On Nov 10, 2011, Alexandre Oliva <ol...@lsd.ic.unicamp.br> wrote:
> Experimental patch to be able to compact only the metadata after
> clustered allocation allocated lots of unnecessary metadata block
> groups. It's also useful to measure performance differences between
> -o cluster and -o nocluster.
> I guess it should be implemented as a balance option rather than a
> separate ioctl, but this was good enough for me to try it.
And here's a corresponding patch for the btrfs program, on a (probably
very old) btrfs-progs tree.
>From 8765d64f95966eec28cad83bd870fc2270afaebd Mon Sep 17 00:00:00 2001
From: Alexandre Oliva <lxol...@fsfla.org>
Date: Thu, 10 Nov 2011 17:35:29 -0200
Subject: [PATCH] Introduce balance-md to balance metadata only.
Patch for btrfs to use a separate experimental IOCTL to rebalance
only metadata block groups.
Signed-off-by: Alexandre Oliva <ol...@lsd.ic.unicamp.br>
---
btrfs.c | 4 ++++
btrfs_cmds.c | 25 +++++++++++++++++++++++++
btrfs_cmds.h | 1 +
ioctl.h | 3 +++
4 files changed, 33 insertions(+), 0 deletions(-)
diff --git a/btrfs.c b/btrfs.c
index 46314cf..9edaebe 100644
--- a/btrfs.c
+++ b/btrfs.c
@@ -95,6 +95,10 @@ static struct Command commands[] = {
"filesystem balance", "<path>\n"
"Balance the chunks across the device."
},
+ { do_balance_md, 1,
+ "filesystem balance-md", "<path>\n"
+ "Balance the chunks across the device."
+ },
{ do_scan,
999, "device scan", "[<device> [<device>..]\n"
"Scan all device for or the passed device for a btrfs\n"
diff --git a/btrfs_cmds.c b/btrfs_cmds.c
index 8031c58..b8f4c05 100644
--- a/btrfs_cmds.c
+++ b/btrfs_cmds.c
@@ -776,6 +776,31 @@ int do_balance(int argc, char **argv)
}
return 0;
}
+
+int do_balance_md(int argc, char **argv)
+{
+
+ int fdmnt, ret=0;
+ struct btrfs_ioctl_vol_args args;
+ char *path = argv[1];
+
+ fdmnt = open_file_or_dir(path);
+ if (fdmnt < 0) {
+ fprintf(stderr, "ERROR: can't access to '%s'\n", path);
+ return 12;
+ }
+
+ memset(&args, 0, sizeof(args));
+ ret = ioctl(fdmnt, BTRFS_IOC_BALANCE_METADATA, &args);
+ close(fdmnt);
+ if(ret<0){
+ fprintf(stderr, "ERROR: balancing '%s'\n", path);
+
+ return 19;
+ }
+ return 0;
+}
+
int do_remove_volume(int nargs, char **args)
{
diff --git a/btrfs_cmds.h b/btrfs_cmds.h
index 7bde191..96cab6d 100644
--- a/btrfs_cmds.h
+++ b/btrfs_cmds.h
@@ -23,6 +23,7 @@ int do_defrag(int argc, char **argv);
int do_show_filesystem(int nargs, char **argv);
int do_add_volume(int nargs, char **args);
int do_balance(int nargs, char **argv);
+int do_balance_md(int nargs, char **argv);
int do_remove_volume(int nargs, char **args);
int do_scan(int nargs, char **argv);
int do_resize(int nargs, char **argv);
diff --git a/ioctl.h b/ioctl.h
index 776d7a9..5210c0b 100644
--- a/ioctl.h
+++ b/ioctl.h
@@ -169,4 +169,7 @@ struct btrfs_ioctl_space_args {
#define BTRFS_IOC_DEFAULT_SUBVOL _IOW(BTRFS_IOCTL_MAGIC, 19, u64)
#define BTRFS_IOC_SPACE_INFO _IOWR(BTRFS_IOCTL_MAGIC, 20, \
struct btrfs_ioctl_space_args)
+
+#define BTRFS_IOC_BALANCE_METADATA _IOW(BTRFS_IOCTL_MAGIC, 37, \
+ struct btrfs_ioctl_vol_args)
#endif
--
1.7.4.4
--
Alexandre Oliva, freedom fighter http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/ FSF Latin America board member
Free Software Evangelist Red Hat Brazil Compiler Engineer
