nilfs2: move pointer to super root block into logs

This moves a pointer to buffer storing super root block to each log
buffer from nilfs_sc_info struct for simplicity.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

4 files changed, 25 insertions, 26 deletions

diff --git a/fs/nilfs2/segbuf.c b/fs/nilfs2/segbuf.c
index 17851f77f739..a24ca9cc6afb 100644
--- a/fs/nilfs2/segbuf.c
+++ b/fs/nilfs2/segbuf.c
@@ -81,6 +81,7 @@ struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *sb)
         INIT_LIST_HEAD(&segbuf->sb_list);
         INIT_LIST_HEAD(&segbuf->sb_segsum_buffers);
         INIT_LIST_HEAD(&segbuf->sb_payload_buffers);
+        segbuf->sb_super_root = NULL;
 
         init_completion(&segbuf->sb_bio_event);
         atomic_set(&segbuf->sb_err, 0);
@@ -282,6 +283,7 @@ static void nilfs_segbuf_clear(struct nilfs_segment_buffer *segbuf)
 {
         nilfs_release_buffers(&segbuf->sb_segsum_buffers);
         nilfs_release_buffers(&segbuf->sb_payload_buffers);
+        segbuf->sb_super_root = NULL;
 }
 
 /*
diff --git a/fs/nilfs2/segbuf.h b/fs/nilfs2/segbuf.h
index 94dfd3517bc0..a1a0af6119ea 100644
--- a/fs/nilfs2/segbuf.h
+++ b/fs/nilfs2/segbuf.h
@@ -76,6 +76,7 @@ struct nilfs_segsum_info {
  * @sb_rest_blocks: Number of residual blocks in the current segment
  * @sb_segsum_buffers: List of buffers for segment summaries
  * @sb_payload_buffers: List of buffers for segment payload
+ * @sb_super_root: Pointer to buffer storing a super root block (if exists)
  * @sb_nbio: Number of flying bio requests
  * @sb_err: I/O error status
  * @sb_bio_event: Completion event of log writing
@@ -95,6 +96,7 @@ struct nilfs_segment_buffer {
         /* Buffers */
         struct list_head        sb_segsum_buffers;
         struct list_head        sb_payload_buffers; /* including super root */
+        struct buffer_head     *sb_super_root;
 
         /* io status */
         int                     sb_nbio;
diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index 6a7dbd8451db..7ab0270b2629 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -435,7 +435,7 @@ static int nilfs_segctor_add_super_root(struct nilfs_sc_info *sci)
                         return err;
                 segbuf = sci->sc_curseg;
         }
-        err = nilfs_segbuf_extend_payload(segbuf, &sci->sc_super_root);
+        err = nilfs_segbuf_extend_payload(segbuf, &segbuf->sb_super_root);
         if (likely(!err))
                 segbuf->sb_sum.flags |= NILFS_SS_SR;
         return err;
@@ -952,10 +952,10 @@ static void nilfs_segctor_fill_in_checksums(struct nilfs_sc_info *sci,
 {
         struct nilfs_segment_buffer *segbuf;
 
-        if (sci->sc_super_root)
-                nilfs_fill_in_super_root_crc(sci->sc_super_root, seed);
-
         list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
+                if (segbuf->sb_super_root)
+                        nilfs_fill_in_super_root_crc(segbuf->sb_super_root,
+                                                     seed);
                 nilfs_segbuf_fill_in_segsum_crc(segbuf, seed);
                 nilfs_segbuf_fill_in_data_crc(segbuf, seed);
         }
@@ -964,11 +964,13 @@ static void nilfs_segctor_fill_in_checksums(struct nilfs_sc_info *sci,
 static void nilfs_segctor_fill_in_super_root(struct nilfs_sc_info *sci,
                                              struct the_nilfs *nilfs)
 {
-        struct buffer_head *bh_sr = sci->sc_super_root;
-        struct nilfs_super_root *raw_sr =
-                (struct nilfs_super_root *)bh_sr->b_data;
+        struct buffer_head *bh_sr;
+        struct nilfs_super_root *raw_sr;
         unsigned isz = nilfs->ns_inode_size;
 
+        bh_sr = NILFS_LAST_SEGBUF(&sci->sc_segbufs)->sb_super_root;
+        raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
+
         raw_sr->sr_bytes = cpu_to_le16(NILFS_SR_BYTES);
         raw_sr->sr_nongc_ctime
                 = cpu_to_le64(nilfs_doing_gc() ?
@@ -1491,7 +1493,6 @@ static int nilfs_segctor_collect(struct nilfs_sc_info *sci,
 
         /* Collection retry loop */
         for (;;) {
-                sci->sc_super_root = NULL;
                 sci->sc_nblk_this_inc = 0;
                 sci->sc_curseg = NILFS_FIRST_SEGBUF(&sci->sc_segbufs);
 
@@ -1568,7 +1569,7 @@ nilfs_segctor_update_payload_blocknr(struct nilfs_sc_info *sci,
         ssp.offset = sizeof(struct nilfs_segment_summary);
 
         list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
-                if (bh == sci->sc_super_root)
+                if (bh == segbuf->sb_super_root)
                         break;
                 if (!finfo) {
                         finfo = nilfs_segctor_map_segsum_entry(
@@ -1729,7 +1730,7 @@ static int nilfs_segctor_prepare_write(struct nilfs_sc_info *sci,
 
                 list_for_each_entry(bh, &segbuf->sb_payload_buffers,
                                     b_assoc_buffers) {
-                        if (bh == sci->sc_super_root) {
+                        if (bh == segbuf->sb_super_root) {
                                 if (bh->b_page != bd_page) {
                                         lock_page(bd_page);
                                         clear_page_dirty_for_io(bd_page);
@@ -1848,7 +1849,7 @@ static void nilfs_clear_copied_buffers(struct list_head *list, int err)
 }
 
 static void nilfs_abort_logs(struct list_head *logs, struct page *failed_page,
-                             struct buffer_head *bh_sr, int err)
+                             int err)
 {
         struct nilfs_segment_buffer *segbuf;
         struct page *bd_page = NULL, *fs_page = NULL;
@@ -1869,7 +1870,7 @@ static void nilfs_abort_logs(struct list_head *logs, struct page *failed_page,
 
                 list_for_each_entry(bh, &segbuf->sb_payload_buffers,
                                     b_assoc_buffers) {
-                        if (bh == bh_sr) {
+                        if (bh == segbuf->sb_super_root) {
                                 if (bh->b_page != bd_page) {
                                         end_page_writeback(bd_page);
                                         bd_page = bh->b_page;
@@ -1898,7 +1899,7 @@ static void nilfs_segctor_abort_construction(struct nilfs_sc_info *sci,
 
         list_splice_tail_init(&sci->sc_write_logs, &logs);
         ret = nilfs_wait_on_logs(&logs);
-        nilfs_abort_logs(&logs, NULL, sci->sc_super_root, ret ? : err);
+        nilfs_abort_logs(&logs, NULL, ret ? : err);
 
         list_splice_tail_init(&sci->sc_segbufs, &logs);
         nilfs_cancel_segusage(&logs, nilfs->ns_sufile);
@@ -1914,7 +1915,6 @@ static void nilfs_segctor_abort_construction(struct nilfs_sc_info *sci,
         }
 
         nilfs_destroy_logs(&logs);
-        sci->sc_super_root = NULL;
 }
 
 static void nilfs_set_next_segment(struct the_nilfs *nilfs,
@@ -1933,7 +1933,7 @@ static void nilfs_segctor_complete_write(struct nilfs_sc_info *sci)
         struct nilfs_segment_buffer *segbuf;
         struct page *bd_page = NULL, *fs_page = NULL;
         struct the_nilfs *nilfs = sci->sc_sbi->s_nilfs;
-        int update_sr = (sci->sc_super_root != NULL);
+        int update_sr = false;
 
         list_for_each_entry(segbuf, &sci->sc_write_logs, sb_list) {
                 struct buffer_head *bh;
@@ -1964,11 +1964,12 @@ static void nilfs_segctor_complete_write(struct nilfs_sc_info *sci)
                         set_buffer_uptodate(bh);
                         clear_buffer_dirty(bh);
                         clear_buffer_nilfs_volatile(bh);
-                        if (bh == sci->sc_super_root) {
+                        if (bh == segbuf->sb_super_root) {
                                 if (bh->b_page != bd_page) {
                                         end_page_writeback(bd_page);
                                         bd_page = bh->b_page;
                                 }
+                                update_sr = true;
                                 break;
                         }
                         if (bh->b_page != fs_page) {
@@ -2115,7 +2116,7 @@ static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
         struct nilfs_sb_info *sbi = sci->sc_sbi;
         struct the_nilfs *nilfs = sbi->s_nilfs;
         struct page *failed_page;
-        int err, has_sr = 0;
+        int err;
 
         sci->sc_stage.scnt = NILFS_ST_INIT;
 
@@ -2143,8 +2144,6 @@ static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
                 if (unlikely(err))
                         goto failed;
 
-                has_sr = (sci->sc_super_root != NULL);
-
                 /* Avoid empty segment */
                 if (sci->sc_stage.scnt == NILFS_ST_DONE &&
                     NILFS_SEG_EMPTY(&sci->sc_curseg->sb_sum)) {
@@ -2159,7 +2158,8 @@ static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
                 if (sci->sc_stage.flags & NILFS_CF_IFILE_STARTED)
                         nilfs_segctor_fill_in_file_bmap(sci, sbi->s_ifile);
 
-                if (has_sr) {
+                if (mode == SC_LSEG_SR &&
+                    sci->sc_stage.scnt >= NILFS_ST_CPFILE) {
                         err = nilfs_segctor_fill_in_checkpoint(sci);
                         if (unlikely(err))
                                 goto failed_to_write;
@@ -2171,8 +2171,7 @@ static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
                 /* Write partial segments */
                 err = nilfs_segctor_prepare_write(sci, &failed_page);
                 if (err) {
-                        nilfs_abort_logs(&sci->sc_segbufs, failed_page,
-                                         sci->sc_super_root, err);
+                        nilfs_abort_logs(&sci->sc_segbufs, failed_page, err);
                         goto failed_to_write;
                 }
                 nilfs_segctor_fill_in_checksums(sci, nilfs->ns_crc_seed);
@@ -2196,8 +2195,6 @@ static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
                 }
         } while (sci->sc_stage.scnt != NILFS_ST_DONE);
 
-        sci->sc_super_root = NULL;
-
  out:
         nilfs_segctor_check_out_files(sci, sbi);
         return err;
diff --git a/fs/nilfs2/segment.h b/fs/nilfs2/segment.h
index 82dfd6a686b9..e61fc797383e 100644
--- a/fs/nilfs2/segment.h
+++ b/fs/nilfs2/segment.h
@@ -100,7 +100,6 @@ struct nilfs_segsum_pointer {
  * @sc_write_logs: List of segment buffers to hold logs under writing
  * @sc_segbuf_nblocks: Number of available blocks in segment buffers.
  * @sc_curseg: Current segment buffer
- * @sc_super_root: Pointer to the super root buffer
  * @sc_stage: Collection stage
  * @sc_finfo_ptr: pointer to the current finfo struct in the segment summary
  * @sc_binfo_ptr: pointer to the current binfo struct in the segment summary
@@ -148,7 +147,6 @@ struct nilfs_sc_info {
         struct list_head        sc_write_logs;
         unsigned long           sc_segbuf_nblocks;
         struct nilfs_segment_buffer *sc_curseg;
-        struct buffer_head     *sc_super_root;
 
         struct nilfs_cstage     sc_stage;