xfs: add DAX block zeroing support (4f69f578) · Commits · 戴 / test

fs/xfs/xfs_bmap_util.c

+19 −4

Original line number	Diff line number	Diff line
		@@ -1133,14 +1133,29 @@ xfs_zero_remaining_bytes(
		break;
		ASSERT(imap.br_blockcount >= 1);
		ASSERT(imap.br_startoff == offset_fsb);
		ASSERT(imap.br_startblock != DELAYSTARTBLOCK);

		if (imap.br_startblock == HOLESTARTBLOCK \|\|
		imap.br_state == XFS_EXT_UNWRITTEN) {
		/* skip the entire extent */
		lastoffset = XFS_FSB_TO_B(mp, imap.br_startoff +
		imap.br_blockcount) - 1;
		continue;
		}

		lastoffset = XFS_FSB_TO_B(mp, imap.br_startoff + 1) - 1;
		if (lastoffset > endoff)
		lastoffset = endoff;
		if (imap.br_startblock == HOLESTARTBLOCK)
		continue;
		ASSERT(imap.br_startblock != DELAYSTARTBLOCK);
		if (imap.br_state == XFS_EXT_UNWRITTEN)

		/* DAX can just zero the backing device directly */
		if (IS_DAX(VFS_I(ip))) {
		error = dax_zero_page_range(VFS_I(ip), offset,
		lastoffset - offset + 1,
		xfs_get_blocks_direct);
		if (error)
		return error;
		continue;
		}

		error = xfs_buf_read_uncached(XFS_IS_REALTIME_INODE(ip) ?
		mp->m_rtdev_targp : mp->m_ddev_targp,

fs/xfs/xfs_file.c

+27 −18

Original line number	Diff line number	Diff line
		@@ -79,14 +79,15 @@ xfs_rw_ilock_demote(
		}

		/*
		* xfs_iozero
		* xfs_iozero clears the specified range supplied via the page cache (except in
		* the DAX case). Writes through the page cache will allocate blocks over holes,
		* though the callers usually map the holes first and avoid them. If a block is
		* not completely zeroed, then it will be read from disk before being partially
		* zeroed.
		*
		* xfs_iozero clears the specified range of buffer supplied,
		* and marks all the affected blocks as valid and modified. If
		* an affected block is not allocated, it will be allocated. If
		* an affected block is not completely overwritten, and is not
		* valid before the operation, it will be read from disk before
		* being partially zeroed.
		* In the DAX case, we can just directly write to the underlying pages. This
		* will not allocate blocks, but will avoid holes and unwritten extents and so
		* not do unnecessary work.
		*/
		int
		xfs_iozero(
		@@ -96,7 +97,8 @@ xfs_iozero(
		{
		struct page *page;
		struct address_space *mapping;
		int status;
		int status = 0;


		mapping = VFS_I(ip)->i_mapping;
		do {
		@@ -108,6 +110,12 @@ xfs_iozero(
		if (bytes > count)
		bytes = count;

		if (IS_DAX(VFS_I(ip))) {
		status = dax_zero_page_range(VFS_I(ip), pos, bytes,
		xfs_get_blocks_direct);
		if (status)
		break;
		} else {
		status = pagecache_write_begin(NULL, mapping, pos, bytes,
		AOP_FLAG_UNINTERRUPTIBLE,
		&page, &fsdata);
		@@ -116,12 +124,13 @@ xfs_iozero(

		zero_user(page, offset, bytes);

		status = pagecache_write_end(NULL, mapping, pos, bytes, bytes,
		page, fsdata);
		status = pagecache_write_end(NULL, mapping, pos, bytes,
		bytes, page, fsdata);
		WARN_ON(status <= 0); /* can't return less than zero! */
		status = 0;
		}
		pos += bytes;
		count -= bytes;
		status = 0;
		} while (count);

		return (-status);

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