1 files changed, 55 insertions, 62 deletions

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;