ext4: introduce EXT4_FC_TAG_BASE_LEN helper

Introduce EXT4_FC_TAG_BASE_LEN helper for calculate length of
struct ext4_fc_tl.

Signed-off-by: Ye Bin <yebin10@huawei.com>
Link: https://lore.kernel.org/r/20220924075233.2315259-2-yebin10@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
index 54ccc61c713a85f83840b412c7289a6455742c4f..a65772c22f6dbf5b24b716a9686c0aac0ba78e80 100644 (file)
--- a/fs/ext4/fast_commit.c
+++ b/fs/ext4/fast_commit.c
@@ -702,10 +702,10 @@ static u8 *ext4_fc_reserve_space(struct super_block *sb, int len, u32 *crc)
         * After allocating len, we should have space at least for a 0 byte
         * padding.
         */
-       if (len + sizeof(struct ext4_fc_tl) > bsize)
+       if (len + EXT4_FC_TAG_BASE_LEN > bsize)
                return NULL;
 
-       if (bsize - off - 1 > len + sizeof(struct ext4_fc_tl)) {
+       if (bsize - off - 1 > len + EXT4_FC_TAG_BASE_LEN) {
                /*
                 * Only allocate from current buffer if we have enough space for
                 * this request AND we have space to add a zero byte padding.
@@ -722,10 +722,10 @@ static u8 *ext4_fc_reserve_space(struct super_block *sb, int len, u32 *crc)
        /* Need to add PAD tag */
        tl = (struct ext4_fc_tl *)(sbi->s_fc_bh->b_data + off);
        tl->fc_tag = cpu_to_le16(EXT4_FC_TAG_PAD);
-       pad_len = bsize - off - 1 - sizeof(struct ext4_fc_tl);
+       pad_len = bsize - off - 1 - EXT4_FC_TAG_BASE_LEN;
        tl->fc_len = cpu_to_le16(pad_len);
        if (crc)
-               *crc = ext4_chksum(sbi, *crc, tl, sizeof(*tl));
+               *crc = ext4_chksum(sbi, *crc, tl, EXT4_FC_TAG_BASE_LEN);
        if (pad_len > 0)
                ext4_fc_memzero(sb, tl + 1, pad_len, crc);
        ext4_fc_submit_bh(sb, false);
@@ -767,7 +767,7 @@ static int ext4_fc_write_tail(struct super_block *sb, u32 crc)
         * ext4_fc_reserve_space takes care of allocating an extra block if
         * there's no enough space on this block for accommodating this tail.
         */
-       dst = ext4_fc_reserve_space(sb, sizeof(tl) + sizeof(tail), &crc);
+       dst = ext4_fc_reserve_space(sb, EXT4_FC_TAG_BASE_LEN + sizeof(tail), &crc);
        if (!dst)
                return -ENOSPC;
 
@@ -777,8 +777,8 @@ static int ext4_fc_write_tail(struct super_block *sb, u32 crc)
        tl.fc_len = cpu_to_le16(bsize - off - 1 + sizeof(struct ext4_fc_tail));
        sbi->s_fc_bytes = round_up(sbi->s_fc_bytes, bsize);
 
-       ext4_fc_memcpy(sb, dst, &tl, sizeof(tl), &crc);
-       dst += sizeof(tl);
+       ext4_fc_memcpy(sb, dst, &tl, EXT4_FC_TAG_BASE_LEN, &crc);
+       dst += EXT4_FC_TAG_BASE_LEN;
        tail.fc_tid = cpu_to_le32(sbi->s_journal->j_running_transaction->t_tid);
        ext4_fc_memcpy(sb, dst, &tail.fc_tid, sizeof(tail.fc_tid), &crc);
        dst += sizeof(tail.fc_tid);
@@ -800,15 +800,15 @@ static bool ext4_fc_add_tlv(struct super_block *sb, u16 tag, u16 len, u8 *val,
        struct ext4_fc_tl tl;
        u8 *dst;
 
-       dst = ext4_fc_reserve_space(sb, sizeof(tl) + len, crc);
+       dst = ext4_fc_reserve_space(sb, EXT4_FC_TAG_BASE_LEN + len, crc);
        if (!dst)
                return false;
 
        tl.fc_tag = cpu_to_le16(tag);
        tl.fc_len = cpu_to_le16(len);
 
-       ext4_fc_memcpy(sb, dst, &tl, sizeof(tl), crc);
-       ext4_fc_memcpy(sb, dst + sizeof(tl), val, len, crc);
+       ext4_fc_memcpy(sb, dst, &tl, EXT4_FC_TAG_BASE_LEN, crc);
+       ext4_fc_memcpy(sb, dst + EXT4_FC_TAG_BASE_LEN, val, len, crc);
 
        return true;
 }
@@ -820,8 +820,8 @@ static bool ext4_fc_add_dentry_tlv(struct super_block *sb, u32 *crc,
        struct ext4_fc_dentry_info fcd;
        struct ext4_fc_tl tl;
        int dlen = fc_dentry->fcd_name.len;
-       u8 *dst = ext4_fc_reserve_space(sb, sizeof(tl) + sizeof(fcd) + dlen,
-                                       crc);
+       u8 *dst = ext4_fc_reserve_space(sb,
+                       EXT4_FC_TAG_BASE_LEN + sizeof(fcd) + dlen, crc);
 
        if (!dst)
                return false;
@@ -830,8 +830,8 @@ static bool ext4_fc_add_dentry_tlv(struct super_block *sb, u32 *crc,
        fcd.fc_ino = cpu_to_le32(fc_dentry->fcd_ino);
        tl.fc_tag = cpu_to_le16(fc_dentry->fcd_op);
        tl.fc_len = cpu_to_le16(sizeof(fcd) + dlen);
-       ext4_fc_memcpy(sb, dst, &tl, sizeof(tl), crc);
-       dst += sizeof(tl);
+       ext4_fc_memcpy(sb, dst, &tl, EXT4_FC_TAG_BASE_LEN, crc);
+       dst += EXT4_FC_TAG_BASE_LEN;
        ext4_fc_memcpy(sb, dst, &fcd, sizeof(fcd), crc);
        dst += sizeof(fcd);
        ext4_fc_memcpy(sb, dst, fc_dentry->fcd_name.name, dlen, crc);
@@ -868,13 +868,13 @@ static int ext4_fc_write_inode(struct inode *inode, u32 *crc)
 
        ret = -ECANCELED;
        dst = ext4_fc_reserve_space(inode->i_sb,
-                       sizeof(tl) + inode_len + sizeof(fc_inode.fc_ino), crc);
+               EXT4_FC_TAG_BASE_LEN + inode_len + sizeof(fc_inode.fc_ino), crc);
        if (!dst)
                goto err;
 
-       if (!ext4_fc_memcpy(inode->i_sb, dst, &tl, sizeof(tl), crc))
+       if (!ext4_fc_memcpy(inode->i_sb, dst, &tl, EXT4_FC_TAG_BASE_LEN, crc))
                goto err;
-       dst += sizeof(tl);
+       dst += EXT4_FC_TAG_BASE_LEN;
        if (!ext4_fc_memcpy(inode->i_sb, dst, &fc_inode, sizeof(fc_inode), crc))
                goto err;
        dst += sizeof(fc_inode);
@@ -2026,9 +2026,10 @@ static int ext4_fc_replay_scan(journal_t *journal,
        }
 
        state->fc_replay_expected_off++;
-       for (cur = start; cur < end; cur = cur + sizeof(tl) + le16_to_cpu(tl.fc_len)) {
-               memcpy(&tl, cur, sizeof(tl));
-               val = cur + sizeof(tl);
+       for (cur = start; cur < end;
+            cur = cur + EXT4_FC_TAG_BASE_LEN + le16_to_cpu(tl.fc_len)) {
+               memcpy(&tl, cur, EXT4_FC_TAG_BASE_LEN);
+               val = cur + EXT4_FC_TAG_BASE_LEN;
                ext4_debug("Scan phase, tag:%s, blk %lld\n",
                          tag2str(le16_to_cpu(tl.fc_tag)), bh->b_blocknr);
                switch (le16_to_cpu(tl.fc_tag)) {
@@ -2051,13 +2052,13 @@ static int ext4_fc_replay_scan(journal_t *journal,
                case EXT4_FC_TAG_PAD:
                        state->fc_cur_tag++;
                        state->fc_crc = ext4_chksum(sbi, state->fc_crc, cur,
-                                       sizeof(tl) + le16_to_cpu(tl.fc_len));
+                               EXT4_FC_TAG_BASE_LEN + le16_to_cpu(tl.fc_len));
                        break;
                case EXT4_FC_TAG_TAIL:
                        state->fc_cur_tag++;
                        memcpy(&tail, val, sizeof(tail));
                        state->fc_crc = ext4_chksum(sbi, state->fc_crc, cur,
-                                               sizeof(tl) +
+                                               EXT4_FC_TAG_BASE_LEN +
                                                offsetof(struct ext4_fc_tail,
                                                fc_crc));
                        if (le32_to_cpu(tail.fc_tid) == expected_tid &&
@@ -2084,7 +2085,7 @@ static int ext4_fc_replay_scan(journal_t *journal,
                        }
                        state->fc_cur_tag++;
                        state->fc_crc = ext4_chksum(sbi, state->fc_crc, cur,
-                                           sizeof(tl) + le16_to_cpu(tl.fc_len));
+                               EXT4_FC_TAG_BASE_LEN + le16_to_cpu(tl.fc_len));
                        break;
                default:
                        ret = state->fc_replay_num_tags ?
@@ -2139,9 +2140,10 @@ static int ext4_fc_replay(journal_t *journal, struct buffer_head *bh,
        start = (u8 *)bh->b_data;
        end = (__u8 *)bh->b_data + journal->j_blocksize - 1;
 
-       for (cur = start; cur < end; cur = cur + sizeof(tl) + le16_to_cpu(tl.fc_len)) {
-               memcpy(&tl, cur, sizeof(tl));
-               val = cur + sizeof(tl);
+       for (cur = start; cur < end;
+            cur = cur + EXT4_FC_TAG_BASE_LEN + le16_to_cpu(tl.fc_len)) {
+               memcpy(&tl, cur, EXT4_FC_TAG_BASE_LEN);
+               val = cur + EXT4_FC_TAG_BASE_LEN;
 
                if (state->fc_replay_num_tags == 0) {
                        ret = JBD2_FC_REPLAY_STOP;

diff --git a/fs/ext4/fast_commit.h b/fs/ext4/fast_commit.h
index 1db12847a83b643a230cea68d2dd370dd33358a1..a6154c3ed1357cbe4fcf12c7ea0e511723ce4505 100644 (file)
--- a/fs/ext4/fast_commit.h
+++ b/fs/ext4/fast_commit.h
@@ -70,6 +70,9 @@ struct ext4_fc_tail {
        __le32 fc_crc;
 };
 
+/* Tag base length */
+#define EXT4_FC_TAG_BASE_LEN (sizeof(struct ext4_fc_tl))
+
 /*
  * Fast commit status codes
  */