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Date: Wed, 13 Aug 2014 15:20:46 +0800
From: Chao Yu <chao2.yu@...sung.com>
To: 'Jaegeuk Kim' <jaegeuk@...nel.org>,
Changman Lee <cm224.lee@...sung.com>
Cc: linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
linux-f2fs-devel@...ts.sourceforge.net
Subject: RE: [f2fs-dev] [PATCH 01/13] f2fs: should convert inline_data during
the mkwrite
Hi Jaegeuk,
> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk@...nel.org]
> Sent: Wednesday, August 13, 2014 3:49 AM
> To: linux-kernel@...r.kernel.org; linux-fsdevel@...r.kernel.org;
> linux-f2fs-devel@...ts.sourceforge.net
> Cc: Jaegeuk Kim
> Subject: [f2fs-dev] [PATCH 01/13] f2fs: should convert inline_data during the mkwrite
>
> If mkwrite is called to an inode having inline_data, it can overwrite the data
> index space as NEW_ADDR. (e.g., the first 4 bytes are coincidently zero)
Good catch!
As I did some simple tests, I found that thread will receive SIGBUS when
operating mmaped page exceed file size, so here, we will meet a inline data
inode only when we mkwrite the first page.
Please correct me if I'm wrong.
In this case, why not just do f2fs_read_inline_data & skip f2fs_reserve_block,
instead of converting inline_data and following f2fs_write_inline_data in
->writepage().
>
> Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
> ---
> fs/f2fs/data.c | 2 +-
> fs/f2fs/f2fs.h | 2 +-
> fs/f2fs/file.c | 11 ++++++++---
> fs/f2fs/inline.c | 20 ++++++++++++--------
> 4 files changed, 22 insertions(+), 13 deletions(-)
>
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 7aef28d..ac3ccc2 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -946,7 +946,7 @@ static int f2fs_write_begin(struct file *file, struct address_space
> *mapping,
>
> f2fs_balance_fs(sbi);
> repeat:
> - err = f2fs_convert_inline_data(inode, pos + len);
> + err = f2fs_convert_inline_data(inode, pos + len, NULL);
> if (err)
> goto fail;
>
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 790a073..c8288c9 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -1439,7 +1439,7 @@ extern const struct inode_operations f2fs_special_inode_operations;
> */
> bool f2fs_may_inline(struct inode *);
> int f2fs_read_inline_data(struct inode *, struct page *);
> -int f2fs_convert_inline_data(struct inode *, pgoff_t);
> +int f2fs_convert_inline_data(struct inode *, pgoff_t, struct page *);
> int f2fs_write_inline_data(struct inode *, struct page *, unsigned int);
> void truncate_inline_data(struct inode *, u64);
> int recover_inline_data(struct inode *, struct page *);
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 87cdac4..ecbdf6a 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -41,6 +41,11 @@ static int f2fs_vm_page_mkwrite(struct vm_area_struct *vma,
>
> sb_start_pagefault(inode->i_sb);
>
> + /* force to convert with normal data indices */
> + err = f2fs_convert_inline_data(inode, MAX_INLINE_DATA + 1, page);
> + if (err)
> + goto out;
> +
> /* block allocation */
> f2fs_lock_op(sbi);
> set_new_dnode(&dn, inode, NULL, NULL, 0);
> @@ -533,7 +538,7 @@ int f2fs_setattr(struct dentry *dentry, struct iattr *attr)
>
> if ((attr->ia_valid & ATTR_SIZE) &&
> attr->ia_size != i_size_read(inode)) {
> - err = f2fs_convert_inline_data(inode, attr->ia_size);
> + err = f2fs_convert_inline_data(inode, attr->ia_size, NULL);
> if (err)
> return err;
>
> @@ -622,7 +627,7 @@ static int punch_hole(struct inode *inode, loff_t offset, loff_t len)
> loff_t off_start, off_end;
> int ret = 0;
>
> - ret = f2fs_convert_inline_data(inode, MAX_INLINE_DATA + 1);
> + ret = f2fs_convert_inline_data(inode, MAX_INLINE_DATA + 1, NULL);
> if (ret)
> return ret;
>
> @@ -678,7 +683,7 @@ static int expand_inode_data(struct inode *inode, loff_t offset,
> if (ret)
> return ret;
>
> - ret = f2fs_convert_inline_data(inode, offset + len);
> + ret = f2fs_convert_inline_data(inode, offset + len, NULL);
> if (ret)
> return ret;
>
> diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
> index 5beecce..1ec512d 100644
> --- a/fs/f2fs/inline.c
> +++ b/fs/f2fs/inline.c
> @@ -124,9 +124,10 @@ out:
> return err;
> }
>
> -int f2fs_convert_inline_data(struct inode *inode, pgoff_t to_size)
> +int f2fs_convert_inline_data(struct inode *inode, pgoff_t to_size,
> + struct page *page)
> {
> - struct page *page;
> + struct page *new_page = page;
> int err;
>
> if (!f2fs_has_inline_data(inode))
> @@ -134,17 +135,20 @@ int f2fs_convert_inline_data(struct inode *inode, pgoff_t to_size)
> else if (to_size <= MAX_INLINE_DATA)
> return 0;
>
> - page = grab_cache_page(inode->i_mapping, 0);
> - if (!page)
> - return -ENOMEM;
> + if (!page || page->index != 0) {
> + new_page = grab_cache_page(inode->i_mapping, 0);
> + if (!new_page)
> + return -ENOMEM;
> + }
>
> - err = __f2fs_convert_inline_data(inode, page);
> - f2fs_put_page(page, 1);
> + err = __f2fs_convert_inline_data(inode, new_page);
> + if (!page || page->index != 0)
> + f2fs_put_page(new_page, 1);
> return err;
> }
>
> int f2fs_write_inline_data(struct inode *inode,
> - struct page *page, unsigned size)
> + struct page *page, unsigned size)
> {
> void *src_addr, *dst_addr;
> struct page *ipage;
> --
> 1.8.5.2 (Apple Git-48)
>
>
> ------------------------------------------------------------------------------
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@...ts.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
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