From 7239ff4b2be8ec0c3160da7fdd1475785fdb4cb9 Mon Sep 17 00:00:00 2001 From: Nikolay Borisov Date: Tue, 30 Oct 2018 16:43:23 +0200 Subject: btrfs: Introduce support for FSID change without metadata rewrite This field is going to be used when the user wants to change the UUID of the filesystem without having to rewrite all metadata blocks. This field adds another level of indirection such that when the FSID is changed what really happens is the current UUID (the one with which the fs was created) is copied to the 'metadata_uuid' field in the superblock as well as a new incompat flag is set METADATA_UUID. When the kernel detects this flag is set it knows that the superblock in fact has 2 UUIDs: 1. Is the UUID which is user-visible, currently known as FSID. 2. Metadata UUID - this is the UUID which is stamped into all on-disk datastructures belonging to this file system. When the new incompat flag is present device scanning checks whether both fsid/metadata_uuid of the scanned device match any of the registered filesystems. When the flag is not set then both UUIDs are equal and only the FSID is retained on disk, metadata_uuid is set only in-memory during mount. Additionally a new metadata_uuid field is also added to the fs_info struct. It's initialised either with the FSID in case METADATA_UUID incompat flag is not set or with the metdata_uuid of the superblock otherwise. This commit introduces the new fields as well as the new incompat flag and switches all users of the fsid to the new logic. Signed-off-by: Nikolay Borisov Reviewed-by: David Sterba [ minor updates in comments ] Signed-off-by: David Sterba --- include/uapi/linux/btrfs.h | 1 + include/uapi/linux/btrfs_tree.h | 1 + 2 files changed, 2 insertions(+) (limited to 'include') diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h index 5ca1d21fc4a7..e0763bc4158e 100644 --- a/include/uapi/linux/btrfs.h +++ b/include/uapi/linux/btrfs.h @@ -269,6 +269,7 @@ struct btrfs_ioctl_fs_info_args { #define BTRFS_FEATURE_INCOMPAT_RAID56 (1ULL << 7) #define BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA (1ULL << 8) #define BTRFS_FEATURE_INCOMPAT_NO_HOLES (1ULL << 9) +#define BTRFS_FEATURE_INCOMPAT_METADATA_UUID (1ULL << 10) struct btrfs_ioctl_feature_flags { __u64 compat_flags; diff --git a/include/uapi/linux/btrfs_tree.h b/include/uapi/linux/btrfs_tree.h index aff1356c2bb8..e974f4bb5378 100644 --- a/include/uapi/linux/btrfs_tree.h +++ b/include/uapi/linux/btrfs_tree.h @@ -458,6 +458,7 @@ struct btrfs_free_space_header { #define BTRFS_SUPER_FLAG_METADUMP (1ULL << 33) #define BTRFS_SUPER_FLAG_METADUMP_V2 (1ULL << 34) #define BTRFS_SUPER_FLAG_CHANGING_FSID (1ULL << 35) +#define BTRFS_SUPER_FLAG_CHANGING_FSID_V2 (1ULL << 36) /* -- cgit v1.2.3 From de37aa513105f864d3c21105bf5542d498f21ca2 Mon Sep 17 00:00:00 2001 From: Nikolay Borisov Date: Tue, 30 Oct 2018 16:43:24 +0200 Subject: btrfs: Remove fsid/metadata_fsid fields from btrfs_info Currently btrfs_fs_info structure contains a copy of the fsid/metadata_uuid fields. Same values are also contained in the btrfs_fs_devices structure which fs_info has a reference to. Let's reduce duplication by removing the fields from fs_info and always refer to the ones in fs_devices. No functional changes. Signed-off-by: Nikolay Borisov Reviewed-by: David Sterba Signed-off-by: David Sterba --- include/trace/events/btrfs.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include') diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h index 8568946f491d..4b8400f7d4fa 100644 --- a/include/trace/events/btrfs.h +++ b/include/trace/events/btrfs.h @@ -92,7 +92,7 @@ TRACE_DEFINE_ENUM(COMMIT_TRANS); #define TP_STRUCT__entry_fsid __array(u8, fsid, BTRFS_FSID_SIZE) #define TP_fast_assign_fsid(fs_info) \ - memcpy(__entry->fsid, fs_info->fsid, BTRFS_FSID_SIZE) + memcpy(__entry->fsid, fs_info->fs_devices->fsid, BTRFS_FSID_SIZE) #define TP_STRUCT__entry_btrfs(args...) \ TP_STRUCT__entry( \ -- cgit v1.2.3 From 413df7252d5256df406a23d7efb679f46d19a23d Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Mon, 3 Dec 2018 10:20:35 -0500 Subject: btrfs: add new flushing states for the delayed refs rsv A nice thing we gain with the delayed refs rsv is the ability to flush the delayed refs on demand to deal with enospc pressure. Add states to flush delayed refs on demand, and this will allow us to remove a lot of ad-hoc work around checking to see if we should commit the transaction to run our delayed refs. Signed-off-by: Josef Bacik Signed-off-by: David Sterba --- include/trace/events/btrfs.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include') diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h index 4b8400f7d4fa..2887503e4d12 100644 --- a/include/trace/events/btrfs.h +++ b/include/trace/events/btrfs.h @@ -1048,6 +1048,8 @@ TRACE_EVENT(btrfs_trigger_flush, { FLUSH_DELAYED_ITEMS, "FLUSH_DELAYED_ITEMS"}, \ { FLUSH_DELALLOC, "FLUSH_DELALLOC"}, \ { FLUSH_DELALLOC_WAIT, "FLUSH_DELALLOC_WAIT"}, \ + { FLUSH_DELAYED_REFS_NR, "FLUSH_DELAYED_REFS_NR"}, \ + { FLUSH_DELAYED_REFS, "FLUSH_ELAYED_REFS"}, \ { ALLOC_CHUNK, "ALLOC_CHUNK"}, \ { COMMIT_TRANS, "COMMIT_TRANS"}) -- cgit v1.2.3