ocfs2: Local alloc window size changeable via mount option

Local alloc is a performance optimization in ocfs2 in which a node
takes a window of bits from the global bitmap and then uses that for
all small local allocations. This window size is fixed to 8MB currently.
This patch allows users to specify the window size in MB including
disabling it by passing in 0. If the number specified is too large,
the fs will use the default value of 8MB.

mount -o localalloc=X /dev/sdX /mntpoint

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index 8044ed9..1104f14 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -87,6 +87,7 @@ struct mount_options
 	unsigned long	mount_opt;
 	unsigned int	atime_quantum;
 	signed short	slot;
+	unsigned int	localalloc_opt;
 };
 
 static int ocfs2_parse_options(struct super_block *sb, char *options,
@@ -151,6 +152,7 @@ enum {
 	Opt_atime_quantum,
 	Opt_slot,
 	Opt_commit,
+	Opt_localalloc,
 	Opt_err,
 };
 
@@ -167,6 +169,7 @@ static match_table_t tokens = {
 	{Opt_atime_quantum, "atime_quantum=%u"},
 	{Opt_slot, "preferred_slot=%u"},
 	{Opt_commit, "commit=%u"},
+	{Opt_localalloc, "localalloc=%d"},
 	{Opt_err, NULL}
 };
 
@@ -602,6 +605,7 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
 	osb->s_atime_quantum = parsed_options.atime_quantum;
 	osb->preferred_slot = parsed_options.slot;
 	osb->osb_commit_interval = parsed_options.commit_interval;
+	osb->local_alloc_size = parsed_options.localalloc_opt;
 
 	sb->s_magic = OCFS2_SUPER_MAGIC;
 
@@ -756,6 +760,7 @@ static int ocfs2_parse_options(struct super_block *sb,
 	mopt->mount_opt = 0;
 	mopt->atime_quantum = OCFS2_DEFAULT_ATIME_QUANTUM;
 	mopt->slot = OCFS2_INVALID_SLOT;
+	mopt->localalloc_opt = OCFS2_DEFAULT_LOCAL_ALLOC_SIZE;
 
 	if (!options) {
 		status = 1;
@@ -834,6 +839,15 @@ static int ocfs2_parse_options(struct super_block *sb,
 				option = JBD_DEFAULT_MAX_COMMIT_AGE;
 			mopt->commit_interval = HZ * option;
 			break;
+		case Opt_localalloc:
+			option = 0;
+			if (match_int(&args[0], &option)) {
+				status = 0;
+				goto bail;
+			}
+			if (option >= 0 && (option <= ocfs2_local_alloc_size(sb) * 8))
+				mopt->localalloc_opt = option;
+			break;
 		default:
 			mlog(ML_ERROR,
 			     "Unrecognized mount option \"%s\" "
@@ -886,6 +900,9 @@ static int ocfs2_show_options(struct seq_file *s, struct vfsmount *mnt)
 		seq_printf(s, ",commit=%u",
 			   (unsigned) (osb->osb_commit_interval / HZ));
 
+	if (osb->local_alloc_size != OCFS2_DEFAULT_LOCAL_ALLOC_SIZE)
+		seq_printf(s, ",localalloc=%d", osb->local_alloc_size);
+
 	return 0;
 }