On Tue, 2011-05-03 at 09:48 -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, 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. > Just want to make sure that in the case of ENOSPC, the reserved root blocks are used/consumed to allow extent being splitted and then punch hole being proceeded. The reserved blocks, if I understand right, is being used, not returned back. No? Mingming > The routine then returns the number of blocks successfully > punched out. > > Signed-off-by: Allison Henderson <achender@xxxxxxxxxx> > --- > :100644 100644 0afb746... 7f0fcc1... 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 0afb746..7f0fcc1 100644 > --- a/fs/ext4/extents.c > +++ b/fs/ext4/extents.c > @@ -3290,15 +3290,19 @@ 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) { > /* > @@ -3363,16 +3367,84 @@ 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; > } > } > > @@ -3517,7 +3589,11 @@ 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) -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html