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Commit 63a64403 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-linus 

* git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-linus:
  squashfs: update documentation to include description of xattr layout
  squashfs: fix name reading in squashfs_xattr_get
  squashfs: constify xattr handlers
  squashfs: xattr fix sparse warnings
  squashfs: xattr_lookup sparse fix
  squashfs: add xattr support configure option
  squashfs: add new extended inode types
  squashfs: add support for xattr reading
  squashfs: add xattr id support
parents f45471cb 899f4530

Documentation/filesystems/squashfs.txt

+27 −5
Original line number Diff line number Diff line
@@ -38,7 +38,8 @@ Hard link support: yes no 
Real inode numbers:		yes			no

32-bit uids/gids:		yes			no

File creation time:		yes			no

Xattr and ACL support:		no			no

Xattr support:			yes			no

ACL support:			no			no



Squashfs compresses data, inodes and directories.  In addition, inode and

directory data are highly compacted, and packed on byte boundaries.  Each
@@ -58,7 +59,7 @@ obtained from this site also. 
3. SQUASHFS FILESYSTEM DESIGN

-----------------------------



A squashfs filesystem consists of seven parts, packed together on a byte

A squashfs filesystem consists of a maximum of eight parts, packed together on a byte

alignment:



	 ---------------
@@ -80,6 +81,9 @@ alignment: 
	|---------------|

	|    uid/gid	|

	|  lookup table	|

	|---------------|

	|     xattr     |

	|     table	|

	 ---------------



Compressed data blocks are written to the filesystem as files are read from
@@ -192,6 +196,26 @@ This table is stored compressed into metadata blocks. A second index table is 
used to locate these.  This second index table for speed of access (and because

it is small) is read at mount time and cached in memory.



3.7 Xattr table

---------------



The xattr table contains extended attributes for each inode.  The xattrs

for each inode are stored in a list, each list entry containing a type,

name and value field.  The type field encodes the xattr prefix

("user.", "trusted." etc) and it also encodes how the name/value fields

should be interpreted.  Currently the type indicates whether the value

is stored inline (in which case the value field contains the xattr value),

or if it is stored out of line (in which case the value field stores a

reference to where the actual value is stored).  This allows large values

to be stored out of line improving scanning and lookup performance and it

also allows values to be de-duplicated, the value being stored once, and

all other occurences holding an out of line reference to that value.



The xattr lists are packed into compressed 8K metadata blocks.

To reduce overhead in inodes, rather than storing the on-disk

location of the xattr list inside each inode, a 32-bit xattr id

is stored.  This xattr id is mapped into the location of the xattr

list using a second xattr id lookup table.



4. TODOS AND OUTSTANDING ISSUES

-------------------------------
@@ -199,9 +223,7 @@ it is small) is read at mount time and cached in memory. 
4.1 Todo list

-------------



Implement Xattr and ACL support.  The Squashfs 4.0 filesystem layout has hooks

for these but the code has not been written.  Once the code has been written

the existing layout should not require modification.

Implement ACL support.



4.2 Squashfs internal cache

---------------------------

fs/squashfs/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -26,6 +26,17 @@ config SQUASHFS 


	  If unsure, say N.



config SQUASHFS_XATTRS

	bool "Squashfs XATTR support"

	depends on SQUASHFS

	default n

	help

	  Saying Y here includes support for extended attributes (xattrs).

	  Xattrs are name:value pairs associated with inodes by

	  the kernel or by users (see the attr(5) manual page).



	  If unsure, say N.



config SQUASHFS_EMBEDDED



	bool "Additional option for memory-constrained systems"

fs/squashfs/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -5,3 +5,5 @@ 
obj-$(CONFIG_SQUASHFS) += squashfs.o

squashfs-y += block.o cache.o dir.o export.o file.o fragment.o id.o inode.o

squashfs-y += namei.o super.o symlink.o zlib_wrapper.o decompressor.o

squashfs-$(CONFIG_SQUASHFS_XATTRS) += xattr.o xattr_id.o

fs/squashfs/inode.c

+85 −7
Original line number Diff line number Diff line
@@ -40,11 +40,13 @@ 


#include <linux/fs.h>

#include <linux/vfs.h>

#include <linux/xattr.h>



#include "squashfs_fs.h"

#include "squashfs_fs_sb.h"

#include "squashfs_fs_i.h"

#include "squashfs.h"

#include "xattr.h"



/*

 * Initialise VFS inode with the base inode information common to all
@@ -111,6 +113,7 @@ int squashfs_read_inode(struct inode *inode, long long ino) 
	int err, type, offset = SQUASHFS_INODE_OFFSET(ino);

	union squashfs_inode squashfs_ino;

	struct squashfs_base_inode *sqshb_ino = &squashfs_ino.base;

	int xattr_id = SQUASHFS_INVALID_XATTR;



	TRACE("Entered squashfs_read_inode\n");
@@ -199,8 +202,10 @@ int squashfs_read_inode(struct inode *inode, long long ino) 
			frag_offset = 0;

		}



		xattr_id = le32_to_cpu(sqsh_ino->xattr);

		inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);

		inode->i_size = le64_to_cpu(sqsh_ino->file_size);

		inode->i_op = &squashfs_inode_ops;

		inode->i_fop = &generic_ro_fops;

		inode->i_mode |= S_IFREG;

		inode->i_blocks = ((inode->i_size -
@@ -251,6 +256,7 @@ int squashfs_read_inode(struct inode *inode, long long ino) 
		if (err < 0)

			goto failed_read;



		xattr_id = le32_to_cpu(sqsh_ino->xattr);

		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;
@@ -280,21 +286,33 @@ int squashfs_read_inode(struct inode *inode, long long ino) 


		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_op = &squashfs_symlink_inode_ops;

		inode->i_data.a_ops = &squashfs_symlink_aops;

		inode->i_mode |= S_IFLNK;

		squashfs_i(inode)->start = block;

		squashfs_i(inode)->offset = offset;



		if (type == SQUASHFS_LSYMLINK_TYPE) {

			__le32 xattr;



			err = squashfs_read_metadata(sb, NULL, &block,

						&offset, inode->i_size);

			if (err < 0)

				goto failed_read;

			err = squashfs_read_metadata(sb, &xattr, &block,

						&offset, sizeof(xattr));

			if (err < 0)

				goto failed_read;

			xattr_id = le32_to_cpu(xattr);

		}



		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: {

	case SQUASHFS_CHRDEV_TYPE: {

		struct squashfs_dev_inode *sqsh_ino = &squashfs_ino.dev;

		unsigned int rdev;
@@ -315,10 +333,32 @@ int squashfs_read_inode(struct inode *inode, long long ino) 
				SQUASHFS_INODE_BLK(ino), offset, rdev);

		break;

	}

	case SQUASHFS_LBLKDEV_TYPE:

	case SQUASHFS_LCHRDEV_TYPE: {

		struct squashfs_ldev_inode *sqsh_ino = &squashfs_ino.ldev;

		unsigned int rdev;



		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,

				sizeof(*sqsh_ino));

		if (err < 0)

			goto failed_read;



		if (type == SQUASHFS_LCHRDEV_TYPE)

			inode->i_mode |= S_IFCHR;

		else

			inode->i_mode |= S_IFBLK;

		xattr_id = le32_to_cpu(sqsh_ino->xattr);

		inode->i_op = &squashfs_inode_ops;

		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: {

	case SQUASHFS_SOCKET_TYPE: {

		struct squashfs_ipc_inode *sqsh_ino = &squashfs_ino.ipc;



		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
@@ -334,14 +374,52 @@ int squashfs_read_inode(struct inode *inode, long long ino) 
		init_special_inode(inode, inode->i_mode, 0);

		break;

	}

	case SQUASHFS_LFIFO_TYPE:

	case SQUASHFS_LSOCKET_TYPE: {

		struct squashfs_lipc_inode *sqsh_ino = &squashfs_ino.lipc;



		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,

				sizeof(*sqsh_ino));

		if (err < 0)

			goto failed_read;



		if (type == SQUASHFS_LFIFO_TYPE)

			inode->i_mode |= S_IFIFO;

		else

			inode->i_mode |= S_IFSOCK;

		xattr_id = le32_to_cpu(sqsh_ino->xattr);

		inode->i_op = &squashfs_inode_ops;

		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;

	}



	if (xattr_id != SQUASHFS_INVALID_XATTR && msblk->xattr_id_table) {

		err = squashfs_xattr_lookup(sb, xattr_id,

					&squashfs_i(inode)->xattr_count,

					&squashfs_i(inode)->xattr_size,

					&squashfs_i(inode)->xattr);

		if (err < 0)

			goto failed_read;

		inode->i_blocks += ((squashfs_i(inode)->xattr_size - 1) >> 9)

				+ 1;

	} else

		squashfs_i(inode)->xattr_count = 0;



	return 0;



failed_read:

	ERROR("Unable to read inode 0x%llx\n", ino);

	return err;

}





const struct inode_operations squashfs_inode_ops = {

	.getxattr = generic_getxattr,

	.listxattr = squashfs_listxattr

};

fs/squashfs/namei.c

+5 −1
Original line number Diff line number Diff line
@@ -57,11 +57,13 @@ 
#include <linux/slab.h>

#include <linux/string.h>

#include <linux/dcache.h>

#include <linux/xattr.h>



#include "squashfs_fs.h"

#include "squashfs_fs_sb.h"

#include "squashfs_fs_i.h"

#include "squashfs.h"

#include "xattr.h"



/*

 * Lookup name in the directory index, returning the location of the metadata
@@ -237,5 +239,7 @@ static struct dentry *squashfs_lookup(struct inode *dir, struct dentry *dentry, 




const struct inode_operations squashfs_dir_inode_ops = {

	.lookup = squashfs_lookup

	.lookup = squashfs_lookup,

	.getxattr = generic_getxattr,

	.listxattr = squashfs_listxattr

};