f2fs: shrink node_write lock coverage

- to avoid race between checkpoint and quota file writeback, it
just needs to hold read lock of node_write in writeback path.
- node_write lock has covered all LFS data write paths, it's not
necessary, we only need to hold node_write lock at write path of
quota file.

This refactors commit ca7f76e68074 ("f2fs: fix wrong discard space").

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index 7dbd56a..5643aa2 100644 (file)
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -1096,8 +1096,16 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc,
        loff_t psize;
        int i, err;
 
-       if (!IS_NOQUOTA(inode) && !f2fs_trylock_op(sbi))
+       if (IS_NOQUOTA(inode)) {
+               /*
+                * We need to wait for node_write to avoid block allocation during
+                * checkpoint. This can only happen to quota writes which can cause
+                * the below discard race condition.
+                */
+               down_read(&sbi->node_write);
+       } else if (!f2fs_trylock_op(sbi)) {
                return -EAGAIN;
+       }
 
        set_new_dnode(&dn, cc->inode, NULL, NULL, 0);
 
@@ -1203,7 +1211,9 @@ unlock_continue:
                set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
 
        f2fs_put_dnode(&dn);
-       if (!IS_NOQUOTA(inode))
+       if (IS_NOQUOTA(inode))
+               up_read(&sbi->node_write);
+       else
                f2fs_unlock_op(sbi);
 
        spin_lock(&fi->i_size_lock);
@@ -1230,7 +1240,9 @@ out_put_cic:
 out_put_dnode:
        f2fs_put_dnode(&dn);
 out_unlock_op:
-       if (!IS_NOQUOTA(inode))
+       if (IS_NOQUOTA(inode))
+               up_read(&sbi->node_write);
+       else
                f2fs_unlock_op(sbi);
        return -EAGAIN;
 }

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index c78ce08..cbdf062 100644 (file)
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2719,8 +2719,20 @@ write:
 
        /* Dentry/quota blocks are controlled by checkpoint */
        if (S_ISDIR(inode->i_mode) || IS_NOQUOTA(inode)) {
+               /*
+                * We need to wait for node_write to avoid block allocation during
+                * checkpoint. This can only happen to quota writes which can cause
+                * the below discard race condition.
+                */
+               if (IS_NOQUOTA(inode))
+                       down_read(&sbi->node_write);
+
                fio.need_lock = LOCK_DONE;
                err = f2fs_do_write_data_page(&fio);
+
+               if (IS_NOQUOTA(inode))
+                       up_read(&sbi->node_write);
+
                goto done;
        }
 

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index cf693a0..2e3098f 100644 (file)
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -3133,14 +3133,6 @@ void f2fs_allocate_data_block(struct f2fs_sb_info *sbi, struct page *page,
                type = CURSEG_COLD_DATA;
        }
 
-       /*
-        * We need to wait for node_write to avoid block allocation during
-        * checkpoint. This can only happen to quota writes which can cause
-        * the below discard race condition.
-        */
-       if (IS_DATASEG(type))
-               down_write(&sbi->node_write);
-
        down_read(&SM_I(sbi)->curseg_lock);
 
        mutex_lock(&curseg->curseg_mutex);
@@ -3206,9 +3198,6 @@ void f2fs_allocate_data_block(struct f2fs_sb_info *sbi, struct page *page,
 
        up_read(&SM_I(sbi)->curseg_lock);
 
-       if (IS_DATASEG(type))
-               up_write(&sbi->node_write);
-
        if (put_pin_sem)
                up_read(&sbi->pin_sem);
 }