Merge branch 'for-chris' of git://git.kernel.org/pub/scm/linux/kernel/git/josef/btrfs-work into for-linus

7 files changed, 180 insertions, 124 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 3458b5725540..0d00a07b5b29 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2576,6 +2576,11 @@ int btrfs_drop_extents(struct btrfs_trans_handle *trans, struct inode *inode,
 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
                               struct inode *inode, u64 start, u64 end);
 int btrfs_release_file(struct inode *inode, struct file *file);
+void btrfs_drop_pages(struct page **pages, size_t num_pages);
+int btrfs_dirty_pages(struct btrfs_root *root, struct inode *inode,
+                      struct page **pages, size_t num_pages,
+                      loff_t pos, size_t write_bytes,
+                      struct extent_state **cached);
 
 /* tree-defrag.c */
 int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index a272bfd74ea0..ef6865c17cd6 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3136,7 +3136,7 @@ static int btrfs_cleanup_transaction(struct btrfs_root *root)
                 btrfs_destroy_pinned_extent(root,
                                             root->fs_info->pinned_extents);
 
-                t->use_count = 0;
+                atomic_set(&t->use_count, 0);
                 list_del_init(&t->list);
                 memset(t, 0, sizeof(*t));
                 kmem_cache_free(btrfs_transaction_cachep, t);
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index e621ea54a3fd..75899a01dded 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -104,7 +104,7 @@ static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
 /*
  * unlocks pages after btrfs_file_write is done with them
  */
-static noinline void btrfs_drop_pages(struct page **pages, size_t num_pages)
+void btrfs_drop_pages(struct page **pages, size_t num_pages)
 {
         size_t i;
         for (i = 0; i < num_pages; i++) {
@@ -127,16 +127,13 @@ static noinline void btrfs_drop_pages(struct page **pages, size_t num_pages)
  * this also makes the decision about creating an inline extent vs
  * doing real data extents, marking pages dirty and delalloc as required.
  */
-static noinline int dirty_and_release_pages(struct btrfs_root *root,
-                                            struct file *file,
-                                            struct page **pages,
-                                            size_t num_pages,
-                                            loff_t pos,
-                                            size_t write_bytes)
+int btrfs_dirty_pages(struct btrfs_root *root, struct inode *inode,
+                      struct page **pages, size_t num_pages,
+                      loff_t pos, size_t write_bytes,
+                      struct extent_state **cached)
 {
         int err = 0;
         int i;
-        struct inode *inode = fdentry(file)->d_inode;
         u64 num_bytes;
         u64 start_pos;
         u64 end_of_last_block;
@@ -149,7 +146,7 @@ static noinline int dirty_and_release_pages(struct btrfs_root *root,
 
         end_of_last_block = start_pos + num_bytes - 1;
         err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
-                                        NULL);
+                                        cached);
         if (err)
                 return err;
 
@@ -992,9 +989,9 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
                 }
 
                 if (copied > 0) {
-                        ret = dirty_and_release_pages(root, file, pages,
-                                                      dirty_pages, pos,
-                                                      copied);
+                        ret = btrfs_dirty_pages(root, inode, pages,
+                                                dirty_pages, pos, copied,
+                                                NULL);
                         if (ret) {
                                 btrfs_delalloc_release_space(inode,
                                         dirty_pages << PAGE_CACHE_SHIFT);
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index f561c953205b..a3f420def0e9 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -508,6 +508,7 @@ int btrfs_write_out_cache(struct btrfs_root *root,
         struct inode *inode;
         struct rb_node *node;
         struct list_head *pos, *n;
+        struct page **pages;
         struct page *page;
         struct extent_state *cached_state = NULL;
         struct btrfs_free_cluster *cluster = NULL;
@@ -517,13 +518,13 @@ int btrfs_write_out_cache(struct btrfs_root *root,
         u64 start, end, len;
         u64 bytes = 0;
         u32 *crc, *checksums;
-        pgoff_t index = 0, last_index = 0;
         unsigned long first_page_offset;
-        int num_checksums;
+        int index = 0, num_pages = 0;
         int entries = 0;
         int bitmaps = 0;
         int ret = 0;
         bool next_page = false;
+        bool out_of_space = false;
 
         root = root->fs_info->tree_root;
 
@@ -551,24 +552,31 @@ int btrfs_write_out_cache(struct btrfs_root *root,
                 return 0;
         }
 
-        last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
+        num_pages = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
+                PAGE_CACHE_SHIFT;
         filemap_write_and_wait(inode->i_mapping);
         btrfs_wait_ordered_range(inode, inode->i_size &
                                  ~(root->sectorsize - 1), (u64)-1);
 
         /* We need a checksum per page. */
-        num_checksums = i_size_read(inode) / PAGE_CACHE_SIZE;
-        crc = checksums  = kzalloc(sizeof(u32) * num_checksums, GFP_NOFS);
+        crc = checksums = kzalloc(sizeof(u32) * num_pages, GFP_NOFS);
         if (!crc) {
                 iput(inode);
                 return 0;
         }
 
+        pages = kzalloc(sizeof(struct page *) * num_pages, GFP_NOFS);
+        if (!pages) {
+                kfree(crc);
+                iput(inode);
+                return 0;
+        }
+
         /* Since the first page has all of our checksums and our generation we
          * need to calculate the offset into the page that we can start writing
          * our entries.
          */
-        first_page_offset = (sizeof(u32) * num_checksums) + sizeof(u64);
+        first_page_offset = (sizeof(u32) * num_pages) + sizeof(u64);
 
         /* Get the cluster for this block_group if it exists */
         if (!list_empty(&block_group->cluster_list))
@@ -590,20 +598,18 @@ int btrfs_write_out_cache(struct btrfs_root *root,
          * after find_get_page at this point.  Just putting this here so people
          * know and don't freak out.
          */
-        while (index <= last_index) {
+        while (index < num_pages) {
                 page = grab_cache_page(inode->i_mapping, index);
                 if (!page) {
-                        pgoff_t i = 0;
+                        int i;
 
-                        while (i < index) {
-                                page = find_get_page(inode->i_mapping, i);
-                                unlock_page(page);
-                                page_cache_release(page);
-                                page_cache_release(page);
-                                i++;
+                        for (i = 0; i < num_pages; i++) {
+                                unlock_page(pages[i]);
+                                page_cache_release(pages[i]);
                         }
                         goto out_free;
                 }
+                pages[index] = page;
                 index++;
         }
 
@@ -631,7 +637,12 @@ int btrfs_write_out_cache(struct btrfs_root *root,
                         offset = start_offset;
                 }
 
-                page = find_get_page(inode->i_mapping, index);
+                if (index >= num_pages) {
+                        out_of_space = true;
+                        break;
+                }
+
+                page = pages[index];
 
                 addr = kmap(page);
                 entry = addr + start_offset;
@@ -708,23 +719,6 @@ int btrfs_write_out_cache(struct btrfs_root *root,
 
                 bytes += PAGE_CACHE_SIZE;
 
-                ClearPageChecked(page);
-                set_page_extent_mapped(page);
-                SetPageUptodate(page);
-                set_page_dirty(page);
-
-                /*
-                 * We need to release our reference we got for grab_cache_page,
-                 * except for the first page which will hold our checksums, we
-                 * do that below.
-                 */
-                if (index != 0) {
-                        unlock_page(page);
-                        page_cache_release(page);
-                }
-
-                page_cache_release(page);
-
                 index++;
         } while (node || next_page);
 
@@ -734,6 +728,10 @@ int btrfs_write_out_cache(struct btrfs_root *root,
                 struct btrfs_free_space *entry =
                         list_entry(pos, struct btrfs_free_space, list);
 
+                if (index >= num_pages) {
+                        out_of_space = true;
+                        break;
+                }
                 page = find_get_page(inode->i_mapping, index);
 
                 addr = kmap(page);
@@ -745,64 +743,58 @@ int btrfs_write_out_cache(struct btrfs_root *root,
                 crc++;
                 bytes += PAGE_CACHE_SIZE;
 
-                ClearPageChecked(page);
-                set_page_extent_mapped(page);
-                SetPageUptodate(page);
-                set_page_dirty(page);
-                unlock_page(page);
-                page_cache_release(page);
-                page_cache_release(page);
                 list_del_init(&entry->list);
                 index++;
         }
 
+        if (out_of_space) {
+                btrfs_drop_pages(pages, num_pages);
+                unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
+                                     i_size_read(inode) - 1, &cached_state,
+                                     GFP_NOFS);
+                ret = 0;
+                goto out_free;
+        }
+
         /* Zero out the rest of the pages just to make sure */
-        while (index <= last_index) {
+        while (index < num_pages) {
                 void *addr;
 
-                page = find_get_page(inode->i_mapping, index);
-
+                page = pages[index];
                 addr = kmap(page);
                 memset(addr, 0, PAGE_CACHE_SIZE);
                 kunmap(page);
-                ClearPageChecked(page);
-                set_page_extent_mapped(page);
-                SetPageUptodate(page);
-                set_page_dirty(page);
-                unlock_page(page);
-                page_cache_release(page);
-                page_cache_release(page);
                 bytes += PAGE_CACHE_SIZE;
                 index++;
         }
 
-        btrfs_set_extent_delalloc(inode, 0, bytes - 1, &cached_state);
-
         /* Write the checksums and trans id to the first page */
         {
                 void *addr;
                 u64 *gen;
 
-                page = find_get_page(inode->i_mapping, 0);
+                page = pages[0];
 
                 addr = kmap(page);
-                memcpy(addr, checksums, sizeof(u32) * num_checksums);
-                gen = addr + (sizeof(u32) * num_checksums);
+                memcpy(addr, checksums, sizeof(u32) * num_pages);
+                gen = addr + (sizeof(u32) * num_pages);
                 *gen = trans->transid;
                 kunmap(page);
-                ClearPageChecked(page);
-                set_page_extent_mapped(page);
-                SetPageUptodate(page);
-                set_page_dirty(page);
-                unlock_page(page);
-                page_cache_release(page);
-                page_cache_release(page);
         }
-        BTRFS_I(inode)->generation = trans->transid;
 
+        ret = btrfs_dirty_pages(root, inode, pages, num_pages, 0,
+                                            bytes, &cached_state);
+        btrfs_drop_pages(pages, num_pages);
         unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
                              i_size_read(inode) - 1, &cached_state, GFP_NOFS);
 
+        if (ret) {
+                ret = 0;
+                goto out_free;
+        }
+
+        BTRFS_I(inode)->generation = trans->transid;
+
         filemap_write_and_wait(inode->i_mapping);
 
         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
@@ -853,6 +845,7 @@ out_free:
                 BTRFS_I(inode)->generation = 0;
         }
         kfree(checksums);
+        kfree(pages);
         btrfs_update_inode(trans, root, inode);
         iput(inode);
         return ret;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 5a993e0ec865..55a6a0b416d7 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1769,9 +1769,12 @@ static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
         add_pending_csums(trans, inode, ordered_extent->file_offset,
                           &ordered_extent->list);
 
-        btrfs_ordered_update_i_size(inode, 0, ordered_extent);
-        ret = btrfs_update_inode(trans, root, inode);
-        BUG_ON(ret);
+        ret = btrfs_ordered_update_i_size(inode, 0, ordered_extent);
+        if (!ret) {
+                ret = btrfs_update_inode(trans, root, inode);
+                BUG_ON(ret);
+        }
+        ret = 0;
 out:
         if (nolock) {
                 if (trans)
@@ -2589,6 +2592,13 @@ static void fill_inode_item(struct btrfs_trans_handle *trans,
                             struct btrfs_inode_item *item,
                             struct inode *inode)
 {
+        if (!leaf->map_token)
+                map_private_extent_buffer(leaf, (unsigned long)item,
+                                          sizeof(struct btrfs_inode_item),
+                                          &leaf->map_token, &leaf->kaddr,
+                                          &leaf->map_start, &leaf->map_len,
+                                          KM_USER1);
+
         btrfs_set_inode_uid(leaf, item, inode->i_uid);
         btrfs_set_inode_gid(leaf, item, inode->i_gid);
         btrfs_set_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size);
@@ -2617,6 +2627,11 @@ static void fill_inode_item(struct btrfs_trans_handle *trans,
         btrfs_set_inode_rdev(leaf, item, inode->i_rdev);
         btrfs_set_inode_flags(leaf, item, BTRFS_I(inode)->flags);
         btrfs_set_inode_block_group(leaf, item, BTRFS_I(inode)->block_group);
+
+        if (leaf->map_token) {
+                unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
+                leaf->map_token = NULL;
+        }
 }
 
 /*
@@ -5433,17 +5448,30 @@ out:
 }
 
 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
+                                                  struct extent_map *em,
                                                   u64 start, u64 len)
 {
         struct btrfs_root *root = BTRFS_I(inode)->root;
         struct btrfs_trans_handle *trans;
-        struct extent_map *em;
         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
         struct btrfs_key ins;
         u64 alloc_hint;
         int ret;
+        bool insert = false;
 
-        btrfs_drop_extent_cache(inode, start, start + len - 1, 0);
+        /*
+         * Ok if the extent map we looked up is a hole and is for the exact
+         * range we want, there is no reason to allocate a new one, however if
+         * it is not right then we need to free this one and drop the cache for
+         * our range.
+         */
+        if (em->block_start != EXTENT_MAP_HOLE || em->start != start ||
+            em->len != len) {
+                free_extent_map(em);
+                em = NULL;
+                insert = true;
+                btrfs_drop_extent_cache(inode, start, start + len - 1, 0);
+        }
 
         trans = btrfs_join_transaction(root, 0);
         if (IS_ERR(trans))
@@ -5459,10 +5487,12 @@ static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
                 goto out;
         }
 
-        em = alloc_extent_map(GFP_NOFS);
         if (!em) {
-                em = ERR_PTR(-ENOMEM);
-                goto out;
+                em = alloc_extent_map(GFP_NOFS);
+                if (!em) {
+                        em = ERR_PTR(-ENOMEM);
+                        goto out;
+                }
         }
 
         em->start = start;
@@ -5472,9 +5502,15 @@ static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
         em->block_start = ins.objectid;
         em->block_len = ins.offset;
         em->bdev = root->fs_info->fs_devices->latest_bdev;
+
+        /*
+         * We need to do this because if we're using the original em we searched
+         * for, we could have EXTENT_FLAG_VACANCY set, and we don't want that.
+         */
+        em->flags = 0;
         set_bit(EXTENT_FLAG_PINNED, &em->flags);
 
-        while (1) {
+        while (insert) {
                 write_lock(&em_tree->lock);
                 ret = add_extent_mapping(em_tree, em);
                 write_unlock(&em_tree->lock);
@@ -5692,8 +5728,7 @@ must_cow:
          * it above
          */
         len = bh_result->b_size;
-        free_extent_map(em);
-        em = btrfs_new_extent_direct(inode, start, len);
+        em = btrfs_new_extent_direct(inode, em, start, len);
         if (IS_ERR(em))
                 return PTR_ERR(em);
         len = min(len, em->len - (start - em->start));
@@ -5856,8 +5891,10 @@ again:
         }
 
         add_pending_csums(trans, inode, ordered->file_offset, &ordered->list);
-        btrfs_ordered_update_i_size(inode, 0, ordered);
-        btrfs_update_inode(trans, root, inode);
+        ret = btrfs_ordered_update_i_size(inode, 0, ordered);
+        if (!ret)
+                btrfs_update_inode(trans, root, inode);
+        ret = 0;
 out_unlock:
         unlock_extent_cached(&BTRFS_I(inode)->io_tree, ordered->file_offset,
                              ordered->file_offset + ordered->len - 1,
@@ -5943,7 +5980,7 @@ static struct bio *btrfs_dio_bio_alloc(struct block_device *bdev,
 
 static inline int __btrfs_submit_dio_bio(struct bio *bio, struct inode *inode,
                                          int rw, u64 file_offset, int skip_sum,
-                                         u32 *csums)
+                                         u32 *csums, int async_submit)
 {
         int write = rw & REQ_WRITE;
         struct btrfs_root *root = BTRFS_I(inode)->root;
@@ -5954,13 +5991,24 @@ static inline int __btrfs_submit_dio_bio(struct bio *bio, struct inode *inode,
         if (ret)
                 goto err;
 
-        if (write && !skip_sum) {
+        if (skip_sum)
+                goto map;
+
+        if (write && async_submit) {
                 ret = btrfs_wq_submit_bio(root->fs_info,
                                    inode, rw, bio, 0, 0,
                                    file_offset,
                                    __btrfs_submit_bio_start_direct_io,
                                    __btrfs_submit_bio_done);
                 goto err;
+        } else if (write) {
+                /*
+                 * If we aren't doing async submit, calculate the csum of the
+                 * bio now.
+                 */
+                ret = btrfs_csum_one_bio(root, inode, bio, file_offset, 1);
+                if (ret)
+                        goto err;
         } else if (!skip_sum) {
                 ret = btrfs_lookup_bio_sums_dio(root, inode, bio,
                                           file_offset, csums);
@@ -5968,7 +6016,8 @@ static inline int __btrfs_submit_dio_bio(struct bio *bio, struct inode *inode,
                         goto err;
         }
 
-        ret = btrfs_map_bio(root, rw, bio, 0, 1);
+map:
+        ret = btrfs_map_bio(root, rw, bio, 0, async_submit);
 err:
         bio_put(bio);
         return ret;
@@ -5990,15 +6039,9 @@ static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip,
         int nr_pages = 0;
         u32 *csums = dip->csums;
         int ret = 0;
+        int async_submit = 0;
         int write = rw & REQ_WRITE;
 
-        bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev, start_sector, GFP_NOFS);
-        if (!bio)
-                return -ENOMEM;
-        bio->bi_private = dip;
-        bio->bi_end_io = btrfs_end_dio_bio;
-        atomic_inc(&dip->pending_bios);
-
         map_length = orig_bio->bi_size;
         ret = btrfs_map_block(map_tree, READ, start_sector << 9,
                               &map_length, NULL, 0);
@@ -6007,6 +6050,19 @@ static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip,
                 return -EIO;
         }
 
+        if (map_length >= orig_bio->bi_size) {
+                bio = orig_bio;
+                goto submit;
+        }
+
+        async_submit = 1;
+        bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev, start_sector, GFP_NOFS);
+        if (!bio)
+                return -ENOMEM;
+        bio->bi_private = dip;
+        bio->bi_end_io = btrfs_end_dio_bio;
+        atomic_inc(&dip->pending_bios);
+
         while (bvec <= (orig_bio->bi_io_vec + orig_bio->bi_vcnt - 1)) {
                 if (unlikely(map_length < submit_len + bvec->bv_len ||
                     bio_add_page(bio, bvec->bv_page, bvec->bv_len,
@@ -6020,7 +6076,7 @@ static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip,
                         atomic_inc(&dip->pending_bios);
                         ret = __btrfs_submit_dio_bio(bio, inode, rw,
                                                      file_offset, skip_sum,
-                                                     csums);
+                                                     csums, async_submit);
                         if (ret) {
                                 bio_put(bio);
                                 atomic_dec(&dip->pending_bios);
@@ -6057,8 +6113,9 @@ static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip,
                 }
         }
 
+submit:
         ret = __btrfs_submit_dio_bio(bio, inode, rw, file_offset, skip_sum,
-                                     csums);
+                                     csums, async_submit);
         if (!ret)
                 return 0;
 
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 5b158da7e0bb..c571734d5e5a 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -32,10 +32,8 @@
 
 static noinline void put_transaction(struct btrfs_transaction *transaction)
 {
-        WARN_ON(transaction->use_count == 0);
-        transaction->use_count--;
-        if (transaction->use_count == 0) {
-                list_del_init(&transaction->list);
+        WARN_ON(atomic_read(&transaction->use_count) == 0);
+        if (atomic_dec_and_test(&transaction->use_count)) {
                 memset(transaction, 0, sizeof(*transaction));
                 kmem_cache_free(btrfs_transaction_cachep, transaction);
         }
@@ -60,14 +58,14 @@ static noinline int join_transaction(struct btrfs_root *root)
                 if (!cur_trans)
                         return -ENOMEM;
                 root->fs_info->generation++;
-                cur_trans->num_writers = 1;
+                atomic_set(&cur_trans->num_writers, 1);
                 cur_trans->num_joined = 0;
                 cur_trans->transid = root->fs_info->generation;
                 init_waitqueue_head(&cur_trans->writer_wait);
                 init_waitqueue_head(&cur_trans->commit_wait);
                 cur_trans->in_commit = 0;
                 cur_trans->blocked = 0;
-                cur_trans->use_count = 1;
+                atomic_set(&cur_trans->use_count, 1);
                 cur_trans->commit_done = 0;
                 cur_trans->start_time = get_seconds();
 
@@ -88,7 +86,7 @@ static noinline int join_transaction(struct btrfs_root *root)
                 root->fs_info->running_transaction = cur_trans;
                 spin_unlock(&root->fs_info->new_trans_lock);
         } else {
-                cur_trans->num_writers++;
+                atomic_inc(&cur_trans->num_writers);
                 cur_trans->num_joined++;
         }
 
@@ -145,7 +143,7 @@ static void wait_current_trans(struct btrfs_root *root)
         cur_trans = root->fs_info->running_transaction;
         if (cur_trans && cur_trans->blocked) {
                 DEFINE_WAIT(wait);
-                cur_trans->use_count++;
+                atomic_inc(&cur_trans->use_count);
                 while (1) {
                         prepare_to_wait(&root->fs_info->transaction_wait, &wait,
                                         TASK_UNINTERRUPTIBLE);
@@ -181,6 +179,7 @@ static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
 {
         struct btrfs_trans_handle *h;
         struct btrfs_transaction *cur_trans;
+        int retries = 0;
         int ret;
 
         if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)
@@ -204,7 +203,7 @@ again:
         }
 
         cur_trans = root->fs_info->running_transaction;
-        cur_trans->use_count++;
+        atomic_inc(&cur_trans->use_count);
         if (type != TRANS_JOIN_NOLOCK)
                 mutex_unlock(&root->fs_info->trans_mutex);
 
@@ -224,10 +223,18 @@ again:
 
         if (num_items > 0) {
                 ret = btrfs_trans_reserve_metadata(h, root, num_items);
-                if (ret == -EAGAIN) {
+                if (ret == -EAGAIN && !retries) {
+                        retries++;
                         btrfs_commit_transaction(h, root);
                         goto again;
+                } else if (ret == -EAGAIN) {
+                        /*
+                         * We have already retried and got EAGAIN, so really we
+                         * don't have space, so set ret to -ENOSPC.
+                         */
+                        ret = -ENOSPC;
                 }
+
                 if (ret < 0) {
                         btrfs_end_transaction(h, root);
                         return ERR_PTR(ret);
@@ -327,7 +334,7 @@ int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid)
                         goto out_unlock;  /* nothing committing|committed */
         }
 
-        cur_trans->use_count++;
+        atomic_inc(&cur_trans->use_count);
         mutex_unlock(&root->fs_info->trans_mutex);
 
         wait_for_commit(root, cur_trans);
@@ -457,18 +464,14 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
                         wake_up_process(info->transaction_kthread);
         }
 
-        if (lock)
-                mutex_lock(&info->trans_mutex);
         WARN_ON(cur_trans != info->running_transaction);
-        WARN_ON(cur_trans->num_writers < 1);
-        cur_trans->num_writers--;
+        WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
+        atomic_dec(&cur_trans->num_writers);
 
         smp_mb();
         if (waitqueue_active(&cur_trans->writer_wait))
                 wake_up(&cur_trans->writer_wait);
         put_transaction(cur_trans);
-        if (lock)
-                mutex_unlock(&info->trans_mutex);
 
         if (current->journal_info == trans)
                 current->journal_info = NULL;
@@ -1178,7 +1181,7 @@ int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans,
         /* take transaction reference */
         mutex_lock(&root->fs_info->trans_mutex);
         cur_trans = trans->transaction;
-        cur_trans->use_count++;
+        atomic_inc(&cur_trans->use_count);
         mutex_unlock(&root->fs_info->trans_mutex);
 
         btrfs_end_transaction(trans, root);
@@ -1237,7 +1240,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 
         mutex_lock(&root->fs_info->trans_mutex);
         if (cur_trans->in_commit) {
-                cur_trans->use_count++;
+                atomic_inc(&cur_trans->use_count);
                 mutex_unlock(&root->fs_info->trans_mutex);
                 btrfs_end_transaction(trans, root);
 
@@ -1259,7 +1262,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
                 prev_trans = list_entry(cur_trans->list.prev,
                                         struct btrfs_transaction, list);
                 if (!prev_trans->commit_done) {
-                        prev_trans->use_count++;
+                        atomic_inc(&prev_trans->use_count);
                         mutex_unlock(&root->fs_info->trans_mutex);
 
                         wait_for_commit(root, prev_trans);
@@ -1300,14 +1303,14 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
                                 TASK_UNINTERRUPTIBLE);
 
                 smp_mb();
-                if (cur_trans->num_writers > 1)
+                if (atomic_read(&cur_trans->num_writers) > 1)
                         schedule_timeout(MAX_SCHEDULE_TIMEOUT);
                 else if (should_grow)
                         schedule_timeout(1);
 
                 mutex_lock(&root->fs_info->trans_mutex);
                 finish_wait(&cur_trans->writer_wait, &wait);
-        } while (cur_trans->num_writers > 1 ||
+        } while (atomic_read(&cur_trans->num_writers) > 1 ||
                  (should_grow && cur_trans->num_joined != joined));
 
         ret = create_pending_snapshots(trans, root->fs_info);
@@ -1394,6 +1397,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 
         wake_up(&cur_trans->commit_wait);
 
+        list_del_init(&cur_trans->list);
         put_transaction(cur_trans);
         put_transaction(cur_trans);
 
diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h
index 229a594cacd5..e441acc6c584 100644
--- a/fs/btrfs/transaction.h
+++ b/fs/btrfs/transaction.h
@@ -27,11 +27,11 @@ struct btrfs_transaction {
          * total writers in this transaction, it must be zero before the
          * transaction can end
          */
-        unsigned long num_writers;
+        atomic_t num_writers;
 
         unsigned long num_joined;
         int in_commit;
-        int use_count;
+        atomic_t use_count;
         int commit_done;
         int blocked;
         struct list_head list;