From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Marzinski Date: Tue, 24 Jun 2008 12:53:38 -0500 Subject: [Cluster-devel] [GFS2 Patch] bz 450641 try2 - fix gfs2 block allocation (cleaned up) Message-ID: <20080624175337.GA9546@ether.msp.redhat.com> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit This patch fixes bz 450641. This patch changes the computation for zero_metapath_length(), which it renames to metapath_branch_start(). When you are extending the metadata tree, The indirect blocks that point to the new data block must either diverge from the existing tree either at the inode, or at the first indirect block. They can diverge at the first indirect block because the inode has room for 483 pointers while the indirect blocks have room for 509 pointers, so when the tree is grown, there is some free space in the first indirect block. What metapath_branch_start() now computes is the height where the first indirect block for the new data block is located. It can either be 1 (if the indirect block diverges from the inode) or 2 (if it diverges from the first indirect block). This patch is the same as the last one, plus some cosmetic changes. -Ben Signed-off-by: Benjamin Marzinski --- bmap.c | 23 +++++++++-------------- 1 file changed, 9 insertions(+), 14 deletions(-) -------------- next part -------------- Index: gfs2-2.6-nmw-patched/fs/gfs2/bmap.c =================================================================== --- gfs2-2.6-nmw-patched.orig/fs/gfs2/bmap.c +++ gfs2-2.6-nmw-patched/fs/gfs2/bmap.c @@ -246,15 +246,11 @@ static void find_metapath(const struct g } -static inline unsigned int zero_metapath_length(const struct metapath *mp, - unsigned height) +static inline unsigned int metapath_branch_start(const struct metapath *mp) { - unsigned int i; - for (i = 0; i < height - 1; i++) { - if (mp->mp_list[i] != 0) - return i; - } - return height; + if (mp->mp_list[0] == 0) + return 2; + return 1; } /** @@ -436,7 +432,7 @@ static int gfs2_bmap_alloc(struct inode struct gfs2_sbd *sdp = GFS2_SB(inode); struct buffer_head *dibh = mp->mp_bh[0]; u64 bn, dblock = 0; - unsigned n, i, blks, alloced = 0, iblks = 0, zmpl = 0; + unsigned n, i, blks, alloced = 0, iblks = 0, branch_start = 0; unsigned dblks = 0; unsigned ptrs_per_blk; const unsigned end_of_metadata = height - 1; @@ -471,9 +467,8 @@ static int gfs2_bmap_alloc(struct inode /* Building up tree height */ state = ALLOC_GROW_HEIGHT; iblks = height - ip->i_height; - zmpl = zero_metapath_length(mp, height); - iblks -= zmpl; - iblks += height; + branch_start = metapath_branch_start(mp); + iblks += (height - branch_start); } } @@ -509,13 +504,13 @@ static int gfs2_bmap_alloc(struct inode sizeof(struct gfs2_meta_header)); *ptr = zero_bn; state = ALLOC_GROW_DEPTH; - for(i = zmpl; i < height; i++) { + for(i = branch_start; i < height; i++) { if (mp->mp_bh[i] == NULL) break; brelse(mp->mp_bh[i]); mp->mp_bh[i] = NULL; } - i = zmpl; + i = branch_start; } if (n == 0) break;