Hi Richard,
On Sun, May 21, 2017 at 10:20:49PM +0200, Richard Weinberger wrote:
> The new feature UBIFS_FLG_PARENTPOINTER allows looking
> up the parent. Usually the Linux VFS walks down the filesystem
> and no parent pointers are needed. But when a filesystem
> is exportable via NFS such a lookup is needed.
> We can use a padding field in struct ubifs_ino_node to
> maintain a pointer to the parent inode.
>
> Signed-off-by: Richard Weinberger <rich...@nod.at>
> ---
> fs/ubifs/dir.c | 21 +++++++++++++++++++--
> fs/ubifs/journal.c | 5 ++++-
> fs/ubifs/sb.c | 2 ++
> fs/ubifs/super.c | 1 +
> fs/ubifs/ubifs-media.h | 12 +++++++++---
> fs/ubifs/ubifs.h | 4 ++++
> 6 files changed, 39 insertions(+), 6 deletions(-)
>
> diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
> index e79b529df9c3..a6eadb52a1a8 100644
> --- a/fs/ubifs/dir.c
> +++ b/fs/ubifs/dir.c
> @@ -171,6 +171,7 @@ struct inode *ubifs_new_inode(struct ubifs_info *c,
> struct inode *dir,
> }
>
> inode->i_ino = ++c->highest_inum;
> + ui->parent_inum = dir->i_ino;
> /*
> * The creation sequence number remains with this inode for its
> * lifetime. All nodes for this inode have a greater sequence number,
> @@ -1374,7 +1375,7 @@ static int do_rename(struct inode *old_dir, struct
> dentry *old_dentry,
> if (unlink)
> ubifs_assert(inode_is_locked(new_inode));
>
> - if (old_dir != new_dir) {
> + if (move) {
> if (ubifs_crypt_is_encrypted(new_dir) &&
> !fscrypt_has_permitted_context(new_dir, old_inode))
> return -EPERM;
> @@ -1528,8 +1529,12 @@ static int do_rename(struct inode *old_dir, struct
> dentry *old_dentry,
> mark_inode_dirty(whiteout);
> whiteout->i_state &= ~I_LINKABLE;
> iput(whiteout);
> + whiteout_ui->parent_inum = new_dir->i_ino;
> }
>
> + if (move)
> + old_inode_ui->parent_inum = new_dir->i_ino;
> +
> err = ubifs_jnl_rename(c, old_dir, old_inode, &old_nm, new_dir,
> new_inode, &new_nm, whiteout, sync);
I think that old_inode_ui->parent_inum could point old_dir, even though
old_inode
is a child of new_dir. this could happen that there is power-cut before
old_inode is synced. so I guess that old_inode is needed to be written with
rename's node group in ubifs_jnl_rename. is it right?
> if (err)
> @@ -1571,6 +1576,8 @@ static int do_rename(struct inode *old_dir, struct
> dentry *old_dentry,
> inc_nlink(old_dir);
> }
> }
> + if (move)
> + old_inode_ui->parent_inum = old_dir->i_ino;
> if (whiteout) {
> drop_nlink(whiteout);
> iput(whiteout);
> @@ -1592,6 +1599,8 @@ static int ubifs_xrename(struct inode *old_dir, struct
> dentry *old_dentry,
> int sync = IS_DIRSYNC(old_dir) || IS_DIRSYNC(new_dir);
> struct inode *fst_inode = d_inode(old_dentry);
> struct inode *snd_inode = d_inode(new_dentry);
> + struct ubifs_inode *fst_inode_ui = ubifs_inode(fst_inode);
> + struct ubifs_inode *snd_inode_ui = ubifs_inode(snd_inode);
> struct timespec time;
> int err;
> struct fscrypt_name fst_nm, snd_nm;
> @@ -1623,7 +1632,10 @@ static int ubifs_xrename(struct inode *old_dir, struct
> dentry *old_dentry,
> old_dir->i_mtime = old_dir->i_ctime = time;
> new_dir->i_mtime = new_dir->i_ctime = time;
>
> - if (old_dir != new_dir) {
> + if (new_dir != old_dir) {
> + fst_inode_ui->parent_inum = new_dir->i_ino;
> + snd_inode_ui->parent_inum = old_dir->i_ino;
> +
> if (S_ISDIR(fst_inode->i_mode) && !S_ISDIR(snd_inode->i_mode)) {
> inc_nlink(new_dir);
> drop_nlink(old_dir);
> @@ -1637,6 +1649,11 @@ static int ubifs_xrename(struct inode *old_dir, struct
> dentry *old_dentry,
> err = ubifs_jnl_xrename(c, old_dir, fst_inode, &fst_nm, new_dir,
> snd_inode, &snd_nm, sync);
>
> + if (err && new_dir != old_dir) {
> + fst_inode_ui->parent_inum = old_dir->i_ino;
> + snd_inode_ui->parent_inum = new_dir->i_ino;
> + }
> +
> unlock_4_inodes(old_dir, new_dir, NULL, NULL);
> ubifs_release_budget(c, &req);
>
> diff --git a/fs/ubifs/journal.c b/fs/ubifs/journal.c
> index 294519b98874..8eaf8f2f1fe1 100644
> --- a/fs/ubifs/journal.c
> +++ b/fs/ubifs/journal.c
> @@ -66,7 +66,6 @@
> */
> static inline void zero_ino_node_unused(struct ubifs_ino_node *ino)
> {
> - memset(ino->padding1, 0, 4);
> memset(ino->padding2, 0, 26);
> }
>
> @@ -470,6 +469,10 @@ static void pack_inode(struct ubifs_info *c, struct
> ubifs_ino_node *ino,
> ino->xattr_cnt = cpu_to_le32(ui->xattr_cnt);
> ino->xattr_size = cpu_to_le32(ui->xattr_size);
> ino->xattr_names = cpu_to_le32(ui->xattr_names);
> + if (c->parent_pointer)
> + ino->parent_inum = cpu_to_le32(ui->parent_inum);
> + else
> + ino->parent_inum = 0;
> zero_ino_node_unused(ino);
>
> /*
> diff --git a/fs/ubifs/sb.c b/fs/ubifs/sb.c
> index 8c25081a5109..f2097c47f629 100644
> --- a/fs/ubifs/sb.c
> +++ b/fs/ubifs/sb.c
> @@ -166,6 +166,7 @@ static int create_default_filesystem(struct ubifs_info *c)
> if (big_lpt)
> sup_flags |= UBIFS_FLG_BIGLPT;
> sup_flags |= UBIFS_FLG_DOUBLE_HASH;
> + sup_flags |= UBIFS_FLG_PARENTPOINTER;
>
> sup->ch.node_type = UBIFS_SB_NODE;
> sup->key_hash = UBIFS_KEY_HASH_R5;
> @@ -639,6 +640,7 @@ int ubifs_read_superblock(struct ubifs_info *c)
> c->space_fixup = !!(sup_flags & UBIFS_FLG_SPACE_FIXUP);
> c->double_hash = !!(sup_flags & UBIFS_FLG_DOUBLE_HASH);
> c->encrypted = !!(sup_flags & UBIFS_FLG_ENCRYPTION);
> + c->parent_pointer = !!(sup_flags & UBIFS_FLG_PARENTPOINTER);
>
> if ((sup_flags & ~UBIFS_FLG_MASK) != 0) {
> ubifs_err(c, "Unknown feature flags found: %#x",
> diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
> index cf4cc99b75b5..7560071534bf 100644
> --- a/fs/ubifs/super.c
> +++ b/fs/ubifs/super.c
> @@ -154,6 +154,7 @@ struct inode *ubifs_iget(struct super_block *sb, unsigned
> long inum)
> ui->synced_i_size = ui->ui_size = inode->i_size;
>
> ui->xattr = (ui->flags & UBIFS_XATTR_FL) ? 1 : 0;
> + ui->parent_inum = le32_to_cpu(ino->parent_inum);
>
> err = validate_inode(c, inode);
> if (err)
> diff --git a/fs/ubifs/ubifs-media.h b/fs/ubifs/ubifs-media.h
> index 5939776c7359..b3cb76cedf20 100644
> --- a/fs/ubifs/ubifs-media.h
> +++ b/fs/ubifs/ubifs-media.h
> @@ -427,15 +427,21 @@ enum {
> * UBIFS_FLG_DOUBLE_HASH: store a 32bit cookie in directory entry nodes to
> * support 64bit cookies for lookups by hash
> * UBIFS_FLG_ENCRYPTION: this filesystem contains encrypted files
> + * UBIFS_FLG_PARENTPOINTER: inode nodes maintain a pointer to the parent dir
> */
> enum {
> UBIFS_FLG_BIGLPT = 0x02,
> UBIFS_FLG_SPACE_FIXUP = 0x04,
> UBIFS_FLG_DOUBLE_HASH = 0x08,
> UBIFS_FLG_ENCRYPTION = 0x10,
> + UBIFS_FLG_PARENTPOINTER = 0x20,
> };
>
> -#define UBIFS_FLG_MASK
> (UBIFS_FLG_BIGLPT|UBIFS_FLG_SPACE_FIXUP|UBIFS_FLG_DOUBLE_HASH|UBIFS_FLG_ENCRYPTION)
> +#define UBIFS_FLG_MASK (UBIFS_FLG_BIGLPT \
> + |UBIFS_FLG_SPACE_FIXUP \
> + |UBIFS_FLG_DOUBLE_HASH \
> + |UBIFS_FLG_ENCRYPTION \
> + |UBIFS_FLG_PARENTPOINTER)
>
> /**
> * struct ubifs_ch - common header node.
> @@ -494,7 +500,7 @@ union ubifs_dev_desc {
> * @data_len: inode data length
> * @xattr_cnt: count of extended attributes this inode has
> * @xattr_size: summarized size of all extended attributes in bytes
> - * @padding1: reserved for future, zeroes
> + * @parent_inum: parent inode number
> * @xattr_names: sum of lengths of all extended attribute names belonging to
> * this inode
> * @compr_type: compression type used for this inode
> @@ -528,7 +534,7 @@ struct ubifs_ino_node {
> __le32 data_len;
> __le32 xattr_cnt;
> __le32 xattr_size;
> - __u8 padding1[4]; /* Watch 'zero_ino_node_unused()' if changing! */
> + __le32 parent_inum;
> __le32 xattr_names;
> __le16 compr_type;
> __u8 padding2[26]; /* Watch 'zero_ino_node_unused()' if changing! */
> diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
> index f14dcc890e47..3c64481f4032 100644
> --- a/fs/ubifs/ubifs.h
> +++ b/fs/ubifs/ubifs.h
> @@ -353,6 +353,7 @@ struct ubifs_gced_idx_leb {
> * currently stored on the flash; used only for regular file
> * inodes
> * @ui_size: inode size used by UBIFS when writing to flash
> + * @parent_inum: inode number of the parent directory
> * @flags: inode flags (@UBIFS_COMPR_FL, etc)
> * @compr_type: default compression type used for this inode
> * @last_page_read: page number of last page read (for bulk read)
> @@ -404,6 +405,7 @@ struct ubifs_inode {
> spinlock_t ui_lock;
> loff_t synced_i_size;
> loff_t ui_size;
> + ino_t parent_inum;
> int flags;
> pgoff_t last_page_read;
> pgoff_t read_in_a_row;
> @@ -1012,6 +1014,7 @@ struct ubifs_debug_info;
> * @space_fixup: flag indicating that free space in LEBs needs to be cleaned
> up
> * @double_hash: flag indicating that we can do lookups by hash
> * @encrypted: flag indicating that this file system contains encrypted files
> + * @parent_pointer: flag indicating that inodes have pointers to the parent
> dir
> * @no_chk_data_crc: do not check CRCs when reading data nodes (except during
> * recovery)
> * @bulk_read: enable bulk-reads
> @@ -1255,6 +1258,7 @@ struct ubifs_info {
> unsigned int space_fixup:1;
> unsigned int double_hash:1;
> unsigned int encrypted:1;
> + unsigned int parent_pointer:1;
> unsigned int no_chk_data_crc:1;
> unsigned int bulk_read:1;
> unsigned int default_compr:2;
> --
> 2.12.0
>
>
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> http://lists.infradead.org/mailman/listinfo/linux-mtd/
--
Thanks,
Hyunchul
