Messages in this thread | | | Date | Wed, 26 Sep 2018 22:05:09 -0700 | From | Jaegeuk Kim <> | Subject | Re: [PATCH] f2fs: refactor ->page_mkwrite() flow |
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This makes xfstests/083 stuck. So, I'll drop it for a while.
On 09/26, Chao Yu wrote: > From: Chao Yu <yuchao0@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 <yuchao0@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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