From 0bbbccb17fea86818e1a058faf5903aefd20b31a Mon Sep 17 00:00:00 2001 From: David Sterba Date: Mon, 25 Jan 2016 17:32:11 +0100 Subject: [PATCH 1/6] btrfs: introduce key type for persistent temporary items The number of distinct key types is not that big that we could waste one for something new we want to store in the tree. We'll introduce a new name for an existing key value and use the objectid for further extension. The victim is the BTRFS_BALANCE_ITEM_KEY (248). The nature of the balance status item is a good example of the temporary item. It exists from beginning of the balance, keeps the status until it finishes. Signed-off-by: David Sterba --- fs/btrfs/ctree.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index bfe4a337fb4d..e20f40649917 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -2185,8 +2185,24 @@ struct btrfs_ioctl_defrag_range_args { */ #define BTRFS_QGROUP_RELATION_KEY 246 +/* + * Obsolete name, see BTRFS_TEMPORARY_ITEM_KEY. + */ #define BTRFS_BALANCE_ITEM_KEY 248 +/* + * The key type for tree items that are stored persistently, but do not need to + * exist for extended period of time. The items can exist in any tree. + * + * [subtype, BTRFS_TEMPORARY_ITEM_KEY, data] + * + * Existing items: + * + * - balance status item + * (BTRFS_BALANCE_OBJECTID, BTRFS_TEMPORARY_ITEM_KEY, 0) + */ +#define BTRFS_TEMPORARY_ITEM_KEY 248 + /* * Persistantly stores the io stats in the device tree. * One key for all stats, (0, BTRFS_DEV_STATS_KEY, devid). From c479cb4f14f99868108da99568950e5311e1fe4c Mon Sep 17 00:00:00 2001 From: David Sterba Date: Mon, 25 Jan 2016 17:51:31 +0100 Subject: [PATCH 2/6] btrfs: switch balance item to the temporary item key No visible change. Signed-off-by: David Sterba --- fs/btrfs/volumes.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 366b335946fa..b306a205504b 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -2966,7 +2966,7 @@ static int insert_balance_item(struct btrfs_root *root, } key.objectid = BTRFS_BALANCE_OBJECTID; - key.type = BTRFS_BALANCE_ITEM_KEY; + key.type = BTRFS_TEMPORARY_ITEM_KEY; key.offset = 0; ret = btrfs_insert_empty_item(trans, root, path, &key, @@ -3015,7 +3015,7 @@ static int del_balance_item(struct btrfs_root *root) } key.objectid = BTRFS_BALANCE_OBJECTID; - key.type = BTRFS_BALANCE_ITEM_KEY; + key.type = BTRFS_TEMPORARY_ITEM_KEY; key.offset = 0; ret = btrfs_search_slot(trans, root, &key, path, -1, 1); @@ -3867,7 +3867,7 @@ int btrfs_recover_balance(struct btrfs_fs_info *fs_info) return -ENOMEM; key.objectid = BTRFS_BALANCE_OBJECTID; - key.type = BTRFS_BALANCE_ITEM_KEY; + key.type = BTRFS_TEMPORARY_ITEM_KEY; key.offset = 0; ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0); From 50c2d5abe64c1726b48d292a2ab04f60e8238933 Mon Sep 17 00:00:00 2001 From: David Sterba Date: Mon, 25 Jan 2016 17:32:11 +0100 Subject: [PATCH 3/6] btrfs: introduce key type for persistent permanent items The number of distinct key types is not that big that we could waste one for something new we want to store in the tree. Similar to the temporary items, we'll introduce a new name for an existing key value and use the objectid for further extension. The victim is the BTRFS_DEV_STATS_KEY (248). The device stats are an example of a permanent item. Signed-off-by: David Sterba --- fs/btrfs/ctree.h | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index e20f40649917..ffc081e11277 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -2204,10 +2204,24 @@ struct btrfs_ioctl_defrag_range_args { #define BTRFS_TEMPORARY_ITEM_KEY 248 /* - * Persistantly stores the io stats in the device tree. - * One key for all stats, (0, BTRFS_DEV_STATS_KEY, devid). + * Obsolete name, see BTRFS_PERSISTENT_ITEM_KEY */ -#define BTRFS_DEV_STATS_KEY 249 +#define BTRFS_DEV_STATS_KEY 249 + +/* + * The key type for tree items that are stored persistently and usually exist + * for a long period, eg. filesystem lifetime. The item kinds can be status + * information, stats or preference values. The item can exist in any tree. + * + * [subtype, BTRFS_PERSISTENT_ITEM_KEY, data] + * + * Existing items: + * + * - device statistics, store IO stats in the device tree, one key for all + * stats + * (0, BTRFS_DEV_STATS_KEY, 0) + */ +#define BTRFS_PERSISTENT_ITEM_KEY 249 /* * Persistantly stores the device replace state in the device tree. From 242e2956e4afde7727fffe21adc0a7b198b77f96 Mon Sep 17 00:00:00 2001 From: David Sterba Date: Mon, 25 Jan 2016 17:51:31 +0100 Subject: [PATCH 4/6] btrfs: switch dev stats item to the permanent item key Signed-off-by: David Sterba --- fs/btrfs/ctree.h | 5 ++++- fs/btrfs/volumes.c | 8 ++++---- 2 files changed, 8 insertions(+), 5 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index ffc081e11277..70054ed2bd7b 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -100,6 +100,9 @@ struct btrfs_ordered_sum; /* tracks free space in block groups. */ #define BTRFS_FREE_SPACE_TREE_OBJECTID 10ULL +/* device stats in the device tree */ +#define BTRFS_DEV_STATS_OBJECTID 0ULL + /* for storing balance parameters in the root tree */ #define BTRFS_BALANCE_OBJECTID -4ULL @@ -2219,7 +2222,7 @@ struct btrfs_ioctl_defrag_range_args { * * - device statistics, store IO stats in the device tree, one key for all * stats - * (0, BTRFS_DEV_STATS_KEY, 0) + * (BTRFS_DEV_STATS_OBJECTID, BTRFS_DEV_STATS_KEY, 0) */ #define BTRFS_PERSISTENT_ITEM_KEY 249 diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index b306a205504b..177a0a8dfd31 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -6705,8 +6705,8 @@ int btrfs_init_dev_stats(struct btrfs_fs_info *fs_info) int item_size; struct btrfs_dev_stats_item *ptr; - key.objectid = 0; - key.type = BTRFS_DEV_STATS_KEY; + key.objectid = BTRFS_DEV_STATS_OBJECTID; + key.type = BTRFS_PERSISTENT_ITEM_KEY; key.offset = device->devid; ret = btrfs_search_slot(NULL, dev_root, &key, path, 0, 0); if (ret) { @@ -6753,8 +6753,8 @@ static int update_dev_stat_item(struct btrfs_trans_handle *trans, int ret; int i; - key.objectid = 0; - key.type = BTRFS_DEV_STATS_KEY; + key.objectid = BTRFS_DEV_STATS_OBJECTID; + key.type = BTRFS_PERSISTENT_ITEM_KEY; key.offset = device->devid; path = btrfs_alloc_path(); From 585a3d0d238dfe42909cb58b0d05f644365fed14 Mon Sep 17 00:00:00 2001 From: David Sterba Date: Mon, 25 Jan 2016 18:44:13 +0100 Subject: [PATCH 5/6] btrfs: teach print_leaf about permanent item subtypes Signed-off-by: David Sterba --- fs/btrfs/print-tree.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/print-tree.c b/fs/btrfs/print-tree.c index 647ab12fdf5d..7bd0bdfc9812 100644 --- a/fs/btrfs/print-tree.c +++ b/fs/btrfs/print-tree.c @@ -295,8 +295,16 @@ void btrfs_print_leaf(struct btrfs_root *root, struct extent_buffer *l) btrfs_dev_extent_chunk_offset(l, dev_extent), btrfs_dev_extent_length(l, dev_extent)); break; - case BTRFS_DEV_STATS_KEY: - printk(KERN_INFO "\t\tdevice stats\n"); + case BTRFS_PERSISTENT_ITEM_KEY: + printk(KERN_INFO "\t\tpersistent item objectid %llu offset %llu\n", + key.objectid, key.offset); + switch (key.objectid) { + case BTRFS_DEV_STATS_OBJECTID: + printk(KERN_INFO "\t\tdevice stats\n"); + break; + default: + printk(KERN_INFO "\t\tunknown persistent item\n"); + } break; case BTRFS_DEV_REPLACE_KEY: printk(KERN_INFO "\t\tdev replace\n"); From 9f07e1d76eaeeddedcf9651395b4a8f870df31f0 Mon Sep 17 00:00:00 2001 From: David Sterba Date: Mon, 25 Jan 2016 18:44:13 +0100 Subject: [PATCH 6/6] btrfs: teach print_leaf about temporary item subtypes Signed-off-by: David Sterba --- fs/btrfs/print-tree.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/fs/btrfs/print-tree.c b/fs/btrfs/print-tree.c index 7bd0bdfc9812..147dc6ca5de1 100644 --- a/fs/btrfs/print-tree.c +++ b/fs/btrfs/print-tree.c @@ -306,6 +306,17 @@ void btrfs_print_leaf(struct btrfs_root *root, struct extent_buffer *l) printk(KERN_INFO "\t\tunknown persistent item\n"); } break; + case BTRFS_TEMPORARY_ITEM_KEY: + printk(KERN_INFO "\t\ttemporary item objectid %llu offset %llu\n", + key.objectid, key.offset); + switch (key.objectid) { + case BTRFS_BALANCE_OBJECTID: + printk(KERN_INFO "\t\tbalance status\n"); + break; + default: + printk(KERN_INFO "\t\tunknown temporary item\n"); + } + break; case BTRFS_DEV_REPLACE_KEY: printk(KERN_INFO "\t\tdev replace\n"); break;