jbd2: remove journal_head from descriptor buffers

Similarly as for metadata buffers, also log descriptor buffers don't
really need the journal head. So strip it and remove BJ_LogCtl list.

Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

5 files changed, 57 insertions, 81 deletions

diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index 2735fef6e55e..65ec076e41f2 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -691,7 +691,6 @@ void __jbd2_journal_drop_transaction(journal_t *journal, transaction_t *transact
         J_ASSERT(transaction->t_buffers == NULL);
         J_ASSERT(transaction->t_forget == NULL);
         J_ASSERT(transaction->t_shadow_list == NULL);
-        J_ASSERT(transaction->t_log_list == NULL);
         J_ASSERT(transaction->t_checkpoint_list == NULL);
         J_ASSERT(transaction->t_checkpoint_io_list == NULL);
         J_ASSERT(atomic_read(&transaction->t_updates) == 0);
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 57bd2ff97888..7c6f7eea2316 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -85,8 +85,7 @@ nope:
         __brelse(bh);
 }
 
-static void jbd2_commit_block_csum_set(journal_t *j,
-                                       struct journal_head *descriptor)
+static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
 {
         struct commit_header *h;
         __u32 csum;
@@ -94,12 +93,11 @@ static void jbd2_commit_block_csum_set(journal_t *j,
         if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
                 return;
 
-        h = (struct commit_header *)(jh2bh(descriptor)->b_data);
+        h = (struct commit_header *)(bh->b_data);
         h->h_chksum_type = 0;
         h->h_chksum_size = 0;
         h->h_chksum[0] = 0;
-        csum = jbd2_chksum(j, j->j_csum_seed, jh2bh(descriptor)->b_data,
-                           j->j_blocksize);
+        csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
         h->h_chksum[0] = cpu_to_be32(csum);
 }
 
@@ -116,7 +114,6 @@ static int journal_submit_commit_record(journal_t *journal,
                                         struct buffer_head **cbh,
                                         __u32 crc32_sum)
 {
-        struct journal_head *descriptor;
         struct commit_header *tmp;
         struct buffer_head *bh;
         int ret;
@@ -127,12 +124,10 @@ static int journal_submit_commit_record(journal_t *journal,
         if (is_journal_aborted(journal))
                 return 0;
 
-        descriptor = jbd2_journal_get_descriptor_buffer(journal);
-        if (!descriptor)
+        bh = jbd2_journal_get_descriptor_buffer(journal);
+        if (!bh)
                 return 1;
 
-        bh = jh2bh(descriptor);
-
         tmp = (struct commit_header *)bh->b_data;
         tmp->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
         tmp->h_blocktype = cpu_to_be32(JBD2_COMMIT_BLOCK);
@@ -146,9 +141,9 @@ static int journal_submit_commit_record(journal_t *journal,
                 tmp->h_chksum_size      = JBD2_CRC32_CHKSUM_SIZE;
                 tmp->h_chksum[0]        = cpu_to_be32(crc32_sum);
         }
-        jbd2_commit_block_csum_set(journal, descriptor);
+        jbd2_commit_block_csum_set(journal, bh);
 
-        JBUFFER_TRACE(descriptor, "submit commit block");
+        BUFFER_TRACE(bh, "submit commit block");
         lock_buffer(bh);
         clear_buffer_dirty(bh);
         set_buffer_uptodate(bh);
@@ -180,7 +175,6 @@ static int journal_wait_on_commit_record(journal_t *journal,
         if (unlikely(!buffer_uptodate(bh)))
                 ret = -EIO;
         put_bh(bh);            /* One for getblk() */
-        jbd2_journal_put_journal_head(bh2jh(bh));
 
         return ret;
 }
@@ -321,7 +315,7 @@ static void write_tag_block(int tag_bytes, journal_block_tag_t *tag,
 }
 
 static void jbd2_descr_block_csum_set(journal_t *j,
-                                      struct journal_head *descriptor)
+                                      struct buffer_head *bh)
 {
         struct jbd2_journal_block_tail *tail;
         __u32 csum;
@@ -329,12 +323,10 @@ static void jbd2_descr_block_csum_set(journal_t *j,
         if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
                 return;
 
-        tail = (struct jbd2_journal_block_tail *)
-                        (jh2bh(descriptor)->b_data + j->j_blocksize -
+        tail = (struct jbd2_journal_block_tail *)(bh->b_data + j->j_blocksize -
                         sizeof(struct jbd2_journal_block_tail));
         tail->t_checksum = 0;
-        csum = jbd2_chksum(j, j->j_csum_seed, jh2bh(descriptor)->b_data,
-                           j->j_blocksize);
+        csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
         tail->t_checksum = cpu_to_be32(csum);
 }
 
@@ -369,7 +361,8 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 {
         struct transaction_stats_s stats;
         transaction_t *commit_transaction;
-        struct journal_head *jh, *descriptor;
+        struct journal_head *jh;
+        struct buffer_head *descriptor;
         struct buffer_head **wbuf = journal->j_wbuf;
         int bufs;
         int flags;
@@ -394,6 +387,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
         int update_tail;
         int csum_size = 0;
         LIST_HEAD(io_bufs);
+        LIST_HEAD(log_bufs);
 
         if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2))
                 csum_size = sizeof(struct jbd2_journal_block_tail);
@@ -547,7 +541,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 
         blk_start_plug(&plug);
         jbd2_journal_write_revoke_records(journal, commit_transaction,
-                                          WRITE_SYNC);
+                                          &log_bufs, WRITE_SYNC);
         blk_finish_plug(&plug);
 
         jbd_debug(3, "JBD2: commit phase 2\n");
@@ -573,8 +567,8 @@ void jbd2_journal_commit_transaction(journal_t *journal)
                  atomic_read(&commit_transaction->t_outstanding_credits));
 
         err = 0;
-        descriptor = NULL;
         bufs = 0;
+        descriptor = NULL;
         blk_start_plug(&plug);
         while (commit_transaction->t_buffers) {
 
@@ -606,8 +600,6 @@ void jbd2_journal_commit_transaction(journal_t *journal)
                    record the metadata buffer. */
 
                 if (!descriptor) {
-                        struct buffer_head *bh;
-
                         J_ASSERT (bufs == 0);
 
                         jbd_debug(4, "JBD2: get descriptor\n");
@@ -618,26 +610,26 @@ void jbd2_journal_commit_transaction(journal_t *journal)
                                 continue;
                         }
 
-                        bh = jh2bh(descriptor);
                         jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
-                                (unsigned long long)bh->b_blocknr, bh->b_data);
-                        header = (journal_header_t *)&bh->b_data[0];
+                                (unsigned long long)descriptor->b_blocknr,
+                                descriptor->b_data);
+                        header = (journal_header_t *)descriptor->b_data;
                         header->h_magic     = cpu_to_be32(JBD2_MAGIC_NUMBER);
                         header->h_blocktype = cpu_to_be32(JBD2_DESCRIPTOR_BLOCK);
                         header->h_sequence  = cpu_to_be32(commit_transaction->t_tid);
 
-                        tagp = &bh->b_data[sizeof(journal_header_t)];
-                        space_left = bh->b_size - sizeof(journal_header_t);
+                        tagp = &descriptor->b_data[sizeof(journal_header_t)];
+                        space_left = descriptor->b_size -
+                                                sizeof(journal_header_t);
                         first_tag = 1;
-                        set_buffer_jwrite(bh);
-                        set_buffer_dirty(bh);
-                        wbuf[bufs++] = bh;
+                        set_buffer_jwrite(descriptor);
+                        set_buffer_dirty(descriptor);
+                        wbuf[bufs++] = descriptor;
 
                         /* Record it so that we can wait for IO
                            completion later */
-                        BUFFER_TRACE(bh, "ph3: file as descriptor");
-                        jbd2_journal_file_buffer(descriptor, commit_transaction,
-                                        BJ_LogCtl);
+                        BUFFER_TRACE(descriptor, "ph3: file as descriptor");
+                        jbd2_file_log_bh(&log_bufs, descriptor);
                 }
 
                 /* Where is the buffer to be written? */
@@ -864,26 +856,19 @@ start_journal_io:
         jbd_debug(3, "JBD2: commit phase 4\n");
 
         /* Here we wait for the revoke record and descriptor record buffers */
- wait_for_ctlbuf:
-        while (commit_transaction->t_log_list != NULL) {
+        while (!list_empty(&log_bufs)) {
                 struct buffer_head *bh;
 
-                jh = commit_transaction->t_log_list->b_tprev;
-                bh = jh2bh(jh);
-                if (buffer_locked(bh)) {
-                        wait_on_buffer(bh);
-                        goto wait_for_ctlbuf;
-                }
-                if (cond_resched())
-                        goto wait_for_ctlbuf;
+                bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
+                wait_on_buffer(bh);
+                cond_resched();
 
                 if (unlikely(!buffer_uptodate(bh)))
                         err = -EIO;
 
                 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
                 clear_buffer_jwrite(bh);
-                jbd2_journal_unfile_buffer(journal, jh);
-                jbd2_journal_put_journal_head(jh);
+                jbd2_unfile_log_bh(bh);
                 __brelse(bh);           /* One for getblk */
                 /* AKPM: bforget here */
         }
@@ -934,7 +919,6 @@ start_journal_io:
         J_ASSERT(commit_transaction->t_buffers == NULL);
         J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
         J_ASSERT(commit_transaction->t_shadow_list == NULL);
-        J_ASSERT(commit_transaction->t_log_list == NULL);
 
 restart_loop:
         /*
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 45cdc080e466..b0a8d1e4703e 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -790,7 +790,7 @@ int jbd2_journal_bmap(journal_t *journal, unsigned long blocknr,
  * But we don't bother doing that, so there will be coherency problems with
  * mmaps of blockdevs which hold live JBD-controlled filesystems.
  */
-struct journal_head *jbd2_journal_get_descriptor_buffer(journal_t *journal)
+struct buffer_head *jbd2_journal_get_descriptor_buffer(journal_t *journal)
 {
         struct buffer_head *bh;
         unsigned long long blocknr;
@@ -809,7 +809,7 @@ struct journal_head *jbd2_journal_get_descriptor_buffer(journal_t *journal)
         set_buffer_uptodate(bh);
         unlock_buffer(bh);
         BUFFER_TRACE(bh, "return this buffer");
-        return jbd2_journal_add_journal_head(bh);
+        return bh;
 }
 
 /*
diff --git a/fs/jbd2/revoke.c b/fs/jbd2/revoke.c
index f30b80b4ce8b..198c9c10276d 100644
--- a/fs/jbd2/revoke.c
+++ b/fs/jbd2/revoke.c
@@ -122,9 +122,10 @@ struct jbd2_revoke_table_s
 
 #ifdef __KERNEL__
 static void write_one_revoke_record(journal_t *, transaction_t *,
-                                    struct journal_head **, int *,
+                                    struct list_head *,
+                                    struct buffer_head **, int *,
                                     struct jbd2_revoke_record_s *, int);
-static void flush_descriptor(journal_t *, struct journal_head *, int, int);
+static void flush_descriptor(journal_t *, struct buffer_head *, int, int);
 #endif
 
 /* Utility functions to maintain the revoke table */
@@ -531,9 +532,10 @@ void jbd2_journal_switch_revoke_table(journal_t *journal)
  */
 void jbd2_journal_write_revoke_records(journal_t *journal,
                                        transaction_t *transaction,
+                                       struct list_head *log_bufs,
                                        int write_op)
 {
-        struct journal_head *descriptor;
+        struct buffer_head *descriptor;
         struct jbd2_revoke_record_s *record;
         struct jbd2_revoke_table_s *revoke;
         struct list_head *hash_list;
@@ -553,7 +555,7 @@ void jbd2_journal_write_revoke_records(journal_t *journal,
                 while (!list_empty(hash_list)) {
                         record = (struct jbd2_revoke_record_s *)
                                 hash_list->next;
-                        write_one_revoke_record(journal, transaction,
+                        write_one_revoke_record(journal, transaction, log_bufs,
                                                 &descriptor, &offset,
                                                 record, write_op);
                         count++;
@@ -573,13 +575,14 @@ void jbd2_journal_write_revoke_records(journal_t *journal,
 
 static void write_one_revoke_record(journal_t *journal,
                                     transaction_t *transaction,
-                                    struct journal_head **descriptorp,
+                                    struct list_head *log_bufs,
+                                    struct buffer_head **descriptorp,
                                     int *offsetp,
                                     struct jbd2_revoke_record_s *record,
                                     int write_op)
 {
         int csum_size = 0;
-        struct journal_head *descriptor;
+        struct buffer_head *descriptor;
         int offset;
         journal_header_t *header;
 
@@ -609,26 +612,26 @@ static void write_one_revoke_record(journal_t *journal,
                 descriptor = jbd2_journal_get_descriptor_buffer(journal);
                 if (!descriptor)
                         return;
-                header = (journal_header_t *) &jh2bh(descriptor)->b_data[0];
+                header = (journal_header_t *)descriptor->b_data;
                 header->h_magic     = cpu_to_be32(JBD2_MAGIC_NUMBER);
                 header->h_blocktype = cpu_to_be32(JBD2_REVOKE_BLOCK);
                 header->h_sequence  = cpu_to_be32(transaction->t_tid);
 
                 /* Record it so that we can wait for IO completion later */
-                JBUFFER_TRACE(descriptor, "file as BJ_LogCtl");
-                jbd2_journal_file_buffer(descriptor, transaction, BJ_LogCtl);
+                BUFFER_TRACE(descriptor, "file in log_bufs");
+                jbd2_file_log_bh(log_bufs, descriptor);
 
                 offset = sizeof(jbd2_journal_revoke_header_t);
                 *descriptorp = descriptor;
         }
 
         if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT)) {
-                * ((__be64 *)(&jh2bh(descriptor)->b_data[offset])) =
+                * ((__be64 *)(&descriptor->b_data[offset])) =
                         cpu_to_be64(record->blocknr);
                 offset += 8;
 
         } else {
-                * ((__be32 *)(&jh2bh(descriptor)->b_data[offset])) =
+                * ((__be32 *)(&descriptor->b_data[offset])) =
                         cpu_to_be32(record->blocknr);
                 offset += 4;
         }
@@ -636,8 +639,7 @@ static void write_one_revoke_record(journal_t *journal,
         *offsetp = offset;
 }
 
-static void jbd2_revoke_csum_set(journal_t *j,
-                                 struct journal_head *descriptor)
+static void jbd2_revoke_csum_set(journal_t *j, struct buffer_head *bh)
 {
         struct jbd2_journal_revoke_tail *tail;
         __u32 csum;
@@ -645,12 +647,10 @@ static void jbd2_revoke_csum_set(journal_t *j,
         if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
                 return;
 
-        tail = (struct jbd2_journal_revoke_tail *)
-                        (jh2bh(descriptor)->b_data + j->j_blocksize -
+        tail = (struct jbd2_journal_revoke_tail *)(bh->b_data + j->j_blocksize -
                         sizeof(struct jbd2_journal_revoke_tail));
         tail->r_checksum = 0;
-        csum = jbd2_chksum(j, j->j_csum_seed, jh2bh(descriptor)->b_data,
-                           j->j_blocksize);
+        csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
         tail->r_checksum = cpu_to_be32(csum);
 }
 
@@ -662,25 +662,24 @@ static void jbd2_revoke_csum_set(journal_t *j,
  */
 
 static void flush_descriptor(journal_t *journal,
-                             struct journal_head *descriptor,
+                             struct buffer_head *descriptor,
                              int offset, int write_op)
 {
         jbd2_journal_revoke_header_t *header;
-        struct buffer_head *bh = jh2bh(descriptor);
 
         if (is_journal_aborted(journal)) {
-                put_bh(bh);
+                put_bh(descriptor);
                 return;
         }
 
-        header = (jbd2_journal_revoke_header_t *) jh2bh(descriptor)->b_data;
+        header = (jbd2_journal_revoke_header_t *)descriptor->b_data;
         header->r_count = cpu_to_be32(offset);
         jbd2_revoke_csum_set(journal, descriptor);
 
-        set_buffer_jwrite(bh);
-        BUFFER_TRACE(bh, "write");
-        set_buffer_dirty(bh);
-        write_dirty_buffer(bh, write_op);
+        set_buffer_jwrite(descriptor);
+        BUFFER_TRACE(descriptor, "write");
+        set_buffer_dirty(descriptor);
+        write_dirty_buffer(descriptor, write_op);
 }
 #endif
 
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 983010900258..f1c5392e62b6 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -1637,9 +1637,6 @@ static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh)
         case BJ_Shadow:
                 list = &transaction->t_shadow_list;
                 break;
-        case BJ_LogCtl:
-                list = &transaction->t_log_list;
-                break;
         case BJ_Reserved:
                 list = &transaction->t_reserved_list;
                 break;
@@ -2148,9 +2145,6 @@ void __jbd2_journal_file_buffer(struct journal_head *jh,
         case BJ_Shadow:
                 list = &transaction->t_shadow_list;
                 break;
-        case BJ_LogCtl:
-                list = &transaction->t_log_list;
-                break;
         case BJ_Reserved:
                 list = &transaction->t_reserved_list;
                 break;