From e968350aadf34c86eedd9cb43f6324263845586b Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 27 Apr 2020 11:14:59 -0700 Subject: [PATCH] xfs: refactor the buffer cancellation table helpers Replace the somewhat convoluted use of xlog_peek_buffer_cancelled and xlog_check_buffer_cancelled with two obvious helpers: xlog_is_buffer_cancelled, which returns true if there is a buffer in the cancellation table, and xlog_put_buffer_cancelled, which also decrements the reference count of the buffer cancellation table. Both share a little helper to look up the entry. Signed-off-by: Christoph Hellwig Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong --- fs/xfs/xfs_log_recover.c | 109 ++++++++++++++++++++++------------------------- 1 file changed, 50 insertions(+), 59 deletions(-) diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c index 5f803083ddc3..b944ff91646d 100644 --- a/fs/xfs/xfs_log_recover.c +++ b/fs/xfs/xfs_log_recover.c @@ -1972,26 +1972,17 @@ xlog_recover_buffer_pass1( return 0; } -/* - * Check to see whether the buffer being recovered has a corresponding - * entry in the buffer cancel record table. If it is, return the cancel - * buffer structure to the caller. - */ -STATIC struct xfs_buf_cancel * -xlog_peek_buffer_cancelled( +static struct xfs_buf_cancel * +xlog_find_buffer_cancelled( struct xlog *log, xfs_daddr_t blkno, - uint len, - unsigned short flags) + uint len) { struct list_head *bucket; struct xfs_buf_cancel *bcp; - if (!log->l_buf_cancel_table) { - /* empty table means no cancelled buffers in the log */ - ASSERT(!(flags & XFS_BLF_CANCEL)); + if (!log->l_buf_cancel_table) return NULL; - } bucket = XLOG_BUF_CANCEL_BUCKET(log, blkno); list_for_each_entry(bcp, bucket, bc_list) { @@ -1999,50 +1990,48 @@ xlog_peek_buffer_cancelled( return bcp; } - /* - * We didn't find a corresponding entry in the table, so return 0 so - * that the buffer is NOT cancelled. - */ - ASSERT(!(flags & XFS_BLF_CANCEL)); return NULL; } /* - * If the buffer is being cancelled then return 1 so that it will be cancelled, - * otherwise return 0. If the buffer is actually a buffer cancel item - * (XFS_BLF_CANCEL is set), then decrement the refcount on the entry in the - * table and remove it from the table if this is the last reference. + * Check if there is and entry for blkno, len in the buffer cancel record table. + */ +static bool +xlog_is_buffer_cancelled( + struct xlog *log, + xfs_daddr_t blkno, + uint len) +{ + return xlog_find_buffer_cancelled(log, blkno, len) != NULL; +} + +/* + * Check if there is and entry for blkno, len in the buffer cancel record table, + * and decremented the reference count on it if there is one. * - * We remove the cancel record from the table when we encounter its last - * occurrence in the log so that if the same buffer is re-used again after its - * last cancellation we actually replay the changes made at that point. + * Remove the cancel record once the refcount hits zero, so that if the same + * buffer is re-used again after its last cancellation we actually replay the + * changes made at that point. */ -STATIC int -xlog_check_buffer_cancelled( +static bool +xlog_put_buffer_cancelled( struct xlog *log, xfs_daddr_t blkno, - uint len, - unsigned short flags) + uint len) { struct xfs_buf_cancel *bcp; - bcp = xlog_peek_buffer_cancelled(log, blkno, len, flags); - if (!bcp) - return 0; + bcp = xlog_find_buffer_cancelled(log, blkno, len); + if (!bcp) { + ASSERT(0); + return false; + } - /* - * We've go a match, so return 1 so that the recovery of this buffer - * is cancelled. If this buffer is actually a buffer cancel log - * item, then decrement the refcount on the one in the table and - * remove it if this is the last reference. - */ - if (flags & XFS_BLF_CANCEL) { - if (--bcp->bc_refcount == 0) { - list_del(&bcp->bc_list); - kmem_free(bcp); - } + if (--bcp->bc_refcount == 0) { + list_del(&bcp->bc_list); + kmem_free(bcp); } - return 1; + return true; } /* @@ -2733,10 +2722,15 @@ xlog_recover_buffer_pass2( * In this pass we only want to recover all the buffers which have * not been cancelled and are not cancellation buffers themselves. */ - if (xlog_check_buffer_cancelled(log, buf_f->blf_blkno, - buf_f->blf_len, buf_f->blf_flags)) { - trace_xfs_log_recover_buf_cancel(log, buf_f); - return 0; + if (buf_f->blf_flags & XFS_BLF_CANCEL) { + if (xlog_put_buffer_cancelled(log, buf_f->blf_blkno, + buf_f->blf_len)) + goto cancelled; + } else { + + if (xlog_is_buffer_cancelled(log, buf_f->blf_blkno, + buf_f->blf_len)) + goto cancelled; } trace_xfs_log_recover_buf_recover(log, buf_f); @@ -2820,6 +2814,9 @@ xlog_recover_buffer_pass2( out_release: xfs_buf_relse(bp); return error; +cancelled: + trace_xfs_log_recover_buf_cancel(log, buf_f); + return 0; } /* @@ -2937,8 +2934,7 @@ xlog_recover_inode_pass2( * Inode buffers can be freed, look out for it, * and do not replay the inode. */ - if (xlog_check_buffer_cancelled(log, in_f->ilf_blkno, - in_f->ilf_len, 0)) { + if (xlog_is_buffer_cancelled(log, in_f->ilf_blkno, in_f->ilf_len)) { error = 0; trace_xfs_log_recover_inode_cancel(log, in_f); goto error; @@ -3840,7 +3836,7 @@ xlog_recover_do_icreate_pass2( daddr = XFS_AGB_TO_DADDR(mp, agno, agbno + i * igeo->blocks_per_cluster); - if (xlog_check_buffer_cancelled(log, daddr, bb_per_cluster, 0)) + if (xlog_is_buffer_cancelled(log, daddr, bb_per_cluster)) cancel_count++; } @@ -3876,11 +3872,8 @@ xlog_recover_buffer_ra_pass2( struct xfs_buf_log_format *buf_f = item->ri_buf[0].i_addr; struct xfs_mount *mp = log->l_mp; - if (xlog_peek_buffer_cancelled(log, buf_f->blf_blkno, - buf_f->blf_len, buf_f->blf_flags)) { + if (xlog_is_buffer_cancelled(log, buf_f->blf_blkno, buf_f->blf_len)) return; - } - xfs_buf_readahead(mp->m_ddev_targp, buf_f->blf_blkno, buf_f->blf_len, NULL); } @@ -3905,9 +3898,8 @@ xlog_recover_inode_ra_pass2( return; } - if (xlog_peek_buffer_cancelled(log, ilfp->ilf_blkno, ilfp->ilf_len, 0)) + if (xlog_is_buffer_cancelled(log, ilfp->ilf_blkno, ilfp->ilf_len)) return; - xfs_buf_readahead(mp->m_ddev_targp, ilfp->ilf_blkno, ilfp->ilf_len, &xfs_inode_buf_ra_ops); } @@ -3943,9 +3935,8 @@ xlog_recover_dquot_ra_pass2( ASSERT(dq_f->qlf_len == 1); len = XFS_FSB_TO_BB(mp, dq_f->qlf_len); - if (xlog_peek_buffer_cancelled(log, dq_f->qlf_blkno, len, 0)) + if (xlog_is_buffer_cancelled(log, dq_f->qlf_blkno, len)) return; - xfs_buf_readahead(mp->m_ddev_targp, dq_f->qlf_blkno, len, &xfs_dquot_buf_ra_ops); } -- 2.11.0