f2fs: add an ioctl to disable GC for specific file

This patch gives a flag to disable GC on given file, which would be useful, when
user wants to keep its block map. It also conducts in-place-update for dontmove
file.

Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 83 insertions, 0 deletions

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 05779077cbf2..493457a200b1 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -2672,6 +2672,83 @@ static int f2fs_ioc_fssetxattr(struct file *filp, unsigned long arg)
 	return 0;
 }
 
+int f2fs_pin_file_control(struct inode *inode, bool inc)
+{
+	struct f2fs_inode_info *fi = F2FS_I(inode);
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+
+	/* Use i_gc_failures for normal file as a risk signal. */
+	if (inc)
+		f2fs_i_gc_failures_write(inode, fi->i_gc_failures + 1);
+
+	if (fi->i_gc_failures > sbi->gc_pin_file_threshold) {
+		f2fs_msg(sbi->sb, KERN_WARNING,
+			"%s: Enable GC = ino %lx after %x GC trials\n",
+			__func__, inode->i_ino, fi->i_gc_failures);
+		clear_inode_flag(inode, FI_PIN_FILE);
+		return -EAGAIN;
+	}
+	return 0;
+}
+
+static int f2fs_ioc_set_pin_file(struct file *filp, unsigned long arg)
+{
+	struct inode *inode = file_inode(filp);
+	__u32 pin;
+	int ret = 0;
+
+	if (!inode_owner_or_capable(inode))
+		return -EACCES;
+
+	if (get_user(pin, (__u32 __user *)arg))
+		return -EFAULT;
+
+	if (!S_ISREG(inode->i_mode))
+		return -EINVAL;
+
+	if (f2fs_readonly(F2FS_I_SB(inode)->sb))
+		return -EROFS;
+
+	ret = mnt_want_write_file(filp);
+	if (ret)
+		return ret;
+
+	inode_lock(inode);
+
+	if (!pin) {
+		clear_inode_flag(inode, FI_PIN_FILE);
+		F2FS_I(inode)->i_gc_failures = 1;
+		goto done;
+	}
+
+	if (f2fs_pin_file_control(inode, false)) {
+		ret = -EAGAIN;
+		goto out;
+	}
+	ret = f2fs_convert_inline_inode(inode);
+	if (ret)
+		goto out;
+
+	set_inode_flag(inode, FI_PIN_FILE);
+	ret = F2FS_I(inode)->i_gc_failures;
+done:
+	f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);
+out:
+	inode_unlock(inode);
+	mnt_drop_write_file(filp);
+	return ret;
+}
+
+static int f2fs_ioc_get_pin_file(struct file *filp, unsigned long arg)
+{
+	struct inode *inode = file_inode(filp);
+	__u32 pin = 0;
+
+	if (is_inode_flag_set(inode, FI_PIN_FILE))
+		pin = F2FS_I(inode)->i_gc_failures;
+	return put_user(pin, (u32 __user *)arg);
+}
+
 long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	if (unlikely(f2fs_cp_error(F2FS_I_SB(file_inode(filp)))))
@@ -2722,6 +2799,10 @@ long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		return f2fs_ioc_fsgetxattr(filp, arg);
 	case F2FS_IOC_FSSETXATTR:
 		return f2fs_ioc_fssetxattr(filp, arg);
+	case F2FS_IOC_GET_PIN_FILE:
+		return f2fs_ioc_get_pin_file(filp, arg);
+	case F2FS_IOC_SET_PIN_FILE:
+		return f2fs_ioc_set_pin_file(filp, arg);
 	default:
 		return -ENOTTY;
 	}
@@ -2797,6 +2878,8 @@ long f2fs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	case F2FS_IOC_GET_FEATURES:
 	case F2FS_IOC_FSGETXATTR:
 	case F2FS_IOC_FSSETXATTR:
+	case F2FS_IOC_GET_PIN_FILE:
+	case F2FS_IOC_SET_PIN_FILE:
 		break;
 	default:
 		return -ENOIOCTLCMD;