From a79322506c294cd8840c05f226c79a1ef84b26ed Mon Sep 17 00:00:00 2001 From: Christian Schwarz Date: Fri, 25 Sep 2020 22:06:34 +0200 Subject: [PATCH] zfs_log_write: simplify data copying code for WR_COPIED records lr_write_t records that are WR_COPIED have the record data directly appended to them (see lr_write_t type definition). The data is copied from the debuf using dmu_read_by_dnode. This function was called, only for WR_COPIED records, as part of a short-circuiting if-statement's if-expression. I found this side-effectful call to dmu_read_by_dnode pretty hard to spot. This patch improves readability by moving the call to its own line. Reviewed-by: Brian Behlendorf Reviewed-by: George Wilson Signed-off-by: Christian Schwarz Closes #10956 --- module/zfs/zfs_log.c | 23 +++++++++++++++-------- 1 file changed, 15 insertions(+), 8 deletions(-) diff --git a/module/zfs/zfs_log.c b/module/zfs/zfs_log.c index 4eae855f4274..fb44007fefc3 100644 --- a/module/zfs/zfs_log.c +++ b/module/zfs/zfs_log.c @@ -584,15 +584,22 @@ zfs_log_write(zilog_t *zilog, dmu_tx_t *tx, int txtype, (wr_state == WR_COPIED ? len : 0)); lr = (lr_write_t *)&itx->itx_lr; - DB_DNODE_ENTER(db); - if (wr_state == WR_COPIED && dmu_read_by_dnode(DB_DNODE(db), - off, len, lr + 1, DMU_READ_NO_PREFETCH) != 0) { - zil_itx_destroy(itx); - itx = zil_itx_create(txtype, sizeof (*lr)); - lr = (lr_write_t *)&itx->itx_lr; - wr_state = WR_NEED_COPY; + /* + * For WR_COPIED records, copy the data into the lr_write_t. + */ + if (wr_state == WR_COPIED) { + int err; + DB_DNODE_ENTER(db); + err = dmu_read_by_dnode(DB_DNODE(db), off, len, lr + 1, + DMU_READ_NO_PREFETCH); + if (err != 0) { + zil_itx_destroy(itx); + itx = zil_itx_create(txtype, sizeof (*lr)); + lr = (lr_write_t *)&itx->itx_lr; + wr_state = WR_NEED_COPY; + } + DB_DNODE_EXIT(db); } - DB_DNODE_EXIT(db); itx->itx_wr_state = wr_state; lr->lr_foid = zp->z_id;