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nilfs2: simplify handling of active state of segments
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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>
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Ryusuke Konishi authored and Linus Torvalds committed Apr 7, 2009
1 parent c96fa46 commit cece552
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Showing 8 changed files with 29 additions and 208 deletions.
12 changes: 1 addition & 11 deletions fs/nilfs2/recovery.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -463,16 +463,6 @@ static int nilfs_prepare_segment_for_recovery(struct the_nilfs *nilfs,
nilfs_free_segment_entry(ent);
}

/*
* The segment having the latest super root is active, and
* should be deactivated on the next construction for recovery.
*/
err = -ENOMEM;
ent = nilfs_alloc_segment_entry(segnum[0]);
if (unlikely(!ent))
goto failed;
list_add_tail(&ent->list, &ri->ri_used_segments);

/* Allocate new segments for recovery */
err = nilfs_sufile_alloc(sufile, &segnum[0]);
if (unlikely(err))
Expand Down Expand Up @@ -757,7 +747,7 @@ int nilfs_recover_logical_segments(struct the_nilfs *nilfs,
goto failed;
}

err = nilfs_attach_segment_constructor(sbi, ri);
err = nilfs_attach_segment_constructor(sbi);
if (unlikely(err))
goto failed;

Expand Down
24 changes: 1 addition & 23 deletions fs/nilfs2/segbuf.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -64,46 +64,24 @@ 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_segent = NULL;
return segbuf;
}

void nilfs_segbuf_free(struct nilfs_segment_buffer *segbuf)
{
struct nilfs_segment_entry *ent = segbuf->sb_segent;

if (ent != NULL && list_empty(&ent->list)) {
/* free isolated segment list head */
nilfs_free_segment_entry(segbuf->sb_segent);
segbuf->sb_segent = NULL;
}
kmem_cache_free(nilfs_segbuf_cachep, segbuf);
}

int nilfs_segbuf_map(struct nilfs_segment_buffer *segbuf, __u64 segnum,
void nilfs_segbuf_map(struct nilfs_segment_buffer *segbuf, __u64 segnum,
unsigned long offset, struct the_nilfs *nilfs)
{
struct nilfs_segment_entry *ent;

segbuf->sb_segnum = segnum;
nilfs_get_segment_range(nilfs, segnum, &segbuf->sb_fseg_start,
&segbuf->sb_fseg_end);

segbuf->sb_pseg_start = segbuf->sb_fseg_start + offset;
segbuf->sb_rest_blocks =
segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1;

/* Attach a segment list head */
ent = segbuf->sb_segent;
if (ent == NULL) {
segbuf->sb_segent = nilfs_alloc_segment_entry(segnum);
if (unlikely(!segbuf->sb_segent))
return -ENOMEM;
} else {
BUG_ON(ent->bh_su || !list_empty(&ent->list));
ent->segnum = segnum;
}
return 0;
}

void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *segbuf,
Expand Down
6 changes: 2 additions & 4 deletions fs/nilfs2/segbuf.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -68,7 +68,6 @@ struct nilfs_segsum_info {
* struct nilfs_segment_buffer - Segment buffer
* @sb_super: back pointer to a superblock struct
* @sb_list: List head to chain this structure
* @sb_segent: Pointer for attaching a segment entry
* @sb_sum: On-memory segment summary
* @sb_segnum: Index number of the full segment
* @sb_nextnum: Index number of the next full segment
Expand All @@ -83,7 +82,6 @@ struct nilfs_segsum_info {
struct nilfs_segment_buffer {
struct super_block *sb_super;
struct list_head sb_list;
struct nilfs_segment_entry *sb_segent;

/* Segment information */
struct nilfs_segsum_info sb_sum;
Expand Down Expand Up @@ -125,8 +123,8 @@ int __init nilfs_init_segbuf_cache(void);
void nilfs_destroy_segbuf_cache(void);
struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *);
void nilfs_segbuf_free(struct nilfs_segment_buffer *);
int nilfs_segbuf_map(struct nilfs_segment_buffer *, __u64, unsigned long,
struct the_nilfs *);
void nilfs_segbuf_map(struct nilfs_segment_buffer *, __u64, unsigned long,
struct the_nilfs *);
void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *, __u64,
struct the_nilfs *);
int nilfs_segbuf_reset(struct nilfs_segment_buffer *, unsigned, time_t);
Expand Down
173 changes: 11 additions & 162 deletions fs/nilfs2/segment.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand All @@ -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;

Expand All @@ -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
Expand All @@ -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,
Expand Down Expand Up @@ -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 */
Expand Down Expand Up @@ -2177,102 +2148,6 @@ static void nilfs_segctor_check_out_files(struct nilfs_sc_info *sci,
spin_unlock(&sbi->s_inode_lock);
}

/*
* 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
*/
Expand Down Expand Up @@ -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);

Expand All @@ -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);
}
Expand All @@ -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())
Expand Down Expand Up @@ -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);
}

/*
Expand All @@ -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);

Expand Down Expand Up @@ -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);
Expand All @@ -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.
Expand All @@ -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;
Expand All @@ -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);
Expand Down
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