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-rw-r--r--fs/btrfs/extent_io.c33
-rw-r--r--fs/btrfs/extent_io.h2
-rw-r--r--fs/btrfs/inode.c14
3 files changed, 49 insertions, 0 deletions
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index f173c5af6461..cdee391fc7bf 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1257,6 +1257,39 @@ int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end)
GFP_NOFS);
}
+int extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end)
+{
+ unsigned long index = start >> PAGE_CACHE_SHIFT;
+ unsigned long end_index = end >> PAGE_CACHE_SHIFT;
+ struct page *page;
+
+ while (index <= end_index) {
+ page = find_get_page(inode->i_mapping, index);
+ BUG_ON(!page); /* Pages should be in the extent_io_tree */
+ clear_page_dirty_for_io(page);
+ page_cache_release(page);
+ index++;
+ }
+ return 0;
+}
+
+int extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end)
+{
+ unsigned long index = start >> PAGE_CACHE_SHIFT;
+ unsigned long end_index = end >> PAGE_CACHE_SHIFT;
+ struct page *page;
+
+ while (index <= end_index) {
+ page = find_get_page(inode->i_mapping, index);
+ BUG_ON(!page); /* Pages should be in the extent_io_tree */
+ account_page_redirty(page);
+ __set_page_dirty_nobuffers(page);
+ page_cache_release(page);
+ index++;
+ }
+ return 0;
+}
+
/*
* helper function to set both pages and extents in the tree writeback
*/
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 6068a1985560..258c92156857 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -325,6 +325,8 @@ int map_private_extent_buffer(struct extent_buffer *eb, unsigned long offset,
unsigned long *map_len);
int extent_range_uptodate(struct extent_io_tree *tree,
u64 start, u64 end);
+int extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end);
+int extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end);
int extent_clear_unlock_delalloc(struct inode *inode,
struct extent_io_tree *tree,
u64 start, u64 end, struct page *locked_page,
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 1f26888825e2..6a6e13c53086 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -353,6 +353,7 @@ static noinline int compress_file_range(struct inode *inode,
int i;
int will_compress;
int compress_type = root->fs_info->compress_type;
+ int redirty = 0;
/* if this is a small write inside eof, kick off a defrag */
if ((end - start + 1) < 16 * 1024 &&
@@ -415,6 +416,17 @@ again:
if (BTRFS_I(inode)->force_compress)
compress_type = BTRFS_I(inode)->force_compress;
+ /*
+ * we need to call clear_page_dirty_for_io on each
+ * page in the range. Otherwise applications with the file
+ * mmap'd can wander in and change the page contents while
+ * we are compressing them.
+ *
+ * If the compression fails for any reason, we set the pages
+ * dirty again later on.
+ */
+ extent_range_clear_dirty_for_io(inode, start, end);
+ redirty = 1;
ret = btrfs_compress_pages(compress_type,
inode->i_mapping, start,
total_compressed, pages,
@@ -554,6 +566,8 @@ cleanup_and_bail_uncompressed:
__set_page_dirty_nobuffers(locked_page);
/* unlocked later on in the async handlers */
}
+ if (redirty)
+ extent_range_redirty_for_io(inode, start, end);
add_async_extent(async_cow, start, end - start + 1,
0, NULL, 0, BTRFS_COMPRESS_NONE);
*num_added += 1;