squashfs: add xattr id support
authorPhillip Lougher <phillip@lougher.demon.co.uk>
Fri, 14 May 2010 19:48:47 +0000 (20:48 +0100)
committerPhillip Lougher <phillip@lougher.demon.co.uk>
Mon, 17 May 2010 18:54:05 +0000 (19:54 +0100)
This patch adds support for mapping xattr ids (stored in inodes)
into the on-disk location of the xattrs themselves.

Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
fs/squashfs/Makefile
fs/squashfs/squashfs.h
fs/squashfs/squashfs_fs.h
fs/squashfs/squashfs_fs_sb.h
fs/squashfs/super.c
fs/squashfs/xattr_id.c [new file with mode: 0644]

index df8a19e..c0da4a1 100644 (file)
@@ -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-y += xattr_id.o
+
index fe2587a..133befe 100644 (file)
@@ -73,6 +73,12 @@ extern struct inode *squashfs_iget(struct super_block *, long long,
                                unsigned int);
 extern int squashfs_read_inode(struct inode *, long long);
 
+/* xattr_id.c */
+extern int squashfs_xattr_lookup(struct super_block *, unsigned int, int *,
+                               int *, long long *);
+extern __le64 *squashfs_read_xattr_id_table(struct super_block *, u64,
+                               u64 *, int *);
+
 /*
  * Inodes, files and decompressor operations
  */
index 7902424..c654e86 100644 (file)
 
 #define SQUASHFS_ID_BLOCK_BYTES(A)     (SQUASHFS_ID_BLOCKS(A) *\
                                        sizeof(u64))
+/* xattr id lookup table defines */
+#define SQUASHFS_XATTR_BYTES(A)                ((A) * sizeof(struct squashfs_xattr_id))
+
+#define SQUASHFS_XATTR_BLOCK(A)                (SQUASHFS_XATTR_BYTES(A) / \
+                                       SQUASHFS_METADATA_SIZE)
+
+#define SQUASHFS_XATTR_BLOCK_OFFSET(A) (SQUASHFS_XATTR_BYTES(A) % \
+                                       SQUASHFS_METADATA_SIZE)
+
+#define SQUASHFS_XATTR_BLOCKS(A)       ((SQUASHFS_XATTR_BYTES(A) + \
+                                       SQUASHFS_METADATA_SIZE - 1) / \
+                                       SQUASHFS_METADATA_SIZE)
+
+#define SQUASHFS_XATTR_BLOCK_BYTES(A)  (SQUASHFS_XATTR_BLOCKS(A) *\
+                                       sizeof(u64))
+#define SQUASHFS_XATTR_BLK(A)          ((unsigned int) ((A) >> 16))
+
+#define SQUASHFS_XATTR_OFFSET(A)       ((unsigned int) ((A) & 0xffff))
 
 /* cached data constants for filesystem */
 #define SQUASHFS_CACHED_BLKS           8
@@ -228,7 +246,7 @@ struct squashfs_super_block {
        __le64                  root_inode;
        __le64                  bytes_used;
        __le64                  id_table_start;
-       __le64                  xattr_table_start;
+       __le64                  xattr_id_table_start;
        __le64                  inode_table_start;
        __le64                  directory_table_start;
        __le64                  fragment_table_start;
@@ -377,4 +395,16 @@ struct squashfs_fragment_entry {
        unsigned int            unused;
 };
 
+struct squashfs_xattr_id {
+       __le64                  xattr;
+       __le32                  count;
+       __le32                  size;
+};
+
+struct squashfs_xattr_id_table {
+       __le64                  xattr_table_start;
+       __le32                  xattr_ids;
+       __le32                  unused;
+};
+
 #endif
index 2e77dc5..d9037a5 100644 (file)
@@ -61,6 +61,7 @@ struct squashfs_sb_info {
        int                                     next_meta_index;
        __le64                                  *id_table;
        __le64                                  *fragment_index;
+       __le64                                  *xattr_id_table;
        struct mutex                            read_data_mutex;
        struct mutex                            meta_index_mutex;
        struct meta_index                       *meta_index;
@@ -68,9 +69,11 @@ struct squashfs_sb_info {
        __le64                                  *inode_lookup_table;
        u64                                     inode_table;
        u64                                     directory_table;
+       u64                                     xattr_table;
        unsigned int                            block_size;
        unsigned short                          block_log;
        long long                               bytes_used;
        unsigned int                            inodes;
+       int                                     xattr_ids;
 };
 #endif
index 48b6f4a..c4dfc39 100644 (file)
@@ -36,6 +36,7 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/magic.h>
+#include <linux/xattr.h>
 
 #include "squashfs_fs.h"
 #include "squashfs_fs_sb.h"
@@ -82,7 +83,7 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
        long long root_inode;
        unsigned short flags;
        unsigned int fragments;
-       u64 lookup_table_start;
+       u64 lookup_table_start, xattr_id_table_start;
        int err;
 
        TRACE("Entered squashfs_fill_superblock\n");
@@ -143,7 +144,7 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
         * Check if there's xattrs in the filesystem.  These are not
         * supported in this version, so warn that they will be ignored.
         */
-       if (le64_to_cpu(sblk->xattr_table_start) != SQUASHFS_INVALID_BLK)
+       if (le64_to_cpu(sblk->xattr_id_table_start) != SQUASHFS_INVALID_BLK)
                ERROR("Xattrs in filesystem, these will be ignored\n");
 
        /* Check the filesystem does not extend beyond the end of the
@@ -253,7 +254,7 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
 allocate_lookup_table:
        lookup_table_start = le64_to_cpu(sblk->lookup_table_start);
        if (lookup_table_start == SQUASHFS_INVALID_BLK)
-               goto allocate_root;
+               goto allocate_xattr_table;
 
        /* Allocate and read inode lookup table */
        msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb,
@@ -266,6 +267,19 @@ allocate_lookup_table:
 
        sb->s_export_op = &squashfs_export_ops;
 
+allocate_xattr_table:
+       xattr_id_table_start = le64_to_cpu(sblk->xattr_id_table_start);
+       if (xattr_id_table_start == SQUASHFS_INVALID_BLK)
+               goto allocate_root;
+
+       /* Allocate and read xattr id lookup table */
+       msblk->xattr_id_table = squashfs_read_xattr_id_table(sb,
+               xattr_id_table_start, &msblk->xattr_table, &msblk->xattr_ids);
+       if (IS_ERR(msblk->xattr_id_table)) {
+               err = PTR_ERR(msblk->xattr_id_table);
+               msblk->xattr_id_table = NULL;
+               goto failed_mount;
+       }
 allocate_root:
        root = new_inode(sb);
        if (!root) {
@@ -301,6 +315,7 @@ failed_mount:
        kfree(msblk->inode_lookup_table);
        kfree(msblk->fragment_index);
        kfree(msblk->id_table);
+       kfree(msblk->xattr_id_table);
        kfree(sb->s_fs_info);
        sb->s_fs_info = NULL;
        kfree(sblk);
@@ -355,6 +370,7 @@ static void squashfs_put_super(struct super_block *sb)
                kfree(sbi->fragment_index);
                kfree(sbi->meta_index);
                kfree(sbi->inode_lookup_table);
+               kfree(sbi->xattr_id_table);
                kfree(sb->s_fs_info);
                sb->s_fs_info = NULL;
        }
diff --git a/fs/squashfs/xattr_id.c b/fs/squashfs/xattr_id.c
new file mode 100644 (file)
index 0000000..a741012
--- /dev/null
@@ -0,0 +1,100 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2010
+ * 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.
+ *
+ * xattr_id.c
+ */
+
+/*
+ * This file implements code to map the 32-bit xattr id stored in the inode
+ * into the on disk location of the xattr data.
+ */
+
+#include <linux/fs.h>
+#include <linux/vfs.h>
+#include <linux/slab.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs_fs_i.h"
+#include "squashfs.h"
+
+/*
+ * Map xattr id using the xattr id look up table
+ */
+int squashfs_xattr_lookup(struct super_block *sb, unsigned int index,
+               int *count, int *size, long long *xattr)
+{
+       struct squashfs_sb_info *msblk = sb->s_fs_info;
+       int block = SQUASHFS_XATTR_BLOCK(index);
+       int offset = SQUASHFS_XATTR_BLOCK_OFFSET(index);
+       u64 start_block = le64_to_cpu(msblk->xattr_id_table[block]);
+       struct squashfs_xattr_id id;
+       int err;
+
+       err = squashfs_read_metadata(sb, &id, &start_block, &offset,
+                                                       sizeof(id));
+       if (err < 0)
+               return err;
+
+       *xattr = le64_to_cpu(id.xattr);
+       *size = le32_to_cpu(id.size);
+       *count = le32_to_cpu(id.count);
+       return 0;
+}
+
+
+/*
+ * Read uncompressed xattr id lookup table indexes from disk into memory
+ */
+__le64 *squashfs_read_xattr_id_table(struct super_block *sb, u64 start,
+               u64 *xattr_table_start, int *xattr_ids)
+{
+       unsigned int len;
+       __le64 *xid_table;
+       struct squashfs_xattr_id_table id_table;
+       int err;
+
+       err = squashfs_read_table(sb, &id_table, start, sizeof(id_table));
+       if (err < 0) {
+               ERROR("unable to read xattr id table\n");
+               return ERR_PTR(err);
+       }
+       *xattr_table_start = le64_to_cpu(id_table.xattr_table_start);
+       *xattr_ids = le32_to_cpu(id_table.xattr_ids);
+       len = SQUASHFS_XATTR_BLOCK_BYTES(*xattr_ids);
+
+       TRACE("In read_xattr_index_table, length %d\n", len);
+
+       /* Allocate xattr id lookup table indexes */
+       xid_table = kmalloc(len, GFP_KERNEL);
+       if (xid_table == NULL) {
+               ERROR("Failed to allocate xattr id index table\n");
+               return ERR_PTR(-ENOMEM);
+       }
+
+       err = squashfs_read_table(sb, xid_table, start + sizeof(id_table), len);
+       if (err < 0) {
+               ERROR("unable to read xattr id index table\n");
+               kfree(xid_table);
+               return ERR_PTR(err);
+       }
+
+       return xid_table;
+}