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Commit 88b88a66 authored by Jaegeuk Kim's avatar Jaegeuk Kim
Browse files

f2fs: support atomic writes 



This patch introduces a very limited functionality for atomic write support.
In order to support atomic write, this patch adds two ioctls:
 o F2FS_IOC_START_ATOMIC_WRITE
 o F2FS_IOC_COMMIT_ATOMIC_WRITE

The database engine should be aware of the following sequence.
1. open
 -> ioctl(F2FS_IOC_START_ATOMIC_WRITE);
2. writes
  : all the written data will be treated as atomic pages.
3. commit
 -> ioctl(F2FS_IOC_COMMIT_ATOMIC_WRITE);
  : this flushes all the data blocks to the disk, which will be shown all or
  nothing by f2fs recovery procedure.
4. repeat to #2.

The IO pattens should be:

  ,- START_ATOMIC_WRITE                  ,- COMMIT_ATOMIC_WRITE
 CP | D D D D D D | FSYNC | D D D D | FSYNC ...
                      `- COMMIT_ATOMIC_WRITE

Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 120c2cba

fs/f2fs/data.c

+4 −1
Original line number Diff line number Diff line
@@ -1052,6 +1052,9 @@ static int f2fs_write_end(struct file *file, 


	trace_f2fs_write_end(inode, pos, len, copied);



	if (f2fs_is_atomic_file(inode))

		register_inmem_page(inode, page);

	else

		set_page_dirty(page);



	if (pos + copied > i_size_read(inode)) {

fs/f2fs/f2fs.h

+18 −3
Original line number Diff line number Diff line
@@ -195,6 +195,10 @@ static inline bool __has_cursum_space(struct f2fs_summary_block *sum, int size, 
#define F2FS_IOC_GETFLAGS		FS_IOC_GETFLAGS

#define F2FS_IOC_SETFLAGS		FS_IOC_SETFLAGS



#define F2FS_IOCTL_MAGIC		0xf5

#define F2FS_IOC_START_ATOMIC_WRITE	_IO(F2FS_IOCTL_MAGIC, 1)

#define F2FS_IOC_COMMIT_ATOMIC_WRITE	_IO(F2FS_IOCTL_MAGIC, 2)



#if defined(__KERNEL__) && defined(CONFIG_COMPAT)

/*

 * ioctl commands in 32 bit emulation
@@ -263,6 +267,9 @@ struct f2fs_inode_info { 
	unsigned long long xattr_ver;	/* cp version of xattr modification */

	struct extent_info ext;		/* in-memory extent cache entry */

	struct dir_inode_entry *dirty_dir;	/* the pointer of dirty dir */



	struct list_head inmem_pages;	/* inmemory pages managed by f2fs */

	struct mutex inmem_lock;	/* lock for inmemory pages */

};



static inline void get_extent_info(struct extent_info *ext,
@@ -1051,7 +1058,8 @@ enum { 
	FI_INLINE_DATA,		/* used for inline data*/

	FI_APPEND_WRITE,	/* inode has appended data */

	FI_UPDATE_WRITE,	/* inode has in-place-update data */

	FI_NEED_IPU,		/* used fo ipu for fdatasync */

	FI_NEED_IPU,		/* used for ipu per file */

	FI_ATOMIC_FILE,		/* indicate atomic file */

};



static inline void set_inode_flag(struct f2fs_inode_info *fi, int flag)
@@ -1138,6 +1146,11 @@ static inline int f2fs_has_inline_data(struct inode *inode) 
	return is_inode_flag_set(F2FS_I(inode), FI_INLINE_DATA);

}



static inline bool f2fs_is_atomic_file(struct inode *inode)

{

	return is_inode_flag_set(F2FS_I(inode), FI_ATOMIC_FILE);

}



static inline void *inline_data_addr(struct page *page)

{

	struct f2fs_inode *ri = F2FS_INODE(page);
@@ -1275,6 +1288,8 @@ void destroy_node_manager_caches(void); 
/*

 * segment.c

 */

void register_inmem_page(struct inode *, struct page *);

void commit_inmem_pages(struct inode *, bool);

void f2fs_balance_fs(struct f2fs_sb_info *);

void f2fs_balance_fs_bg(struct f2fs_sb_info *);

int f2fs_issue_flush(struct f2fs_sb_info *);

fs/f2fs/file.c

+39 −0
Original line number Diff line number Diff line
@@ -862,6 +862,41 @@ static int f2fs_ioc_setflags(struct file *filp, unsigned long arg) 
	return ret;

}



static int f2fs_ioc_start_atomic_write(struct file *filp)

{

	struct inode *inode = file_inode(filp);

	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);



	if (!inode_owner_or_capable(inode))

		return -EACCES;



	f2fs_balance_fs(sbi);



	set_inode_flag(F2FS_I(inode), FI_ATOMIC_FILE);



	return f2fs_convert_inline_data(inode, MAX_INLINE_DATA + 1, NULL);

}



static int f2fs_ioc_commit_atomic_write(struct file *filp)

{

	struct inode *inode = file_inode(filp);

	int ret;



	if (!inode_owner_or_capable(inode))

		return -EACCES;



	ret = mnt_want_write_file(filp);

	if (ret)

		return ret;



	if (f2fs_is_atomic_file(inode))

		commit_inmem_pages(inode, false);



	ret = f2fs_sync_file(filp, 0, LONG_MAX, 0);

	mnt_drop_write_file(filp);

	return ret;

}



static int f2fs_ioc_fitrim(struct file *filp, unsigned long arg)

{

	struct inode *inode = file_inode(filp);
@@ -899,6 +934,10 @@ long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 
		return f2fs_ioc_getflags(filp, arg);

	case F2FS_IOC_SETFLAGS:

		return f2fs_ioc_setflags(filp, arg);

	case F2FS_IOC_START_ATOMIC_WRITE:

		return f2fs_ioc_start_atomic_write(filp);

	case F2FS_IOC_COMMIT_ATOMIC_WRITE:

		return f2fs_ioc_commit_atomic_write(filp);

	case FITRIM:

		return f2fs_ioc_fitrim(filp, arg);

	default:

fs/f2fs/inline.c

+3 −0
Original line number Diff line number Diff line
@@ -21,6 +21,9 @@ bool f2fs_may_inline(struct inode *inode) 
	if (!test_opt(F2FS_I_SB(inode), INLINE_DATA))

		return false;



	if (f2fs_is_atomic_file(inode))

		return false;



	nr_blocks = F2FS_I(inode)->i_xattr_nid ? 3 : 2;

	if (inode->i_blocks > nr_blocks)

		return false;

fs/f2fs/inode.c

+4 −0
Original line number Diff line number Diff line
@@ -269,6 +269,10 @@ void f2fs_evict_inode(struct inode *inode) 
	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);

	nid_t xnid = F2FS_I(inode)->i_xattr_nid;



	/* some remained atomic pages should discarded */

	if (f2fs_is_atomic_file(inode))

		commit_inmem_pages(inode, true);



	trace_f2fs_evict_inode(inode);

	truncate_inode_pages_final(&inode->i_data);