[PATCH V3 01/17] Squashfs: inode operations

[PATCH V3 01/17] Squashfs: inode operations

[Phillip Lougher]

Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
---
 fs/squashfs/inode.c |  346 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 346 insertions(+), 0 deletions(-)

diff --git a/fs/squashfs/inode.c b/fs/squashfs/inode.c
new file mode 100644
index 0000000..7a63398
--- /dev/null
+++ b/fs/squashfs/inode.c
@@ -0,0 +1,346 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
+ * Phillip Lougher <phillip@lougher.demon.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2,
+ * or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * inode.c
+ */
+
+/*
+ * This file implements code to create and read inodes from disk.
+ *
+ * Inodes in Squashfs are identified by a 48-bit inode which encodes the
+ * location of the compressed metadata block containing the inode, and the byte
+ * offset into that block where the inode is placed (<block, offset>).
+ *
+ * To maximise compression there are different inodes for each file type
+ * (regular file, directory, device, etc.), the inode contents and length
+ * varying with the type.
+ *
+ * To further maximise compression, two types of regular file inode and
+ * directory inode are defined: inodes optimised for frequently occurring
+ * regular files and directories, and extended types where extra
+ * information has to be stored.
+ */
+
+#include <linux/fs.h>
+#include <linux/vfs.h>
+#include <linux/zlib.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs_fs_i.h"
+#include "squashfs.h"
+
+/*
+ * Initialise VFS inode with the base inode information common to all
+ * Squashfs inode types.  Sqsh_ino contains the unswapped base inode
+ * off disk.
+ */
+static int squashfs_new_inode(struct super_block *sb, struct inode *inode,
+				struct squashfs_base_inode *sqsh_ino)
+{
+	int err;
+
+	err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->uid), &inode->i_uid);
+	if (err)
+		return err;
+
+	err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->guid), &inode->i_gid);
+	if (err)
+		return err;
+
+	inode->i_ino = le32_to_cpu(sqsh_ino->inode_number);
+	inode->i_mtime.tv_sec = le32_to_cpu(sqsh_ino->mtime);
+	inode->i_atime.tv_sec = inode->i_mtime.tv_sec;
+	inode->i_ctime.tv_sec = inode->i_mtime.tv_sec;
+	inode->i_mode = le16_to_cpu(sqsh_ino->mode);
+	inode->i_size = 0;
+
+	return err;
+}
+
+
+struct inode *squashfs_iget(struct super_block *sb, long long ino,
+				unsigned int ino_number)
+{
+	struct inode *inode = iget_locked(sb, ino_number);
+	int err;
+
+	TRACE("Entered squashfs_iget\n");
+
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+	if (!(inode->i_state & I_NEW))
+		return inode;
+
+	err = squashfs_read_inode(inode, ino);
+	if (err) {
+		iget_failed(inode);
+		return ERR_PTR(err);
+	}
+
+	unlock_new_inode(inode);
+	return inode;
+}
+
+
+/*
+ * Initialise VFS inode by reading inode from inode table (compressed
+ * metadata).  The format and amount of data read depends on type.
+ */
+int squashfs_read_inode(struct inode *inode, long long ino)
+{
+	struct super_block *sb = inode->i_sb;
+	struct squashfs_sb_info *msblk = sb->s_fs_info;
+	u64 block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
+	int err, type, offset = SQUASHFS_INODE_OFFSET(ino);
+	union squashfs_inode squashfs_ino;
+	struct squashfs_base_inode *sqshb_ino = &squashfs_ino.base;
+
+	TRACE("Entered squashfs_read_inode\n");
+
+	/*
+	 * Read inode base common to all inode types.
+	 */
+	err = squashfs_read_metadata(sb, sqshb_ino, &block,
+				&offset, sizeof(*sqshb_ino));
+	if (err < 0)
+		goto failed_read;
+
+	err = squashfs_new_inode(sb, inode, sqshb_ino);
+	if (err)
+		goto failed_read;
+
+	block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
+	offset = SQUASHFS_INODE_OFFSET(ino);
+
+	type = le16_to_cpu(sqshb_ino->inode_type);
+	switch (type) {
+	case SQUASHFS_REG_TYPE: {
+		unsigned int frag_offset, frag_size, frag;
+		u64 frag_blk;
+		struct squashfs_reg_inode *sqsh_ino = &squashfs_ino.reg;
+
+		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
+							sizeof(*sqsh_ino));
+		if (err < 0)
+			goto failed_read;
+
+		frag = le32_to_cpu(sqsh_ino->fragment);
+		if (frag != SQUASHFS_INVALID_FRAG) {
+			frag_offset = le32_to_cpu(sqsh_ino->offset);
+			frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
+			if (frag_size < 0) {
+				err = frag_size;
+				goto failed_read;
+			}
+		} else {
+			frag_blk = SQUASHFS_INVALID_BLK;
+			frag_size = 0;
+			frag_offset = 0;
+		}
+
+		inode->i_nlink = 1;
+		inode->i_size = le32_to_cpu(sqsh_ino->file_size);
+		inode->i_fop = &generic_ro_fops;
+		inode->i_mode |= S_IFREG;
+		inode->i_blocks = ((inode->i_size - 1) >> 9) + 1;
+		squashfs_i(inode)->fragment_block = frag_blk;
+		squashfs_i(inode)->fragment_size = frag_size;
+		squashfs_i(inode)->fragment_offset = frag_offset;
+		squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
+		squashfs_i(inode)->block_list_start = block;
+		squashfs_i(inode)->offset = offset;
+		inode->i_data.a_ops = &squashfs_aops;
+
+		TRACE("File inode %x:%x, start_block %llx, block_list_start "
+			"%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
+			offset, squashfs_i(inode)->start, block, offset);
+		break;
+	}
+	case SQUASHFS_LREG_TYPE: {
+		unsigned int frag_offset, frag_size, frag;
+		u64 frag_blk;
+		struct squashfs_lreg_inode *sqsh_ino = &squashfs_ino.lreg;
+
+		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
+							sizeof(*sqsh_ino));
+		if (err < 0)
+			goto failed_read;
+
+		frag = le32_to_cpu(sqsh_ino->fragment);
+		if (frag != SQUASHFS_INVALID_FRAG) {
+			frag_offset = le32_to_cpu(sqsh_ino->offset);
+			frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
+			if (frag_size < 0) {
+				err = frag_size;
+				goto failed_read;
+			}
+		} else {
+			frag_blk = SQUASHFS_INVALID_BLK;
+			frag_size = 0;
+			frag_offset = 0;
+		}
+
+		inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
+		inode->i_size = le64_to_cpu(sqsh_ino->file_size);
+		inode->i_fop = &generic_ro_fops;
+		inode->i_mode |= S_IFREG;
+		inode->i_blocks = ((inode->i_size -
+				le64_to_cpu(sqsh_ino->sparse) - 1) >> 9) + 1;
+
+		squashfs_i(inode)->fragment_block = frag_blk;
+		squashfs_i(inode)->fragment_size = frag_size;
+		squashfs_i(inode)->fragment_offset = frag_offset;
+		squashfs_i(inode)->start = le64_to_cpu(sqsh_ino->start_block);
+		squashfs_i(inode)->block_list_start = block;
+		squashfs_i(inode)->offset = offset;
+		inode->i_data.a_ops = &squashfs_aops;
+
+		TRACE("File inode %x:%x, start_block %llx, block_list_start "
+			"%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
+			offset, squashfs_i(inode)->start, block, offset);
+		break;
+	}
+	case SQUASHFS_DIR_TYPE: {
+		struct squashfs_dir_inode *sqsh_ino = &squashfs_ino.dir;
+
+		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
+				sizeof(*sqsh_ino));
+		if (err < 0)
+			goto failed_read;
+
+		inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
+		inode->i_size = le16_to_cpu(sqsh_ino->file_size);
+		inode->i_op = &squashfs_dir_inode_ops;
+		inode->i_fop = &squashfs_dir_ops;
+		inode->i_mode |= S_IFDIR;
+		squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
+		squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
+		squashfs_i(inode)->dir_idx_cnt = 0;
+		squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
+
+		TRACE("Directory inode %x:%x, start_block %llx, offset %x\n",
+				SQUASHFS_INODE_BLK(ino), offset,
+				squashfs_i(inode)->start,
+				le16_to_cpu(sqsh_ino->offset));
+		break;
+	}
+	case SQUASHFS_LDIR_TYPE: {
+		struct squashfs_ldir_inode *sqsh_ino = &squashfs_ino.ldir;
+
+		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
+				sizeof(*sqsh_ino));
+		if (err < 0)
+			goto failed_read;
+
+		inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
+		inode->i_size = le32_to_cpu(sqsh_ino->file_size);
+		inode->i_op = &squashfs_dir_inode_ops;
+		inode->i_fop = &squashfs_dir_ops;
+		inode->i_mode |= S_IFDIR;
+		squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
+		squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
+		squashfs_i(inode)->dir_idx_start = block;
+		squashfs_i(inode)->dir_idx_offset = offset;
+		squashfs_i(inode)->dir_idx_cnt = le16_to_cpu(sqsh_ino->i_count);
+		squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
+
+		TRACE("Long directory inode %x:%x, start_block %llx, offset "
+				"%x\n", SQUASHFS_INODE_BLK(ino), offset,
+				squashfs_i(inode)->start,
+				le16_to_cpu(sqsh_ino->offset));
+		break;
+	}
+	case SQUASHFS_SYMLINK_TYPE:
+	case SQUASHFS_LSYMLINK_TYPE: {
+		struct squashfs_symlink_inode *sqsh_ino = &squashfs_ino.symlink;
+
+		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
+				sizeof(*sqsh_ino));
+		if (err < 0)
+			goto failed_read;
+
+		inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
+		inode->i_size = le32_to_cpu(sqsh_ino->symlink_size);
+		inode->i_op = &page_symlink_inode_operations;
+		inode->i_data.a_ops = &squashfs_symlink_aops;
+		inode->i_mode |= S_IFLNK;
+		squashfs_i(inode)->start = block;
+		squashfs_i(inode)->offset = offset;
+
+		TRACE("Symbolic link inode %x:%x, start_block %llx, offset "
+				"%x\n", SQUASHFS_INODE_BLK(ino), offset,
+				block, offset);
+		break;
+	}
+	case SQUASHFS_BLKDEV_TYPE:
+	case SQUASHFS_CHRDEV_TYPE:
+	case SQUASHFS_LBLKDEV_TYPE:
+	case SQUASHFS_LCHRDEV_TYPE: {
+		struct squashfs_dev_inode *sqsh_ino = &squashfs_ino.dev;
+		unsigned int rdev;
+
+		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
+				sizeof(*sqsh_ino));
+		if (err < 0)
+			goto failed_read;
+
+		if (type == SQUASHFS_CHRDEV_TYPE)
+			inode->i_mode |= S_IFCHR;
+		else
+			inode->i_mode |= S_IFBLK;
+		inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
+		rdev = le32_to_cpu(sqsh_ino->rdev);
+		init_special_inode(inode, inode->i_mode, new_decode_dev(rdev));
+
+		TRACE("Device inode %x:%x, rdev %x\n",
+				SQUASHFS_INODE_BLK(ino), offset, rdev);
+		break;
+	}
+	case SQUASHFS_FIFO_TYPE:
+	case SQUASHFS_SOCKET_TYPE:
+	case SQUASHFS_LFIFO_TYPE:
+	case SQUASHFS_LSOCKET_TYPE: {
+		struct squashfs_ipc_inode *sqsh_ino = &squashfs_ino.ipc;
+
+		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
+				sizeof(*sqsh_ino));
+		if (err < 0)
+			goto failed_read;
+
+		if (type == SQUASHFS_FIFO_TYPE)
+			inode->i_mode |= S_IFIFO;
+		else
+			inode->i_mode |= S_IFSOCK;
+		inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
+		init_special_inode(inode, inode->i_mode, 0);
+		break;
+	}
+	default:
+		ERROR("Unknown inode type %d in squashfs_iget!\n", type);
+		return -EINVAL;
+	}
+
+	return 0;
+
+failed_read:
+	ERROR("Unable to read inode 0x%llx\n", ino);
+	return err;
+}
-- 
1.5.6.3

Re: [PATCH V3 01/17] Squashfs: inode operations

[Evgeniy Polyakov]

Hi.

On Mon, Jan 05, 2009 at 11:08:23AM +0000, Phillip Lougher (phillip@lougher.demon.co.uk) wrote:
> +int squashfs_read_inode(struct inode *inode, long long ino)
> +{
> +	struct super_block *sb = inode->i_sb;
> +	struct squashfs_sb_info *msblk = sb->s_fs_info;
> +	u64 block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
> +	int err, type, offset = SQUASHFS_INODE_OFFSET(ino);
> +	union squashfs_inode squashfs_ino;
> +	struct squashfs_base_inode *sqshb_ino = &squashfs_ino.base;
> +

What's the size of that union? If big enough it will lead to some
problems.

> +	TRACE("Entered squashfs_read_inode\n");
> +
> +	/*
> +	 * Read inode base common to all inode types.
> +	 */
> +	err = squashfs_read_metadata(sb, sqshb_ino, &block,
> +				&offset, sizeof(*sqshb_ino));
> +	if (err < 0)
> +		goto failed_read;
> +
> +	err = squashfs_new_inode(sb, inode, sqshb_ino);
> +	if (err)
> +		goto failed_read;
> +
> +	block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
> +	offset = SQUASHFS_INODE_OFFSET(ino);
> +
> +	type = le16_to_cpu(sqshb_ino->inode_type);
> +	switch (type) {
> +	case SQUASHFS_REG_TYPE: {
> +		unsigned int frag_offset, frag_size, frag;
> +		u64 frag_blk;

Above variables can be moved out of the switch, since they are used in
some other cases too.

-- 
	Evgeniy Polyakov

Re: [PATCH V3 01/17] Squashfs: inode operations

[Geert Uytterhoeven]

On Mon, 5 Jan 2009, Phillip Lougher wrote:
> diff --git a/fs/squashfs/inode.c b/fs/squashfs/inode.c
> new file mode 100644
> index 0000000..7a63398
> --- /dev/null
> +++ b/fs/squashfs/inode.c
> @@ -0,0 +1,346 @@

> +int squashfs_read_inode(struct inode *inode, long long ino)
> +{
> +	struct super_block *sb = inode->i_sb;
> +	struct squashfs_sb_info *msblk = sb->s_fs_info;
> +	u64 block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
        ^^^

> +		TRACE("File inode %x:%x, start_block %llx, block_list_start "
                                                     ^^^^
> +			"%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
                         ^^^^
> +			offset, squashfs_i(inode)->start, block, offset);

Note that I get lots of

| warning: format '%llx' expects type 'long long unsigned int', but argument 3 has type 'u64'

on ppc64, since you switched from `unsigned long long' to 'u64', as `u64' is
(still -- this is being changed) `unsigned long' on pp64.

I guess no action has to be taken, for now?

With kind regards,

Geert Uytterhoeven
Software Architect

Sony Techsoft Centre Europe
The Corporate Village · Da Vincilaan 7-D1 · B-1935 Zaventem · Belgium

Phone:    +32 (0)2 700 8453
Fax:      +32 (0)2 700 8622
E-mail:   Geert.Uytterhoeven@sonycom.com
Internet: http://www.sony-europe.com/

A division of Sony Europe (Belgium) N.V.
VAT BE 0413.825.160 · RPR Brussels
Fortis · BIC GEBABEBB · IBAN BE41293037680010

Re: [PATCH V3 01/17] Squashfs: inode operations

[Stephen Rothwell]

[-- Attachment #1: Type: text/plain, Size: 636 bytes --]

Hi Geert,

On Wed, 7 Jan 2009 19:00:24 +0100 (CET) Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com> wrote:
>
> Note that I get lots of
> 
> | warning: format '%llx' expects type 'long long unsigned int', but argument 3 has type 'u64'
> 
> on ppc64, since you switched from `unsigned long long' to 'u64', as `u64' is
> (still -- this is being changed) `unsigned long' on pp64.
> 
> I guess no action has to be taken, for now?

Correct, as we are in the process of changing u64 to unsigned long long for
powerpc.
-- 
Cheers,
Stephen Rothwell                    sfr@canb.auug.org.au
http://www.canb.auug.org.au/~sfr/

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