9 files changed, 68 insertions, 11 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index fdce8799b98d..e1aa8d607bc7 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -359,10 +359,14 @@ static int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
 
         tree = &BTRFS_I(page->mapping->host)->io_tree;
 
-        if (page->private == EXTENT_PAGE_PRIVATE)
+        if (page->private == EXTENT_PAGE_PRIVATE) {
+                WARN_ON(1);
                 goto out;
-        if (!page->private)
+        }
+        if (!page->private) {
+                WARN_ON(1);
                 goto out;
+        }
         len = page->private >> 2;
         WARN_ON(len == 0);
 
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 4e7e012ad667..f3c96fc01439 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -6583,7 +6583,7 @@ static noinline int relocate_data_extent(struct inode *reloc_inode,
         u64 end = start + extent_key->offset - 1;
 
         em = alloc_extent_map(GFP_NOFS);
-        BUG_ON(!em || IS_ERR(em));
+        BUG_ON(!em);
 
         em->start = start;
         em->len = extent_key->offset;
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 5e76a474cb7e..92ac5192c518 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1946,6 +1946,7 @@ void set_page_extent_mapped(struct page *page)
 
 static void set_page_extent_head(struct page *page, unsigned long len)
 {
+        WARN_ON(!PagePrivate(page));
         set_page_private(page, EXTENT_PAGE_PRIVATE_FIRST_PAGE | len << 2);
 }
 
@@ -2821,9 +2822,17 @@ int try_release_extent_state(struct extent_map_tree *map,
                  * at this point we can safely clear everything except the
                  * locked bit and the nodatasum bit
                  */
-                clear_extent_bit(tree, start, end,
+                ret = clear_extent_bit(tree, start, end,
                                  ~(EXTENT_LOCKED | EXTENT_NODATASUM),
                                  0, 0, NULL, mask);
+
+                /* if clear_extent_bit failed for enomem reasons,
+                 * we can't allow the release to continue.
+                 */
+                if (ret < 0)
+                        ret = 0;
+                else
+                        ret = 1;
         }
         return ret;
 }
@@ -3194,7 +3203,13 @@ struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
                 }
                 if (!PageUptodate(p))
                         uptodate = 0;
-                unlock_page(p);
+
+                /*
+                 * see below about how we avoid a nasty race with release page
+                 * and why we unlock later
+                 */
+                if (i != 0)
+                        unlock_page(p);
         }
         if (uptodate)
                 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
@@ -3218,9 +3233,26 @@ struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
         atomic_inc(&eb->refs);
         spin_unlock(&tree->buffer_lock);
         radix_tree_preload_end();
+
+        /*
+         * there is a race where release page may have
+         * tried to find this extent buffer in the radix
+         * but failed.  It will tell the VM it is safe to
+         * reclaim the, and it will clear the page private bit.
+         * We must make sure to set the page private bit properly
+         * after the extent buffer is in the radix tree so
+         * it doesn't get lost
+         */
+        set_page_extent_mapped(eb->first_page);
+        set_page_extent_head(eb->first_page, eb->len);
+        if (!page0)
+                unlock_page(eb->first_page);
         return eb;
 
 free_eb:
+        if (eb->first_page && !page0)
+                unlock_page(eb->first_page);
+
         if (!atomic_dec_and_test(&eb->refs))
                 return exists;
         btrfs_release_extent_buffer(eb);
@@ -3271,10 +3303,11 @@ int clear_extent_buffer_dirty(struct extent_io_tree *tree,
                         continue;
 
                 lock_page(page);
+                WARN_ON(!PagePrivate(page));
+
+                set_page_extent_mapped(page);
                 if (i == 0)
                         set_page_extent_head(page, eb->len);
-                else
-                        set_page_private(page, EXTENT_PAGE_PRIVATE);
 
                 clear_page_dirty_for_io(page);
                 spin_lock_irq(&page->mapping->tree_lock);
@@ -3464,6 +3497,13 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
 
         for (i = start_i; i < num_pages; i++) {
                 page = extent_buffer_page(eb, i);
+
+                WARN_ON(!PagePrivate(page));
+
+                set_page_extent_mapped(page);
+                if (i == 0)
+                        set_page_extent_head(page, eb->len);
+
                 if (inc_all_pages)
                         page_cache_get(page);
                 if (!PageUptodate(page)) {
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index b0e1fce12530..2b6c12e983b3 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -51,8 +51,8 @@ struct extent_map *alloc_extent_map(gfp_t mask)
 {
         struct extent_map *em;
         em = kmem_cache_alloc(extent_map_cache, mask);
-        if (!em || IS_ERR(em))
-                return em;
+        if (!em)
+                return NULL;
         em->in_tree = 0;
         em->flags = 0;
         em->compress_type = BTRFS_COMPRESS_NONE;
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index c1d3a818731a..7084140d5940 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -186,6 +186,7 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
                         split = alloc_extent_map(GFP_NOFS);
                 if (!split2)
                         split2 = alloc_extent_map(GFP_NOFS);
+                BUG_ON(!split || !split2);
 
                 write_lock(&em_tree->lock);
                 em = lookup_extent_mapping(em_tree, start, len);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index bcc461a9695f..fb9bd7832b6d 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -644,6 +644,7 @@ retry:
                                         async_extent->ram_size - 1, 0);
 
                 em = alloc_extent_map(GFP_NOFS);
+                BUG_ON(!em);
                 em->start = async_extent->start;
                 em->len = async_extent->ram_size;
                 em->orig_start = em->start;
@@ -820,6 +821,7 @@ static noinline int cow_file_range(struct inode *inode,
                 BUG_ON(ret);
 
                 em = alloc_extent_map(GFP_NOFS);
+                BUG_ON(!em);
                 em->start = start;
                 em->orig_start = em->start;
                 ram_size = ins.offset;
@@ -1169,6 +1171,7 @@ out_check:
                         struct extent_map_tree *em_tree;
                         em_tree = &BTRFS_I(inode)->extent_tree;
                         em = alloc_extent_map(GFP_NOFS);
+                        BUG_ON(!em);
                         em->start = cur_offset;
                         em->orig_start = em->start;
                         em->len = num_bytes;
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 02d224e8c83f..be2d4f6aaa5e 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -2208,7 +2208,7 @@ long btrfs_ioctl_space_info(struct btrfs_root *root, void __user *arg)
         int num_types = 4;
         int alloc_size;
         int ret = 0;
-        int slot_count = 0;
+        u64 slot_count = 0;
         int i, c;
 
         if (copy_from_user(&space_args,
@@ -2247,7 +2247,7 @@ long btrfs_ioctl_space_info(struct btrfs_root *root, void __user *arg)
                 goto out;
         }
 
-        slot_count = min_t(int, space_args.space_slots, slot_count);
+        slot_count = min_t(u64, space_args.space_slots, slot_count);
 
         alloc_size = sizeof(*dest) * slot_count;
 
@@ -2267,6 +2267,9 @@ long btrfs_ioctl_space_info(struct btrfs_root *root, void __user *arg)
         for (i = 0; i < num_types; i++) {
                 struct btrfs_space_info *tmp;
 
+                if (!slot_count)
+                        break;
+
                 info = NULL;
                 rcu_read_lock();
                 list_for_each_entry_rcu(tmp, &root->fs_info->space_info,
@@ -2288,7 +2291,10 @@ long btrfs_ioctl_space_info(struct btrfs_root *root, void __user *arg)
                                 memcpy(dest, &space, sizeof(space));
                                 dest++;
                                 space_args.total_spaces++;
+                                slot_count--;
                         }
+                        if (!slot_count)
+                                break;
                 }
                 up_read(&info->groups_sem);
         }
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 1f5556acb530..0825e4ed9447 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -1157,6 +1157,7 @@ static int clone_backref_node(struct btrfs_trans_handle *trans,
         new_node->bytenr = dest->node->start;
         new_node->level = node->level;
         new_node->lowest = node->lowest;
+        new_node->checked = 1;
         new_node->root = dest;
 
         if (!node->lowest) {
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 2636a051e4b2..af7dbca15276 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1605,12 +1605,14 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
 
         ret = find_next_devid(root, &device->devid);
         if (ret) {
+                kfree(device->name);
                 kfree(device);
                 goto error;
         }
 
         trans = btrfs_start_transaction(root, 0);
         if (IS_ERR(trans)) {
+                kfree(device->name);
                 kfree(device);
                 ret = PTR_ERR(trans);
                 goto error;