From: Souptick Joarder Subject: Re: [PATCH] fs: Convert return type int to vm_fault_t Date: Thu, 30 Aug 2018 22:08:41 +0530 Message-ID: References: <20180828192528.GA24453@jordon-HP-15-Notebook-PC> <20180830.165629.1747893038794269821.konishi.ryusuke@lab.ntt.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Cc: Matthew Wilcox , Al Viro , "Theodore Ts'o" , adilger.kernel@dilger.ca, "Darrick J. Wong" , Jens Axboe , Eric Biggers , Thomas Gleixner , Greg KH , kemi.wang@intel.com, Andrew Morton , linux-fsdevel , linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-nilfs To: Ryusuke Konishi Return-path: In-Reply-To: <20180830.165629.1747893038794269821.konishi.ryusuke@lab.ntt.co.jp> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Thu, Aug 30, 2018 at 1:26 PM Ryusuke Konishi wrote: > > 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. Agree. > > > + 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 > >