nilfs2: simplify handling of active state of segments

will reduce some lines of segment constructor.  Previously, the state was
complexly controlled through a list of segments in order to keep
consistency in meta data of usage state of segments.  Instead, this
presents ``calculated'' active flags to userland cleaner program and stop
maintaining its real flag on disk.

Only by this fake flag, the cleaner cannot exactly know if each segment is
reclaimable or not.  However, the recent extension of nilfs_sustat ioctl
struct (nilfs2-extend-nilfs_sustat-ioctl-struct.patch) can prevent the
cleaner from reclaiming in-use segment wrongly.

So, now I can apply this for simplification.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 162 deletions

diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index 2879704509f..e43558d50e7 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -1304,25 +1304,6 @@ static int nilfs_segctor_collect_blocks(struct nilfs_sc_info *sci, int mode)
 	return err;
 }
 
-static int nilfs_segctor_terminate_segment(struct nilfs_sc_info *sci,
-					   struct nilfs_segment_buffer *segbuf,
-					   struct inode *sufile)
-{
-	struct nilfs_segment_entry *ent = segbuf->sb_segent;
-	int err;
-
-	err = nilfs_open_segment_entry(ent, sufile);
-	if (unlikely(err))
-		return err;
-	nilfs_mdt_mark_buffer_dirty(ent->bh_su);
-	nilfs_mdt_mark_dirty(sufile);
-	nilfs_close_segment_entry(ent, sufile);
-
-	list_add_tail(&ent->list, &sci->sc_active_segments);
-	segbuf->sb_segent = NULL;
-	return 0;
-}
-
 static int nilfs_touch_segusage(struct inode *sufile, __u64 segnum)
 {
 	struct buffer_head *bh_su;
@@ -1342,7 +1323,6 @@ static int nilfs_segctor_begin_construction(struct nilfs_sc_info *sci,
 					    struct the_nilfs *nilfs)
 {
 	struct nilfs_segment_buffer *segbuf, *n;
-	struct inode *sufile = nilfs->ns_sufile;
 	__u64 nextnum;
 	int err;
 
@@ -1354,28 +1334,22 @@ static int nilfs_segctor_begin_construction(struct nilfs_sc_info *sci,
 	} else
 		segbuf = NILFS_FIRST_SEGBUF(&sci->sc_segbufs);
 
-	err = nilfs_segbuf_map(segbuf, nilfs->ns_segnum,
-			       nilfs->ns_pseg_offset, nilfs);
-	if (unlikely(err))
-		return err;
+	nilfs_segbuf_map(segbuf, nilfs->ns_segnum, nilfs->ns_pseg_offset,
+			 nilfs);
 
 	if (segbuf->sb_rest_blocks < NILFS_PSEG_MIN_BLOCKS) {
-		err = nilfs_segctor_terminate_segment(sci, segbuf, sufile);
-		if (unlikely(err))
-			return err;
-
 		nilfs_shift_to_next_segment(nilfs);
-		err = nilfs_segbuf_map(segbuf, nilfs->ns_segnum, 0, nilfs);
+		nilfs_segbuf_map(segbuf, nilfs->ns_segnum, 0, nilfs);
 	}
 	sci->sc_segbuf_nblocks = segbuf->sb_rest_blocks;
 
-	err = nilfs_touch_segusage(sufile, segbuf->sb_segnum);
+	err = nilfs_touch_segusage(nilfs->ns_sufile, segbuf->sb_segnum);
 	if (unlikely(err))
 		return err;
 
 	if (nilfs->ns_segnum == nilfs->ns_nextnum) {
 		/* Start from the head of a new full segment */
-		err = nilfs_sufile_alloc(sufile, &nextnum);
+		err = nilfs_sufile_alloc(nilfs->ns_sufile, &nextnum);
 		if (unlikely(err))
 			return err;
 	} else
@@ -1390,7 +1364,7 @@ static int nilfs_segctor_begin_construction(struct nilfs_sc_info *sci,
 		list_del_init(&segbuf->sb_list);
 		nilfs_segbuf_free(segbuf);
 	}
-	return err;
+	return 0;
 }
 
 static int nilfs_segctor_extend_segments(struct nilfs_sc_info *sci,
@@ -1421,10 +1395,7 @@ static int nilfs_segctor_extend_segments(struct nilfs_sc_info *sci,
 			goto failed;
 
 		/* map this buffer to region of segment on-disk */
-		err = nilfs_segbuf_map(segbuf, prev->sb_nextnum, 0, nilfs);
-		if (unlikely(err))
-			goto failed_segbuf;
-
+		nilfs_segbuf_map(segbuf, prev->sb_nextnum, 0, nilfs);
 		sci->sc_segbuf_nblocks += segbuf->sb_rest_blocks;
 
 		/* allocate the next next full segment */
@@ -2178,102 +2149,6 @@ static void nilfs_segctor_check_out_files(struct nilfs_sc_info *sci,
 }
 
 /*
- * Nasty routines to manipulate active flags on sufile.
- * These would be removed in a future release.
- */
-static void nilfs_segctor_reactivate_segments(struct nilfs_sc_info *sci,
-					      struct the_nilfs *nilfs)
-{
-	struct nilfs_segment_buffer *segbuf, *last;
-	struct nilfs_segment_entry *ent, *n;
-	struct inode *sufile = nilfs->ns_sufile;
-	struct list_head *head;
-
-	last = NILFS_LAST_SEGBUF(&sci->sc_segbufs);
-	nilfs_for_each_segbuf_before(segbuf, last, &sci->sc_segbufs) {
-		ent = segbuf->sb_segent;
-		if (!ent)
-			break; /* ignore unmapped segments (should check it?)*/
-		nilfs_segment_usage_set_active(ent->raw_su);
-		nilfs_close_segment_entry(ent, sufile);
-	}
-
-	head = &sci->sc_active_segments;
-	list_for_each_entry_safe(ent, n, head, list) {
-		nilfs_segment_usage_set_active(ent->raw_su);
-		nilfs_close_segment_entry(ent, sufile);
-	}
-}
-
-static int nilfs_segctor_deactivate_segments(struct nilfs_sc_info *sci,
-					     struct the_nilfs *nilfs)
-{
-	struct nilfs_segment_buffer *segbuf, *last;
-	struct nilfs_segment_entry *ent;
-	struct inode *sufile = nilfs->ns_sufile;
-	int err;
-
-	last = NILFS_LAST_SEGBUF(&sci->sc_segbufs);
-	nilfs_for_each_segbuf_before(segbuf, last, &sci->sc_segbufs) {
-		/*
-		 * Deactivate ongoing full segments.  The last segment is kept
-		 * active because it is a start point of recovery, and is not
-		 * relocatable until the super block points to a newer
-		 * checkpoint.
-		 */
-		ent = segbuf->sb_segent;
-		if (!ent)
-			break; /* ignore unmapped segments (should check it?)*/
-		err = nilfs_open_segment_entry(ent, sufile);
-		if (unlikely(err))
-			goto failed;
-		nilfs_segment_usage_clear_active(ent->raw_su);
-		BUG_ON(!buffer_dirty(ent->bh_su));
-	}
-
-	list_for_each_entry(ent, &sci->sc_active_segments, list) {
-		err = nilfs_open_segment_entry(ent, sufile);
-		if (unlikely(err))
-			goto failed;
-		nilfs_segment_usage_clear_active(ent->raw_su);
-		WARN_ON(!buffer_dirty(ent->bh_su));
-	}
-	return 0;
-
- failed:
-	nilfs_segctor_reactivate_segments(sci, nilfs);
-	return err;
-}
-
-static void nilfs_segctor_bead_completed_segments(struct nilfs_sc_info *sci)
-{
-	struct nilfs_segment_buffer *segbuf, *last;
-	struct nilfs_segment_entry *ent;
-
-	/* move each segbuf->sb_segent to the list of used active segments */
-	last = NILFS_LAST_SEGBUF(&sci->sc_segbufs);
-	nilfs_for_each_segbuf_before(segbuf, last, &sci->sc_segbufs) {
-		ent = segbuf->sb_segent;
-		if (!ent)
-			break; /* ignore unmapped segments (should check it?)*/
-		list_add_tail(&ent->list, &sci->sc_active_segments);
-		segbuf->sb_segent = NULL;
-	}
-}
-
-static void nilfs_segctor_commit_deactivate_segments(struct nilfs_sc_info *sci,
-						     struct the_nilfs *nilfs)
-{
-	struct nilfs_segment_entry *ent, *n;
-
-	list_for_each_entry_safe(ent, n, &sci->sc_active_segments, list) {
-		list_del(&ent->list);
-		nilfs_close_segment_entry(ent, nilfs->ns_sufile);
-		nilfs_free_segment_entry(ent);
-	}
-}
-
-/*
  * Main procedure of segment constructor
  */
 static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
@@ -2322,11 +2197,6 @@ static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
 		if (unlikely(err))
 			goto failed;
 
-		if (has_sr) {
-			err = nilfs_segctor_deactivate_segments(sci, nilfs);
-			if (unlikely(err))
-				goto failed;
-		}
 		if (sci->sc_stage.flags & NILFS_CF_IFILE_STARTED)
 			nilfs_segctor_fill_in_file_bmap(sci, sbi->s_ifile);
 
@@ -2353,12 +2223,10 @@ static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
 		nilfs_segctor_complete_write(sci);
 
 		/* Commit segments */
-		nilfs_segctor_bead_completed_segments(sci);
 		if (has_sr) {
 			down_write(&nilfs->ns_sem);
 			nilfs_update_last_segment(sbi, 1);
 			up_write(&nilfs->ns_sem);
-			nilfs_segctor_commit_deactivate_segments(sci, nilfs);
 			nilfs_segctor_commit_free_segments(sci);
 			nilfs_segctor_clear_metadata_dirty(sci);
 		}
@@ -2379,8 +2247,6 @@ static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
  failed_to_make_up:
 	if (sci->sc_stage.flags & NILFS_CF_IFILE_STARTED)
 		nilfs_redirty_inodes(&sci->sc_dirty_files);
-	if (has_sr)
-		nilfs_segctor_reactivate_segments(sci, nilfs);
 
  failed:
 	if (nilfs_doing_gc())
@@ -2942,23 +2808,11 @@ static void nilfs_segctor_kill_thread(struct nilfs_sc_info *sci)
 	}
 }
 
-static int nilfs_segctor_init(struct nilfs_sc_info *sci,
-			      struct nilfs_recovery_info *ri)
+static int nilfs_segctor_init(struct nilfs_sc_info *sci)
 {
-	int err;
-
 	sci->sc_seq_done = sci->sc_seq_request;
-	if (ri)
-		list_splice_init(&ri->ri_used_segments,
-				 sci->sc_active_segments.prev);
 
-	err = nilfs_segctor_start_thread(sci);
-	if (err) {
-		if (ri)
-			list_splice_init(&sci->sc_active_segments,
-					 ri->ri_used_segments.prev);
-	}
-	return err;
+	return nilfs_segctor_start_thread(sci);
 }
 
 /*
@@ -2982,7 +2836,6 @@ static struct nilfs_sc_info *nilfs_segctor_new(struct nilfs_sb_info *sbi)
 	INIT_LIST_HEAD(&sci->sc_dirty_files);
 	INIT_LIST_HEAD(&sci->sc_segbufs);
 	INIT_LIST_HEAD(&sci->sc_gc_inodes);
-	INIT_LIST_HEAD(&sci->sc_active_segments);
 	INIT_LIST_HEAD(&sci->sc_cleaning_segments);
 	INIT_LIST_HEAD(&sci->sc_copied_buffers);
 
@@ -3048,8 +2901,6 @@ static void nilfs_segctor_destroy(struct nilfs_sc_info *sci)
 			      "dirty file(s) after the final construction\n");
 		nilfs_dispose_list(sbi, &sci->sc_dirty_files, 1);
 	}
-	if (!list_empty(&sci->sc_active_segments))
-		nilfs_dispose_segment_list(&sci->sc_active_segments);
 
 	if (!list_empty(&sci->sc_cleaning_segments))
 		nilfs_dispose_segment_list(&sci->sc_cleaning_segments);
@@ -3064,7 +2915,6 @@ static void nilfs_segctor_destroy(struct nilfs_sc_info *sci)
 /**
  * nilfs_attach_segment_constructor - attach a segment constructor
  * @sbi: nilfs_sb_info
- * @ri: nilfs_recovery_info
  *
  * nilfs_attach_segment_constructor() allocates a struct nilfs_sc_info,
  * initilizes it, and starts the segment constructor.
@@ -3074,8 +2924,7 @@ static void nilfs_segctor_destroy(struct nilfs_sc_info *sci)
  *
  * %-ENOMEM - Insufficient memory available.
  */
-int nilfs_attach_segment_constructor(struct nilfs_sb_info *sbi,
-				     struct nilfs_recovery_info *ri)
+int nilfs_attach_segment_constructor(struct nilfs_sb_info *sbi)
 {
 	struct the_nilfs *nilfs = sbi->s_nilfs;
 	int err;
@@ -3087,7 +2936,7 @@ int nilfs_attach_segment_constructor(struct nilfs_sb_info *sbi,
 		return -ENOMEM;
 
 	nilfs_attach_writer(nilfs, sbi);
-	err = nilfs_segctor_init(NILFS_SC(sbi), ri);
+	err = nilfs_segctor_init(NILFS_SC(sbi));
 	if (err) {
 		nilfs_detach_writer(nilfs, sbi);
 		kfree(sbi->s_sc_info);