[f2fs-dev] [PATCH -next 2/4] f2fs: extent cache: support extent for no-compressed file

[Zhang Qilong via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net>]

No-compressed file may suffer read performance issue due to it can't
use extent cache or the largest extent in inode can't covered other
parts of continuous blocks in readonly format f2fs image.

Now it won't build extent cacge tree for no-compressed file in
readonly format f2fs image.

For readonly format f2fs image, maybe the no-compressed file don't
have the largest extent, or it have more than one part which have
internally continuous blocks. So we add extent cache tree for the
no-compressed file in readonly format f2fs image.

The cache policy is almost same with compressed file. The difference
is that, the no-compressed file part will set min-number of continuous
blocks F2FS_MIN_EXTENT_LEN in order to reduce cache fragmentation.

Signed-off-by: Zhang Qilong <zhangqilong3@huawei.com>
---
 fs/f2fs/extent_cache.c | 52 ++++++++++++++++++++++++++++++++++--------
 1 file changed, 42 insertions(+), 10 deletions(-)

diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c
index 387d53a61270..7e39381edca0 100644
--- a/fs/f2fs/extent_cache.c
+++ b/fs/f2fs/extent_cache.c
@@ -695,9 +695,12 @@ static void f2fs_update_extent_tree_range_compressed(struct inode *inode,
 	set_extent_info(&ei, fofs, blkaddr, llen);
 	ei.c_len = c_len;
 
-	if (!__try_merge_extent_node(sbi, et, &ei, prev_en, next_en))
+	if (!__try_merge_extent_node(sbi, et, &ei, prev_en, next_en)) {
+		if (!c_len && llen < F2FS_MIN_EXTENT_LEN)
+			goto unlock_out;
 		__insert_extent_tree(sbi, et, &ei,
 				insert_p, insert_parent, leftmost);
+	}
 unlock_out:
 	write_unlock(&et->lock);
 }
@@ -726,24 +729,53 @@ static unsigned int f2fs_cluster_blocks_are_contiguous(struct dnode_of_data *dn)
 	return compressed ? i - 1 : i;
 }
 
+/*
+ * check whether normal file blocks are contiguous, and add extent cache
+ * entry only if remained blocks are logically and physically contiguous.
+ */
+static unsigned int f2fs_normal_blocks_are_contiguous(struct dnode_of_data *dn)
+{
+	int i = 0;
+	struct inode *inode = dn->inode;
+	block_t first_blkaddr = data_blkaddr(inode, dn->node_page,
+						dn->ofs_in_node);
+	unsigned int max_blocks = ADDRS_PER_PAGE(dn->node_page, inode)
+					- dn->ofs_in_node;
+
+	for (i = 1; i < max_blocks; i++) {
+		block_t blkaddr = data_blkaddr(inode, dn->node_page,
+				dn->ofs_in_node + i);
+
+		if (!__is_valid_data_blkaddr(blkaddr) ||
+				first_blkaddr + i != blkaddr)
+			return i;
+	}
+
+	return i;
+}
+
 void f2fs_readonly_update_extent_cache(struct dnode_of_data *dn,
 					pgoff_t index)
 {
-	unsigned int c_len = f2fs_cluster_blocks_are_contiguous(dn);
+	unsigned int c_len = 0;
+	unsigned int llen = 0;
 	block_t blkaddr;
 
-	if (!c_len)
-		return;
-
 	blkaddr = f2fs_data_blkaddr(dn);
-	if (blkaddr == COMPRESS_ADDR)
-		blkaddr = data_blkaddr(dn->inode, dn->node_page,
+	if (f2fs_compressed_file(dn->inode)) {
+		c_len = f2fs_cluster_blocks_are_contiguous(dn);
+		if (!c_len)
+			return;
+		llen = F2FS_I(dn->inode)->i_cluster_size;
+		if (blkaddr == COMPRESS_ADDR)
+			blkaddr = data_blkaddr(dn->inode, dn->node_page,
 					dn->ofs_in_node + 1);
+	} else {
+		llen = f2fs_normal_blocks_are_contiguous(dn);
+	}
 
 	f2fs_update_extent_tree_range_compressed(dn->inode,
-				index, blkaddr,
-				F2FS_I(dn->inode)->i_cluster_size,
-				c_len);
+				index, blkaddr, llen, c_len);
 }
 #endif
 
-- 
2.25.1



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