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>

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 641b4b9..c0d74ff 100644 (file)
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -144,6 +144,7 @@ struct f2fs_mount_info {
 #define F2FS_FEATURE_FLEXIBLE_INLINE_XATTR     0x0040
 #define F2FS_FEATURE_QUOTA_INO         0x0080
 #define F2FS_FEATURE_INODE_CRTIME      0x0100
+#define F2FS_FEATURE_LOST_FOUND                0x0200
 
 #define F2FS_HAS_FEATURE(sb, mask)                                     \
        ((F2FS_SB(sb)->raw_super->feature & cpu_to_le32(mask)) != 0)
@@ -3214,6 +3215,7 @@ F2FS_FEATURE_FUNCS(inode_chksum, INODE_CHKSUM);
 F2FS_FEATURE_FUNCS(flexible_inline_xattr, FLEXIBLE_INLINE_XATTR);
 F2FS_FEATURE_FUNCS(quota_ino, QUOTA_INO);
 F2FS_FEATURE_FUNCS(inode_crtime, INODE_CRTIME);
+F2FS_FEATURE_FUNCS(lost_found, LOST_FOUND);
 
 #ifdef CONFIG_BLK_DEV_ZONED
 static inline int get_blkz_type(struct f2fs_sb_info *sbi,

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 419eaac..dcdae3f 100644 (file)
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1891,6 +1891,18 @@ static int f2fs_get_context(struct inode *inode, void *ctx, size_t len)
 static int f2fs_set_context(struct inode *inode, const void *ctx, size_t len,
                                                        void *fs_data)
 {
+       struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+
+       /*
+        * Encrypting the root directory is not allowed because fsck
+        * expects lost+found directory to exist and remain unencrypted
+        * if LOST_FOUND feature is enabled.
+        *
+        */
+       if (f2fs_sb_has_lost_found(sbi->sb) &&
+                       inode->i_ino == F2FS_ROOT_INO(sbi))
+               return -EPERM;
+
        return f2fs_setxattr(inode, F2FS_XATTR_INDEX_ENCRYPTION,
                                F2FS_XATTR_NAME_ENCRYPTION_CONTEXT,
                                ctx, len, fs_data, XATTR_CREATE);

diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 7d983ad..f33a56d 100644 (file)
--- 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,
 };