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ext4: introduce EXT4_FC_TAG_BASE_LEN helper
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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>
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Ye Bin authored and Theodore Ts'o committed Oct 1, 2022
1 parent 7ff5fdd commit fdc2a3c
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Showing 2 changed files with 31 additions and 26 deletions.
54 changes: 28 additions & 26 deletions fs/ext4/fast_commit.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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.
Expand All @@ -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);
Expand Down Expand Up @@ -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;

Expand All @@ -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);
Expand All @@ -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;
}
Expand All @@ -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;
Expand All @@ -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);
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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)) {
Expand All @@ -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 &&
Expand All @@ -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 ?
Expand Down Expand Up @@ -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;
Expand Down
3 changes: 3 additions & 0 deletions fs/ext4/fast_commit.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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
*/
Expand Down

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