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Commit b6453fcb authored by Jaegeuk Kim's avatar Jaegeuk Kim
Browse files

f2fs: do not preallocate blocks which has wrong buffer 



Sheng Yong reports needless preallocation if write(small_buffer, large_size)
is called.

In that case, f2fs preallocates large_size, but vfs returns early due to
small_buffer size. Let's detect it before preallocation phase in f2fs.

Reported-by: default avatarSheng Yong <shengyong1@huawei.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent bee58ad4

fs/f2fs/data.c

+5 −1
Original line number Diff line number Diff line
@@ -839,6 +839,9 @@ int f2fs_preallocate_blocks(struct inode *inode, loff_t pos, 
			return err;

	}



	if (is_inode_flag_set(inode, FI_NO_PREALLOC))

		return 0;



	map.m_lblk = F2FS_BLK_ALIGN(pos);

	map.m_len = F2FS_BYTES_TO_BLK(pos + count);

	if (map.m_len > map.m_lblk)
@@ -1864,7 +1867,8 @@ static int prepare_write_begin(struct f2fs_sb_info *sbi, 
	 * we already allocated all the blocks, so we don't need to get

	 * the block addresses when there is no need to fill the page.

	 */

	if (!f2fs_has_inline_data(inode) && len == PAGE_SIZE)

	if (!f2fs_has_inline_data(inode) && len == PAGE_SIZE &&

			!is_inode_flag_set(inode, FI_NO_PREALLOC))

		return 0;



	if (f2fs_has_inline_data(inode) ||

fs/f2fs/f2fs.h

+1 −0
Original line number Diff line number Diff line
@@ -2201,6 +2201,7 @@ enum { 
	FI_INLINE_DOTS,		/* indicate inline dot dentries */

	FI_DO_DEFRAG,		/* indicate defragment is running */

	FI_DIRTY_FILE,		/* indicate regular/symlink has dirty pages */

	FI_NO_PREALLOC,		/* indicate skipped preallocated blocks */

	FI_HOT_DATA,		/* indicate file is hot */

	FI_EXTRA_ATTR,		/* indicate file has extra attribute */

	FI_PROJ_INHERIT,	/* indicate file inherits projectid */

fs/f2fs/file.c

+9 −1
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 
#include <linux/uaccess.h>

#include <linux/mount.h>

#include <linux/pagevec.h>

#include <linux/uio.h>

#include <linux/random.h>

#include <linux/aio.h>

#include <linux/uuid.h>
@@ -2536,15 +2537,22 @@ static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from) 
	inode_lock(inode);

	ret = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));

	if (!ret) {

		int err = f2fs_preallocate_blocks(inode, pos, count,

		int err;



		if (iov_iter_fault_in_readable(from, iov_iter_count(from)))

			set_inode_flag(inode, FI_NO_PREALLOC);



		err = f2fs_preallocate_blocks(inode, pos, count,

				file->f_flags & O_DIRECT);

		if (err) {

			clear_inode_flag(inode, FI_NO_PREALLOC);

			inode_unlock(inode);

			return err;

		}

		blk_start_plug(&plug);

		ret = __generic_file_write_iter(iocb, from);

		blk_finish_plug(&plug);

		clear_inode_flag(inode, FI_NO_PREALLOC);



		if (ret > 0)

			f2fs_update_iostat(F2FS_I_SB(inode), APP_WRITE_IO, ret);