From b394e43e995d08821588a22561c6a71a63b4ff27 Mon Sep 17 00:00:00 2001 From: Lachlan McIlroy Date: Fri, 14 Sep 2007 15:23:04 +1000 Subject: [XFS] Avoid replaying inode buffer initialisation log items if on-disk version is newer. SGI-PV: 969656 SGI-Modid: xfs-linux-melb:xfs-kern:29676a Signed-off-by: Lachlan McIlroy Signed-off-by: David Chinner Signed-off-by: Tim Shimmin --- fs/xfs/xfs_log_recover.c | 51 +++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 48 insertions(+), 3 deletions(-) (limited to 'fs/xfs/xfs_log_recover.c') diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c index 8ae6e8e5f3db..dacb19739cc2 100644 --- a/fs/xfs/xfs_log_recover.c +++ b/fs/xfs/xfs_log_recover.c @@ -1874,6 +1874,7 @@ xlog_recover_do_inode_buffer( /*ARGSUSED*/ STATIC void xlog_recover_do_reg_buffer( + xfs_mount_t *mp, xlog_recover_item_t *item, xfs_buf_t *bp, xfs_buf_log_format_t *buf_f) @@ -1884,6 +1885,50 @@ xlog_recover_do_reg_buffer( unsigned int *data_map = NULL; unsigned int map_size = 0; int error; + int stale_buf = 1; + + /* + * Scan through the on-disk inode buffer and attempt to + * determine if it has been written to since it was logged. + * + * - If any of the magic numbers are incorrect then the buffer is stale + * - If any of the modes are non-zero then the buffer is not stale + * - If all of the modes are zero and at least one of the generation + * counts is non-zero then the buffer is stale + * + * If the end result is a stale buffer then the log buffer is replayed + * otherwise it is skipped. + * + * This heuristic is not perfect. It can be improved by scanning the + * entire inode chunk for evidence that any of the inode clusters have + * been updated. To fix this problem completely we will need a major + * architectural change to the logging system. + */ + if (buf_f->blf_flags & XFS_BLI_INODE_NEW_BUF) { + xfs_dinode_t *dip; + int inodes_per_buf; + int mode_count = 0; + int gen_count = 0; + + stale_buf = 0; + inodes_per_buf = XFS_BUF_COUNT(bp) >> mp->m_sb.sb_inodelog; + for (i = 0; i < inodes_per_buf; i++) { + dip = (xfs_dinode_t *)xfs_buf_offset(bp, + i * mp->m_sb.sb_inodesize); + if (be16_to_cpu(dip->di_core.di_magic) != + XFS_DINODE_MAGIC) { + stale_buf = 1; + break; + } + if (be16_to_cpu(dip->di_core.di_mode)) + mode_count++; + if (be16_to_cpu(dip->di_core.di_gen)) + gen_count++; + } + + if (!mode_count && gen_count) + stale_buf = 1; + } switch (buf_f->blf_type) { case XFS_LI_BUF: @@ -1917,7 +1962,7 @@ xlog_recover_do_reg_buffer( -1, 0, XFS_QMOPT_DOWARN, "dquot_buf_recover"); } - if (!error) + if (!error && stale_buf) memcpy(xfs_buf_offset(bp, (uint)bit << XFS_BLI_SHIFT), /* dest */ item->ri_buf[i].i_addr, /* source */ @@ -2089,7 +2134,7 @@ xlog_recover_do_dquot_buffer( if (log->l_quotaoffs_flag & type) return; - xlog_recover_do_reg_buffer(item, bp, buf_f); + xlog_recover_do_reg_buffer(mp, item, bp, buf_f); } /* @@ -2190,7 +2235,7 @@ xlog_recover_do_buffer_trans( (XFS_BLI_UDQUOT_BUF|XFS_BLI_PDQUOT_BUF|XFS_BLI_GDQUOT_BUF)) { xlog_recover_do_dquot_buffer(mp, log, item, bp, buf_f); } else { - xlog_recover_do_reg_buffer(item, bp, buf_f); + xlog_recover_do_reg_buffer(mp, item, bp, buf_f); } if (error) return XFS_ERROR(error); -- cgit v1.2.1