From 427cc7cb30a14c2569190cae4b93f91828795229 Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Wed, 26 Jun 2019 18:23:05 -0700 Subject: [PATCH] f2fs: allocate blocks for pinned file This patch allows fallocate to allocate physical blocks for pinned file. Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim --- Documentation/filesystems/f2fs.txt | 25 +++++++++++++++++++++++++ fs/f2fs/file.c | 7 ++++++- 2 files changed, 31 insertions(+), 1 deletion(-) diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt index 3c9c89222bac..c2e941317b87 100644 --- a/Documentation/filesystems/f2fs.txt +++ b/Documentation/filesystems/f2fs.txt @@ -744,3 +744,28 @@ algorithm. In order to identify whether the data in the victim segment are valid or not, F2FS manages a bitmap. Each bit represents the validity of a block, and the bitmap is composed of a bit stream covering whole blocks in main area. + +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) diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index aee2b7ea0ad2..dca0b4a45ec3 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -1537,7 +1537,12 @@ 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; -- 2.11.0