f2fs: introduce F2FS_FEATURE_LOST_FOUND feature

This patch introduces a new feature, F2FS_FEATURE_LOST_FOUND, which
is set by mkfs. mkfs creates a directory named lost+found, which saves
unreachable files. If fsck finds a file which has no parent, or its
parent is removed by fsck, the file will be placed under lost+found
directory by fsck.

lost+found directory could not be encrypted. As a result, the root
directory cannot be encrypted too. So if LOST_FOUND feature is enabled,
let's avoid to encrypt root directory.

Signed-off-by: Sheng Yong <shengyong1@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 7d983ad19da4..f33a56d6e6dd 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -116,6 +116,9 @@ static ssize_t features_show(struct f2fs_attr *a,
         if (f2fs_sb_has_inode_crtime(sb))
                 len += snprintf(buf + len, PAGE_SIZE - len, "%s%s",
                                 len ? ", " : "", "inode_crtime");
+        if (f2fs_sb_has_lost_found(sb))
+                len += snprintf(buf + len, PAGE_SIZE - len, "%s%s",
+                                len ? ", " : "", "lost_found");
         len += snprintf(buf + len, PAGE_SIZE - len, "\n");
         return len;
 }
@@ -292,6 +295,7 @@ enum feat_id {
         FEAT_FLEXIBLE_INLINE_XATTR,
         FEAT_QUOTA_INO,
         FEAT_INODE_CRTIME,
+        FEAT_LOST_FOUND,
 };
 
 static ssize_t f2fs_feature_show(struct f2fs_attr *a,
@@ -307,6 +311,7 @@ static ssize_t f2fs_feature_show(struct f2fs_attr *a,
         case FEAT_FLEXIBLE_INLINE_XATTR:
         case FEAT_QUOTA_INO:
         case FEAT_INODE_CRTIME:
+        case FEAT_LOST_FOUND:
                 return snprintf(buf, PAGE_SIZE, "supported\n");
         }
         return 0;
@@ -386,6 +391,7 @@ F2FS_FEATURE_RO_ATTR(inode_checksum, FEAT_INODE_CHECKSUM);
 F2FS_FEATURE_RO_ATTR(flexible_inline_xattr, FEAT_FLEXIBLE_INLINE_XATTR);
 F2FS_FEATURE_RO_ATTR(quota_ino, FEAT_QUOTA_INO);
 F2FS_FEATURE_RO_ATTR(inode_crtime, FEAT_INODE_CRTIME);
+F2FS_FEATURE_RO_ATTR(lost_found, FEAT_LOST_FOUND);
 
 #define ATTR_LIST(name) (&f2fs_attr_##name.attr)
 static struct attribute *f2fs_attrs[] = {
@@ -441,6 +447,7 @@ static struct attribute *f2fs_feat_attrs[] = {
         ATTR_LIST(flexible_inline_xattr),
         ATTR_LIST(quota_ino),
         ATTR_LIST(inode_crtime),
+        ATTR_LIST(lost_found),
         NULL,
 };