4 files changed, 44 insertions, 13 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 05e1386b8bec..4eb4d2748bec 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4203,12 +4203,17 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
         struct btrfs_root *root = BTRFS_I(inode)->root;
         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
         u64 to_reserve = 0;
+        u64 csum_bytes;
         unsigned nr_extents = 0;
+        int extra_reserve = 0;
         int flush = 1;
         int ret;
 
+        /* Need to be holding the i_mutex here if we aren't free space cache */
         if (btrfs_is_free_space_inode(root, inode))
                 flush = 0;
+        else
+                WARN_ON(!mutex_is_locked(&inode->i_mutex));
 
         if (flush && btrfs_transaction_in_commit(root->fs_info))
                 schedule_timeout(1);
@@ -4219,11 +4224,9 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
         BTRFS_I(inode)->outstanding_extents++;
 
         if (BTRFS_I(inode)->outstanding_extents >
-            BTRFS_I(inode)->reserved_extents) {
+            BTRFS_I(inode)->reserved_extents)
                 nr_extents = BTRFS_I(inode)->outstanding_extents -
                         BTRFS_I(inode)->reserved_extents;
-                BTRFS_I(inode)->reserved_extents += nr_extents;
-        }
 
         /*
          * Add an item to reserve for updating the inode when we complete the
@@ -4231,11 +4234,12 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
          */
         if (!BTRFS_I(inode)->delalloc_meta_reserved) {
                 nr_extents++;
-                BTRFS_I(inode)->delalloc_meta_reserved = 1;
+                extra_reserve = 1;
         }
 
         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
+        csum_bytes = BTRFS_I(inode)->csum_bytes;
         spin_unlock(&BTRFS_I(inode)->lock);
 
         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
@@ -4245,22 +4249,35 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
 
                 spin_lock(&BTRFS_I(inode)->lock);
                 dropped = drop_outstanding_extent(inode);
-                to_free = calc_csum_metadata_size(inode, num_bytes, 0);
-                spin_unlock(&BTRFS_I(inode)->lock);
-                to_free += btrfs_calc_trans_metadata_size(root, dropped);
-
                 /*
-                 * Somebody could have come in and twiddled with the
-                 * reservation, so if we have to free more than we would have
-                 * reserved from this reservation go ahead and release those
-                 * bytes.
+                 * If the inodes csum_bytes is the same as the original
+                 * csum_bytes then we know we haven't raced with any free()ers
+                 * so we can just reduce our inodes csum bytes and carry on.
+                 * Otherwise we have to do the normal free thing to account for
+                 * the case that the free side didn't free up its reserve
+                 * because of this outstanding reservation.
                  */
-                to_free -= to_reserve;
+                if (BTRFS_I(inode)->csum_bytes == csum_bytes)
+                        calc_csum_metadata_size(inode, num_bytes, 0);
+                else
+                        to_free = calc_csum_metadata_size(inode, num_bytes, 0);
+                spin_unlock(&BTRFS_I(inode)->lock);
+                if (dropped)
+                        to_free += btrfs_calc_trans_metadata_size(root, dropped);
+
                 if (to_free)
                         btrfs_block_rsv_release(root, block_rsv, to_free);
                 return ret;
         }
 
+        spin_lock(&BTRFS_I(inode)->lock);
+        if (extra_reserve) {
+                BTRFS_I(inode)->delalloc_meta_reserved = 1;
+                nr_extents--;
+        }
+        BTRFS_I(inode)->reserved_extents += nr_extents;
+        spin_unlock(&BTRFS_I(inode)->lock);
+
         block_rsv_add_bytes(block_rsv, to_reserve, 1);
 
         return 0;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index eec33b9c953d..8938174e6bc1 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2192,7 +2192,14 @@ int btrfs_orphan_cleanup(struct btrfs_root *root)
                                 continue;
                         }
                         nr_truncate++;
+                        /*
+                         * Need to hold the imutex for reservation purposes, not
+                         * a huge deal here but I have a WARN_ON in
+                         * btrfs_delalloc_reserve_space to catch offenders.
+                         */
+                        mutex_lock(&inode->i_mutex);
                         ret = btrfs_truncate(inode);
+                        mutex_unlock(&inode->i_mutex);
                 } else {
                         nr_unlink++;
                 }
@@ -6342,7 +6349,10 @@ int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
         u64 page_start;
         u64 page_end;
 
+        /* Need this to keep space reservations serialized */
+        mutex_lock(&inode->i_mutex);
         ret  = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
+        mutex_unlock(&inode->i_mutex);
         if (!ret)
                 ret = btrfs_update_time(vma->vm_file);
         if (ret) {
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 72d461656f60..dd8891662355 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -858,8 +858,10 @@ static int cluster_pages_for_defrag(struct inode *inode,
                 return 0;
         file_end = (isize - 1) >> PAGE_CACHE_SHIFT;
 
+        mutex_lock(&inode->i_mutex);
         ret = btrfs_delalloc_reserve_space(inode,
                                            num_pages << PAGE_CACHE_SHIFT);
+        mutex_unlock(&inode->i_mutex);
         if (ret)
                 return ret;
 again:
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index dff29d5e151a..cfb55434a469 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -2947,7 +2947,9 @@ static int relocate_file_extent_cluster(struct inode *inode,
         index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
         last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;
         while (index <= last_index) {
+                mutex_lock(&inode->i_mutex);
                 ret = btrfs_delalloc_reserve_metadata(inode, PAGE_CACHE_SIZE);
+                mutex_unlock(&inode->i_mutex);
                 if (ret)
                         goto out;