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Commit cad3836f authored by Jaegeuk Kim's avatar Jaegeuk Kim
Browse files

f2fs: allocate blocks for pinned file 



This patch allows fallocate to allocate physical blocks for pinned file.

Reviewed-by: default avatarChao Yu <yuchao0@huawei.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 56659ce8

Documentation/filesystems/f2fs.txt

+25 −0
Original line number Diff line number Diff line
@@ -804,3 +804,28 @@ WRITE_LIFE_NOT_SET WARM_DATA WRITE_LIFE_NOT_SET 
WRITE_LIFE_NONE       "                        WRITE_LIFE_NONE

WRITE_LIFE_MEDIUM     "                        WRITE_LIFE_MEDIUM

WRITE_LIFE_LONG       "                        WRITE_LIFE_LONG



Fallocate(2) Policy

-------------------



The default policy follows the below posix rule.



Allocating disk space

    The default operation (i.e., mode is zero) of fallocate() allocates

    the disk space within the range specified by offset and len.  The

    file size (as reported by stat(2)) will be changed if offset+len is

    greater than the file size.  Any subregion within the range specified

    by offset and len that did not contain data before the call will be

    initialized to zero.  This default behavior closely resembles the

    behavior of the posix_fallocate(3) library function, and is intended

    as a method of optimally implementing that function.



However, once F2FS receives ioctl(fd, F2FS_IOC_SET_PIN_FILE) in prior to

fallocate(fd, DEFAULT_MODE), it allocates on-disk blocks addressess having

zero or random data, which is useful to the below scenario where:

 1. create(fd)

 2. ioctl(fd, F2FS_IOC_SET_PIN_FILE)

 3. fallocate(fd, 0, 0, size)

 4. address = fibmap(fd, offset)

 5. open(blkdev)

 6. write(blkdev, address)

fs/f2fs/file.c

+6 −1
Original line number Diff line number Diff line
@@ -1528,7 +1528,12 @@ static int expand_inode_data(struct inode *inode, loff_t offset, 
	if (off_end)

		map.m_len++;



	err = f2fs_map_blocks(inode, &map, 1, F2FS_GET_BLOCK_PRE_AIO);

	if (f2fs_is_pinned_file(inode))

		map.m_seg_type = CURSEG_COLD_DATA;



	err = f2fs_map_blocks(inode, &map, 1, (f2fs_is_pinned_file(inode) ?

						F2FS_GET_BLOCK_PRE_DIO :

						F2FS_GET_BLOCK_PRE_AIO));

	if (err) {

		pgoff_t last_off;