From: Chao Yu <yuch...@huawei.com>
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
- access dn.data_blkaddr under dnode lock
Signed-off-by: Chao Yu <yuch...@huawei.com>
---
fs/f2fs/file.c | 29 ++++++++++++++---------------
1 file changed, 14 insertions(+), 15 deletions(-)
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 6f02c8daff76..fcb4788b48aa 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -47,7 +47,7 @@ static vm_fault_t f2fs_vm_page_mkwrite(struct vm_fault *vmf)
struct page *page = vmf->page;
struct inode *inode = file_inode(vmf->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))) {
@@ -59,19 +59,6 @@ static vm_fault_t f2fs_vm_page_mkwrite(struct vm_fault *vmf)
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(vmf->vma->vm_file);
down_read(&F2FS_I(inode)->i_mmap_sem);
lock_page(page);
@@ -108,12 +95,24 @@ static vm_fault_t f2fs_vm_page_mkwrite(struct vm_fault
*vmf)
/* fill the page */
f2fs_wait_on_page_writeback(page, DATA, false);
+ /* block allocation */
+ __do_map_lock(sbi, F2FS_GET_BLOCK_PRE_AIO, true);
+ set_new_dnode(&dn, inode, NULL, NULL, 0);
+ err = f2fs_reserve_block(&dn, page->index);
+ if (err)
+ goto out_unlock;
+
/* wait for GCed page writeback via META_MAPPING */
f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
+ f2fs_put_dnode(&dn);
+out_unlock:
+ __do_map_lock(sbi, F2FS_GET_BLOCK_PRE_AIO, false);
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:
--
2.18.0
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