From: Ryusuke Konishi Subject: Re: [PATCH] fs: Convert return type int to vm_fault_t Date: Thu, 30 Aug 2018 16:56:29 +0900 (JST) Message-ID: <20180830.165629.1747893038794269821.konishi.ryusuke@lab.ntt.co.jp> References: <20180828192528.GA24453@jordon-HP-15-Notebook-PC> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: willy@infradead.org, viro@zeniv.linux.org.uk, tytso@mit.edu, adilger.kernel@dilger.ca, darrick.wong@oracle.com, axboe@kernel.dk, ebiggers@google.com, tglx@linutronix.de, gregkh@linuxfoundation.org, kemi.wang@intel.com, akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-nilfs@vger.kernel.org To: Souptick Joarder Return-path: In-Reply-To: <20180828192528.GA24453@jordon-HP-15-Notebook-PC> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org Hi, On Wed, 29 Aug 2018 00:55:28 +0530, Souptick Joarder wrote: > Return type for fault handlers in ext4 and nilfs are > changed to use vm_fault_t. > > Return type of block_page_mkwrite() is changed from > int to vm_fault_t. The function signature of > block_page_mkwrite() is changed to add one new parameter > int *err. This will provide a way for caller functions > to get error number along with VM_FAULT return value and > use it further. > > Return type of block_page_mkwrite_return() is also changed > to use new vm_fault_t type. > > Signed-off-by: Souptick Joarder > --- > fs/buffer.c | 20 +++++++++++--------- > fs/ext4/ext4.h | 4 ++-- > fs/ext4/inode.c | 34 ++++++++++++++++++---------------- > fs/nilfs2/file.c | 16 ++++++++++------ > include/linux/buffer_head.h | 7 ++++--- > 5 files changed, 45 insertions(+), 36 deletions(-) > > diff --git a/fs/buffer.c b/fs/buffer.c > index ebf78ab..aacfc73 100644 > --- a/fs/buffer.c > +++ b/fs/buffer.c > @@ -2487,21 +2487,21 @@ int block_commit_write(struct page *page, unsigned from, unsigned to) > * Direct callers of this function should protect against filesystem freezing > * using sb_start_pagefault() - sb_end_pagefault() functions. > */ > -int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, > - get_block_t get_block) > +vm_fault_t block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, > + get_block_t get_block, int *err) > { > struct page *page = vmf->page; > struct inode *inode = file_inode(vma->vm_file); > unsigned long end; > loff_t size; > - int ret; > + int err1; > > lock_page(page); > size = i_size_read(inode); > if ((page->mapping != inode->i_mapping) || > (page_offset(page) > size)) { > /* We overload EFAULT to mean page got truncated */ > - ret = -EFAULT; > + err1 = -EFAULT; > goto out_unlock; > } > > @@ -2511,18 +2511,20 @@ int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, > else > end = PAGE_SIZE; > > - ret = __block_write_begin(page, 0, end, get_block); > - if (!ret) > - ret = block_commit_write(page, 0, end); > + err1 = __block_write_begin(page, 0, end, get_block); > + if (!err1) > + err1 = block_commit_write(page, 0, end); > > - if (unlikely(ret < 0)) > + if (unlikely(err1 < 0)) > goto out_unlock; > + *err = err1; > set_page_dirty(page); > wait_for_stable_page(page); > return 0; > out_unlock: > unlock_page(page); > - return ret; > + *err = err1; > + return block_page_mkwrite_return(err1); > } > EXPORT_SYMBOL(block_page_mkwrite); > > diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h > index 0f0edd1..8506b14 100644 > --- a/fs/ext4/ext4.h > +++ b/fs/ext4/ext4.h > @@ -2469,8 +2469,8 @@ int do_journal_get_write_access(handle_t *handle, > extern int ext4_chunk_trans_blocks(struct inode *, int nrblocks); > extern int ext4_zero_partial_blocks(handle_t *handle, struct inode *inode, > loff_t lstart, loff_t lend); > -extern int ext4_page_mkwrite(struct vm_fault *vmf); > -extern int ext4_filemap_fault(struct vm_fault *vmf); > +extern vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf); > +extern vm_fault_t ext4_filemap_fault(struct vm_fault *vmf); > extern qsize_t *ext4_get_reserved_space(struct inode *inode); > extern int ext4_get_projid(struct inode *inode, kprojid_t *projid); > extern void ext4_da_update_reserve_space(struct inode *inode, > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index 82adee7..1062a8e 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -6151,39 +6151,40 @@ static int ext4_bh_unmapped(handle_t *handle, struct buffer_head *bh) > return !buffer_mapped(bh); > } > > -int ext4_page_mkwrite(struct vm_fault *vmf) > +vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf) > { > struct vm_area_struct *vma = vmf->vma; > struct page *page = vmf->page; > loff_t size; > unsigned long len; > - int ret; > + vm_fault_t ret; > struct file *file = vma->vm_file; > struct inode *inode = file_inode(file); > struct address_space *mapping = inode->i_mapping; > handle_t *handle; > get_block_t *get_block; > - int retries = 0; > + int retries = 0, err; > > sb_start_pagefault(inode->i_sb); > file_update_time(vma->vm_file); > > down_read(&EXT4_I(inode)->i_mmap_sem); > > - ret = ext4_convert_inline_data(inode); > - if (ret) > + err = ext4_convert_inline_data(inode); > + if (err) > goto out_ret; > > + err = 0; > /* Delalloc case is easy... */ > if (test_opt(inode->i_sb, DELALLOC) && > !ext4_should_journal_data(inode) && > !ext4_nonda_switch(inode->i_sb)) { > do { > ret = block_page_mkwrite(vma, vmf, > - ext4_da_get_block_prep); > - } while (ret == -ENOSPC && > + ext4_da_get_block_prep, &err); > + } while (err == -ENOSPC && > ext4_should_retry_alloc(inode->i_sb, &retries)); > - goto out_ret; > + goto out; > } > > lock_page(page); > @@ -6226,36 +6227,37 @@ int ext4_page_mkwrite(struct vm_fault *vmf) > ret = VM_FAULT_SIGBUS; > goto out; > } > - ret = block_page_mkwrite(vma, vmf, get_block); > + err = 0; > + ret = block_page_mkwrite(vma, vmf, get_block, &err); > if (!ret && ext4_should_journal_data(inode)) { > if (ext4_walk_page_buffers(handle, page_buffers(page), 0, > PAGE_SIZE, NULL, do_journal_get_write_access)) { > unlock_page(page); > - ret = VM_FAULT_SIGBUS; > ext4_journal_stop(handle); > goto out; > } > ext4_set_inode_state(inode, EXT4_STATE_JDATA); > } > ext4_journal_stop(handle); > - if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) > + if (err == -ENOSPC && > + ext4_should_retry_alloc(inode->i_sb, &retries)) > goto retry_alloc; > out_ret: > - ret = block_page_mkwrite_return(ret); > + ret = block_page_mkwrite_return(err); > out: > up_read(&EXT4_I(inode)->i_mmap_sem); > sb_end_pagefault(inode->i_sb); > return ret; > } > > -int ext4_filemap_fault(struct vm_fault *vmf) > +vm_fault_t ext4_filemap_fault(struct vm_fault *vmf) > { > struct inode *inode = file_inode(vmf->vma->vm_file); > - int err; > + vm_fault_t ret; > > down_read(&EXT4_I(inode)->i_mmap_sem); > - err = filemap_fault(vmf); > + ret = filemap_fault(vmf); > up_read(&EXT4_I(inode)->i_mmap_sem); > > - return err; > + return ret; > } > diff --git a/fs/nilfs2/file.c b/fs/nilfs2/file.c > index 7da0fac..58d2a81 100644 > --- a/fs/nilfs2/file.c > +++ b/fs/nilfs2/file.c > @@ -57,7 +57,8 @@ static vm_fault_t nilfs_page_mkwrite(struct vm_fault *vmf) > struct page *page = vmf->page; > struct inode *inode = file_inode(vma->vm_file); > struct nilfs_transaction_info ti; > - int ret = 0; > + vm_fault_t ret = VM_FAULT_LOCKED; > + int err = 0; > > if (unlikely(nilfs_near_disk_full(inode->i_sb->s_fs_info))) > return VM_FAULT_SIGBUS; /* -ENOSPC */ > @@ -67,7 +68,7 @@ static vm_fault_t nilfs_page_mkwrite(struct vm_fault *vmf) > if (page->mapping != inode->i_mapping || > page_offset(page) >= i_size_read(inode) || !PageUptodate(page)) { > unlock_page(page); > - ret = -EFAULT; /* make the VM retry the fault */ > + ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */ > goto out; > } > > @@ -99,13 +100,16 @@ static vm_fault_t nilfs_page_mkwrite(struct vm_fault *vmf) > /* > * fill hole blocks > */ > - ret = nilfs_transaction_begin(inode->i_sb, &ti, 1); > + err = nilfs_transaction_begin(inode->i_sb, &ti, 1); > /* never returns -ENOMEM, but may return -ENOSPC */ > - if (unlikely(ret)) > + if (unlikely(err)) { > + ret = block_page_mkwrite_return(err); > goto out; > + } > > + err = 0; This initialization looks unnecessary. "err" is always zero here. Regards, Ryusuke Konishi > file_update_time(vma->vm_file); > - ret = block_page_mkwrite(vma, vmf, nilfs_get_block); > + ret = block_page_mkwrite(vma, vmf, nilfs_get_block, &err); > if (ret) { > nilfs_transaction_abort(inode->i_sb); > goto out; > @@ -117,7 +121,7 @@ static vm_fault_t nilfs_page_mkwrite(struct vm_fault *vmf) > wait_for_stable_page(page); > out: > sb_end_pagefault(inode->i_sb); > - return block_page_mkwrite_return(ret); > + return ret; > } > > static const struct vm_operations_struct nilfs_file_vm_ops = { > diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h > index 96225a7..e212b13 100644 > --- a/include/linux/buffer_head.h > +++ b/include/linux/buffer_head.h > @@ -14,6 +14,7 @@ > #include > #include > #include > +#include > > #ifdef CONFIG_BLOCK > > @@ -239,10 +240,10 @@ int cont_write_begin(struct file *, struct address_space *, loff_t, > get_block_t *, loff_t *); > int generic_cont_expand_simple(struct inode *inode, loff_t size); > int block_commit_write(struct page *page, unsigned from, unsigned to); > -int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, > - get_block_t get_block); > +vm_fault_t block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, > + get_block_t get_block, int *err); > /* Convert errno to return value from ->page_mkwrite() call */ > -static inline int block_page_mkwrite_return(int err) > +static inline vm_fault_t block_page_mkwrite_return(int err) > { > if (err == 0) > return VM_FAULT_LOCKED; > -- > 1.9.1 >