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4b5397dc PL |
1 | /* |
2 | * Squashfs - a compressed read only filesystem for Linux | |
3 | * | |
4 | * Copyright (c) 2010 | |
5 | * Phillip Lougher <phillip@lougher.demon.co.uk> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU General Public License | |
9 | * as published by the Free Software Foundation; either version 2, | |
10 | * or (at your option) any later version. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License | |
18 | * along with this program; if not, write to the Free Software | |
19 | * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. | |
20 | * | |
21 | * xattr_id.c | |
22 | */ | |
23 | ||
24 | /* | |
25 | * This file implements code to map the 32-bit xattr id stored in the inode | |
26 | * into the on disk location of the xattr data. | |
27 | */ | |
28 | ||
29 | #include <linux/fs.h> | |
30 | #include <linux/vfs.h> | |
31 | #include <linux/slab.h> | |
32 | ||
33 | #include "squashfs_fs.h" | |
34 | #include "squashfs_fs_sb.h" | |
4b5397dc | 35 | #include "squashfs.h" |
5f3b321d | 36 | #include "xattr.h" |
4b5397dc PL |
37 | |
38 | /* | |
39 | * Map xattr id using the xattr id look up table | |
40 | */ | |
41 | int squashfs_xattr_lookup(struct super_block *sb, unsigned int index, | |
aa5b1894 | 42 | int *count, unsigned int *size, unsigned long long *xattr) |
4b5397dc PL |
43 | { |
44 | struct squashfs_sb_info *msblk = sb->s_fs_info; | |
45 | int block = SQUASHFS_XATTR_BLOCK(index); | |
46 | int offset = SQUASHFS_XATTR_BLOCK_OFFSET(index); | |
47 | u64 start_block = le64_to_cpu(msblk->xattr_id_table[block]); | |
48 | struct squashfs_xattr_id id; | |
49 | int err; | |
50 | ||
51 | err = squashfs_read_metadata(sb, &id, &start_block, &offset, | |
52 | sizeof(id)); | |
53 | if (err < 0) | |
54 | return err; | |
55 | ||
56 | *xattr = le64_to_cpu(id.xattr); | |
57 | *size = le32_to_cpu(id.size); | |
58 | *count = le32_to_cpu(id.count); | |
59 | return 0; | |
60 | } | |
61 | ||
62 | ||
63 | /* | |
64 | * Read uncompressed xattr id lookup table indexes from disk into memory | |
65 | */ | |
66 | __le64 *squashfs_read_xattr_id_table(struct super_block *sb, u64 start, | |
67 | u64 *xattr_table_start, int *xattr_ids) | |
68 | { | |
69 | unsigned int len; | |
70 | __le64 *xid_table; | |
71 | struct squashfs_xattr_id_table id_table; | |
72 | int err; | |
73 | ||
74 | err = squashfs_read_table(sb, &id_table, start, sizeof(id_table)); | |
75 | if (err < 0) { | |
76 | ERROR("unable to read xattr id table\n"); | |
77 | return ERR_PTR(err); | |
78 | } | |
79 | *xattr_table_start = le64_to_cpu(id_table.xattr_table_start); | |
80 | *xattr_ids = le32_to_cpu(id_table.xattr_ids); | |
81 | len = SQUASHFS_XATTR_BLOCK_BYTES(*xattr_ids); | |
82 | ||
83 | TRACE("In read_xattr_index_table, length %d\n", len); | |
84 | ||
85 | /* Allocate xattr id lookup table indexes */ | |
86 | xid_table = kmalloc(len, GFP_KERNEL); | |
87 | if (xid_table == NULL) { | |
88 | ERROR("Failed to allocate xattr id index table\n"); | |
89 | return ERR_PTR(-ENOMEM); | |
90 | } | |
91 | ||
92 | err = squashfs_read_table(sb, xid_table, start + sizeof(id_table), len); | |
93 | if (err < 0) { | |
94 | ERROR("unable to read xattr id index table\n"); | |
95 | kfree(xid_table); | |
96 | return ERR_PTR(err); | |
97 | } | |
98 | ||
99 | return xid_table; | |
100 | } |