On 2018/9/27 13:05, Jaegeuk Kim wrote:
> This makes xfstests/083 stuck. So, I'll drop it for a while.
Alright, let me check that case again.
Thanks,
>
> On 09/26, Chao Yu wrote:
>> 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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