diff mbox series

[v2] btrfs-progs: support free space tree in mkfs

Message ID cf7462fe8c14448703d845d235dce7aca1faf795.1599157021.git.boris@bur.io (mailing list archive)
State New, archived
Headers show
Series [v2] btrfs-progs: support free space tree in mkfs | expand

Commit Message

Boris Burkov Sept. 3, 2020, 6:19 p.m. UTC
Add a runtime feature (-R) flag for the free space tree. A filesystem
that is mkfs'd with -R free-space-tree then mounted with no options has
the same contents as one mkfs'd without the option, then mounted with
'-o space_cache=v2'.

The only tricky thing is in exactly how to call the tree creation code.
Using btrfs_create_free_space_tree as is did not quite work, because an
extra reference to the eb (root->commit_root) is leaked, which mkfs
complains about with a warning. I opted to follow how the uuid tree is
created by adding it to the dirty roots list for cleanup by
commit_tree_roots in commit_transaction. As a result,
btrfs_create_free_space_tree no longer exactly matches the version in
the kernel sources.

Signed-off-by: Boris Burkov <boris@bur.io>
---
- add mkfs test
- add documentation
- add safe version and sysfs file to feature struct

 Documentation/mkfs.btrfs.asciidoc            |  6 ++++++
 common/fsfeatures.c                          | 10 ++++++++--
 common/fsfeatures.h                          |  3 ++-
 kernel-shared/disk-io.c                      |  5 +++++
 kernel-shared/free-space-tree.c              |  1 +
 mkfs/main.c                                  |  8 ++++++++
 tests/mkfs-tests/023-free-space-tree/test.sh | 21 ++++++++++++++++++++
 7 files changed, 51 insertions(+), 3 deletions(-)
 create mode 100755 tests/mkfs-tests/023-free-space-tree/test.sh

Comments

David Sterba Sept. 8, 2020, 7:55 p.m. UTC | #1
On Thu, Sep 03, 2020 at 11:19:23AM -0700, Boris Burkov wrote:
> Add a runtime feature (-R) flag for the free space tree. A filesystem
> that is mkfs'd with -R free-space-tree then mounted with no options has
> the same contents as one mkfs'd without the option, then mounted with
> '-o space_cache=v2'.
> 
> The only tricky thing is in exactly how to call the tree creation code.
> Using btrfs_create_free_space_tree as is did not quite work, because an
> extra reference to the eb (root->commit_root) is leaked, which mkfs
> complains about with a warning. I opted to follow how the uuid tree is
> created by adding it to the dirty roots list for cleanup by
> commit_tree_roots in commit_transaction. As a result,
> btrfs_create_free_space_tree no longer exactly matches the version in
> the kernel sources.
> 
> Signed-off-by: Boris Burkov <boris@bur.io>
> ---
> - add mkfs test
> - add documentation
> - add safe version and sysfs file to feature struct
> 
>  Documentation/mkfs.btrfs.asciidoc            |  6 ++++++
>  common/fsfeatures.c                          | 10 ++++++++--
>  common/fsfeatures.h                          |  3 ++-
>  kernel-shared/disk-io.c                      |  5 +++++
>  kernel-shared/free-space-tree.c              |  1 +
>  mkfs/main.c                                  |  8 ++++++++
>  tests/mkfs-tests/023-free-space-tree/test.sh | 21 ++++++++++++++++++++
>  7 files changed, 51 insertions(+), 3 deletions(-)
>  create mode 100755 tests/mkfs-tests/023-free-space-tree/test.sh
> 
> diff --git a/Documentation/mkfs.btrfs.asciidoc b/Documentation/mkfs.btrfs.asciidoc
> index 630f575c..8f1e1429 100644
> --- a/Documentation/mkfs.btrfs.asciidoc
> +++ b/Documentation/mkfs.btrfs.asciidoc
> @@ -257,6 +257,12 @@ permanent, this does not replace mount options.
>  Enable quota support (qgroups). The qgroup accounting will be consistent,
>  can be used together with '--rootdir'.  See also `btrfs-quota`(8).
>  
> +*free_space_tree*::
> +(kernel support since 3.4)
> ++
> +Enable the free space tree (mount option space_cache=v2) for persisting the
> +free space cache.
> +
>  BLOCK GROUPS, CHUNKS, RAID
>  --------------------------
>  
> diff --git a/common/fsfeatures.c b/common/fsfeatures.c
> index 48ab37ca..6c391806 100644
> --- a/common/fsfeatures.c
> +++ b/common/fsfeatures.c
> @@ -104,9 +104,15 @@ static const struct btrfs_feature mkfs_features[] = {
>  };
>  
>  static const struct btrfs_feature runtime_features[] = {
> -	{ "quota", BTRFS_RUNTIME_FEATURE_QUOTA, NULL,
> -		VERSION_TO_STRING2(3, 4), NULL, 0, NULL, 0,
> +	{ "quota", BTRFS_RUNTIME_FEATURE_QUOTA,
> +		"free_space_tree",
> +		VERSION_TO_STRING2(3, 4),
> +		VERSION_TO_STRING2(4, 9),
> +		NULL, 0,

This looks mangled, the free_space_tree (sysfs file reference) is in the
quota entry and the 4.9 version for ->safe use should be in the free-space-tree
entry below. I'll fix it.

>  		"quota support (qgroups)" },
> +	{ "free-space-tree", BTRFS_RUNTIME_FEATURE_FREE_SPACE_TREE, NULL,
> +		VERSION_TO_STRING2(4, 5), NULL, 0, NULL, 0,
> +		"free space tree (space_cache=v2)" },

>  	/* Keep this one last */
>  	{ "list-all", BTRFS_FEATURE_LIST_ALL, NULL }
>  };
Boris Burkov Sept. 8, 2020, 8:41 p.m. UTC | #2
On Tue, Sep 08, 2020 at 09:55:59PM +0200, David Sterba wrote:
> On Thu, Sep 03, 2020 at 11:19:23AM -0700, Boris Burkov wrote:
> > Add a runtime feature (-R) flag for the free space tree. A filesystem
> > that is mkfs'd with -R free-space-tree then mounted with no options has
> > the same contents as one mkfs'd without the option, then mounted with
> > '-o space_cache=v2'.
> > 
> > The only tricky thing is in exactly how to call the tree creation code.
> > Using btrfs_create_free_space_tree as is did not quite work, because an
> > extra reference to the eb (root->commit_root) is leaked, which mkfs
> > complains about with a warning. I opted to follow how the uuid tree is
> > created by adding it to the dirty roots list for cleanup by
> > commit_tree_roots in commit_transaction. As a result,
> > btrfs_create_free_space_tree no longer exactly matches the version in
> > the kernel sources.
> > 
> > Signed-off-by: Boris Burkov <boris@bur.io>
> > ---
> > - add mkfs test
> > - add documentation
> > - add safe version and sysfs file to feature struct
> > 
> >  Documentation/mkfs.btrfs.asciidoc            |  6 ++++++
> >  common/fsfeatures.c                          | 10 ++++++++--
> >  common/fsfeatures.h                          |  3 ++-
> >  kernel-shared/disk-io.c                      |  5 +++++
> >  kernel-shared/free-space-tree.c              |  1 +
> >  mkfs/main.c                                  |  8 ++++++++
> >  tests/mkfs-tests/023-free-space-tree/test.sh | 21 ++++++++++++++++++++
> >  7 files changed, 51 insertions(+), 3 deletions(-)
> >  create mode 100755 tests/mkfs-tests/023-free-space-tree/test.sh
> > 
> > diff --git a/Documentation/mkfs.btrfs.asciidoc b/Documentation/mkfs.btrfs.asciidoc
> > index 630f575c..8f1e1429 100644
> > --- a/Documentation/mkfs.btrfs.asciidoc
> > +++ b/Documentation/mkfs.btrfs.asciidoc
> > @@ -257,6 +257,12 @@ permanent, this does not replace mount options.
> >  Enable quota support (qgroups). The qgroup accounting will be consistent,
> >  can be used together with '--rootdir'.  See also `btrfs-quota`(8).
> >  
> > +*free_space_tree*::
> > +(kernel support since 3.4)
> > ++
> > +Enable the free space tree (mount option space_cache=v2) for persisting the
> > +free space cache.
> > +
> >  BLOCK GROUPS, CHUNKS, RAID
> >  --------------------------
> >  
> > diff --git a/common/fsfeatures.c b/common/fsfeatures.c
> > index 48ab37ca..6c391806 100644
> > --- a/common/fsfeatures.c
> > +++ b/common/fsfeatures.c
> > @@ -104,9 +104,15 @@ static const struct btrfs_feature mkfs_features[] = {
> >  };
> >  
> >  static const struct btrfs_feature runtime_features[] = {
> > -	{ "quota", BTRFS_RUNTIME_FEATURE_QUOTA, NULL,
> > -		VERSION_TO_STRING2(3, 4), NULL, 0, NULL, 0,
> > +	{ "quota", BTRFS_RUNTIME_FEATURE_QUOTA,
> > +		"free_space_tree",
> > +		VERSION_TO_STRING2(3, 4),
> > +		VERSION_TO_STRING2(4, 9),
> > +		NULL, 0,
> 
> This looks mangled, the free_space_tree (sysfs file reference) is in the
> quota entry and the 4.9 version for ->safe use should be in the free-space-tree
> entry below. I'll fix it.
> 

My mistake! I'm very sorry for the sloppy patch. Thanks for fixing it.

> >  		"quota support (qgroups)" },
> > +	{ "free-space-tree", BTRFS_RUNTIME_FEATURE_FREE_SPACE_TREE, NULL,
> > +		VERSION_TO_STRING2(4, 5), NULL, 0, NULL, 0,
> > +		"free space tree (space_cache=v2)" },
> 
> >  	/* Keep this one last */
> >  	{ "list-all", BTRFS_FEATURE_LIST_ALL, NULL }
> >  };
diff mbox series

Patch

diff --git a/Documentation/mkfs.btrfs.asciidoc b/Documentation/mkfs.btrfs.asciidoc
index 630f575c..8f1e1429 100644
--- a/Documentation/mkfs.btrfs.asciidoc
+++ b/Documentation/mkfs.btrfs.asciidoc
@@ -257,6 +257,12 @@  permanent, this does not replace mount options.
 Enable quota support (qgroups). The qgroup accounting will be consistent,
 can be used together with '--rootdir'.  See also `btrfs-quota`(8).
 
+*free_space_tree*::
+(kernel support since 3.4)
++
+Enable the free space tree (mount option space_cache=v2) for persisting the
+free space cache.
+
 BLOCK GROUPS, CHUNKS, RAID
 --------------------------
 
diff --git a/common/fsfeatures.c b/common/fsfeatures.c
index 48ab37ca..6c391806 100644
--- a/common/fsfeatures.c
+++ b/common/fsfeatures.c
@@ -104,9 +104,15 @@  static const struct btrfs_feature mkfs_features[] = {
 };
 
 static const struct btrfs_feature runtime_features[] = {
-	{ "quota", BTRFS_RUNTIME_FEATURE_QUOTA, NULL,
-		VERSION_TO_STRING2(3, 4), NULL, 0, NULL, 0,
+	{ "quota", BTRFS_RUNTIME_FEATURE_QUOTA,
+		"free_space_tree",
+		VERSION_TO_STRING2(3, 4),
+		VERSION_TO_STRING2(4, 9),
+		NULL, 0,
 		"quota support (qgroups)" },
+	{ "free-space-tree", BTRFS_RUNTIME_FEATURE_FREE_SPACE_TREE, NULL,
+		VERSION_TO_STRING2(4, 5), NULL, 0, NULL, 0,
+		"free space tree (space_cache=v2)" },
 	/* Keep this one last */
 	{ "list-all", BTRFS_FEATURE_LIST_ALL, NULL }
 };
diff --git a/common/fsfeatures.h b/common/fsfeatures.h
index 13141254..f76fc099 100644
--- a/common/fsfeatures.h
+++ b/common/fsfeatures.h
@@ -39,7 +39,8 @@ 
 
 #define BTRFS_FEATURE_LIST_ALL		(1ULL << 63)
 
-#define BTRFS_RUNTIME_FEATURE_QUOTA	(1ULL << 0)
+#define BTRFS_RUNTIME_FEATURE_QUOTA		(1ULL << 0)
+#define BTRFS_RUNTIME_FEATURE_FREE_SPACE_TREE	(1ULL << 1)
 
 void btrfs_list_all_fs_features(u64 mask_disallowed);
 void btrfs_list_all_runtime_features(u64 mask_disallowed);
diff --git a/kernel-shared/disk-io.c b/kernel-shared/disk-io.c
index 42f733e3..6f584986 100644
--- a/kernel-shared/disk-io.c
+++ b/kernel-shared/disk-io.c
@@ -1003,10 +1003,15 @@  int btrfs_setup_all_roots(struct btrfs_fs_info *fs_info, u64 root_tree_bytenr,
 		ret = find_and_setup_root(root, fs_info, BTRFS_FREE_SPACE_TREE_OBJECTID,
 					  fs_info->free_space_root);
 		if (ret) {
+			free(fs_info->free_space_root);
+			fs_info->free_space_root = NULL;
 			printk("Couldn't read free space tree\n");
 			return -EIO;
 		}
 		fs_info->free_space_root->track_dirty = 1;
+	} else {
+		free(fs_info->free_space_root);
+		fs_info->free_space_root = NULL;
 	}
 
 	ret = find_and_setup_log_root(root, fs_info, sb);
diff --git a/kernel-shared/free-space-tree.c b/kernel-shared/free-space-tree.c
index 3570a9ac..2edc7fc7 100644
--- a/kernel-shared/free-space-tree.c
+++ b/kernel-shared/free-space-tree.c
@@ -1433,6 +1433,7 @@  int btrfs_create_free_space_tree(struct btrfs_fs_info *fs_info)
 		goto abort;
 	}
 	fs_info->free_space_root = free_space_root;
+	add_root_to_dirty_list(free_space_root);
 
 	do {
 		block_group = btrfs_lookup_first_block_group(fs_info, start);
diff --git a/mkfs/main.c b/mkfs/main.c
index 18dc6f8e..3eb74821 100644
--- a/mkfs/main.c
+++ b/mkfs/main.c
@@ -34,6 +34,7 @@ 
 #include <blkid/blkid.h>
 #include "kernel-shared/ctree.h"
 #include "kernel-shared/disk-io.h"
+#include "kernel-shared/free-space-tree.h"
 #include "kernel-shared/volumes.h"
 #include "kernel-shared/transaction.h"
 #include "common/utils.h"
@@ -1495,6 +1496,13 @@  raid_groups:
 			goto out;
 		}
 	}
+	if (runtime_features & BTRFS_RUNTIME_FEATURE_FREE_SPACE_TREE) {
+		ret = btrfs_create_free_space_tree(fs_info);
+		if (ret < 0) {
+			error("failed to create free space tree: %d (%m)", ret);
+			goto out;
+		}
+	}
 	if (verbose) {
 		char features_buf[64];
 
diff --git a/tests/mkfs-tests/023-free-space-tree/test.sh b/tests/mkfs-tests/023-free-space-tree/test.sh
new file mode 100755
index 00000000..1b40325a
--- /dev/null
+++ b/tests/mkfs-tests/023-free-space-tree/test.sh
@@ -0,0 +1,21 @@ 
+#!/bin/bash
+# Check if mkfs supports the runtime feature free_space_tree
+
+source "$TEST_TOP/common"
+
+check_prereq mkfs.btrfs
+check_prereq btrfs
+
+setup_root_helper
+
+setup_loopdevs 4
+prepare_loopdevs
+dev1=${loopdevs[1]}
+
+run_check $SUDO_HELPER "$TOP/mkfs.btrfs" -f -R free-space-tree "$dev1"
+run_check_stdout $SUDO_HELPER "$TOP/btrfs" inspect-internal dump-super "$dev1" | grep -q FREE_SPACE_TREE || _fail "free space tree not created"
+run_check_stdout $SUDO_HELPER "$TOP/btrfs" inspect-internal dump-super "$dev1" | grep -q FREE_SPACE_TREE_VALID || _fail "free space tree not valid"
+
+cleanup_loopdevs
+
+exit 0