From: Mingming Cao Subject: Re: [Ext4 punch hole 4/5 v7] Ext4 Punch Hole Support: Map blocks punch hole flag Date: Mon, 09 May 2011 17:53:00 -0700 Message-ID: <1304988780.2543.9.camel@mingming-laptop> References: <4DC5DBA4.30101@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Ext4 Developers List To: Allison Henderson Return-path: Received: from e8.ny.us.ibm.com ([32.97.182.138]:54774 "EHLO e8.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753849Ab1EJAxD (ORCPT ); Mon, 9 May 2011 20:53:03 -0400 Received: from d01relay01.pok.ibm.com (d01relay01.pok.ibm.com [9.56.227.233]) by e8.ny.us.ibm.com (8.14.4/8.13.1) with ESMTP id p4A0QpRU020143 for ; Mon, 9 May 2011 20:26:52 -0400 Received: from d01av02.pok.ibm.com (d01av02.pok.ibm.com [9.56.224.216]) by d01relay01.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p4A0r107067084 for ; Mon, 9 May 2011 20:53:01 -0400 Received: from d01av02.pok.ibm.com (loopback [127.0.0.1]) by d01av02.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p4A0r1bw021112 for ; Mon, 9 May 2011 21:53:01 -0300 In-Reply-To: <4DC5DBA4.30101@linux.vnet.ibm.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Sat, 2011-05-07 at 16:54 -0700, Allison Henderson wrote: > This patch adds a new flag to map blocks that specifies > the given range of blocks should be punched out. Extents > are first converted to uninitialized extents before they are > punched out. Because punching a hole may require that the > extent be split, it is possible that the splitting may need > more blocks than are available. To deal with this, use of > reserved blocks are enabled to allow the split to proceed. > > The routine then returns the number of blocks successfully > punched out. > > Signed-off-by: Allison Henderson Good to me. Reviewed-by: Mingming Cao > --- > :100644 100644 6dea243... 9c3c008... M fs/ext4/extents.c > fs/ext4/extents.c | 98 +++++++++++++++++++++++++++++++++++++++++++++++------ > 1 files changed, 87 insertions(+), 11 deletions(-) > > diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c > index 6dea243..9c3c008 100644 > --- a/fs/ext4/extents.c > +++ b/fs/ext4/extents.c > @@ -3315,15 +3315,19 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, > ext4_fsblk_t newblock = 0; > int err = 0, depth, ret; > unsigned int allocated = 0; > + unsigned int punched_out = 0; > + unsigned int result = 0; > struct ext4_allocation_request ar; > ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio; > + struct ext4_map_blocks punch_map; > > ext_debug("blocks %u/%u requested for inode %lu\n", > map->m_lblk, map->m_len, inode->i_ino); > trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags); > > /* check in cache */ > - if (ext4_ext_in_cache(inode, map->m_lblk, &newex)) { > + if (ext4_ext_in_cache(inode, map->m_lblk, &newex) && > + ((flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) == 0)) { > if (!newex.ee_start_lo && !newex.ee_start_hi) { > if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) { > /* > @@ -3388,16 +3392,84 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, > ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk, > ee_block, ee_len, newblock); > > - /* Do not put uninitialized extent in the cache */ > - if (!ext4_ext_is_uninitialized(ex)) { > - ext4_ext_put_in_cache(inode, ee_block, > - ee_len, ee_start); > - goto out; > + if ((flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) == 0) { > + /* > + * Do not put uninitialized extent > + * in the cache > + */ > + if (!ext4_ext_is_uninitialized(ex)) { > + ext4_ext_put_in_cache(inode, ee_block, > + ee_len, ee_start); > + goto out; > + } > + ret = ext4_ext_handle_uninitialized_extents( > + handle, inode, map, path, flags, > + allocated, newblock); > + return ret; > } > - ret = ext4_ext_handle_uninitialized_extents(handle, > - inode, map, path, flags, allocated, > - newblock); > - return ret; > + > + /* > + * Punch out the map length, but only to the > + * end of the extent > + */ > + punched_out = allocated < map->m_len ? > + allocated : map->m_len; > + > + /* > + * Sense extents need to be converted to > + * uninitialized, they must fit in an > + * uninitialized extent > + */ > + if (punched_out > EXT_UNINIT_MAX_LEN) > + punched_out = EXT_UNINIT_MAX_LEN; > + > + punch_map.m_lblk = map->m_lblk; > + punch_map.m_pblk = newblock; > + punch_map.m_len = punched_out; > + punch_map.m_flags = 0; > + > + /* Check to see if the extent needs to be split */ > + if (punch_map.m_len != ee_len || > + punch_map.m_lblk != ee_block) { > + > + ret = ext4_split_extent(handle, inode, > + path, &punch_map, 0, > + EXT4_GET_BLOCKS_PUNCH_OUT_EXT | > + EXT4_GET_BLOCKS_PRE_IO); > + > + if (ret < 0) { > + err = ret; > + goto out2; > + } > + /* > + * find extent for the block at > + * the start of the hole > + */ > + ext4_ext_drop_refs(path); > + kfree(path); > + > + path = ext4_ext_find_extent(inode, > + map->m_lblk, NULL); > + if (IS_ERR(path)) { > + err = PTR_ERR(path); > + path = NULL; > + goto out2; > + } > + > + depth = ext_depth(inode); > + ex = path[depth].p_ext; > + ee_len = ext4_ext_get_actual_len(ex); > + ee_block = le32_to_cpu(ex->ee_block); > + ee_start = ext4_ext_pblock(ex); > + > + } > + > + ext4_ext_mark_uninitialized(ex); > + > + err = ext4_ext_remove_space(inode, map->m_lblk, > + map->m_lblk + punched_out); > + > + goto out2; > } > } > > @@ -3542,7 +3614,11 @@ out2: > } > trace_ext4_ext_map_blocks_exit(inode, map->m_lblk, > newblock, map->m_len, err ? err : allocated); > - return err ? err : allocated; > + > + result = (flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) ? > + punched_out : allocated; > + > + return err ? err : result; > } > > void ext4_ext_truncate(struct inode *inode)