Re: [f2fs-dev] [PATCH 2/2] f2fs: support RO feature

Chao Yu
2021-05-24T11:53:33Z

On 2021/5/22 3:02, Jaegeuk Kim wrote:
> Given RO feature in superblock, we don't need to check provisioning/reserve
> spaces and SSA area.

Cool, any solution to update files of ro f2fs image if there is such
scenario?

>
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
> fs/f2fs/f2fs.h | 2 ++
> fs/f2fs/segment.c | 3 +++
> fs/f2fs/super.c | 35 +++++++++++++++++++++++++++++++----
> 3 files changed, 36 insertions(+), 4 deletions(-)
>
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index c0bead0df66a..2c6913261586 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -168,6 +168,7 @@ struct f2fs_mount_info {
> #define F2FS_FEATURE_SB_CHKSUM 0x0800
> #define F2FS_FEATURE_CASEFOLD 0x1000
> #define F2FS_FEATURE_COMPRESSION 0x2000
> +#define F2FS_FEATURE_RO 0x4000
>
> #define __F2FS_HAS_FEATURE(raw_super, mask) \
> ((raw_super->feature & cpu_to_le32(mask)) != 0)
> @@ -939,6 +940,7 @@ static inline void set_new_dnode(struct dnode_of_data *dn, struct inode *inode,
> #define NR_CURSEG_DATA_TYPE (3)
> #define NR_CURSEG_NODE_TYPE (3)
> #define NR_CURSEG_INMEM_TYPE (2)
> +#define NR_CURSEG_RO_TYPE (2)
> #define NR_CURSEG_PERSIST_TYPE (NR_CURSEG_DATA_TYPE + NR_CURSEG_NODE_TYPE)
> #define NR_CURSEG_TYPE (NR_CURSEG_INMEM_TYPE + NR_CURSEG_PERSIST_TYPE)
>
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 8668df7870d0..67cec8f858a2 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -4674,6 +4674,9 @@ static int sanity_check_curseg(struct f2fs_sb_info *sbi)
> {
> int i;
>
> + if (__F2FS_HAS_FEATURE(sbi->raw_super, F2FS_FEATURE_RO))

Why not using F2FS_HAS_FEATURE(sbi, F2FS_FEATURE_RO))?

Ditto for all below __F2FS_HAS_FEATURE().

Thanks,

> + return 0;
> +
> /*
> * In LFS/SSR curseg, .next_blkoff should point to an unused blkaddr;
> * In LFS curseg, all blkaddr after .next_blkoff should be unused.
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index b29de80ab60e..312bfab54693 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -1819,7 +1819,11 @@ 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_HAS_FEATURE(sbi->raw_super, F2FS_FEATURE_RO))
> + 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;
> @@ -1994,6 +1998,11 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
> err = parse_options(sb, data, true);
> if (err)
> goto restore_opts;
> +
> + if (__F2FS_HAS_FEATURE(sbi->raw_super, F2FS_FEATURE_RO) &&
> + !(*flags & SB_RDONLY))
> + goto restore_opts;
> +
> checkpoint_changed =
> disable_checkpoint != test_opt(sbi, DISABLE_CHECKPOINT);
>
> @@ -3137,16 +3146,18 @@ 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 (__F2FS_HAS_FEATURE(sbi->raw_super, F2FS_FEATURE_RO))
> + goto no_reserved;
> if (unlikely(fsmeta < F2FS_MIN_META_SEGMENTS ||
> ovp_segments == 0 || reserved_segments == 0)) {
> f2fs_err(sbi, "Wrong layout: check mkfs.f2fs version");
> return 1;
> }
> -
> +no_reserved:
> user_block_count = le64_to_cpu(ckpt->user_block_count);
> segment_count_main = le32_to_cpu(raw_super->segment_count_main);
> log_blocks_per_seg = le32_to_cpu(raw_super->log_blocks_per_seg);
> - if (!user_block_count || user_block_count >=
> + if (!user_block_count || user_block_count >
> segment_count_main << log_blocks_per_seg) {
> f2fs_err(sbi, "Wrong user_block_count: %u",
> user_block_count);
> @@ -3175,6 +3186,10 @@ 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_HAS_FEATURE(sbi->raw_super, F2FS_FEATURE_RO))
> + 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 +3200,15 @@ 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_HAS_FEATURE(sbi->raw_super, F2FS_FEATURE_RO))
> + 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 +3230,7 @@ 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);
>
> @@ -3703,6 +3723,13 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
> if (err)
> goto free_options;
>
> + if (__F2FS_HAS_FEATURE(sbi->raw_super, F2FS_FEATURE_RO) &&
> + !f2fs_readonly(sbi->sb)) {
> + f2fs_info(sbi, "Allow to mount readonly mode only");
> + err = -EINVAL;
> + goto free_options;
> + }
> +
> sb->s_maxbytes = max_file_blocks(NULL) <<
> le32_to_cpu(raw_super->log_blocksize);
> sb->s_max_links = F2FS_LINK_MAX;
>