Project

General

Profile

BackupTheDataPartition » History » Version 30

Denis 'GNUtoo' Carikli, 11/10/2020 07:30 PM
Add Galaxy Tab 2

1 1 Denis 'GNUtoo' Carikli
h1. How to backup the data partition
2
3
{{toc}}
4
5
h2. /!\ Warning: Draft
6
7
This article is in draft form and is being written:
8
* Everybody is welcome to contribute
9
* Some things might not be accurate yet, so beware before using the information contained in it.
10
11 3 Denis 'GNUtoo' Carikli
h2. What does the data partition contains?
12 1 Denis 'GNUtoo' Carikli
13 8 Denis 'GNUtoo' Carikli
See [[DataPartition]] for more details.
14 1 Denis 'GNUtoo' Carikli
15
h2. Howto
16
17 23 Denis 'GNUtoo' Carikli
h2. Reserve some space
18
19
The data partition is often big as it contains space for user data. For instance on the Galaxy SIII (GT-I9300), its size is about 11.5GiB for the 16GiB versions of that device.
20
21
If you don't need to know precisely how much space it's going to take, you could make sure that you have as much space as the internal storage. For instance for a Galaxy SIII (GT-I9300) with 16GiB of internal storage, just make sure you have 16GiB of free space.
22
23
If instead you need to know the size more precisely (here 11.5GiB), you could look if your device's page has that information in its @Partition@ section. For instance the [[GalaxySIIIGTI9300|Galaxy SIII (GT-I9300)]] wiki page has a [[GalaxySIIIGTI9300#Partitions|Partitions section]] with the relevant information, but only for the 16GiB version of that device.
24
25
26 15 Denis 'GNUtoo' Carikli
h3. Setup ADB
27
28
Follow the instructions for [[ADB|setting up ADB on your computer]] so that you can access a root shell on your device.
29
30
*NOTE*: when prompted on your Replicant device, make sure that you check the box that says *Always allow from this computer* when you grant your computer USB debugging permissions. Otherwise, you will be unable to obtain root shell access on your Replicant device when you reboot it into the recovery OS to actually perform the backup.
31
32
*NOTE*: for security reasons, you may want to [[ADB#Revoking-all-computers-USB-debugging-permissions|revoke these non-expiring permissions]] once the backup is complete.
33
34
h3. Reboot into the recovery
35
36
To reboot in the recovery, you can follow the instructions in the [[RebootIntoTheRecovery]] wiki page.
37
38 16 Denis 'GNUtoo' Carikli
h3. Making sure that the data partition isn't mounted
39 1 Denis 'GNUtoo' Carikli
40
First, you need to make sure that the data partition is not mounted. 
41
42
To do that, you can run this command:
43
<pre>
44
adb shell "umount -l /data"
45
</pre>
46
47 18 Denis 'GNUtoo' Carikli
If the /data partition was mounted, it will unmount it, and your command and its output will look more or less like that:
48 1 Denis 'GNUtoo' Carikli
<pre>
49
$ adb shell "umount -l /data"
50
$ 
51
</pre>
52
53 18 Denis 'GNUtoo' Carikli
If it was not mounted, it will instead show an error that we can ignore. In this case your command and its output will look more or less like that:
54 1 Denis 'GNUtoo' Carikli
<pre>
55
$ adb shell "umount -l /data"
56
umount: /data: Invalid argument
57
</pre>
58
59 16 Denis 'GNUtoo' Carikli
h3. Backuping the data partition
60
61
Once we verified that the data partition isn't mounted, we can finally backup the partition.
62
63
h4. Galaxy S III (GT-I9300)
64
65
For the Galaxy S III (GT-I9300), you can use the following command:
66 1 Denis 'GNUtoo' Carikli
<pre>
67
adb pull /dev/block/platform/dw_mmc/by-name/USERDATA ./USERDATA.img
68 16 Denis 'GNUtoo' Carikli
</pre>
69
70 26 Denis 'GNUtoo' Carikli
h4. Galaxy Nexus (GT-I9250)
71
72
For the Galaxy Nexus (GT-I9250), you can use the following command:
73
<pre>
74
adb pull /dev/block/platform/omap/omap_hsmmc.0/by-name/userdata ./USERDATA.img
75
</pre>
76
77 30 Denis 'GNUtoo' Carikli
h4. Galaxy Tab 2 (GT-P3100, GT-P3110, GT-P5100, GT-P3510)
78
79
For the Tab 2 (GT-P3100, GT-P3110, GT-P5100, GT-P3510), you can use the following command:
80
81
<pre>
82
adb pull /dev/block/platform/omap/omap_hsmmc.1/by-name/DATAFS ./USERDATA.img
83
</pre>
84 26 Denis 'GNUtoo' Carikli
85 16 Denis 'GNUtoo' Carikli
h4. Other devices.
86
87
We don't have instructions yet for other devices yet.
88
89
Feel free to request instructions for the device you have on IRC, the mailing list, or to add the instructions here if you're confortable enough with the command line.
90 10 Denis 'GNUtoo' Carikli
91
h2. Using the backup
92
93
h3. Restoring the partition
94
95 27 Denis 'GNUtoo' Carikli
h4. Finding the real path of the partition
96
97 20 Denis 'GNUtoo' Carikli
Before we did command like that to backup the device:
98
<pre>
99
adb pull /dev/block/platform/dw_mmc/by-name/USERDATA ./USERDATA.img
100
</pre>
101
102 22 Denis 'GNUtoo' Carikli
However if we use the following command:
103
<pre>
104
adb push USERDATA.img /dev/block/platform/dw_mmc/by-name/USERDATA
105 1 Denis 'GNUtoo' Carikli
</pre>
106 22 Denis 'GNUtoo' Carikli
107 25 Denis 'GNUtoo' Carikli
It will fail to write any data to the partition: Instead of writing to it, it deletes the @/dev/block/platform/dw_mmc/by-name/USERDATA@ symlink and recreate a file at the same path with the data from USERDATA.img.
108 22 Denis 'GNUtoo' Carikli
109 25 Denis 'GNUtoo' Carikli
Since no data is being written on the disk, it most often ends up exhausting the ramdisk of the recovery (which is smaller than the data partition) and we are left with this error:
110 22 Denis 'GNUtoo' Carikli
<pre>
111 1 Denis 'GNUtoo' Carikli
adb: error: failed to copy 'USERDATA.img' to '/dev/block/platform/dw_mmc/by-name/USERDATA': remote No space left on device
112
USERDATA.img: 0 files pushed. 4.3 MB/s (436154368 bytes in 96.842s)
113
</pre>
114 22 Denis 'GNUtoo' Carikli
115 28 Denis 'GNUtoo' Carikli
So to avoid that we will need to find the path that symlink points to.
116 1 Denis 'GNUtoo' Carikli
117 27 Denis 'GNUtoo' Carikli
The sections below documents how to do if for various devices.
118
119
You should also really not skip that part, and make sure that the commands in these sections don't output any error. 
120
121
h5. Galaxy SIII (GT-I9300)
122
123
For the Galaxy SIII (GT-I9300) We can get the symlink path with the following command:
124 22 Denis 'GNUtoo' Carikli
<pre>
125
adb shell "readlink /dev/block/platform/dw_mmc/by-name/USERDATA"
126 1 Denis 'GNUtoo' Carikli
</pre>
127
128 27 Denis 'GNUtoo' Carikli
On my Galaxy SIII (GT-I9300), 16GiB version, it gives the following:
129 1 Denis 'GNUtoo' Carikli
<pre>
130 25 Denis 'GNUtoo' Carikli
/dev/block/mmcblk0p12
131 1 Denis 'GNUtoo' Carikli
</pre>
132
133
You will then need to down the result (here @/dev/block/mmcblk0p12@) as we will reuse it later.
134
135 27 Denis 'GNUtoo' Carikli
h5. Galaxy Nexus (GT-I9250)
136 1 Denis 'GNUtoo' Carikli
137 27 Denis 'GNUtoo' Carikli
For the Galaxy Nexus (GT-I9250) We can get the symlink path with the following command:
138
<pre>
139
adb shell "readlink /dev/block/platform/omap/omap_hsmmc.0/by-name/userdata"
140
</pre>
141 1 Denis 'GNUtoo' Carikli
142 27 Denis 'GNUtoo' Carikli
h5. Other devices
143
144
We don't have instructions yet for other devices yet.
145
146
Feel free to request instructions for the device you have on IRC, the mailing list, or to add the instructions here if you're confortable enough with the command line.
147
148
h5. Do not skip the sections above
149
150
If you skip the sections above and use the wrong partition, for instance if you blindly copy @/dev/block/mmcblk0p12@ from this tutorial instead of running the commands above and copying the result of these commands, you could end up breaking your device because some partitions are really needed for the device to work.
151
152
So make sure to do that right.
153
154
This is also why we have backup instructions (like [[BackupTheEFS]] ) to backup important partitions, however other partitions than the EFS are probably crucial too (but less susceptible to data corruption as they are not constantly written to).
155
156
h5. Actually restoring the partition
157 25 Denis 'GNUtoo' Carikli
158 29 Denis 'GNUtoo' Carikli
To restore the data partition, you could use the following command:
159 1 Denis 'GNUtoo' Carikli
<pre>
160 25 Denis 'GNUtoo' Carikli
adb push USERDATA.img /dev/block/PARTITION
161 22 Denis 'GNUtoo' Carikli
</pre>
162
163 25 Denis 'GNUtoo' Carikli
Make sure to replace @/dev/block/PARTITON@ with the data you just wrote down. The example above uses @/dev/block/mmcblk0p12@, but it might differ for your device, so make sure to replace @/dev/block/mmcblk0p12@ with the result you got on your device.
164
165
If everything goes fine, the output of the command above should look like this:
166 22 Denis 'GNUtoo' Carikli
<pre>
167 25 Denis 'GNUtoo' Carikli
USERDATA.img: 1 file pushed. 3.6 MB/s (1760559104 bytes in 466.067s)
168 10 Denis 'GNUtoo' Carikli
</pre>
169
170
h3. Restoring individual application data.
171
172
Here we will use the @udisksctl@ command instead of the more classical @mount@ and @losetup@ as it integrates better with graphical environments like Gnome or KDE.
173
174
As the partition backup is now in a file, to access its data we will make it available as a partition again. This can be done with the following command:
175
<pre>
176
udisksctl loop-setup -f  USERDATA.img
177
</pre>
178
179
If that doesn't work you might need to use @sudo@ like that:
180
<pre>
181
sudo udisksctl loop-setup -f  USERDATA.img
182
</pre>
183
184
Or you may also need to verify that your current users has the right to read and write the file that contains the partition (here USERDATA.img) file.
185
186
If this works, it should produce an output that looks more or less like that:
187
<pre>
188
Mapped file USERDATA.img as /dev/loop0.
189
</pre>
190 19 Denis 'GNUtoo' Carikli
191 10 Denis 'GNUtoo' Carikli
Here you can see that it made the file content available in the @/dev/loop0@ partition. 
192
193
We can then reuse this information to mount that partition. We can do that with the following command:
194
<pre>
195
udisksctl mount -b /dev/loop0 -o ro
196
</pre>
197
198
The @-o ro@ option will make sure that the partition is mounted in read only mode. This will make sure that we don't accidentally change its content.
199
200
The command above should produce an output that looks more or less like that:
201
<pre>
202
Mounted /dev/loop0 at /run/media/gnutoo/2Of967c7-ac7e-7ae0-ef5b-30f0b6e2dc41
203
</pre>
204
205
It most probably change a bit from the output above as:
206
* Your username is probably not @gnutoo@.
207
* The @2Of967c7-ac7e-7ae0-ef5b-30f0b6e2dc41@ is a randomly created identifier for the partition that is created when formatting it.
208
* Even @/run/media/@ can change depending on the GNU/Linux distribution and its version. For instance between Parabola and Trisquel 8 it is different.
209
210 1 Denis 'GNUtoo' Carikli
You can write down the location of the directory where this partition is mounted (here @/run/media/gnutoo/2Of967c7-ac7e-7ae0-ef5b-30f0b6e2dc41@) as we will need it later on.
211 19 Denis 'GNUtoo' Carikli
212
We will also reuse the partition location (here @/dev/loop0@) at the end.
213 10 Denis 'GNUtoo' Carikli
214
Now that this partition is mounted, we will be able to use the RestoreApplicationInternalData tutorial to make a backup of the data of a specific application and restore it.
215
216
To do that, locate the following command in the [[RestoreApplicationInternalData#Backuping-Silences-data-from-the-old-device|Backuping Silence's data from the old device]] section of the RestoreApplicationInternalData wiki page:
217 12 Denis 'GNUtoo' Carikli
<pre>
218 10 Denis 'GNUtoo' Carikli
cd /data/data
219
</pre>
220
221
You will then need to replace it by a command that looks like that:
222
<pre>
223
cd /run/media/gnutoo/2Of967c7-ac7e-7ae0-ef5b-30f0b6e2dc41/data/
224
</pre>
225
226
In the command above, you'll need to replace @/run/media/gnutoo/2Of967c7-ac7e-7ae0-ef5b-30f0b6e2dc41/@ by the location of the directory where the partition is mounted.
227
228
In addition you might not have the permissions to access the applications data. 
229 17 Denis 'GNUtoo' Carikli
230 1 Denis 'GNUtoo' Carikli
For instance we can look at the permissions of the silence data with the following command:
231 17 Denis 'GNUtoo' Carikli
<pre>
232
ls -ld org.smssecure.smssecure/
233
</pre>
234
235
And it should give you something that looks more or less like that:
236 11 Denis 'GNUtoo' Carikli
<pre>
237
drwxr-x--x 9 10063 10063 4096 26 oct.  19:44 org.smssecure.smssecure/
238 1 Denis 'GNUtoo' Carikli
</pre>
239 11 Denis 'GNUtoo' Carikli
240
See the [[RestoreApplicationInternalData#How-to-find-which-directory-holds-the-internal-data-of-an-application|How to find which directory holds the internal data of an application]] section in the RestoreApplicationInternalData wiki page for more details to understand why @org.smssecure.smssecure@ directory has the Silence application's data.
241
242
In the output above, the first @10063@ is the user ID and the second @10063@ is the group id. 
243
244
This is because Android sandboxes applications as part of their security model: each applications run in their own user and group ID. The result is that theses are most likely present on your phone but not on your GNU/Linux computer.
245 10 Denis 'GNUtoo' Carikli
246
To fix that you can become root with the following command:
247
<pre>
248
sudo su
249
</pre>
250 1 Denis 'GNUtoo' Carikli
251 19 Denis 'GNUtoo' Carikli
Now you can then continue to follow the RestoreApplicationInternalData tutorial.
252
253
h4. Unmount and close the loop
254
255
Once you are finished with the RestoreApplicationInternalData tutorial, it would be a good idea to umount the data partition and make it inaccessible again.
256
257
To umount the data partition we can use a command that looks like that:
258
<pre>
259
udisksctl unmount -b /dev/loop0
260
</pre>
261
Here the @/dev/loop0@ may differ, so make sure to use the partition location you used earlier.
262
263
The output of that command will look like that:
264
<pre>
265
Unmounted /dev/loop0.
266
</pre>
267
268
Once it is unmounted you can make it inaccessible again with the following command:
269
<pre>
270
udisksctl unmount -b /dev/loop0
271
</pre>
272
273
Again here may will need to replace @/dev/loop0@ by your partition location if it differs.
274
275
The output of that command should then show something that looks like that:
276
<pre>
277
Unmounted /dev/loop0.
278 1 Denis 'GNUtoo' Carikli
</pre>
279
280
h2. See also
281
282
* The [[BackupsResearch]] page has information on why the backup is done this way. It might also be useful to read and contribute to it if you intend to change the way the backups are done.