[PATCH 4/6] ubifs: Maintain a parent pointer
From: Richard Weinberger
Date: Sun May 21 2017 - 16:21:42 EST
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 <richard@xxxxxx>
---
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);
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