From: Mingming Cao Subject: Re: [Ext4 punch hole 5/6 v5] Ext4 Punch Hole Support: Map blocks punch hole flag Date: Tue, 19 Apr 2011 10:48:25 -0700 Message-ID: <1303235305.2534.5.camel@mingming-laptop> References: <4DAD3D05.8000103@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Allison Henderson , linux-ext4@vger.kernel.org To: Yongqiang Yang Return-path: Received: from e9.ny.us.ibm.com ([32.97.182.139]:35302 "EHLO e9.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752378Ab1DSRsp (ORCPT ); Tue, 19 Apr 2011 13:48:45 -0400 Received: from d01relay06.pok.ibm.com (d01relay06.pok.ibm.com [9.56.227.116]) by e9.ny.us.ibm.com (8.14.4/8.13.1) with ESMTP id p3JHKNDa011955 for ; Tue, 19 Apr 2011 13:20:23 -0400 Received: from d01av04.pok.ibm.com (d01av04.pok.ibm.com [9.56.224.64]) by d01relay06.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p3JHmXPp1147116 for ; Tue, 19 Apr 2011 13:48:33 -0400 Received: from d01av04.pok.ibm.com (loopback [127.0.0.1]) by d01av04.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p3JHmUiB029023 for ; Tue, 19 Apr 2011 13:48:32 -0400 In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: On Tue, 2011-04-19 at 16:35 +0800, Yongqiang Yang wrote: > On Tue, Apr 19, 2011 at 3:43 PM, 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, reserved > > blocks are temporarily borrowed to allow the split to proceed. > > The borrowed blocks are then returned after the hole punch has > > released more blocks. > > > > The routine then returns the number of blocks successfully > > punched out. > > > > Signed-off-by: Allison Henderson > > --- > > :100644 100644 e3a721a... d97bc87... M fs/ext4/extents.c > > fs/ext4/extents.c | 99 +++++++++++++++++++++++++++++++++++++++++++++++------ > > 1 files changed, 88 insertions(+), 11 deletions(-) > > > > diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c > > index e3a721a..d97bc87 100644 > > --- a/fs/ext4/extents.c > > +++ b/fs/ext4/extents.c > > @@ -3456,15 +3456,19 @@ 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) { > > /* > > @@ -3529,16 +3533,85 @@ 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_ext_split_extents(handle, inode, > > + &punch_map, path, > > + EXT4_GET_BLOCKS_PRE_IO | > > + EXT4_HAS_FREE_BLKS_USE_ROOTBLKS, > > + 0); > > + > > + 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); > Is this change journaled? > Looks like so, ext4_ext_map_blocks() takes journal handle as argument, the ext4 punch hole code reserve the journal credits before calling ext4_ext_map_blocks(). > > + > > + err = ext4_ext_remove_space(inode, map->m_lblk, > > + map->m_lblk + punched_out); > > + > > + goto out2; > > } > > } > > > > @@ -3683,7 +3756,11 @@ 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) > > -- > > 1.7.1 > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > >