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>

1 files changed, 31 insertions, 47 deletions

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:
         /*