For now that code just return true
Later more complex heuristic code will be added
Signed-off-by: Timofey Titovets <nefelim4ag@xxxxxxxxx>
---
fs/btrfs/compression.c | 22 ++++++++++++++++++++++
fs/btrfs/compression.h | 2 ++
fs/btrfs/inode.c | 25 ++++++++++++++++---------
3 files changed, 40 insertions(+), 9 deletions(-)
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index a2fad39f79ba..481e56f61461 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -1098,3 +1098,25 @@ int btrfs_decompress_buf2page(const char *buf, unsigned long buf_start,
return 1;
}
+
+/*
+ * Heuristic skeleton
+ * For now just would be a naive and very optimistic 'return true'.
+ */
+int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end)
+{
+ u64 index = start >> PAGE_SHIFT;
+ u64 end_index = end >> PAGE_SHIFT;
+ struct page *page;
+ int ret = 1;
+
+ while (index <= end_index) {
+ page = find_get_page(inode->i_mapping, index);
+ kmap(page);
+ kunmap(page);
+ put_page(page);
+ index++;
+ }
+
+ return ret;
+}
diff --git a/fs/btrfs/compression.h b/fs/btrfs/compression.h
index 680d4265d601..259ea776c9d4 100644
--- a/fs/btrfs/compression.h
+++ b/fs/btrfs/compression.h
@@ -93,4 +93,6 @@ struct btrfs_compress_op {
extern const struct btrfs_compress_op btrfs_zlib_compress;
extern const struct btrfs_compress_op btrfs_lzo_compress;
+int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end);
+
#endif
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 556c93060606..285e5b5eed35 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -510,15 +510,6 @@ static noinline void compress_file_range(struct inode *inode,
*/
if (inode_need_compress(inode)) {
WARN_ON(pages);
- pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS);
- if (!pages) {
- /* just bail out to the uncompressed code */
- goto cont;
- }
-
- 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
@@ -530,6 +521,22 @@ static noinline void compress_file_range(struct inode *inode,
*/
extent_range_clear_dirty_for_io(inode, start, end);
redirty = 1;
+
+ ret = btrfs_compress_heuristic(inode, start, end);
+
+ /* Heuristic say: dont try compress that */
+ if (ret == 0)
+ goto cont;
+
+ pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS);
+ if (!pages) {
+ /* just bail out to the uncompressed code */
+ goto cont;
+ }
+
+ if (BTRFS_I(inode)->force_compress)
+ compress_type = BTRFS_I(inode)->force_compress;
+
ret = btrfs_compress_pages(compress_type,
inode->i_mapping, start,
pages,
--
2.13.2
--
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