[GFS2] Clean up journaled data writing
This patch cleans up the code for writing journaled data into the log.
It also removes the need to allocate a small "tag" structure for each
block written into the log. Instead we just keep count of the outstanding
I/O so that we can be sure that its all been written at the correct time.
Another result of this patch is that a number of ll_rw_block() calls
have become submit_bh() calls, closing some races at the same time.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index 4d04e6f..ee70467 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -104,11 +104,8 @@
gfs2_assert(sdp, bd->bd_ail == ai);
if (!buffer_busy(bh)) {
- if (!buffer_uptodate(bh)) {
- gfs2_log_unlock(sdp);
+ if (!buffer_uptodate(bh))
gfs2_io_error_bh(sdp, bh);
- gfs2_log_lock(sdp);
- }
list_move(&bd->bd_ail_st_list, &ai->ai_ail2_list);
continue;
}
@@ -118,9 +115,16 @@
list_move(&bd->bd_ail_st_list, &ai->ai_ail1_list);
+ get_bh(bh);
gfs2_log_unlock(sdp);
- wait_on_buffer(bh);
- ll_rw_block(WRITE, 1, &bh);
+ lock_buffer(bh);
+ if (test_clear_buffer_dirty(bh)) {
+ bh->b_end_io = end_buffer_write_sync;
+ submit_bh(WRITE, bh);
+ } else {
+ unlock_buffer(bh);
+ brelse(bh);
+ }
gfs2_log_lock(sdp);
retry = 1;
@@ -446,10 +450,10 @@
return tail;
}
-static inline void log_incr_head(struct gfs2_sbd *sdp)
+void gfs2_log_incr_head(struct gfs2_sbd *sdp)
{
if (sdp->sd_log_flush_head == sdp->sd_log_tail)
- gfs2_assert_withdraw(sdp, sdp->sd_log_flush_head == sdp->sd_log_head);
+ BUG_ON(sdp->sd_log_flush_head != sdp->sd_log_head);
if (++sdp->sd_log_flush_head == sdp->sd_jdesc->jd_blocks) {
sdp->sd_log_flush_head = 0;
@@ -458,6 +462,23 @@
}
/**
+ * gfs2_log_write_endio - End of I/O for a log buffer
+ * @bh: The buffer head
+ * @uptodate: I/O Status
+ *
+ */
+
+static void gfs2_log_write_endio(struct buffer_head *bh, int uptodate)
+{
+ struct gfs2_sbd *sdp = bh->b_private;
+ bh->b_private = NULL;
+
+ end_buffer_write_sync(bh, uptodate);
+ if (atomic_dec_and_test(&sdp->sd_log_in_flight))
+ wake_up(&sdp->sd_log_flush_wait);
+}
+
+/**
* gfs2_log_get_buf - Get and initialize a buffer to use for log control data
* @sdp: The GFS2 superblock
*
@@ -467,25 +488,42 @@
struct buffer_head *gfs2_log_get_buf(struct gfs2_sbd *sdp)
{
u64 blkno = log_bmap(sdp, sdp->sd_log_flush_head);
- struct gfs2_log_buf *lb;
struct buffer_head *bh;
- lb = kzalloc(sizeof(struct gfs2_log_buf), GFP_NOFS | __GFP_NOFAIL);
- list_add(&lb->lb_list, &sdp->sd_log_flush_list);
-
- bh = lb->lb_bh = sb_getblk(sdp->sd_vfs, blkno);
+ bh = sb_getblk(sdp->sd_vfs, blkno);
lock_buffer(bh);
memset(bh->b_data, 0, bh->b_size);
set_buffer_uptodate(bh);
clear_buffer_dirty(bh);
- unlock_buffer(bh);
-
- log_incr_head(sdp);
+ gfs2_log_incr_head(sdp);
+ atomic_inc(&sdp->sd_log_in_flight);
+ bh->b_private = sdp;
+ bh->b_end_io = gfs2_log_write_endio;
return bh;
}
/**
+ * gfs2_fake_write_endio -
+ * @bh: The buffer head
+ * @uptodate: The I/O Status
+ *
+ */
+
+static void gfs2_fake_write_endio(struct buffer_head *bh, int uptodate)
+{
+ struct buffer_head *real_bh = bh->b_private;
+ struct gfs2_sbd *sdp = GFS2_SB(real_bh->b_page->mapping->host);
+
+ end_buffer_write_sync(bh, uptodate);
+ free_buffer_head(bh);
+ unlock_buffer(real_bh);
+ brelse(real_bh);
+ if (atomic_dec_and_test(&sdp->sd_log_in_flight))
+ wake_up(&sdp->sd_log_flush_wait);
+}
+
+/**
* gfs2_log_fake_buf - Build a fake buffer head to write metadata buffer to log
* @sdp: the filesystem
* @data: the data the buffer_head should point to
@@ -497,22 +535,20 @@
struct buffer_head *real)
{
u64 blkno = log_bmap(sdp, sdp->sd_log_flush_head);
- struct gfs2_log_buf *lb;
struct buffer_head *bh;
- lb = kzalloc(sizeof(struct gfs2_log_buf), GFP_NOFS | __GFP_NOFAIL);
- list_add(&lb->lb_list, &sdp->sd_log_flush_list);
- lb->lb_real = real;
-
- bh = lb->lb_bh = alloc_buffer_head(GFP_NOFS | __GFP_NOFAIL);
+ bh = alloc_buffer_head(GFP_NOFS | __GFP_NOFAIL);
atomic_set(&bh->b_count, 1);
- bh->b_state = (1 << BH_Mapped) | (1 << BH_Uptodate);
+ bh->b_state = (1 << BH_Mapped) | (1 << BH_Uptodate) | (1 << BH_Lock);
set_bh_page(bh, real->b_page, bh_offset(real));
bh->b_blocknr = blkno;
bh->b_size = sdp->sd_sb.sb_bsize;
bh->b_bdev = sdp->sd_vfs->s_bdev;
+ bh->b_private = real;
+ bh->b_end_io = gfs2_fake_write_endio;
- log_incr_head(sdp);
+ gfs2_log_incr_head(sdp);
+ atomic_inc(&sdp->sd_log_in_flight);
return bh;
}
@@ -579,45 +615,24 @@
gfs2_assert_withdraw(sdp, !pull);
sdp->sd_log_idle = (tail == sdp->sd_log_flush_head);
- log_incr_head(sdp);
+ gfs2_log_incr_head(sdp);
}
static void log_flush_commit(struct gfs2_sbd *sdp)
{
- struct list_head *head = &sdp->sd_log_flush_list;
- struct gfs2_log_buf *lb;
- struct buffer_head *bh;
- int flushcount = 0;
+ DEFINE_WAIT(wait);
- while (!list_empty(head)) {
- lb = list_entry(head->next, struct gfs2_log_buf, lb_list);
- list_del(&lb->lb_list);
- bh = lb->lb_bh;
-
- wait_on_buffer(bh);
- if (!buffer_uptodate(bh))
- gfs2_io_error_bh(sdp, bh);
- if (lb->lb_real) {
- while (atomic_read(&bh->b_count) != 1) /* Grrrr... */
- schedule();
- free_buffer_head(bh);
- } else
- brelse(bh);
- kfree(lb);
- flushcount++;
+ if (atomic_read(&sdp->sd_log_in_flight)) {
+ do {
+ prepare_to_wait(&sdp->sd_log_flush_wait, &wait,
+ TASK_UNINTERRUPTIBLE);
+ if (atomic_read(&sdp->sd_log_in_flight))
+ io_schedule();
+ } while(atomic_read(&sdp->sd_log_in_flight));
+ finish_wait(&sdp->sd_log_flush_wait, &wait);
}
- /* If nothing was journaled, the header is unplanned and unwanted. */
- if (flushcount) {
- log_write_header(sdp, 0, 0);
- } else {
- unsigned int tail;
- tail = current_tail(sdp);
-
- gfs2_ail1_empty(sdp, 0);
- if (sdp->sd_log_tail != tail)
- log_pull_tail(sdp, tail);
- }
+ log_write_header(sdp, 0, 0);
}
static void gfs2_ordered_write(struct gfs2_sbd *sdp)
@@ -698,10 +713,16 @@
INIT_LIST_HEAD(&ai->ai_ail1_list);
INIT_LIST_HEAD(&ai->ai_ail2_list);
- gfs2_assert_withdraw(sdp,
- sdp->sd_log_num_buf + sdp->sd_log_num_databuf ==
- sdp->sd_log_commited_buf +
- sdp->sd_log_commited_databuf);
+ if (sdp->sd_log_num_buf != sdp->sd_log_commited_buf) {
+ printk(KERN_INFO "GFS2: log buf %u %u\n", sdp->sd_log_num_buf,
+ sdp->sd_log_commited_buf);
+ gfs2_assert_withdraw(sdp, 0);
+ }
+ if (sdp->sd_log_num_databuf != sdp->sd_log_commited_databuf) {
+ printk(KERN_INFO "GFS2: log databuf %u %u\n",
+ sdp->sd_log_num_databuf, sdp->sd_log_commited_databuf);
+ gfs2_assert_withdraw(sdp, 0);
+ }
gfs2_assert_withdraw(sdp,
sdp->sd_log_num_revoke == sdp->sd_log_commited_revoke);
@@ -713,7 +734,7 @@
lops_before_commit(sdp);
gfs2_ordered_wait(sdp);
- if (!list_empty(&sdp->sd_log_flush_list))
+ if (sdp->sd_log_head != sdp->sd_log_flush_head)
log_flush_commit(sdp);
else if (sdp->sd_log_tail != current_tail(sdp) && !sdp->sd_log_idle){
gfs2_log_lock(sdp);