From: Eric Sandeen Subject: [PATCH 2/3] reinstate ext4_ext_walk_space() Date: Wed, 26 Mar 2008 10:42:08 -0500 Message-ID: <47EA6ED0.6050504@redhat.com> References: <47EA6DA9.4010103@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit To: ext4 development Return-path: Received: from mx1.redhat.com ([66.187.233.31]:41064 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756161AbYCZPmK (ORCPT ); Wed, 26 Mar 2008 11:42:10 -0400 Received: from int-mx1.corp.redhat.com (int-mx1.corp.redhat.com [172.16.52.254]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id m2QFg99J017881 for ; Wed, 26 Mar 2008 11:42:09 -0400 Received: from lacrosse.corp.redhat.com (lacrosse.corp.redhat.com [172.16.52.154]) by int-mx1.corp.redhat.com (8.13.1/8.13.1) with ESMTP id m2QFg9m0012949 for ; Wed, 26 Mar 2008 11:42:09 -0400 Received: from neon.msp.redhat.com (neon.msp.redhat.com [10.15.80.10]) by lacrosse.corp.redhat.com (8.12.11.20060308/8.11.6) with ESMTP id m2QFg8mN015751 for ; Wed, 26 Mar 2008 11:42:09 -0400 In-Reply-To: <47EA6DA9.4010103@redhat.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: the ext4 fiemap call needs this helper function. I need to dig for the original author to see what signed-off-by lines should be here. -Eric Index: linux-2.6.25-rc1/fs/ext4/extents.c =================================================================== --- linux-2.6.25-rc1.orig/fs/ext4/extents.c +++ linux-2.6.25-rc1/fs/ext4/extents.c @@ -1588,6 +1588,112 @@ cleanup: return err; } +int ext4_ext_walk_space(struct inode *inode, ext4_lblk_t block, + ext4_lblk_t num, ext_prepare_callback func, + void *cbdata) +{ + struct ext4_ext_path *path = NULL; + struct ext4_ext_cache cbex; + struct ext4_extent *ex; + ext4_lblk_t next, start = 0, end = 0; + ext4_lblk_t last = block + num; + int depth, exists, err = 0; + + BUG_ON(func == NULL); + BUG_ON(inode == NULL); + + while (block < last && block != EXT_MAX_BLOCK) { + num = last - block; + /* find extent for this block */ + path = ext4_ext_find_extent(inode, block, path); + if (IS_ERR(path)) { + err = PTR_ERR(path); + path = NULL; + break; + } + + depth = ext_depth(inode); + BUG_ON(path[depth].p_hdr == NULL); + ex = path[depth].p_ext; + next = ext4_ext_next_allocated_block(path); + + exists = 0; + if (!ex) { + /* there is no extent yet, so try to allocate + * all requested space */ + start = block; + end = block + num; + } else if (le32_to_cpu(ex->ee_block) > block) { + /* need to allocate space before found extent */ + start = block; + end = le32_to_cpu(ex->ee_block); + if (block + num < end) + end = block + num; + } else if (block >= le32_to_cpu(ex->ee_block) + + ext4_ext_get_actual_len(ex)) { + /* need to allocate space after found extent */ + start = block; + end = block + num; + if (end >= next) + end = next; + } else if (block >= le32_to_cpu(ex->ee_block)) { + /* + * some part of requested space is covered + * by found extent + */ + start = block; + end = le32_to_cpu(ex->ee_block) + + ext4_ext_get_actual_len(ex); + if (block + num < end) + end = block + num; + exists = 1; + } else { + BUG(); + } + BUG_ON(end <= start); + + if (!exists) { + cbex.ec_block = start; + cbex.ec_len = end - start; + cbex.ec_start = 0; + cbex.ec_type = EXT4_EXT_CACHE_GAP; + } else { + cbex.ec_block = le32_to_cpu(ex->ee_block); + cbex.ec_len = ext4_ext_get_actual_len(ex); + cbex.ec_start = ext_pblock(ex); + cbex.ec_type = EXT4_EXT_CACHE_EXTENT; + } + + BUG_ON(cbex.ec_len == 0); + err = func(inode, path, &cbex, cbdata); + ext4_ext_drop_refs(path); + + if (err < 0) + break; + if (err == EXT_REPEAT) + continue; + else if (err == EXT_BREAK) { + err = 0; + break; + } + + if (ext_depth(inode) != depth) { + /* depth was changed. we have to realloc path */ + kfree(path); + path = NULL; + } + + block = cbex.ec_block + cbex.ec_len; + } + + if (path) { + ext4_ext_drop_refs(path); + kfree(path); + } + + return err; +} + static void ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block, __u32 len, ext4_fsblk_t start, int type) Index: linux-2.6.25-rc1/include/linux/ext4_fs_extents.h =================================================================== --- linux-2.6.25-rc1.orig/include/linux/ext4_fs_extents.h +++ linux-2.6.25-rc1/include/linux/ext4_fs_extents.h @@ -124,6 +124,19 @@ struct ext4_ext_path { #define EXT4_EXT_CACHE_GAP 1 #define EXT4_EXT_CACHE_EXTENT 2 +/* + * to be called by ext4_ext_walk_space() + * negative retcode - error + * positive retcode - signal for ext4_ext_walk_space(), see below + * callback must return valid extent (passed or newly created) + */ +typedef int (*ext_prepare_callback)(struct inode *, struct ext4_ext_path *, + struct ext4_ext_cache *, + void *); + +#define EXT_CONTINUE 0 +#define EXT_BREAK 1 +#define EXT_REPEAT 2 #define EXT_MAX_BLOCK 0xffffffff @@ -221,6 +234,7 @@ extern int ext4_ext_try_to_merge(struct struct ext4_extent *); extern unsigned int ext4_ext_check_overlap(struct inode *, struct ext4_extent *, struct ext4_ext_path *); extern int ext4_ext_insert_extent(handle_t *, struct inode *, struct ext4_ext_path *, struct ext4_extent *); +extern int ext4_ext_walk_space(struct inode *, ext4_lblk_t, ext4_lblk_t, ext_prepare_callback, void *); extern struct ext4_ext_path *ext4_ext_find_extent(struct inode *, ext4_lblk_t, struct ext4_ext_path *); extern int ext4_ext_search_left(struct inode *, struct ext4_ext_path *,