From: amir73il@users.sourceforge.net Subject: [PATCH RFC 08/30] ext4: snapshot hooks - move extent file data blocks Date: Mon, 9 May 2011 19:41:26 +0300 Message-ID: <1304959308-11122-9-git-send-email-amir73il@users.sourceforge.net> References: <1304959308-11122-1-git-send-email-amir73il@users.sourceforge.net> Cc: tytso@mit.edu, Amir Goldstein , Yongqiang Yang To: linux-ext4@vger.kernel.org Return-path: Received: from mail-wy0-f174.google.com ([74.125.82.174]:33538 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752701Ab1EIQn3 (ORCPT ); Mon, 9 May 2011 12:43:29 -0400 Received: by mail-wy0-f174.google.com with SMTP id 21so4026020wya.19 for ; Mon, 09 May 2011 09:43:28 -0700 (PDT) In-Reply-To: <1304959308-11122-1-git-send-email-amir73il@users.sourceforge.net> Sender: linux-ext4-owner@vger.kernel.org List-ID: From: Amir Goldstein Extent mapped file data is moved into snapshot in ext4_ext_map_blocks(). If a part of a extent is to be moved, the extent is splitted. Fragmentation is light because of delayed-move-on-write. Signed-off-by: Amir Goldstein Signed-off-by: Yongqiang Yang --- fs/ext4/ext4_jbd2.h | 2 - fs/ext4/extents.c | 143 +++++++++++++++++++++++++++++++++++++++++++++------ fs/ext4/inode.c | 3 +- 3 files changed, 128 insertions(+), 20 deletions(-) diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h index 1c119cc..ea3a0a0 100644 --- a/fs/ext4/ext4_jbd2.h +++ b/fs/ext4/ext4_jbd2.h @@ -369,8 +369,6 @@ static inline int ext4_snapshot_should_move_data(struct inode *inode) return 0; if (EXT4_JOURNAL(inode) == NULL) return 0; - if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) - return 0; /* when a data block is journaled, it is already COWed as metadata */ if (ext4_should_journal_data(inode)) return 0; diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index c8cab3d..11fe058 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -1256,11 +1256,10 @@ static int ext4_ext_search_left(struct inode *inode, return 0; } - if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) { - EXT4_ERROR_INODE(inode, - "logical %d < ee_block %d + ee_len %d!", - *logical, le32_to_cpu(ex->ee_block), ee_len); - return -EIO; + if (*logical < (le32_to_cpu(ex->ee_block) + ee_len)) { + *logical -= 1; + *phys = ext4_ext_pblock(ex) + *logical; + return 0; } *logical = le32_to_cpu(ex->ee_block) + ee_len - 1; @@ -1324,11 +1323,10 @@ static int ext4_ext_search_right(struct inode *inode, return 0; } - if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) { - EXT4_ERROR_INODE(inode, - "logical %d < ee_block %d + ee_len %d!", - *logical, le32_to_cpu(ex->ee_block), ee_len); - return -EIO; + if (*logical < (le32_to_cpu(ex->ee_block) + ee_len)) { + *logical += 1; + *phys = ext4_ext_pblock(ex) + *logical; + return 0; } if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) { @@ -3155,7 +3153,8 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, struct ext4_map_blocks *map, int flags) { struct ext4_ext_path *path = NULL; - struct ext4_extent newex, *ex; + struct ext4_extent newex, *ex = NULL; + ext4_fsblk_t oldblock = 0; ext4_fsblk_t newblock = 0; int err = 0, depth, ret; unsigned int allocated = 0; @@ -3184,7 +3183,7 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, /* number of remaining blocks in the extent */ allocated = ext4_ext_get_actual_len(&newex) - (map->m_lblk - le32_to_cpu(newex.ee_block)); - goto out; + goto found; } } @@ -3235,7 +3234,7 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, if (!ext4_ext_is_uninitialized(ex)) { ext4_ext_put_in_cache(inode, ee_block, ee_len, ee_start); - goto out; + goto found; } ret = ext4_ext_handle_uninitialized_extents(handle, inode, map, path, flags, allocated, @@ -3256,6 +3255,59 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, ext4_ext_put_gap_in_cache(inode, path, map->m_lblk); goto out2; } + + /* + * two cases: + * 1. the request block is found. + * a. If EXT4_GET_BLOCKS_CREATE is not set, we will test + * if MOW is needed. + * b. If EXT4_GET_BLOCKS_CREATE is set. MOW will be done + * if MOW is needed. + * + * 2. the request block is not found, EXT4_GET_BLOCKS_CREATE + * must be set and MOW must be not needed. + */ +found: + if (newblock && (flags & EXT4_GET_BLOCKS_MOVE_ON_WRITE)) { + BUG_ON(!ext4_snapshot_should_move_data(inode)); + /* + * Should move 1 block to snapshot? + * + * XXX With delayed-move-write support, + * multi-blocks should be moved each time. + */ + allocated = allocated < map->m_len ? allocated : map->m_len; + err = ext4_snapshot_get_move_access(handle, inode, newblock, + &allocated, 0); + map->m_len = allocated; + if (err > 0) { + if (!(flags & EXT4_GET_BLOCKS_CREATE)) { + /* Do not map found block. */ + map->m_flags |= EXT4_MAP_REMAP; + err = 0; + goto out; + } else { + oldblock = newblock; + } + } else if (err < 0) + goto out2; + + if ((path == NULL) && (flags & EXT4_GET_BLOCKS_CREATE)) { + /* find extent for this block */ + 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; + } + } + + if (!(flags & EXT4_GET_BLOCKS_CREATE)) + goto out; + /* * Okay, we need to do block allocation. */ @@ -3265,7 +3317,7 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft); if (err) goto out2; - ar.lright = map->m_lblk; + ar.lright = map->m_lblk + allocated; err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright); if (err) goto out2; @@ -3286,7 +3338,11 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */ newex.ee_block = cpu_to_le32(map->m_lblk); newex.ee_len = cpu_to_le16(map->m_len); - err = ext4_ext_check_overlap(inode, &newex, path); + if (oldblock) { + /* Overlap checking is not needed for MOW case. */ + err = 0; + } else + err = ext4_ext_check_overlap(inode, &newex, path); if (err) allocated = ext4_ext_get_actual_len(&newex); else @@ -3337,7 +3393,55 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, if (err) goto out2; - err = ext4_ext_insert_extent(handle, inode, path, &newex, flags); + if (oldblock) { + /* + * Move oldblocks to snapshot. + */ + map->m_len = ar.len; + err = ext4_snapshot_get_move_access(handle, inode, + oldblock, &map->m_len, 1); + if (err <= 0 || map->m_len < ar.len) { + /* failed to move to snapshot - abort! */ + err = err ? : -EIO; + ext4_journal_abort_handle(__func__, __LINE__, + "ext4_snapshot_get_move_access", NULL, + handle, err); + } else { + /* + * Move to snapshot successfully. + * TODO merge extent after finishing MOW + */ + err = ext4_split_extent(handle, inode, path, map, 0, + flags | EXT4_GET_BLOCKS_PRE_IO); + if (err < 0) + goto out; + + /* extent tree may be changed. */ + depth = ext_depth(inode); + ext4_ext_drop_refs(path); + path = ext4_ext_find_extent(inode, map->m_lblk, path); + if (IS_ERR(path)) { + err = PTR_ERR(path); + goto out; + } + + /* just verify splitting. */ + ex = path[depth].p_ext; + BUG_ON(le32_to_cpu(ex->ee_block) != map->m_lblk || + ext4_ext_get_actual_len(ex) != map->m_len); + + err = ext4_ext_get_access(handle, inode, path + depth); + if (!err) { + /* splice new blocks to the inode*/ + ext4_ext_store_pblock(ex, newblock); + err = ext4_ext_dirty(handle, inode, + path + depth); + } + } + + } else + err = ext4_ext_insert_extent(handle, inode, + path, &newex, flags); if (err) { /* free data blocks we just allocated */ /* not a good idea to call discard here directly, @@ -3366,7 +3470,12 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, * Cache the extent and update transaction to commit on fdatasync only * when it is _not_ an uninitialized extent. */ - if ((flags & EXT4_GET_BLOCKS_UNINIT_EXT) == 0) { + if (IS_COWING(handle)) { + /* + * snapshot does not supprt fdatasync and fsync + * and there is no need to cache extent + */ + } else if ((flags & EXT4_GET_BLOCKS_UNINIT_EXT) == 0) { ext4_ext_put_in_cache(inode, map->m_lblk, allocated, newblock); ext4_update_inode_fsync_trans(handle, inode, 1); } else diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 476606b..866ac36 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1357,7 +1357,8 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode, */ down_read((&EXT4_I(inode)->i_data_sem)); if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) { - retval = ext4_ext_map_blocks(handle, inode, map, 0); + retval = ext4_ext_map_blocks(handle, inode, map, + flags & EXT4_GET_BLOCKS_MOVE_ON_WRITE); } else { retval = ext4_ind_map_blocks(handle, inode, map, flags & EXT4_GET_BLOCKS_MOVE_ON_WRITE); -- 1.7.0.4