f2fs: refactor ->page_mkwrite() flow
Thread A Thread B
- f2fs_vm_page_mkwrite
- f2fs_setattr
- down_write(i_mmap_sem)
- truncate_setsize
- f2fs_truncate
- up_write(i_mmap_sem)
- f2fs_reserve_block
reserve NEW_ADDR
- skip dirty page due to truncation
1. we don't need to rserve new block address for a truncated page.
2. dn.data_blkaddr is used out of node page lock coverage.
Refactor ->page_mkwrite() flow to fix above issues:
- use __do_map_lock() to avoid racing checkpoint()
- lock data page in prior to dnode page
- cover f2fs_reserve_block with i_mmap_sem lock
- wait page writeback before zeroing page
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index c8fd91c..e4a3991 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -969,7 +969,7 @@
return err;
}
-static inline void __do_map_lock(struct f2fs_sb_info *sbi, int flag, bool lock)
+void __do_map_lock(struct f2fs_sb_info *sbi, int flag, bool lock)
{
if (flag == F2FS_GET_BLOCK_PRE_AIO) {
if (lock)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 326b992..0ea205d 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3084,6 +3084,7 @@
struct page *f2fs_get_new_data_page(struct inode *inode,
struct page *ipage, pgoff_t index, bool new_i_size);
int f2fs_do_write_data_page(struct f2fs_io_info *fio);
+void __do_map_lock(struct f2fs_sb_info *sbi, int flag, bool lock);
int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
int create, int flag);
int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 0e69cc9..e5cfa43 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -49,7 +49,7 @@
struct page *page = vmf->page;
struct inode *inode = file_inode(vma->vm_file);
struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
- struct dnode_of_data dn;
+ struct dnode_of_data dn = { .node_changed = false };
int err;
if (unlikely(f2fs_cp_error(sbi))) {
@@ -61,19 +61,6 @@
f2fs_bug_on(sbi, f2fs_has_inline_data(inode));
- /* block allocation */
- f2fs_lock_op(sbi);
- set_new_dnode(&dn, inode, NULL, NULL, 0);
- err = f2fs_reserve_block(&dn, page->index);
- if (err) {
- f2fs_unlock_op(sbi);
- goto out;
- }
- f2fs_put_dnode(&dn);
- f2fs_unlock_op(sbi);
-
- f2fs_balance_fs(sbi, dn.node_changed);
-
file_update_time(vma->vm_file);
down_read(&F2FS_I(inode)->i_mmap_sem);
lock_page(page);
@@ -85,11 +72,28 @@
goto out_sem;
}
+ /* block allocation */
+ __do_map_lock(sbi, F2FS_GET_BLOCK_PRE_AIO, true);
+ set_new_dnode(&dn, inode, NULL, NULL, 0);
+ err = f2fs_get_block(&dn, page->index);
+ f2fs_put_dnode(&dn);
+ __do_map_lock(sbi, F2FS_GET_BLOCK_PRE_AIO, false);
+ if (err) {
+ unlock_page(page);
+ goto out_sem;
+ }
+
+ /* fill the page */
+ f2fs_wait_on_page_writeback(page, DATA, false);
+
+ /* wait for GCed page writeback via META_MAPPING */
+ f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
+
/*
* check to see if the page is mapped already (no holes)
*/
if (PageMappedToDisk(page))
- goto mapped;
+ goto out_sem;
/* page is wholly or partially inside EOF */
if (((loff_t)(page->index + 1) << PAGE_SHIFT) >
@@ -106,16 +110,11 @@
f2fs_update_iostat(sbi, APP_MAPPED_IO, F2FS_BLKSIZE);
trace_f2fs_vm_page_mkwrite(page, DATA);
-mapped:
- /* fill the page */
- f2fs_wait_on_page_writeback(page, DATA, false);
-
- /* wait for GCed page writeback via META_MAPPING */
- f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
-
out_sem:
up_read(&F2FS_I(inode)->i_mmap_sem);
-out:
+
+ f2fs_balance_fs(sbi, dn.node_changed);
+
sb_end_pagefault(inode->i_sb);
f2fs_update_time(sbi, REQ_TIME);
err: