f2fs: support in batch multi blocks preallocation

This patch introduces reserve_new_blocks to make preallocation of multi
blocks as in batch operation, so it can avoid lots of redundant
operation, result in better performance.

In virtual machine, with rotational device:

time fallocate -l 32G /mnt/f2fs/file

Before:
real	0m4.584s
user	0m0.000s
sys	0m4.580s

After:
real	0m0.292s
user	0m0.000s
sys	0m0.272s

In x86, with SSD:

time fallocate -l 500G $MNT/testfile

Before : 24.758 s
After  :  1.604 s

Signed-off-by: Chao Yu <yuchao0@huawei.com>
[Jaegeuk Kim: fix bugs and add performance numbers measured in x86.]
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 13 insertions, 7 deletions

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 052f5a8c96f1..1401c96724c6 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1094,7 +1094,7 @@ static inline bool f2fs_has_xattr_block(unsigned int ofs)
 }
 
 static inline bool inc_valid_block_count(struct f2fs_sb_info *sbi,
-                                 struct inode *inode, blkcnt_t count)
+                                 struct inode *inode, blkcnt_t *count)
 {
         block_t valid_block_count;
 
@@ -1106,14 +1106,19 @@ static inline bool inc_valid_block_count(struct f2fs_sb_info *sbi,
         }
 #endif
         valid_block_count =
-                sbi->total_valid_block_count + (block_t)count;
+                sbi->total_valid_block_count + (block_t)(*count);
         if (unlikely(valid_block_count > sbi->user_block_count)) {
-                spin_unlock(&sbi->stat_lock);
-                return false;
+                *count = sbi->user_block_count - sbi->total_valid_block_count;
+                if (!*count) {
+                        spin_unlock(&sbi->stat_lock);
+                        return false;
+                }
         }
-        inode->i_blocks += count;
-        sbi->total_valid_block_count = valid_block_count;
-        sbi->alloc_valid_block_count += (block_t)count;
+        /* *count can be recalculated */
+        inode->i_blocks += *count;
+        sbi->total_valid_block_count =
+                sbi->total_valid_block_count + (block_t)(*count);
+        sbi->alloc_valid_block_count += (block_t)(*count);
         spin_unlock(&sbi->stat_lock);
         return true;
 }
@@ -1945,6 +1950,7 @@ int f2fs_submit_page_bio(struct f2fs_io_info *);
 void f2fs_submit_page_mbio(struct f2fs_io_info *);
 void set_data_blkaddr(struct dnode_of_data *);
 void f2fs_update_data_blkaddr(struct dnode_of_data *, block_t);
+int reserve_new_blocks(struct dnode_of_data *, blkcnt_t);
 int reserve_new_block(struct dnode_of_data *);
 int f2fs_get_block(struct dnode_of_data *, pgoff_t);
 ssize_t f2fs_preallocate_blocks(struct kiocb *, struct iov_iter *);