SQLite App GC Thread Shrinker
- f2fs_ioc_start_atomic_write
- f2fs_ioc_commit_atomic_write
- f2fs_commit_atomic_write
- filemap_write_and_wait_range
: write atomic_file's data to cow_inode
echo 3 > drop_caches
- f2fs_gc
- gc_data_segment
- move_data_page
- set_page_dirty
: it may load data of previous
transaction into pagecache.
- f2fs_down_write(&fi->i_gc_rwsem[WRITE])
- __f2fs_commit_atomic_write
- f2fs_up_write(&fi->i_gc_rwsem[WRITE])
During committing atomic_file, GC may be triggered to migrate
atomic_file's block, so it may contain data of previous transaction
in page cache, we should drop atomic_file's cache once it was
migrated by GC.
And also, we should writeback atomic_file and cow_file's data
w/ i_gc_rwsem lock held, in order to avoid block address change
during __f2fs_commit_atomic_write().
Meahwhile, this patch adds f2fs_wait_on_block_writeback_range()
to wait completion of block migration.
Fixes: 3db1de0e582c ("f2fs: change the current atomic write way")
Signed-off-by: Chao Yu <c...@kernel.org>
---
v2:
- fix error path handling.
fs/f2fs/segment.c | 27 +++++++++++++++++++++++----
1 file changed, 23 insertions(+), 4 deletions(-)
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 3aee71c9f3c6..a43054ab0cf1 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -236,6 +236,9 @@ static int __replace_atomic_write_block(struct inode
*inode, pgoff_t index,
return err;
}
+ if (__is_valid_data_blkaddr(dn.data_blkaddr))
+ f2fs_wait_on_block_writeback_range(inode, dn.data_blkaddr, 1);
+
if (recover) {
/* dn.data_blkaddr is always valid */
if (!__is_valid_data_blkaddr(new_addr)) {
@@ -339,6 +342,9 @@ static int __f2fs_commit_atomic_write(struct inode *inode)
goto out;
}
+ f2fs_wait_on_block_writeback_range(cow_inode,
+ blkaddr, 1);
+
new = f2fs_kmem_cache_alloc(revoke_entry_slab, GFP_NOFS,
true, NULL);
@@ -379,16 +385,29 @@ int f2fs_commit_atomic_write(struct inode *inode)
struct f2fs_inode_info *fi = F2FS_I(inode);
int err;
+ f2fs_down_write(&fi->i_gc_rwsem[WRITE]);
+
err = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX);
if (err)
- return err;
+ goto out;
- f2fs_down_write(&fi->i_gc_rwsem[WRITE]);
- f2fs_lock_op(sbi);
+ /* writeback GCing page of cow_inode */
+ err = filemap_write_and_wait_range(fi->cow_inode->i_mapping,
+ 0, LLONG_MAX);
+ if (err)
+ goto out;
- err = __f2fs_commit_atomic_write(inode);
+ filemap_invalidate_lock(inode->i_mapping);
+
+ /* don't allow clean page loaded by GC to pollute atomic_file */
+ truncate_pagecache(inode, 0);
+ f2fs_lock_op(sbi);
+ err = __f2fs_commit_atomic_write(inode);
f2fs_unlock_op(sbi);
+
+ filemap_invalidate_unlock(inode->i_mapping);
+out:
f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
return err;
--
2.40.1
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
