f2fs: add new ioctl F2FS_IOC_GARBAGE_COLLECT

When background gc is off, the only way to trigger gc is executing
a force gc in some operations who wants to grab space in disk.

The executing condition is limited: to execute force gc, we should
wait for the time when there is almost no more free section for LFS
allocation. This seems not reasonable for our user who wants to
control triggering gc by himself.

This patch introduces F2FS_IOC_GARBAGE_COLLECT interface for
triggering garbage collection by using ioctl. It provides our users
one more option to trigger gc.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 32 insertions, 0 deletions

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index fe8398f1d627..dcc01137fca0 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -27,6 +27,7 @@
 #include "segment.h"
 #include "xattr.h"
 #include "acl.h"
+#include "gc.h"
 #include "trace.h"
 #include <trace/events/f2fs.h>
 
@@ -1558,6 +1559,35 @@ got_it:
 	return 0;
 }
 
+static int f2fs_ioc_gc(struct file *filp, unsigned long arg)
+{
+	struct inode *inode = file_inode(filp);
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	__u32 i, count;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (get_user(count, (__u32 __user *)arg))
+		return -EFAULT;
+
+	if (!count || count > F2FS_BATCH_GC_MAX_NUM)
+		return -EINVAL;
+
+	for (i = 0; i < count; i++) {
+		if (!mutex_trylock(&sbi->gc_mutex))
+			break;
+
+		if (f2fs_gc(sbi))
+			break;
+	}
+
+	if (put_user(i, (__u32 __user *)arg))
+		return -EFAULT;
+
+	return 0;
+}
+
 long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	switch (cmd) {
@@ -1587,6 +1617,8 @@ long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		return f2fs_ioc_get_encryption_policy(filp, arg);
 	case F2FS_IOC_GET_ENCRYPTION_PWSALT:
 		return f2fs_ioc_get_encryption_pwsalt(filp, arg);
+	case F2FS_IOC_GARBAGE_COLLECT:
+		return f2fs_ioc_gc(filp, arg);
 	default:
 		return -ENOTTY;
 	}