdp->bg_checksum = ext4_group_desc_csum(sbi, ac->ac_b_ex.fe_group, gdp);
+       ext4_group_desc_csum_set(sb, ac->ac_b_ex.fe_group, gdp);
 
        ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
        percpu_counter_sub(&sbi->s_freeclusters_counter, ac->ac_b_ex.fe_len);
@@ -4663,7 +4663,7 @@ do_more:
        ext4_free_group_clusters_set(sb, gdp, ret);
        ext4_block_bitmap_csum_set(sb, block_group, gdp, bitmap_bh,
                                   EXT4_BLOCKS_PER_GROUP(sb) / 8);
-       gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp);
+       ext4_group_desc_csum_set(sb, block_group, gdp);
        ext4_unlock_group(sb, block_group);
        percpu_counter_add(&sbi->s_freeclusters_counter, count_clusters);
 
@@ -4809,7 +4809,7 @@ int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
        ext4_free_group_clusters_set(sb, desc, blk_free_count);
        ext4_block_bitmap_csum_set(sb, block_group, desc, bitmap_bh,
                                   EXT4_BLOCKS_PER_GROUP(sb) / 8);
-       desc->bg_checksum = ext4_group_desc_csum(sbi, block_group, desc);
+       ext4_group_desc_csum_set(sb, block_group, desc);
        ext4_unlock_group(sb, block_group);
        percpu_counter_add(&sbi->s_freeclusters_counter,
                           EXT4_B2C(sbi, blocks_freed));

diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index dc597e0..a58ce7c 100644 (file)
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -1160,7 +1160,7 @@ static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
                                             EXT4_B2C(sbi, group_data->free_blocks_count));
                ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
                gdp->bg_flags = cpu_to_le16(*bg_flags);
-               gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
+               ext4_group_desc_csum_set(sb, group, gdp);
 
                err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
                if (unlikely(err)) {
@@ -1399,17 +1399,14 @@ static int ext4_setup_next_flex_gd(struct super_block *sb,
                           (1 + ext4_bg_num_gdb(sb, group + i) +
                            le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
                group_data[i].free_blocks_count = blocks_per_group - overhead;
-               if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
-                                              EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
+               if (ext4_has_group_desc_csum(sb))
                        flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
                                               EXT4_BG_INODE_UNINIT;
                else
                        flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
        }
 
-       if (last_group == n_group &&
-           EXT4_HAS_RO_COMPAT_FEATURE(sb,
-                                      EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
+       if (last_group == n_group && ext4_has_group_desc_csum(sb))
                /* We need to initialize block bitmap of last group. */
                flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
 

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index f80c7e6..c18c596 100644 (file)
--- 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)),