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[PATCH 0/6] UBIFS NFS export support

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  [PATCH 0/6] UBIFS NFS export support Richard Weinberger <richard@nod.at> - 2016-12-01 23:10 +0100
    [PATCH 2/6] ubifs: Provide a custom llseek for directories Richard Weinberger <richard@nod.at> - 2016-12-01 23:10 +0100
    [PATCH 4/6] ubifs: Maintain a parent pointer Richard Weinberger <richard@nod.at> - 2016-12-01 23:10 +0100
      Re: [PATCH 4/6] ubifs: Maintain a parent pointer Marcus Folkesson <marcus.folkesson@gmail.com> - 2016-12-02 10:40 +0100
        Re: [PATCH 4/6] ubifs: Maintain a parent pointer Richard Weinberger <richard@nod.at> - 2016-12-02 11:40 +0100

#1534493 — [PATCH 0/6] UBIFS NFS export support

Adding fscrypto support to UBIFS forced us to implement 64bit
cookies. Using this building block we can finally implement
export operations and allow UBIFS being exported via NFS.
This series adds the last missing bits.

It can be obtained from:
git://git.infradead.org/users/rw/linux.git ubifs_export_v1

Richard Weinberger (6):
  ext4: Move is_32bit_api() to generic code
  ubifs: Provide a custom llseek for directories
  ubifs: Use 64bit readdir cookies
  ubifs: Maintain a parent pointer
  ubifs: Implement export_operations
  ubifs: Wire up NFS support

 fs/ext4/dir.c          |  9 ------
 fs/ubifs/dir.c         | 88 ++++++++++++++++++++++++++++++++++++++------------
 fs/ubifs/journal.c     |  5 ++-
 fs/ubifs/key.h         | 59 +++++++++++++++++++++++++++++++++
 fs/ubifs/sb.c          |  2 ++
 fs/ubifs/super.c       | 35 ++++++++++++++++++++
 fs/ubifs/ubifs-media.h | 18 +++++++++--
 fs/ubifs/ubifs.h       |  6 ++++
 include/linux/compat.h |  2 ++
 9 files changed, 190 insertions(+), 34 deletions(-)

-- 
2.7.3

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#1534494 — [PATCH 2/6] ubifs: Provide a custom llseek for directories

When UBIFS is using 64bit cookies for directory offsets,
we have to support seeking that deep into direcoties.
Since generic_file_llseek() is uses sb->s_maxbytes it will
fail for use because on ubifs sb->s_maxbytes is the real maxmal
file size which can be much smaller than 64bit due to limitations
of the flash device.

Therefore provie a custom llseek operation.

Signed-off-by: Richard Weinberger <richard@nod.at>
---
 fs/ubifs/dir.c         | 12 +++++++++++-
 fs/ubifs/ubifs-media.h |  6 ++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index 7f01f3d2ac3b..883b2fdf51df 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -1721,6 +1721,16 @@ static int ubifs_dir_open(struct inode *dir, struct file *file)
 	return 0;
 }
 
+static loff_t ubifs_dir_llseek(struct file *file, loff_t offset, int whence)
+{
+	struct inode *inode = file->f_mapping->host;
+
+	return generic_file_llseek_size(file, offset, whence,
+					(loff_t)UBIFS_S_KEY_HASH_MASK <<
+					UBIFS_DH_BITS | UBIFS_DH_MASK,
+					i_size_read(inode));
+}
+
 const struct inode_operations ubifs_dir_inode_operations = {
 	.lookup      = ubifs_lookup,
 	.create      = ubifs_create,
@@ -1741,7 +1751,7 @@ const struct inode_operations ubifs_dir_inode_operations = {
 };
 
 const struct file_operations ubifs_dir_operations = {
-	.llseek         = generic_file_llseek,
+	.llseek         = ubifs_dir_llseek,
 	.release        = ubifs_dir_release,
 	.read           = generic_read_dir,
 	.iterate_shared = ubifs_readdir,
diff --git a/fs/ubifs/ubifs-media.h b/fs/ubifs/ubifs-media.h
index e8c23c9d4f4a..5939776c7359 100644
--- a/fs/ubifs/ubifs-media.h
+++ b/fs/ubifs/ubifs-media.h
@@ -214,6 +214,12 @@ enum {
 #define UBIFS_S_KEY_HASH_MASK  UBIFS_S_KEY_BLOCK_MASK
 
 /*
+ * We use 32 bits for the double hash cookie.
+ */
+#define UBIFS_DH_MASK 0xffffffff
+#define UBIFS_DH_BITS 32
+
+/*
  * Key types.
  *
  * UBIFS_INO_KEY: inode node key
-- 
2.7.3

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#1534495 — [PATCH 4/6] ubifs: Maintain a parent pointer

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@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, 40 insertions(+), 5 deletions(-)

diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index 3b8c08dad75b..5485d836af21 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 = inode->i_ino;
 	/*
 	 * The creation sequence number remains with this inode for its
 	 * lifetime. All nodes for this inode have a greater sequence number,
@@ -1409,7 +1410,7 @@ 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;
@@ -1563,8 +1564,12 @@ 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)
@@ -1606,6 +1611,8 @@ 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);
@@ -1627,6 +1634,8 @@ 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;
@@ -1658,6 +1667,11 @@ 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 (new_dir != old_dir) {
+		fst_inode_ui->parent_inum = new_dir->i_ino;
+		snd_inode_ui->parent_inum = old_dir->i_ino;
+	}
+
 	if (old_dir != new_dir) {
 		if (S_ISDIR(fst_inode->i_mode) && !S_ISDIR(snd_inode->i_mode)) {
 			inc_nlink(new_dir);
@@ -1672,6 +1686,11 @@ 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 a459211a1c21..4a76c14fb07c 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 7f1ead29e727..f012cd411382 100644
--- a/fs/ubifs/sb.c
+++ b/fs/ubifs/sb.c
@@ -164,6 +164,7 @@ 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;
@@ -633,6 +634,7 @@ 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 e08aa04fc835..c50952f43e36 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 0532a6f82b1d..e1b7531650af 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;
@@ -1018,6 +1020,7 @@ 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
@@ -1262,6 +1265,7 @@ 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;
-- 
2.7.3

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#1534767 — Re: [PATCH 4/6] ubifs: Maintain a parent pointer

On Thu, Dec 01, 2016 at 11:02:19PM +0100, Richard Weinberger wrote:
>  
> +	if (new_dir != old_dir) {
> +		fst_inode_ui->parent_inum = new_dir->i_ino;
> +		snd_inode_ui->parent_inum = old_dir->i_ino;
> +	}
> +
>  	if (old_dir != new_dir) {
>  		if (S_ISDIR(fst_inode->i_mode) && !S_ISDIR(snd_inode->i_mode)) {
>  			inc_nlink(new_dir);

Insignificant thing, but use the existing if-statment instead?

Cheers,
Marcus Folkesson

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#1534806 — Re: [PATCH 4/6] ubifs: Maintain a parent pointer

On 02.12.2016 10:28, Marcus Folkesson wrote:
> On Thu, Dec 01, 2016 at 11:02:19PM +0100, Richard Weinberger wrote:
>>  
>> +	if (new_dir != old_dir) {
>> +		fst_inode_ui->parent_inum = new_dir->i_ino;
>> +		snd_inode_ui->parent_inum = old_dir->i_ino;
>> +	}
>> +
>>  	if (old_dir != new_dir) {
>>  		if (S_ISDIR(fst_inode->i_mode) && !S_ISDIR(snd_inode->i_mode)) {
>>  			inc_nlink(new_dir);
> 
> Insignificant thing, but use the existing if-statment instead?

Of course.
I moved the line around and oversaw the existing branch. :)

Thanks,
//richard

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