[PATCH 3/4] f2fs: check IPU before cp to avoid IPU being blocked by cp

[Hou Pengyang <houpengyang@huawei.com>]

IPU checking is under f2fs_lock_op, as a result, some IPU page(such as fsync/fdatasync IPU)
may be blocked by a long time cp.

This patch fix this by doing IPU checking before f2fs_lock_op, so fsync IPU could go along with cp.

Suggested-by: He Yunlei <heyunlei@huawei.com>
Signed-off-by: Hou Pengyang <houpengyang@huawei.com>
---
 fs/f2fs/data.c    | 14 +++++++-------
 fs/f2fs/gc.c      |  1 +
 fs/f2fs/segment.c |  1 +
 3 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 183a426..9bf9c7d 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1380,19 +1380,20 @@ int do_write_data_page(struct f2fs_io_info *fio)
 	 * it had better in-place writes for updated data.
 	 */
 	if (need_inplace_update(fio)) {
-		f2fs_bug_on(fio->sbi, !fio->cp_rwsem_locked);
-		f2fs_unlock_op(fio->sbi);
-		fio->cp_rwsem_locked = false;
-
+		f2fs_bug_on(fio->sbi, fio->cp_rwsem_locked);
 		err = rewrite_data_page(fio);
 		trace_f2fs_do_write_data_page(fio->page, IPU);
 		set_inode_flag(inode, FI_UPDATE_WRITE);
 	} else {
+		if (!fio->cp_rwsem_locked)
+			f2fs_lock_op(fio->sbi);
 		write_data_page(&dn, fio);
 		trace_f2fs_do_write_data_page(page, OPU);
 		set_inode_flag(inode, FI_APPEND_WRITE);
 		if (page->index == 0)
 			set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
+		if (!fio->cp_rwsem_locked)
+			f2fs_unlock_op(fio->sbi);
 	}
 out_writepage:
 	f2fs_put_dnode(&dn);
@@ -1473,13 +1474,12 @@ static int __write_data_page(struct page *page, bool *submitted,
 		if (!err)
 			goto out;
 	}
-	f2fs_lock_op(sbi);
+
+	fio.cp_rwsem_locked = false;
 	if (err == -EAGAIN)
 		err = do_write_data_page(&fio);
 	if (F2FS_I(inode)->last_disk_size < psize)
 		F2FS_I(inode)->last_disk_size = psize;
-	if (fio.cp_rwsem_locked)
-		f2fs_unlock_op(sbi);
 done:
 	if (err && err != -ENOENT)
 		goto redirty_out;
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index e034857..b32cc30 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -715,6 +715,7 @@ static void move_data_page(struct inode *inode, block_t bidx, int gc_type,
 			.old_blkaddr = NULL_ADDR,
 			.page = page,
 			.encrypted_page = NULL,
+			.cp_rwsem_locked = true,
 		};
 		bool is_dirty = PageDirty(page);
 		int err;
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 9f86b98..463a77b 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -293,6 +293,7 @@ static int __commit_inmem_pages(struct inode *inode,
 		.op_flags = REQ_SYNC | REQ_PRIO,
 		.old_blkaddr = NULL_ADDR,
 		.encrypted_page = NULL,
+		.cp_rwsem_locked = true,
 	};
 	pgoff_t last_idx = ULONG_MAX;
 	int err = 0;
-- 
2.10.1


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