bcachefs: Refactor journal code to not use unwritten_idx

It makes the code more readable if we work off of sequence numbers,
instead of direct indexes into the array of journal buffers.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

diff --git a/fs/bcachefs/journal.c b/fs/bcachefs/journal.c
index 41616db..3de1a74 100644 (file)
--- a/fs/bcachefs/journal.c
+++ b/fs/bcachefs/journal.c
@@ -19,11 +19,6 @@
 #include "super-io.h"
 #include "trace.h"
 
-static u64 last_unwritten_seq(struct journal *j)
-{
-       return j->seq_ondisk + 1;
-}
-
 static inline bool journal_seq_unwritten(struct journal *j, u64 seq)
 {
        return seq > j->seq_ondisk;
@@ -34,6 +29,11 @@ static bool __journal_entry_is_open(union journal_res_state state)
        return state.cur_entry_offset < JOURNAL_ENTRY_CLOSED_VAL;
 }
 
+static inline unsigned nr_unwritten_journal_entries(struct journal *j)
+{
+       return atomic64_read(&j->seq) - j->seq_ondisk;
+}
+
 static bool journal_entry_is_open(struct journal *j)
 {
        return __journal_entry_is_open(j->reservations);
@@ -166,6 +166,7 @@ static bool __journal_entry_close(struct journal *j)
         */
        buf->last_seq           = journal_last_seq(j);
        buf->data->last_seq     = cpu_to_le64(buf->last_seq);
+       BUG_ON(buf->last_seq > le64_to_cpu(buf->data->seq));
 
        __bch2_journal_pin_put(j, le64_to_cpu(buf->data->seq));
 
@@ -179,18 +180,19 @@ static bool __journal_entry_close(struct journal *j)
 
 static bool journal_entry_want_write(struct journal *j)
 {
-       union journal_res_state s = READ_ONCE(j->reservations);
-       struct journal_buf *buf = journal_cur_buf(j);
-       bool ret = false;
-
-       if (!buf->flush_time) {
-               buf->flush_time = local_clock() ?: 1;
-               buf->expires = jiffies;
-       }
+       bool ret = !journal_entry_is_open(j) ||
+               (journal_cur_seq(j) == journal_last_unwritten_seq(j) &&
+                __journal_entry_close(j));
 
        /* Don't close it yet if we already have a write in flight: */
-       if (s.idx == s.unwritten_idx)
-               ret = __journal_entry_close(j);
+       if (!ret && nr_unwritten_journal_entries(j)) {
+               struct journal_buf *buf = journal_cur_buf(j);
+
+               if (!buf->flush_time) {
+                       buf->flush_time = local_clock() ?: 1;
+                       buf->expires = jiffies;
+               }
+       }
 
        return ret;
 }
@@ -310,8 +312,8 @@ static int journal_entry_open(struct journal *j)
 
 static bool journal_quiesced(struct journal *j)
 {
-       union journal_res_state s = READ_ONCE(j->reservations);
-       bool ret = s.idx == s.unwritten_idx && !__journal_entry_is_open(s);
+       bool ret = atomic64_read(&j->seq) == j->seq_ondisk ||
+               bch2_journal_error(j);
 
        if (!ret)
                journal_entry_close(j);
@@ -416,7 +418,7 @@ unlock:
        if ((ret == cur_entry_journal_full ||
             ret == cur_entry_journal_pin_full) &&
            !can_discard &&
-           j->reservations.idx == j->reservations.unwritten_idx &&
+           !nr_unwritten_journal_entries(j) &&
            (flags & JOURNAL_RES_GET_RESERVED)) {
                struct printbuf buf = PRINTBUF;
 
@@ -576,7 +578,7 @@ int bch2_journal_flush_seq_async(struct journal *j, u64 seq,
        }
 
        /* if seq was written, but not flushed - flush a newer one instead */
-       seq = max(seq, last_unwritten_seq(j));
+       seq = max(seq, journal_last_unwritten_seq(j));
 
 recheck_need_open:
        if (seq > journal_cur_seq(j)) {
@@ -709,13 +711,13 @@ bool bch2_journal_noflush_seq(struct journal *j, u64 seq)
        if (seq <= c->journal.flushed_seq_ondisk)
                goto out;
 
-       for (unwritten_seq = last_unwritten_seq(j);
+       for (unwritten_seq = journal_last_unwritten_seq(j);
             unwritten_seq < seq;
             unwritten_seq++) {
                struct journal_buf *buf = journal_seq_to_buf(j, unwritten_seq);
 
                /* journal write is already in flight, and was a flush write: */
-               if (unwritten_seq == last_unwritten_seq(j) && !buf->noflush)
+               if (unwritten_seq == journal_last_unwritten_seq(j) && !buf->noflush)
                        goto out;
 
                buf->noflush = true;
@@ -940,17 +942,16 @@ int bch2_dev_journal_alloc(struct bch_dev *ca)
 
 static bool bch2_journal_writing_to_device(struct journal *j, unsigned dev_idx)
 {
-       union journal_res_state state;
        bool ret = false;
-       unsigned i;
+       u64 seq;
 
        spin_lock(&j->lock);
-       state = READ_ONCE(j->reservations);
-       i = state.idx;
+       for (seq = journal_last_unwritten_seq(j);
+            seq <= journal_cur_seq(j) && !ret;
+            seq++) {
+               struct journal_buf *buf = journal_seq_to_buf(j, seq);
 
-       while (i != state.unwritten_idx) {
-               i = (i - 1) & JOURNAL_BUF_MASK;
-               if (bch2_bkey_has_device(bkey_i_to_s_c(&j->buf[i].key), dev_idx))
+               if (bch2_bkey_has_device(bkey_i_to_s_c(&buf->key), dev_idx))
                        ret = true;
        }
        spin_unlock(&j->lock);
@@ -1012,6 +1013,7 @@ int bch2_fs_journal_start(struct journal *j, u64 cur_seq,
        j->replay_journal_seq_end = cur_seq;
        j->last_seq_ondisk      = last_seq;
        j->flushed_seq_ondisk   = cur_seq - 1;
+       j->seq_ondisk           = cur_seq - 1;
        j->pin.front            = last_seq;
        j->pin.back             = cur_seq;
        atomic64_set(&j->seq, cur_seq - 1);
@@ -1164,15 +1166,18 @@ void __bch2_journal_debug_to_text(struct printbuf *out, struct journal *j)
        union journal_res_state s;
        struct bch_dev *ca;
        unsigned long now = jiffies;
+       u64 seq;
        unsigned i;
 
        out->atomic++;
+       out->tabstops[0] = 24;
 
        rcu_read_lock();
        s = READ_ONCE(j->reservations);
 
-       pr_buf(out, "active journal entries:\t%llu\n",  fifo_used(&j->pin));
+       pr_buf(out, "dirty journal entries:\t%llu\n",   fifo_used(&j->pin));
        pr_buf(out, "seq:\t\t\t%llu\n",                 journal_cur_seq(j));
+       pr_buf(out, "seq_ondisk:\t\t%llu\n",            j->seq_ondisk);
        pr_buf(out, "last_seq:\t\t%llu\n",              journal_last_seq(j));
        pr_buf(out, "last_seq_ondisk:\t%llu\n",         j->last_seq_ondisk);
        pr_buf(out, "flushed_seq_ondisk:\t%llu\n",      j->flushed_seq_ondisk);
@@ -1191,33 +1196,42 @@ void __bch2_journal_debug_to_text(struct printbuf *out, struct journal *j)
 
        switch (s.cur_entry_offset) {
        case JOURNAL_ENTRY_ERROR_VAL:
-               pr_buf(out, "error\n");
+               pr_buf(out, "error");
                break;
        case JOURNAL_ENTRY_CLOSED_VAL:
-               pr_buf(out, "closed\n");
+               pr_buf(out, "closed");
                break;
        default:
-               pr_buf(out, "%u/%u\n", s.cur_entry_offset, j->cur_entry_u64s);
+               pr_buf(out, "%u/%u", s.cur_entry_offset, j->cur_entry_u64s);
                break;
        }
 
-       pr_buf(out, "current entry:\t\tidx %u refcount %u\n", s.idx, journal_state_count(s, s.idx));
+       pr_newline(out);
 
-       i = s.idx;
-       while (i != s.unwritten_idx) {
-               i = (i - 1) & JOURNAL_BUF_MASK;
+       for (seq = journal_cur_seq(j);
+            seq >= journal_last_unwritten_seq(j);
+            --seq) {
+               i = seq & JOURNAL_BUF_MASK;
 
-               pr_buf(out, "unwritten entry:\tidx %u refcount %u sectors %u\n",
-                      i, journal_state_count(s, i), j->buf[i].sectors);
+               pr_buf(out, "unwritten entry:");
+               pr_tab(out);
+               pr_buf(out, "%llu", seq);
+               pr_newline(out);
                pr_indent_push(out, 2);
 
-               pr_buf(out, "refcount %u", journal_state_count(s, i));
+               pr_buf(out, "refcount:");
+               pr_tab(out);
+               pr_buf(out, "%u", journal_state_count(s, i));
                pr_newline(out);
 
-               pr_buf(out, "sectors %u", j->buf[i].sectors);
+               pr_buf(out, "sectors:");
+               pr_tab(out);
+               pr_buf(out, "%u", j->buf[i].sectors);
                pr_newline(out);
 
-               pr_buf(out, "expires %li ms", jiffies_to_msecs(j->buf[i].expires - jiffies));
+               pr_buf(out, "expires");
+               pr_tab(out);
+               pr_buf(out, "%li jiffies", j->buf[i].expires - jiffies);
                pr_newline(out);
 
                pr_indent_pop(out, 2);

diff --git a/fs/bcachefs/journal.h b/fs/bcachefs/journal.h
index 6c7a38a..409d32b 100644 (file)
--- a/fs/bcachefs/journal.h
+++ b/fs/bcachefs/journal.h
@@ -141,6 +141,11 @@ static inline u64 journal_cur_seq(struct journal *j)
        return j->pin.back - 1;
 }
 
+static inline u64 journal_last_unwritten_seq(struct journal *j)
+{
+       return j->seq_ondisk + 1;
+}
+
 static inline int journal_state_count(union journal_res_state s, int idx)
 {
        switch (idx) {

diff --git a/fs/bcachefs/journal_io.c b/fs/bcachefs/journal_io.c
index 0d6bede..7c8298d 100644 (file)
--- a/fs/bcachefs/journal_io.c
+++ b/fs/bcachefs/journal_io.c
@@ -1331,7 +1331,7 @@ static void journal_buf_realloc(struct journal *j, struct journal_buf *buf)
 
 static inline struct journal_buf *journal_last_unwritten_buf(struct journal *j)
 {
-       return j->buf + j->reservations.unwritten_idx;
+       return j->buf + (journal_last_unwritten_seq(j) & JOURNAL_BUF_MASK);
 }
 
 static void journal_write_done(struct closure *cl)
@@ -1403,12 +1403,13 @@ static void journal_write_done(struct closure *cl)
        closure_wake_up(&w->wait);
        journal_wake(j);
 
-       if (new.unwritten_idx == new.idx) {
+       if (journal_last_unwritten_seq(j) == journal_cur_seq(j)) {
                struct journal_buf *buf = journal_cur_buf(j);
                long delta = buf->expires - jiffies;
 
                mod_delayed_work(c->io_complete_wq, &j->write_work, max(0L, delta));
-       } else if (!journal_state_count(new, new.unwritten_idx))
+       } else if (journal_last_unwritten_seq(j) < journal_cur_seq(j) &&
+                  !journal_state_count(new, new.unwritten_idx))
                closure_call(&j->io, bch2_journal_write, c->io_complete_wq, NULL);
 
        spin_unlock(&j->lock);

diff --git a/fs/bcachefs/journal_reclaim.c b/fs/bcachefs/journal_reclaim.c
index 213047b..39f4b2e 100644 (file)
--- a/fs/bcachefs/journal_reclaim.c
+++ b/fs/bcachefs/journal_reclaim.c
@@ -59,25 +59,13 @@ static void journal_set_remaining(struct journal *j, unsigned u64s_remaining)
                                       old.v, new.v)) != old.v);
 }
 
-static inline unsigned get_unwritten_sectors(struct journal *j, unsigned *idx)
-{
-       unsigned sectors = 0;
-
-       while (!sectors && *idx != j->reservations.idx) {
-               sectors = j->buf[*idx].sectors;
-
-               *idx = (*idx + 1) & JOURNAL_BUF_MASK;
-       }
-
-       return sectors;
-}
-
 static struct journal_space
 journal_dev_space_available(struct journal *j, struct bch_dev *ca,
                            enum journal_space_from from)
 {
        struct journal_device *ja = &ca->journal;
-       unsigned sectors, buckets, unwritten, idx = j->reservations.unwritten_idx;
+       unsigned sectors, buckets, unwritten;
+       u64 seq;
 
        if (from == journal_space_total)
                return (struct journal_space) {
@@ -92,7 +80,14 @@ journal_dev_space_available(struct journal *j, struct bch_dev *ca,
         * We that we don't allocate the space for a journal entry
         * until we write it out - thus, account for it here:
         */
-       while ((unwritten = get_unwritten_sectors(j, &idx))) {
+       for (seq = journal_last_unwritten_seq(j);
+            seq <= journal_cur_seq(j);
+            seq++) {
+               unwritten = j->buf[seq & JOURNAL_BUF_MASK].sectors;
+
+               if (!unwritten)
+                       continue;
+
                /* entry won't fit on this device, skip: */
                if (unwritten > ca->mi.bucket_size)
                        continue;
@@ -214,8 +209,7 @@ void bch2_journal_space_available(struct journal *j)
        total           = j->space[journal_space_total].total;
 
        if (!clean_ondisk &&
-           j->reservations.idx ==
-           j->reservations.unwritten_idx) {
+           journal_cur_seq(j) == j->seq_ondisk) {
                struct printbuf buf = PRINTBUF;
 
                __bch2_journal_debug_to_text(&buf, j);

diff --git a/fs/bcachefs/journal_types.h b/fs/bcachefs/journal_types.h
index 36843fd..3d9810e 100644 (file)
--- a/fs/bcachefs/journal_types.h
+++ b/fs/bcachefs/journal_types.h
@@ -25,7 +25,7 @@ struct journal_buf {
 
        struct closure_waitlist wait;
        u64                     last_seq;       /* copy of data->last_seq */
-       unsigned long           expires;
+       long                    expires;
        u64                     flush_time;
 
        unsigned                buf_size;       /* size in bytes of @data */