bcachefs: Clean up btree write buffer write ref handling

__bch2_btree_write_buffer_flush() now assumes a write ref is already
held (as called by the transaction commit path); and the wrappers
bch2_write_buffer_flush() and flush_sync() take an explicit write ref.

This means internally the write buffer code can always use
BTREE_INSERT_NOCHECK_RW, instead of in the previous code passing flags
around and hoping the NOCHECK_RW flag was always carried around
correctly.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

diff --git a/fs/bcachefs/bcachefs.h b/fs/bcachefs/bcachefs.h
index 991de12974db5af06d41d50382614fb5289b9017..4186779f1e44af4956092c5d15da1ead52296ba0 100644 (file)
--- a/fs/bcachefs/bcachefs.h
+++ b/fs/bcachefs/bcachefs.h
@@ -672,7 +672,8 @@ struct btree_trans_buf {
        x(invalidate)                                                   \
        x(delete_dead_snapshots)                                        \
        x(snapshot_delete_pagecache)                                    \
-       x(sysfs)
+       x(sysfs)                                                        \
+       x(btree_write_buffer)
 
 enum bch_write_ref {
 #define x(n) BCH_WRITE_REF_##n,

diff --git a/fs/bcachefs/btree_trans_commit.c b/fs/bcachefs/btree_trans_commit.c
index 578521216b6ad7237c3f0c0e69b457fc1166f119..a2d0494b58f4b271387097e065da585b8c92d9ae 100644 (file)
--- a/fs/bcachefs/btree_trans_commit.c
+++ b/fs/bcachefs/btree_trans_commit.c
@@ -961,8 +961,7 @@ int bch2_trans_commit_error(struct btree_trans *trans, unsigned flags,
 
                        if (wb->state.nr > wb->size * 3 / 4) {
                                bch2_trans_begin(trans);
-                               ret = __bch2_btree_write_buffer_flush(trans,
-                                               flags|BCH_TRANS_COMMIT_no_check_rw, true);
+                               ret = __bch2_btree_write_buffer_flush(trans, true);
                                if (!ret) {
                                        trace_and_count(c, trans_restart_write_buffer_flush, trans, _THIS_IP_);
                                        ret = btree_trans_restart(trans, BCH_ERR_transaction_restart_write_buffer_flush);
@@ -1077,8 +1076,7 @@ int __bch2_trans_commit(struct btree_trans *trans, unsigned flags)
                bch2_trans_begin(trans);
                bch2_trans_unlock(trans);
 
-               ret = __bch2_btree_write_buffer_flush(trans,
-                                       flags|BCH_TRANS_COMMIT_no_check_rw, true);
+               ret = __bch2_btree_write_buffer_flush(trans, true);
                if (!ret) {
                        trace_and_count(c, trans_restart_write_buffer_flush, trans, _THIS_IP_);
                        ret = btree_trans_restart(trans, BCH_ERR_transaction_restart_write_buffer_flush);

diff --git a/fs/bcachefs/btree_write_buffer.c b/fs/bcachefs/btree_write_buffer.c
index 02ed0f2c5df5f5fd5f085dd66e4962c210bda2e4..eae8d161e9848ab545a0eeb3620c61dcfaf773b9 100644 (file)
--- a/fs/bcachefs/btree_write_buffer.c
+++ b/fs/bcachefs/btree_write_buffer.c
@@ -137,8 +137,7 @@ btree_write_buffered_insert(struct btree_trans *trans,
        return ret;
 }
 
-int __bch2_btree_write_buffer_flush(struct btree_trans *trans, unsigned commit_flags,
-                                   bool locked)
+int __bch2_btree_write_buffer_flush(struct btree_trans *trans, bool locked)
 {
        struct bch_fs *c = trans->c;
        struct journal *j = &c->journal;
@@ -210,8 +209,8 @@ int __bch2_btree_write_buffer_flush(struct btree_trans *trans, unsigned commit_f
                iter.path->preserve = false;
 
                do {
-                       ret = bch2_btree_write_buffer_flush_one(trans, &iter, i,
-                                               commit_flags, &write_locked, &fast);
+                       ret = bch2_btree_write_buffer_flush_one(trans, &iter, i, 0,
+                                                               &write_locked, &fast);
                        if (!write_locked)
                                bch2_trans_begin(trans);
                } while (bch2_err_matches(ret, BCH_ERR_transaction_restart));
@@ -252,9 +251,6 @@ slowpath:
             btree_write_buffered_journal_cmp,
             NULL);
 
-       commit_flags &= ~BCH_WATERMARK_MASK;
-       commit_flags |= BCH_WATERMARK_reclaim;
-
        for (i = keys; i < keys + nr; i++) {
                if (!i->journal_seq)
                        continue;
@@ -263,7 +259,8 @@ slowpath:
                              bch2_btree_write_buffer_journal_flush);
 
                ret = commit_do(trans, NULL, NULL,
-                               commit_flags|
+                               BCH_WATERMARK_reclaim|
+                               BCH_TRANS_COMMIT_no_check_rw|
                                BCH_TRANS_COMMIT_no_enospc|
                                BCH_TRANS_COMMIT_no_journal_res|
                                BCH_TRANS_COMMIT_journal_reclaim,
@@ -279,16 +276,33 @@ int bch2_btree_write_buffer_flush_sync(struct btree_trans *trans)
 {
        struct bch_fs *c = trans->c;
 
+       if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_btree_write_buffer))
+               return -BCH_ERR_erofs_no_writes;
+
        trace_and_count(c, write_buffer_flush_sync, trans, _RET_IP_);
 
        bch2_trans_unlock(trans);
-       mutex_lock(&c->btree_write_buffer.flush_lock);
-       return __bch2_btree_write_buffer_flush(trans, 0, true);
+       mutex_lock(&trans->c->btree_write_buffer.flush_lock);
+       int ret = __bch2_btree_write_buffer_flush(trans, true);
+       bch2_write_ref_put(c, BCH_WRITE_REF_btree_write_buffer);
+       return ret;
+}
+
+int bch2_btree_write_buffer_flush_nocheck_rw(struct btree_trans *trans)
+{
+       return __bch2_btree_write_buffer_flush(trans, false);
 }
 
 int bch2_btree_write_buffer_flush(struct btree_trans *trans)
 {
-       return __bch2_btree_write_buffer_flush(trans, 0, false);
+       struct bch_fs *c = trans->c;
+
+       if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_btree_write_buffer))
+               return -BCH_ERR_erofs_no_writes;
+
+       int ret = bch2_btree_write_buffer_flush_nocheck_rw(trans);
+       bch2_write_ref_put(c, BCH_WRITE_REF_btree_write_buffer);
+       return ret;
 }
 
 static int bch2_btree_write_buffer_journal_flush(struct journal *j,
@@ -300,7 +314,7 @@ static int bch2_btree_write_buffer_journal_flush(struct journal *j,
        mutex_lock(&wb->flush_lock);
 
        return bch2_trans_run(c,
-                       __bch2_btree_write_buffer_flush(trans, BCH_TRANS_COMMIT_no_check_rw, true));
+                       __bch2_btree_write_buffer_flush(trans, true));
 }
 
 static inline u64 btree_write_buffer_ref(int idx)

diff --git a/fs/bcachefs/btree_write_buffer.h b/fs/bcachefs/btree_write_buffer.h
index 322df1c8304e09415238b42f14095789a146ffb3..45388e63663920a35cbac480b11fad368afd5217 100644 (file)
--- a/fs/bcachefs/btree_write_buffer.h
+++ b/fs/bcachefs/btree_write_buffer.h
@@ -2,7 +2,8 @@
 #ifndef _BCACHEFS_BTREE_WRITE_BUFFER_H
 #define _BCACHEFS_BTREE_WRITE_BUFFER_H
 
-int __bch2_btree_write_buffer_flush(struct btree_trans *, unsigned, bool);
+int bch2_btree_write_buffer_flush_nocheck_rw(struct btree_trans *);
+int __bch2_btree_write_buffer_flush(struct btree_trans *, bool);
 int bch2_btree_write_buffer_flush_sync(struct btree_trans *);
 int bch2_btree_write_buffer_flush(struct btree_trans *);
 

diff --git a/fs/bcachefs/ec.c b/fs/bcachefs/ec.c
index 24ec634077a34512560c4927ab54538d85c953d1..bc8b556f19a90fbbd768f360b87b11e4bf7cf86b 100644 (file)
--- a/fs/bcachefs/ec.c
+++ b/fs/bcachefs/ec.c
@@ -1005,7 +1005,7 @@ static int ec_stripe_update_extents(struct bch_fs *c, struct ec_stripe_buf *s)
        unsigned i, nr_data = v->nr_blocks - v->nr_redundant;
        int ret = 0;
 
-       ret = bch2_btree_write_buffer_flush(trans);
+       ret = bch2_btree_write_buffer_flush_nocheck_rw(trans);
        if (ret)
                goto err;
 

diff --git a/fs/bcachefs/inode.c b/fs/bcachefs/inode.c
index abd6cacafe93b3b408f4e94f830c1c52ce000719..0d2bdc7575a812f9d80aa72e3fcca4de164da9ed 100644 (file)
--- a/fs/bcachefs/inode.c
+++ b/fs/bcachefs/inode.c
@@ -1162,10 +1162,6 @@ int bch2_delete_dead_inodes(struct bch_fs *c)
 again:
        need_another_pass = false;
 
-       ret = bch2_btree_write_buffer_flush_sync(trans);
-       if (ret)
-               goto err;
-
        /*
         * Weird transaction restart handling here because on successful delete,
         * bch2_inode_rm_snapshot() will return a nested transaction restart,
@@ -1196,8 +1192,12 @@ again:
        }
        bch2_trans_iter_exit(trans, &iter);
 
-       if (!ret && need_another_pass)
+       if (!ret && need_another_pass) {
+               ret = bch2_btree_write_buffer_flush_sync(trans);
+               if (ret)
+                       goto err;
                goto again;
+       }
 err:
        bch2_trans_put(trans);
 

diff --git a/fs/bcachefs/movinggc.c b/fs/bcachefs/movinggc.c
index b8d0542222c3bb71f1ee195df44394f03697ec84..ba3a323a4843ce2a2a806060934c4658339cf3ce 100644 (file)
--- a/fs/bcachefs/movinggc.c
+++ b/fs/bcachefs/movinggc.c
@@ -154,6 +154,9 @@ static int bch2_copygc_get_buckets(struct moving_context *ctxt,
        move_buckets_wait(ctxt, buckets_in_flight, false);
 
        ret = bch2_btree_write_buffer_flush(trans);
+       if (bch2_err_matches(ret, EROFS))
+               return ret;
+
        if (bch2_fs_fatal_err_on(ret, c, "%s: error %s from bch2_btree_write_buffer_flush()",
                                 __func__, bch2_err_str(ret)))
                return ret;