From 6772fb679a4205427a385d174359b2a5826da613 Mon Sep 17 00:00:00 2001 From: Brian Behlendorf Date: Fri, 25 Jan 2013 14:57:53 -0800 Subject: [PATCH] Use dsl_dataset_snap_lookup() Retire the dmu_snapshot_id() function which was introduced in the initial .zfs control directory implementation. There is already an existing dsl_dataset_snap_lookup() which does exactly what we need, and the dmu_snapshot_id() function as implemented is racy. https://github.com/zfsonlinux/zfs/issues/1215#issuecomment-12579879 Signed-off-by: Brian Behlendorf Closes #1238 --- include/sys/dmu.h | 2 +- include/sys/dsl_dataset.h | 2 ++ module/zfs/dmu_objset.c | 33 ++------------------------------- module/zfs/dsl_dataset.c | 2 +- module/zfs/zfs_ctldir.c | 4 ++-- 5 files changed, 8 insertions(+), 35 deletions(-) diff --git a/include/sys/dmu.h b/include/sys/dmu.h index 7fc876be7..2a3a76486 100644 --- a/include/sys/dmu.h +++ b/include/sys/dmu.h @@ -731,7 +731,7 @@ extern uint64_t dmu_objset_syncprop(objset_t *os); extern uint64_t dmu_objset_logbias(objset_t *os); extern int dmu_snapshot_list_next(objset_t *os, int namelen, char *name, uint64_t *id, uint64_t *offp, boolean_t *case_conflict); -extern int dmu_snapshot_id(objset_t *os, const char *snapname, uint64_t *idp); +extern int dmu_snapshot_lookup(objset_t *os, const char *name, uint64_t *val); extern int dmu_snapshot_realname(objset_t *os, char *name, char *real, int maxlen, boolean_t *conflict); extern int dmu_dir_list_next(objset_t *os, int namelen, char *name, diff --git a/include/sys/dsl_dataset.h b/include/sys/dsl_dataset.h index 547951cd0..afcf2b794 100644 --- a/include/sys/dsl_dataset.h +++ b/include/sys/dsl_dataset.h @@ -251,6 +251,8 @@ int dsl_dataset_block_kill(dsl_dataset_t *ds, const blkptr_t *bp, boolean_t dsl_dataset_block_freeable(dsl_dataset_t *ds, const blkptr_t *bp, uint64_t blk_birth); uint64_t dsl_dataset_prev_snap_txg(dsl_dataset_t *ds); +int dsl_dataset_snap_lookup(dsl_dataset_t *ds, const char *name, + uint64_t *value); void dsl_dataset_dirty(dsl_dataset_t *ds, dmu_tx_t *tx); void dsl_dataset_stats(dsl_dataset_t *os, nvlist_t *nv); diff --git a/module/zfs/dmu_objset.c b/module/zfs/dmu_objset.c index 628b23be1..c59973a77 100644 --- a/module/zfs/dmu_objset.c +++ b/module/zfs/dmu_objset.c @@ -1573,39 +1573,10 @@ dmu_snapshot_list_next(objset_t *os, int namelen, char *name, return (0); } -/* - * Determine the objset id for a given snapshot name. - */ int -dmu_snapshot_id(objset_t *os, const char *snapname, uint64_t *idp) +dmu_snapshot_lookup(objset_t *os, const char *name, uint64_t *value) { - dsl_dataset_t *ds = os->os_dsl_dataset; - zap_cursor_t cursor; - zap_attribute_t attr; - int error; - - if (ds->ds_phys->ds_snapnames_zapobj == 0) - return (ENOENT); - - zap_cursor_init(&cursor, ds->ds_dir->dd_pool->dp_meta_objset, - ds->ds_phys->ds_snapnames_zapobj); - - error = zap_cursor_move_to_key(&cursor, snapname, MT_EXACT); - if (error) { - zap_cursor_fini(&cursor); - return (error); - } - - error = zap_cursor_retrieve(&cursor, &attr); - if (error) { - zap_cursor_fini(&cursor); - return (error); - } - - *idp = attr.za_first_integer; - zap_cursor_fini(&cursor); - - return (0); + return dsl_dataset_snap_lookup(os->os_dsl_dataset, name, value); } int diff --git a/module/zfs/dsl_dataset.c b/module/zfs/dsl_dataset.c index c5b84a26c..55a8b0fc1 100644 --- a/module/zfs/dsl_dataset.c +++ b/module/zfs/dsl_dataset.c @@ -314,7 +314,7 @@ dsl_dataset_get_snapname(dsl_dataset_t *ds) return (err); } -static int +int dsl_dataset_snap_lookup(dsl_dataset_t *ds, const char *name, uint64_t *value) { objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset; diff --git a/module/zfs/zfs_ctldir.c b/module/zfs/zfs_ctldir.c index b3801d494..4fa530b6c 100644 --- a/module/zfs/zfs_ctldir.c +++ b/module/zfs/zfs_ctldir.c @@ -443,7 +443,7 @@ zfsctl_snapdir_lookup(struct inode *dip, char *name, struct inode **ipp, ZFS_ENTER(zsb); - error = dmu_snapshot_id(zsb->z_os, name, &id); + error = dmu_snapshot_lookup(zsb->z_os, name, &id); if (error) { ZFS_EXIT(zsb); return (error); @@ -909,7 +909,7 @@ zfsctl_lookup_objset(struct super_block *sb, uint64_t objsetid, zfs_sb_t **zsbp) */ sep = avl_first(&zsb->z_ctldir_snaps); while (sep != NULL) { - error = dmu_snapshot_id(zsb->z_os, sep->se_name, &id); + error = dmu_snapshot_lookup(zsb->z_os, sep->se_name, &id); if (error) goto out;