f2fs: support RO feature

Given RO feature in superblock, we don't need to check provisioning/reserve
spaces and SSA area.

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

1 files changed, 31 insertions, 6 deletions

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 56f2f2f449c5..3e0e34b4680c 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -555,7 +555,7 @@ static int parse_options(struct super_block *sb, char *options, bool is_remount)
 	int ret;
 
 	if (!options)
-		return 0;
+		goto default_check;
 
 	while ((p = strsep(&options, ",")) != NULL) {
 		int token;
@@ -1090,6 +1090,7 @@ static int parse_options(struct super_block *sb, char *options, bool is_remount)
 			return -EINVAL;
 		}
 	}
+default_check:
 #ifdef CONFIG_QUOTA
 	if (f2fs_check_quota_options(sbi))
 		return -EINVAL;
@@ -1162,6 +1163,11 @@ static int parse_options(struct super_block *sb, char *options, bool is_remount)
 	 */
 	if (F2FS_OPTION(sbi).active_logs != NR_CURSEG_TYPE)
 		F2FS_OPTION(sbi).whint_mode = WHINT_MODE_OFF;
+
+	if (f2fs_sb_has_readonly(sbi) && !f2fs_readonly(sbi->sb)) {
+		f2fs_err(sbi, "Allow to mount readonly mode only");
+		return -EROFS;
+	}
 	return 0;
 }
 
@@ -1819,7 +1825,11 @@ static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
 static void default_options(struct f2fs_sb_info *sbi)
 {
 	/* init some FS parameters */
-	F2FS_OPTION(sbi).active_logs = NR_CURSEG_PERSIST_TYPE;
+	if (f2fs_sb_has_readonly(sbi))
+		F2FS_OPTION(sbi).active_logs = NR_CURSEG_RO_TYPE;
+	else
+		F2FS_OPTION(sbi).active_logs = NR_CURSEG_PERSIST_TYPE;
+
 	F2FS_OPTION(sbi).inline_xattr_size = DEFAULT_INLINE_XATTR_ADDRS;
 	F2FS_OPTION(sbi).whint_mode = WHINT_MODE_OFF;
 	F2FS_OPTION(sbi).alloc_mode = ALLOC_MODE_DEFAULT;
@@ -2004,6 +2014,11 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
 	if (f2fs_readonly(sb) && (*flags & SB_RDONLY))
 		goto skip;
 
+	if (f2fs_sb_has_readonly(sbi) && !(*flags & SB_RDONLY)) {
+		err = -EROFS;
+		goto restore_opts;
+	}
+
 #ifdef CONFIG_QUOTA
 	if (!f2fs_readonly(sb) && (*flags & SB_RDONLY)) {
 		err = dquot_suspend(sb, -1);
@@ -3137,14 +3152,15 @@ int f2fs_sanity_check_ckpt(struct f2fs_sb_info *sbi)
 	ovp_segments = le32_to_cpu(ckpt->overprov_segment_count);
 	reserved_segments = le32_to_cpu(ckpt->rsvd_segment_count);
 
-	if (unlikely(fsmeta < F2FS_MIN_META_SEGMENTS ||
+	if (!f2fs_sb_has_readonly(sbi) &&
+			unlikely(fsmeta < F2FS_MIN_META_SEGMENTS ||
 			ovp_segments == 0 || reserved_segments == 0)) {
 		f2fs_err(sbi, "Wrong layout: check mkfs.f2fs version");
 		return 1;
 	}
-
 	user_block_count = le64_to_cpu(ckpt->user_block_count);
-	segment_count_main = le32_to_cpu(raw_super->segment_count_main);
+	segment_count_main = le32_to_cpu(raw_super->segment_count_main) +
+			(f2fs_sb_has_readonly(sbi) ? 1 : 0);
 	log_blocks_per_seg = le32_to_cpu(raw_super->log_blocks_per_seg);
 	if (!user_block_count || user_block_count >=
 			segment_count_main << log_blocks_per_seg) {
@@ -3175,6 +3191,10 @@ int f2fs_sanity_check_ckpt(struct f2fs_sb_info *sbi)
 		if (le32_to_cpu(ckpt->cur_node_segno[i]) >= main_segs ||
 			le16_to_cpu(ckpt->cur_node_blkoff[i]) >= blocks_per_seg)
 			return 1;
+
+		if (f2fs_sb_has_readonly(sbi))
+			goto check_data;
+
 		for (j = i + 1; j < NR_CURSEG_NODE_TYPE; j++) {
 			if (le32_to_cpu(ckpt->cur_node_segno[i]) ==
 				le32_to_cpu(ckpt->cur_node_segno[j])) {
@@ -3185,10 +3205,15 @@ int f2fs_sanity_check_ckpt(struct f2fs_sb_info *sbi)
 			}
 		}
 	}
+check_data:
 	for (i = 0; i < NR_CURSEG_DATA_TYPE; i++) {
 		if (le32_to_cpu(ckpt->cur_data_segno[i]) >= main_segs ||
 			le16_to_cpu(ckpt->cur_data_blkoff[i]) >= blocks_per_seg)
 			return 1;
+
+		if (f2fs_sb_has_readonly(sbi))
+			goto skip_cross;
+
 		for (j = i + 1; j < NR_CURSEG_DATA_TYPE; j++) {
 			if (le32_to_cpu(ckpt->cur_data_segno[i]) ==
 				le32_to_cpu(ckpt->cur_data_segno[j])) {
@@ -3210,7 +3235,7 @@ int f2fs_sanity_check_ckpt(struct f2fs_sb_info *sbi)
 			}
 		}
 	}
-
+skip_cross:
 	sit_bitmap_size = le32_to_cpu(ckpt->sit_ver_bitmap_bytesize);
 	nat_bitmap_size = le32_to_cpu(ckpt->nat_ver_bitmap_bytesize);