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authorJosef Bacik <jbacik@fb.com>2015-09-23 21:54:14 +0300
committerChris Mason <clm@fb.com>2015-10-22 04:51:43 +0300
commitd0bd456074dca089579818312da7cbe726ad2ff9 (patch)
tree6dcb3498d7b964a19562dccf8322483359ede3ef /fs/btrfs/super.c
parentd9ee522ba3ab51b7e3c6dfcf3743216371bc810f (diff)
downloadlinux-d0bd456074dca089579818312da7cbe726ad2ff9.tar.xz
Btrfs: add fragment=* debug mount option
In tracking down these weird bitmap problems it was helpful to artificially create an extremely fragmented file system. These mount options let us either fragment data or metadata or both. With these options I could reproduce all sorts of weird latencies and hangs that occur under extreme fragmentation and get them fixed. Thanks, Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
Diffstat (limited to 'fs/btrfs/super.c')
-rw-r--r--fs/btrfs/super.c30
1 files changed, 30 insertions, 0 deletions
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index b23d49daa1a2..24154e422945 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -303,6 +303,9 @@ enum {
Opt_commit_interval, Opt_barrier, Opt_nodefrag, Opt_nodiscard,
Opt_noenospc_debug, Opt_noflushoncommit, Opt_acl, Opt_datacow,
Opt_datasum, Opt_treelog, Opt_noinode_cache,
+#ifdef CONFIG_BTRFS_DEBUG
+ Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
+#endif
Opt_err,
};
@@ -355,6 +358,11 @@ static match_table_t tokens = {
{Opt_rescan_uuid_tree, "rescan_uuid_tree"},
{Opt_fatal_errors, "fatal_errors=%s"},
{Opt_commit_interval, "commit=%d"},
+#ifdef CONFIG_BTRFS_DEBUG
+ {Opt_fragment_data, "fragment=data"},
+ {Opt_fragment_metadata, "fragment=metadata"},
+ {Opt_fragment_all, "fragment=all"},
+#endif
{Opt_err, NULL},
};
@@ -721,6 +729,22 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
}
break;
+#ifdef CONFIG_BTRFS_DEBUG
+ case Opt_fragment_all:
+ btrfs_info(root->fs_info, "fragmenting all space");
+ btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
+ btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
+ break;
+ case Opt_fragment_metadata:
+ btrfs_info(root->fs_info, "fragmenting metadata");
+ btrfs_set_opt(info->mount_opt,
+ FRAGMENT_METADATA);
+ break;
+ case Opt_fragment_data:
+ btrfs_info(root->fs_info, "fragmenting data");
+ btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
+ break;
+#endif
case Opt_err:
btrfs_info(root->fs_info, "unrecognized mount option '%s'", p);
ret = -EINVAL;
@@ -1172,6 +1196,12 @@ static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
seq_puts(seq, ",fatal_errors=panic");
if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
seq_printf(seq, ",commit=%d", info->commit_interval);
+#ifdef CONFIG_BTRFS_DEBUG
+ if (btrfs_test_opt(root, FRAGMENT_DATA))
+ seq_puts(seq, ",fragment=data");
+ if (btrfs_test_opt(root, FRAGMENT_METADATA))
+ seq_puts(seq, ",fragment=metadata");
+#endif
seq_printf(seq, ",subvolid=%llu",
BTRFS_I(d_inode(dentry))->root->root_key.objectid);
seq_puts(seq, ",subvol=");