Btrfs: cleanup scrub bio and worker wait code

Just move some code into functions to make everything more readable.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index fcd5bccaa4edd6b9f575485330d3a257ed6e024f..a67b1a17a0092b9a049fbb9de72dffbc0a1ef04e 100644 (file)
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2011 STRATO.  All rights reserved.
+ * Copyright (C) 2011, 2012 STRATO.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public
@@ -104,8 +104,8 @@ struct scrub_ctx {
        struct btrfs_root       *dev_root;
        int                     first_free;
        int                     curr;
-       atomic_t                in_flight;
-       atomic_t                fixup_cnt;
+       atomic_t                bios_in_flight;
+       atomic_t                workers_pending;
        spinlock_t              list_lock;
        wait_queue_head_t       list_wait;
        u16                     csum_size;
@@ -146,6 +146,10 @@ struct scrub_warning {
 };
 
 
+static void scrub_pending_bio_inc(struct scrub_ctx *sctx);
+static void scrub_pending_bio_dec(struct scrub_ctx *sctx);
+static void scrub_pending_trans_workers_inc(struct scrub_ctx *sctx);
+static void scrub_pending_trans_workers_dec(struct scrub_ctx *sctx);
 static int scrub_handle_errored_block(struct scrub_block *sblock_to_check);
 static int scrub_setup_recheck_block(struct scrub_ctx *sctx,
                                     struct btrfs_mapping_tree *map_tree,
@@ -184,6 +188,59 @@ static void scrub_bio_end_io_worker(struct btrfs_work *work);
 static void scrub_block_complete(struct scrub_block *sblock);
 
 
+static void scrub_pending_bio_inc(struct scrub_ctx *sctx)
+{
+       atomic_inc(&sctx->bios_in_flight);
+}
+
+static void scrub_pending_bio_dec(struct scrub_ctx *sctx)
+{
+       atomic_dec(&sctx->bios_in_flight);
+       wake_up(&sctx->list_wait);
+}
+
+/*
+ * used for workers that require transaction commits (i.e., for the
+ * NOCOW case)
+ */
+static void scrub_pending_trans_workers_inc(struct scrub_ctx *sctx)
+{
+       struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;
+
+       /*
+        * increment scrubs_running to prevent cancel requests from
+        * completing as long as a worker is running. we must also
+        * increment scrubs_paused to prevent deadlocking on pause
+        * requests used for transactions commits (as the worker uses a
+        * transaction context). it is safe to regard the worker
+        * as paused for all matters practical. effectively, we only
+        * avoid cancellation requests from completing.
+        */
+       mutex_lock(&fs_info->scrub_lock);
+       atomic_inc(&fs_info->scrubs_running);
+       atomic_inc(&fs_info->scrubs_paused);
+       mutex_unlock(&fs_info->scrub_lock);
+       atomic_inc(&sctx->workers_pending);
+}
+
+/* used for workers that require transaction commits */
+static void scrub_pending_trans_workers_dec(struct scrub_ctx *sctx)
+{
+       struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;
+
+       /*
+        * see scrub_pending_trans_workers_inc() why we're pretending
+        * to be paused in the scrub counters
+        */
+       mutex_lock(&fs_info->scrub_lock);
+       atomic_dec(&fs_info->scrubs_running);
+       atomic_dec(&fs_info->scrubs_paused);
+       mutex_unlock(&fs_info->scrub_lock);
+       atomic_dec(&sctx->workers_pending);
+       wake_up(&fs_info->scrub_pause_wait);
+       wake_up(&sctx->list_wait);
+}
+
 static void scrub_free_csums(struct scrub_ctx *sctx)
 {
        while (!list_empty(&sctx->csum_list)) {
@@ -264,8 +321,8 @@ struct scrub_ctx *scrub_setup_ctx(struct btrfs_device *dev)
        sctx->nodesize = dev->dev_root->nodesize;
        sctx->leafsize = dev->dev_root->leafsize;
        sctx->sectorsize = dev->dev_root->sectorsize;
-       atomic_set(&sctx->in_flight, 0);
-       atomic_set(&sctx->fixup_cnt, 0);
+       atomic_set(&sctx->bios_in_flight, 0);
+       atomic_set(&sctx->workers_pending, 0);
        atomic_set(&sctx->cancel_req, 0);
        sctx->csum_size = btrfs_super_csum_size(fs_info->super_copy);
        INIT_LIST_HEAD(&sctx->csum_list);
@@ -609,14 +666,7 @@ out:
        btrfs_free_path(path);
        kfree(fixup);
 
-       /* see caller why we're pretending to be paused in the scrub counters */
-       mutex_lock(&fs_info->scrub_lock);
-       atomic_dec(&fs_info->scrubs_running);
-       atomic_dec(&fs_info->scrubs_paused);
-       mutex_unlock(&fs_info->scrub_lock);
-       atomic_dec(&sctx->fixup_cnt);
-       wake_up(&fs_info->scrub_pause_wait);
-       wake_up(&sctx->list_wait);
+       scrub_pending_trans_workers_dec(sctx);
 }
 
 /*
@@ -789,20 +839,7 @@ static int scrub_handle_errored_block(struct scrub_block *sblock_to_check)
                fixup_nodatasum->logical = logical;
                fixup_nodatasum->root = fs_info->extent_root;
                fixup_nodatasum->mirror_num = failed_mirror_index + 1;
-               /*
-                * increment scrubs_running to prevent cancel requests from
-                * completing as long as a fixup worker is running. we must also
-                * increment scrubs_paused to prevent deadlocking on pause
-                * requests used for transactions commits (as the worker uses a
-                * transaction context). it is safe to regard the fixup worker
-                * as paused for all matters practical. effectively, we only
-                * avoid cancellation requests from completing.
-                */
-               mutex_lock(&fs_info->scrub_lock);
-               atomic_inc(&fs_info->scrubs_running);
-               atomic_inc(&fs_info->scrubs_paused);
-               mutex_unlock(&fs_info->scrub_lock);
-               atomic_inc(&sctx->fixup_cnt);
+               scrub_pending_trans_workers_inc(sctx);
                fixup_nodatasum->work.func = scrub_fixup_nodatasum;
                btrfs_queue_worker(&fs_info->scrub_workers,
                                   &fixup_nodatasum->work);
@@ -1491,7 +1528,7 @@ static void scrub_submit(struct scrub_ctx *sctx)
 
        sbio = sctx->bios[sctx->curr];
        sctx->curr = -1;
-       atomic_inc(&sctx->in_flight);
+       scrub_pending_bio_inc(sctx);
 
        btrfsic_submit_bio(READ, sbio->bio);
 }
@@ -1692,8 +1729,7 @@ static void scrub_bio_end_io_worker(struct btrfs_work *work)
        sbio->next_free = sctx->first_free;
        sctx->first_free = sbio->index;
        spin_unlock(&sctx->list_lock);
-       atomic_dec(&sctx->in_flight);
-       wake_up(&sctx->list_wait);
+       scrub_pending_bio_dec(sctx);
 }
 
 static void scrub_block_complete(struct scrub_block *sblock)
@@ -1863,7 +1899,7 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
        logical = base + offset;
 
        wait_event(sctx->list_wait,
-                  atomic_read(&sctx->in_flight) == 0);
+                  atomic_read(&sctx->bios_in_flight) == 0);
        atomic_inc(&fs_info->scrubs_paused);
        wake_up(&fs_info->scrub_pause_wait);
 
@@ -1928,7 +1964,7 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
                        /* push queued extents */
                        scrub_submit(sctx);
                        wait_event(sctx->list_wait,
-                                  atomic_read(&sctx->in_flight) == 0);
+                                  atomic_read(&sctx->bios_in_flight) == 0);
                        atomic_inc(&fs_info->scrubs_paused);
                        wake_up(&fs_info->scrub_pause_wait);
                        mutex_lock(&fs_info->scrub_lock);
@@ -2218,7 +2254,7 @@ static noinline_for_stack int scrub_supers(struct scrub_ctx *sctx,
                if (ret)
                        return ret;
        }
-       wait_event(sctx->list_wait, atomic_read(&sctx->in_flight) == 0);
+       wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0);
 
        return 0;
 }
@@ -2363,11 +2399,11 @@ int btrfs_scrub_dev(struct btrfs_root *root, u64 devid, u64 start, u64 end,
        if (!ret)
                ret = scrub_enumerate_chunks(sctx, dev, start, end);
 
-       wait_event(sctx->list_wait, atomic_read(&sctx->in_flight) == 0);
+       wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0);
        atomic_dec(&fs_info->scrubs_running);
        wake_up(&fs_info->scrub_pause_wait);
 
-       wait_event(sctx->list_wait, atomic_read(&sctx->fixup_cnt) == 0);
+       wait_event(sctx->list_wait, atomic_read(&sctx->workers_pending) == 0);
 
        if (progress)
                memcpy(progress, &sctx->stat, sizeof(*progress));