From 4f902c37727bbedbc0508a1477874c58ddcc9af8 Mon Sep 17 00:00:00 2001 From: Mark Fasheh Date: Fri, 9 Mar 2007 16:26:50 -0800 Subject: ocfs2: Fix extent lookup to return true size of holes Initially, we had wired things to return a size '1' of holes. Cook up a small amount of code to find the next extent and calculate the number of clusters between the virtual offset and the next allocated extent. Signed-off-by: Mark Fasheh --- fs/ocfs2/extent_map.c | 107 ++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 103 insertions(+), 4 deletions(-) (limited to 'fs/ocfs2/extent_map.c') diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c index eef6c1887708..f35e04f27f32 100644 --- a/fs/ocfs2/extent_map.c +++ b/fs/ocfs2/extent_map.c @@ -38,6 +38,97 @@ #include "buffer_head_io.h" +/* + * Return the 1st index within el which contains an extent start + * larger than v_cluster. + */ +static int ocfs2_search_for_hole_index(struct ocfs2_extent_list *el, + u32 v_cluster) +{ + int i; + struct ocfs2_extent_rec *rec; + + for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) { + rec = &el->l_recs[i]; + + if (v_cluster < le32_to_cpu(rec->e_cpos)) + break; + } + + return i; +} + +/* + * Figure out the size of a hole which starts at v_cluster within the given + * extent list. + * + * If there is no more allocation past v_cluster, we return the maximum + * cluster size minus v_cluster. + * + * If we have in-inode extents, then el points to the dinode list and + * eb_bh is NULL. Otherwise, eb_bh should point to the extent block + * containing el. + */ +static int ocfs2_figure_hole_clusters(struct inode *inode, + struct ocfs2_extent_list *el, + struct buffer_head *eb_bh, + u32 v_cluster, + u32 *num_clusters) +{ + int ret, i; + struct buffer_head *next_eb_bh = NULL; + struct ocfs2_extent_block *eb, *next_eb; + + i = ocfs2_search_for_hole_index(el, v_cluster); + + if (i == le16_to_cpu(el->l_next_free_rec) && eb_bh) { + eb = (struct ocfs2_extent_block *)eb_bh->b_data; + + /* + * Check the next leaf for any extents. + */ + + if (le64_to_cpu(eb->h_next_leaf_blk) == 0ULL) + goto no_more_extents; + + ret = ocfs2_read_block(OCFS2_SB(inode->i_sb), + le64_to_cpu(eb->h_next_leaf_blk), + &next_eb_bh, OCFS2_BH_CACHED, inode); + if (ret) { + mlog_errno(ret); + goto out; + } + next_eb = (struct ocfs2_extent_block *)next_eb_bh->b_data; + + if (!OCFS2_IS_VALID_EXTENT_BLOCK(next_eb)) { + ret = -EROFS; + OCFS2_RO_ON_INVALID_EXTENT_BLOCK(inode->i_sb, next_eb); + goto out; + } + + el = &next_eb->h_list; + + i = ocfs2_search_for_hole_index(el, v_cluster); + } + +no_more_extents: + if (i == le16_to_cpu(el->l_next_free_rec)) { + /* + * We're at the end of our existing allocation. Just + * return the maximum number of clusters we could + * possibly allocate. + */ + *num_clusters = UINT_MAX - v_cluster; + } else { + *num_clusters = le32_to_cpu(el->l_recs[i].e_cpos) - v_cluster; + } + + ret = 0; +out: + brelse(next_eb_bh); + return ret; +} + /* * Return the index of the extent record which contains cluster #v_cluster. * -1 is returned if it was not found. @@ -117,11 +208,19 @@ int ocfs2_get_clusters(struct inode *inode, u32 v_cluster, if (i == -1) { /* * A hole was found. Return some canned values that - * callers can key on. + * callers can key on. If asked for, num_clusters will + * be populated with the size of the hole. */ *p_cluster = 0; - if (num_clusters) - *num_clusters = 1; + if (num_clusters) { + ret = ocfs2_figure_hole_clusters(inode, el, eb_bh, + v_cluster, + num_clusters); + if (ret) { + mlog_errno(ret); + goto out; + } + } } else { rec = &el->l_recs[i]; @@ -162,7 +261,7 @@ out: * all while the map is in the process of being updated. */ int ocfs2_extent_map_get_blocks(struct inode *inode, u64 v_blkno, u64 *p_blkno, - int *ret_count, unsigned int *extent_flags) + u64 *ret_count, unsigned int *extent_flags) { int ret; int bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1); -- cgit v1.2.2