Merge branch 'for-linus-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs

Pull btrfs cleanups and fixes from Chris Mason:
 "These are small cleanups, and also some fixes for our async worker
  thread initialization.

  I was having some trouble testing these, but it ended up being a
  combination of changing around my test servers and a shiny new
  schedule while atomic from the new start/finish_plug in
  writeback_sb_inodes().

  That one only hits on btrfs raid5/6 or MD raid10, and if I wasn't
  changing a bunch of things in my test setup at once it would have been
  really clear.  Fix for writeback_sb_inodes() on the way as well"

* 'for-linus-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: cleanup: remove unnecessary check before btrfs_free_path is called
  btrfs: async_thread: Fix workqueue 'max_active' value when initializing
  btrfs: Add raid56 support for updating  num_tolerated_disk_barrier_failures in btrfs_balance
  btrfs: Cleanup for btrfs_calc_num_tolerated_disk_barrier_failures
  btrfs: Remove noused chunk_tree and chunk_objectid from scrub_enumerate_chunks and scrub_chunk
  btrfs: Update out-of-date "skip parity stripe" comment

9 files changed, 82 insertions, 96 deletions

diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
index 1ce06c849a86..3e36e4adc4a3 100644
--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -42,8 +42,14 @@ struct __btrfs_workqueue {
 
         /* Thresholding related variants */
         atomic_t pending;
-        int max_active;
-        int current_max;
+
+        /* Up limit of concurrency workers */
+        int limit_active;
+
+        /* Current number of concurrency workers */
+        int current_active;
+
+        /* Threshold to change current_active */
         int thresh;
         unsigned int count;
         spinlock_t thres_lock;
@@ -88,7 +94,7 @@ BTRFS_WORK_HELPER(scrubnc_helper);
 BTRFS_WORK_HELPER(scrubparity_helper);
 
 static struct __btrfs_workqueue *
-__btrfs_alloc_workqueue(const char *name, unsigned int flags, int max_active,
+__btrfs_alloc_workqueue(const char *name, unsigned int flags, int limit_active,
                          int thresh)
 {
         struct __btrfs_workqueue *ret = kzalloc(sizeof(*ret), GFP_NOFS);
@@ -96,26 +102,31 @@ __btrfs_alloc_workqueue(const char *name, unsigned int flags, int max_active,
         if (!ret)
                 return NULL;
 
-        ret->max_active = max_active;
+        ret->limit_active = limit_active;
         atomic_set(&ret->pending, 0);
         if (thresh == 0)
                 thresh = DFT_THRESHOLD;
         /* For low threshold, disabling threshold is a better choice */
         if (thresh < DFT_THRESHOLD) {
-                ret->current_max = max_active;
+                ret->current_active = limit_active;
                 ret->thresh = NO_THRESHOLD;
         } else {
-                ret->current_max = 1;
+                /*
+                 * For threshold-able wq, let its concurrency grow on demand.
+                 * Use minimal max_active at alloc time to reduce resource
+                 * usage.
+                 */
+                ret->current_active = 1;
                 ret->thresh = thresh;
         }
 
         if (flags & WQ_HIGHPRI)
                 ret->normal_wq = alloc_workqueue("%s-%s-high", flags,
-                                                 ret->max_active,
-                                                 "btrfs", name);
+                                                 ret->current_active, "btrfs",
+                                                 name);
         else
                 ret->normal_wq = alloc_workqueue("%s-%s", flags,
-                                                 ret->max_active, "btrfs",
+                                                 ret->current_active, "btrfs",
                                                  name);
         if (!ret->normal_wq) {
                 kfree(ret);
@@ -134,7 +145,7 @@ __btrfs_destroy_workqueue(struct __btrfs_workqueue *wq);
 
 struct btrfs_workqueue *btrfs_alloc_workqueue(const char *name,
                                               unsigned int flags,
-                                              int max_active,
+                                              int limit_active,
                                               int thresh)
 {
         struct btrfs_workqueue *ret = kzalloc(sizeof(*ret), GFP_NOFS);
@@ -143,14 +154,14 @@ struct btrfs_workqueue *btrfs_alloc_workqueue(const char *name,
                 return NULL;
 
         ret->normal = __btrfs_alloc_workqueue(name, flags & ~WQ_HIGHPRI,
-                                              max_active, thresh);
+                                              limit_active, thresh);
         if (!ret->normal) {
                 kfree(ret);
                 return NULL;
         }
 
         if (flags & WQ_HIGHPRI) {
-                ret->high = __btrfs_alloc_workqueue(name, flags, max_active,
+                ret->high = __btrfs_alloc_workqueue(name, flags, limit_active,
                                                     thresh);
                 if (!ret->high) {
                         __btrfs_destroy_workqueue(ret->normal);
@@ -180,7 +191,7 @@ static inline void thresh_queue_hook(struct __btrfs_workqueue *wq)
  */
 static inline void thresh_exec_hook(struct __btrfs_workqueue *wq)
 {
-        int new_max_active;
+        int new_current_active;
         long pending;
         int need_change = 0;
 
@@ -197,7 +208,7 @@ static inline void thresh_exec_hook(struct __btrfs_workqueue *wq)
         wq->count %= (wq->thresh / 4);
         if (!wq->count)
                 goto  out;
-        new_max_active = wq->current_max;
+        new_current_active = wq->current_active;
 
         /*
          * pending may be changed later, but it's OK since we really
@@ -205,19 +216,19 @@ static inline void thresh_exec_hook(struct __btrfs_workqueue *wq)
          */
         pending = atomic_read(&wq->pending);
         if (pending > wq->thresh)
-                new_max_active++;
+                new_current_active++;
         if (pending < wq->thresh / 2)
-                new_max_active--;
-        new_max_active = clamp_val(new_max_active, 1, wq->max_active);
-        if (new_max_active != wq->current_max)  {
+                new_current_active--;
+        new_current_active = clamp_val(new_current_active, 1, wq->limit_active);
+        if (new_current_active != wq->current_active)  {
                 need_change = 1;
-                wq->current_max = new_max_active;
+                wq->current_active = new_current_active;
         }
 out:
         spin_unlock(&wq->thres_lock);
 
         if (need_change) {
-                workqueue_set_max_active(wq->normal_wq, wq->current_max);
+                workqueue_set_max_active(wq->normal_wq, wq->current_active);
         }
 }
 
@@ -351,13 +362,13 @@ void btrfs_destroy_workqueue(struct btrfs_workqueue *wq)
         kfree(wq);
 }
 
-void btrfs_workqueue_set_max(struct btrfs_workqueue *wq, int max)
+void btrfs_workqueue_set_max(struct btrfs_workqueue *wq, int limit_active)
 {
         if (!wq)
                 return;
-        wq->normal->max_active = max;
+        wq->normal->limit_active = limit_active;
         if (wq->high)
-                wq->high->max_active = max;
+                wq->high->limit_active = limit_active;
 }
 
 void btrfs_set_work_high_priority(struct btrfs_work *work)
diff --git a/fs/btrfs/async-thread.h b/fs/btrfs/async-thread.h
index b0b093b6afec..ad4d0647d1a6 100644
--- a/fs/btrfs/async-thread.h
+++ b/fs/btrfs/async-thread.h
@@ -69,7 +69,7 @@ BTRFS_WORK_HELPER_PROTO(scrubparity_helper);
 
 struct btrfs_workqueue *btrfs_alloc_workqueue(const char *name,
                                               unsigned int flags,
-                                              int max_active,
+                                              int limit_active,
                                               int thresh);
 void btrfs_init_work(struct btrfs_work *work, btrfs_work_func_t helper,
                      btrfs_func_t func,
diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index 564a7de17d99..e54dd5905cee 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -183,8 +183,7 @@ no_valid_dev_replace_entry_found:
         }
 
 out:
-        if (path)
-                btrfs_free_path(path);
+        btrfs_free_path(path);
         return ret;
 }
 
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 9ebd34f1c677..0d98aee34fee 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3443,6 +3443,26 @@ static int barrier_all_devices(struct btrfs_fs_info *info)
         return 0;
 }
 
+int btrfs_get_num_tolerated_disk_barrier_failures(u64 flags)
+{
+        if ((flags & (BTRFS_BLOCK_GROUP_DUP |
+                      BTRFS_BLOCK_GROUP_RAID0 |
+                      BTRFS_AVAIL_ALLOC_BIT_SINGLE)) ||
+            ((flags & BTRFS_BLOCK_GROUP_PROFILE_MASK) == 0))
+                return 0;
+
+        if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
+                     BTRFS_BLOCK_GROUP_RAID5 |
+                     BTRFS_BLOCK_GROUP_RAID10))
+                return 1;
+
+        if (flags & BTRFS_BLOCK_GROUP_RAID6)
+                return 2;
+
+        pr_warn("BTRFS: unknown raid type: %llu\n", flags);
+        return 0;
+}
+
 int btrfs_calc_num_tolerated_disk_barrier_failures(
         struct btrfs_fs_info *fs_info)
 {
@@ -3452,13 +3472,12 @@ int btrfs_calc_num_tolerated_disk_barrier_failures(
                        BTRFS_BLOCK_GROUP_SYSTEM,
                        BTRFS_BLOCK_GROUP_METADATA,
                        BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA};
-        int num_types = 4;
         int i;
         int c;
         int num_tolerated_disk_barrier_failures =
                 (int)fs_info->fs_devices->num_devices;
 
-        for (i = 0; i < num_types; i++) {
+        for (i = 0; i < ARRAY_SIZE(types); i++) {
                 struct btrfs_space_info *tmp;
 
                 sinfo = NULL;
@@ -3476,44 +3495,21 @@ int btrfs_calc_num_tolerated_disk_barrier_failures(
 
                 down_read(&sinfo->groups_sem);
                 for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
-                        if (!list_empty(&sinfo->block_groups[c])) {
-                                u64 flags;
-
-                                btrfs_get_block_group_info(
-                                        &sinfo->block_groups[c], &space);
-                                if (space.total_bytes == 0 ||
-                                    space.used_bytes == 0)
-                                        continue;
-                                flags = space.flags;
-                                /*
-                                 * return
-                                 * 0: if dup, single or RAID0 is configured for
-                                 *    any of metadata, system or data, else
-                                 * 1: if RAID5 is configured, or if RAID1 or
-                                 *    RAID10 is configured and only two mirrors
-                                 *    are used, else
-                                 * 2: if RAID6 is configured, else
-                                 * num_mirrors - 1: if RAID1 or RAID10 is
-                                 *                  configured and more than
-                                 *                  2 mirrors are used.
-                                 */
-                                if (num_tolerated_disk_barrier_failures > 0 &&
-                                    ((flags & (BTRFS_BLOCK_GROUP_DUP |
-                                               BTRFS_BLOCK_GROUP_RAID0)) ||
-                                     ((flags & BTRFS_BLOCK_GROUP_PROFILE_MASK)
-                                      == 0)))
-                                        num_tolerated_disk_barrier_failures = 0;
-                                else if (num_tolerated_disk_barrier_failures > 1) {
-                                        if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
-                                            BTRFS_BLOCK_GROUP_RAID5 |
-                                            BTRFS_BLOCK_GROUP_RAID10)) {
-                                                num_tolerated_disk_barrier_failures = 1;
-                                        } else if (flags &
-                                                   BTRFS_BLOCK_GROUP_RAID6) {
-                                                num_tolerated_disk_barrier_failures = 2;
-                                        }
-                                }
-                        }
+                        u64 flags;
+
+                        if (list_empty(&sinfo->block_groups[c]))
+                                continue;
+
+                        btrfs_get_block_group_info(&sinfo->block_groups[c],
+                                                   &space);
+                        if (space.total_bytes == 0 || space.used_bytes == 0)
+                                continue;
+                        flags = space.flags;
+
+                        num_tolerated_disk_barrier_failures = min(
+                                num_tolerated_disk_barrier_failures,
+                                btrfs_get_num_tolerated_disk_barrier_failures(
+                                        flags));
                 }
                 up_read(&sinfo->groups_sem);
         }
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index d4cbfeeeedd4..bdfb479ea859 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -139,6 +139,7 @@ struct btrfs_root *btrfs_create_tree(struct btrfs_trans_handle *trans,
                                      u64 objectid);
 int btree_lock_page_hook(struct page *page, void *data,
                                 void (*flush_fn)(void *));
+int btrfs_get_num_tolerated_disk_barrier_failures(u64 flags);
 int btrfs_calc_num_tolerated_disk_barrier_failures(
         struct btrfs_fs_info *fs_info);
 int __init btrfs_end_io_wq_init(void);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 237da012f7d0..a0fa7253a2d7 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -6909,8 +6909,7 @@ out:
 
         trace_btrfs_get_extent(root, em);
 
-        if (path)
-                btrfs_free_path(path);
+        btrfs_free_path(path);
         if (trans) {
                 ret = btrfs_end_transaction(trans, root);
                 if (!err)
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 9a11db0c47ee..a39f5d1144e8 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -3267,13 +3267,13 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
                         scrub_blocked_if_needed(fs_info);
                 }
 
-                /* for raid56, we skip parity stripe */
                 if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
                         ret = get_raid56_logic_offset(physical, num, map,
                                                       &logical,
                                                       &stripe_logical);
                         logical += base;
                         if (ret) {
+                                /* it is parity strip */
                                 stripe_logical += base;
                                 stripe_end = stripe_logical + increment;
                                 ret = scrub_raid56_parity(sctx, map, scrub_dev,
@@ -3480,7 +3480,6 @@ out:
 
 static noinline_for_stack int scrub_chunk(struct scrub_ctx *sctx,
                                           struct btrfs_device *scrub_dev,
-                                          u64 chunk_tree, u64 chunk_objectid,
                                           u64 chunk_offset, u64 length,
                                           u64 dev_offset, int is_dev_replace)
 {
@@ -3531,8 +3530,6 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx,
         struct btrfs_root *root = sctx->dev_root;
         struct btrfs_fs_info *fs_info = root->fs_info;
         u64 length;
-        u64 chunk_tree;
-        u64 chunk_objectid;
         u64 chunk_offset;
         int ret = 0;
         int slot;
@@ -3596,8 +3593,6 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx,
                 if (found_key.offset + length <= start)
                         goto skip;
 
-                chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
-                chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
 
                 /*
@@ -3630,9 +3625,8 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx,
                 dev_replace->cursor_right = found_key.offset + length;
                 dev_replace->cursor_left = found_key.offset;
                 dev_replace->item_needs_writeback = 1;
-                ret = scrub_chunk(sctx, scrub_dev, chunk_tree, chunk_objectid,
-                                  chunk_offset, length, found_key.offset,
-                                  is_dev_replace);
+                ret = scrub_chunk(sctx, scrub_dev, chunk_offset, length,
+                                  found_key.offset, is_dev_replace);
 
                 /*
                  * flush, submit all pending read and write bios, afterwards
diff --git a/fs/btrfs/tree-defrag.c b/fs/btrfs/tree-defrag.c
index a4b9c8b2d35a..f31db4325339 100644
--- a/fs/btrfs/tree-defrag.c
+++ b/fs/btrfs/tree-defrag.c
@@ -115,8 +115,7 @@ int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
                 ret = -EAGAIN;
         }
 out:
-        if (path)
-                btrfs_free_path(path);
+        btrfs_free_path(path);
         if (ret == -EAGAIN) {
                 if (root->defrag_max.objectid > root->defrag_progress.objectid)
                         goto done;
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 76201d6f6ce4..6fc735869c18 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -3585,23 +3585,10 @@ int btrfs_balance(struct btrfs_balance_control *bctl,
         } while (read_seqretry(&fs_info->profiles_lock, seq));
 
         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
-                int num_tolerated_disk_barrier_failures;
-                u64 target = bctl->sys.target;
-
-                num_tolerated_disk_barrier_failures =
-                        btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
-                if (num_tolerated_disk_barrier_failures > 0 &&
-                    (target &
-                     (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
-                      BTRFS_AVAIL_ALLOC_BIT_SINGLE)))
-                        num_tolerated_disk_barrier_failures = 0;
-                else if (num_tolerated_disk_barrier_failures > 1 &&
-                         (target &
-                          (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)))
-                        num_tolerated_disk_barrier_failures = 1;
-
-                fs_info->num_tolerated_disk_barrier_failures =
-                        num_tolerated_disk_barrier_failures;
+                fs_info->num_tolerated_disk_barrier_failures = min(
+                        btrfs_calc_num_tolerated_disk_barrier_failures(fs_info),
+                        btrfs_get_num_tolerated_disk_barrier_failures(
+                                bctl->sys.target));
         }
 
         ret = insert_balance_item(fs_info->tree_root, bctl);