From: Theodore Ts'o Subject: [PATCH 1/5] ext4: refactor code to read the extent tree block Date: Tue, 16 Jul 2013 11:17:59 -0400 Message-ID: <1373987883-4466-2-git-send-email-tytso@mit.edu> References: <1373987883-4466-1-git-send-email-tytso@mit.edu> Cc: Zheng Liu , Theodore Ts'o To: Ext4 Developers List Return-path: Received: from li9-11.members.linode.com ([67.18.176.11]:38267 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932827Ab3GPPSH (ORCPT ); Tue, 16 Jul 2013 11:18:07 -0400 In-Reply-To: <1373987883-4466-1-git-send-email-tytso@mit.edu> Sender: linux-ext4-owner@vger.kernel.org List-ID: Refactor out the code needed to read the extent tree block into a single read_extent_tree_block() function. In addition to simplifying the code, it also makes sure that we call the ext4_ext_load_extent tracepoint whenever we need to read an extent tree block from disk. Signed-off-by: "Theodore Ts'o" Reviewed-by: Zheng Liu --- fs/ext4/extents.c | 97 ++++++++++++++++++++++++------------------------------- 1 file changed, 43 insertions(+), 54 deletions(-) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index a618738..dd422db 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -464,25 +464,39 @@ int ext4_ext_check_inode(struct inode *inode) return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode)); } -static int __ext4_ext_check_block(const char *function, unsigned int line, - struct inode *inode, - struct ext4_extent_header *eh, - int depth, - struct buffer_head *bh) +static struct buffer_head * +__read_extent_tree_block(const char *function, unsigned int line, + struct inode *inode, ext4_fsblk_t pblk, int depth) { - int ret; + struct buffer_head *bh; + int err; + bh = sb_getblk(inode->i_sb, pblk); + if (unlikely(!bh)) + return ERR_PTR(-ENOMEM); + + if (!bh_uptodate_or_lock(bh)) { + trace_ext4_ext_load_extent(inode, pblk, _RET_IP_); + err = bh_submit_read(bh); + if (err < 0) + goto errout; + } if (buffer_verified(bh)) - return 0; - ret = ext4_ext_check(inode, eh, depth); - if (ret) - return ret; + return bh; + err = __ext4_ext_check(function, line, inode, + ext_block_hdr(bh), depth); + if (err) + goto errout; set_buffer_verified(bh); - return ret; + return bh; +errout: + put_bh(bh); + return ERR_PTR(err); + } -#define ext4_ext_check_block(inode, eh, depth, bh) \ - __ext4_ext_check_block(__func__, __LINE__, inode, eh, depth, bh) +#define read_extent_tree_block(inode, pblk, depth) \ + __read_extent_tree_block(__func__, __LINE__, (inode), (pblk), (depth)) #ifdef EXT_DEBUG static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path) @@ -748,20 +762,12 @@ ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block, path[ppos].p_depth = i; path[ppos].p_ext = NULL; - bh = sb_getblk(inode->i_sb, path[ppos].p_block); - if (unlikely(!bh)) { - ret = -ENOMEM; + bh = read_extent_tree_block(inode, path[ppos].p_block, --i); + if (IS_ERR(bh)) { + ret = PTR_ERR(bh); goto err; } - if (!bh_uptodate_or_lock(bh)) { - trace_ext4_ext_load_extent(inode, block, - path[ppos].p_block); - ret = bh_submit_read(bh); - if (ret < 0) { - put_bh(bh); - goto err; - } - } + eh = ext_block_hdr(bh); ppos++; if (unlikely(ppos > depth)) { @@ -773,11 +779,6 @@ ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block, } path[ppos].p_bh = bh; path[ppos].p_hdr = eh; - i--; - - ret = ext4_ext_check_block(inode, eh, i, bh); - if (ret < 0) - goto err; } path[ppos].p_depth = i; @@ -1412,29 +1413,21 @@ got_index: ix++; block = ext4_idx_pblock(ix); while (++depth < path->p_depth) { - bh = sb_bread(inode->i_sb, block); - if (bh == NULL) - return -EIO; - eh = ext_block_hdr(bh); /* subtract from p_depth to get proper eh_depth */ - if (ext4_ext_check_block(inode, eh, - path->p_depth - depth, bh)) { - put_bh(bh); - return -EIO; - } + bh = read_extent_tree_block(inode, block, + path->p_depth - depth); + if (IS_ERR(bh)) + return PTR_ERR(bh); + eh = ext_block_hdr(bh); ix = EXT_FIRST_INDEX(eh); block = ext4_idx_pblock(ix); put_bh(bh); } - bh = sb_bread(inode->i_sb, block); - if (bh == NULL) - return -EIO; + bh = read_extent_tree_block(inode, block, path->p_depth - depth); + if (IS_ERR(bh)) + return PTR_ERR(bh); eh = ext_block_hdr(bh); - if (ext4_ext_check_block(inode, eh, path->p_depth - depth, bh)) { - put_bh(bh); - return -EIO; - } ex = EXT_FIRST_EXTENT(eh); found_extent: *logical = le32_to_cpu(ex->ee_block); @@ -2829,10 +2822,11 @@ again: ext_debug("move to level %d (block %llu)\n", i + 1, ext4_idx_pblock(path[i].p_idx)); memset(path + i + 1, 0, sizeof(*path)); - bh = sb_bread(sb, ext4_idx_pblock(path[i].p_idx)); - if (!bh) { + bh = read_extent_tree_block(inode, + ext4_idx_pblock(path[i].p_idx), depth - i - 1); + if (IS_ERR(bh)) { /* should we reset i_size? */ - err = -EIO; + err = PTR_ERR(bh); break; } /* Yield here to deal with large extent trees. @@ -2842,11 +2836,6 @@ again: err = -EIO; break; } - if (ext4_ext_check_block(inode, ext_block_hdr(bh), - depth - i - 1, bh)) { - err = -EIO; - break; - } path[i + 1].p_bh = bh; /* save actual number of indexes since this -- 1.7.12.rc0.22.gcdd159b