f2fs: rework write preallocations

f2fs_write_begin() assumes that all blocks were preallocated by
default unless FI_NO_PREALLOC is explicitly set.  This invites data
corruption, as there are cases in which not all blocks are preallocated.
Commit 47501f87c61a ("f2fs: preallocate DIO blocks when forcing
buffered_io") fixed one case, but there are others remaining.

Fix up this logic by replacing this flag with FI_PREALLOCATED_ALL, which
only gets set if all blocks for the current write were preallocated.

Also clean up f2fs_preallocate_blocks(), move it to file.c, and make it
handle some of the logic that was previously in write_iter() directly.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 3 insertions, 52 deletions

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index d8190e836a96..3db0f3049b90 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1384,53 +1384,6 @@ alloc:
 	return 0;
 }
 
-int f2fs_preallocate_blocks(struct kiocb *iocb, struct iov_iter *from)
-{
-	struct inode *inode = file_inode(iocb->ki_filp);
-	struct f2fs_map_blocks map;
-	int flag;
-	int err = 0;
-	bool direct_io = iocb->ki_flags & IOCB_DIRECT;
-
-	map.m_lblk = F2FS_BLK_ALIGN(iocb->ki_pos);
-	map.m_len = F2FS_BYTES_TO_BLK(iocb->ki_pos + iov_iter_count(from));
-	if (map.m_len > map.m_lblk)
-		map.m_len -= map.m_lblk;
-	else
-		map.m_len = 0;
-
-	map.m_next_pgofs = NULL;
-	map.m_next_extent = NULL;
-	map.m_seg_type = NO_CHECK_TYPE;
-	map.m_may_create = true;
-
-	if (direct_io) {
-		map.m_seg_type = f2fs_rw_hint_to_seg_type(iocb->ki_hint);
-		flag = f2fs_force_buffered_io(inode, iocb, from) ?
-					F2FS_GET_BLOCK_PRE_AIO :
-					F2FS_GET_BLOCK_PRE_DIO;
-		goto map_blocks;
-	}
-	if (iocb->ki_pos + iov_iter_count(from) > MAX_INLINE_DATA(inode)) {
-		err = f2fs_convert_inline_inode(inode);
-		if (err)
-			return err;
-	}
-	if (f2fs_has_inline_data(inode))
-		return err;
-
-	flag = F2FS_GET_BLOCK_PRE_AIO;
-
-map_blocks:
-	err = f2fs_map_blocks(inode, &map, 1, flag);
-	if (map.m_len > 0 && err == -ENOSPC) {
-		if (!direct_io)
-			set_inode_flag(inode, FI_NO_PREALLOC);
-		err = 0;
-	}
-	return err;
-}
-
 void f2fs_do_map_lock(struct f2fs_sb_info *sbi, int flag, bool lock)
 {
 	if (flag == F2FS_GET_BLOCK_PRE_AIO) {
@@ -3340,12 +3293,10 @@ static int prepare_write_begin(struct f2fs_sb_info *sbi,
 	int flag;
 
 	/*
-	 * 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 a whole page is being written and we already preallocated all the
+	 * blocks, then there is no need to get a block address now.
 	 */
-	if (!f2fs_has_inline_data(inode) && len == PAGE_SIZE &&
-	    !is_inode_flag_set(inode, FI_NO_PREALLOC) &&
-	    !f2fs_verity_in_progress(inode))
+	if (len == PAGE_SIZE && is_inode_flag_set(inode, FI_PREALLOCATED_ALL))
 		return 0;
 
 	/* f2fs_lock_op avoids race between write CP and convert_inline_page */