CN103853850B - Method and system for eliminating data for user-centered Android system - Google Patents
Method and system for eliminating data for user-centered Android system Download PDFInfo
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- CN103853850B CN103853850B CN201410123655.8A CN201410123655A CN103853850B CN 103853850 B CN103853850 B CN 103853850B CN 201410123655 A CN201410123655 A CN 201410123655A CN 103853850 B CN103853850 B CN 103853850B
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F16/00—Information retrieval; Database structures therefor; File system structures therefor
- G06F16/10—File systems; File servers
- G06F16/16—File or folder operations, e.g. details of user interfaces specifically adapted to file systems
- G06F16/162—Delete operations
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/06—Digital input from, or digital output to, record carriers, e.g. RAID, emulated record carriers or networked record carriers
- G06F3/0601—Interfaces specially adapted for storage systems
- G06F3/0628—Interfaces specially adapted for storage systems making use of a particular technique
- G06F3/0646—Horizontal data movement in storage systems, i.e. moving data in between storage devices or systems
- G06F3/0652—Erasing, e.g. deleting, data cleaning, moving of data to a wastebasket
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Abstract
The invention provides a method and system for eliminating data for a user-centered Android system. The method comprises the following steps: 1, inputting file information of an object to be processed by the user, and reversely scanning all object head pages matched with the file information; 2, judging according to the object head information matched in the step 1 and correspondingly operating the object to be processed; 3, calling a write operation function of a file system, and performing full zero overwrite on a target surface of the object to be processed according to the block number and physical page address stored in the step 2; 4, checking whether effective pages of other files exist in target blocks of the object to be processed, and performing corresponding processing; and 5, triggering a garbage collection mechanism of the file system, recovering the target blocks according to the block number, and inserting the target blocks into a free block linked list to serve as a distributable storage space for reutilization. According to the system, the storage space of the object files can be recovered, and the utilization rate of the storage space is improved.
Description
Technical field
The present invention relates to Android technical field of intelligence, the android system data of more particularly, to a kind of user-center
Sweep-out method and system.
Background technology
With the extensive application of Android intelligent platform of new generation, increasing user profile data is had to be stored in
On the Flash flash memory of Android intelligent terminal, the such as data such as address list, note, picture, memorandum, the sensitivity wherein comprising
Property information, significant data, user would generally be deleted using common deletion action and prevent leaking data.But common deletes
Data is not deleted from storage medium by division operation, simply the file system modification object page be designated idle condition or
Delete the index of file, deleted file is not presented to operating system and user；Common formatting does not interfere with yet deposits
Data on storage media, only creates an empty file index for operating system, allows operating system to think on storage medium
There is no file.In this case, can be by logical method or physical method and deleted data recovery, do not ensure that
User data is not compromised.The least unit of flash memory write operation is page, but erasing operation is using block as least unit, so storage
Medium release physically will wait until that in a block, all pages all become idle condition, and file system just can carry out garbage reclamation
This block is wiped.
Android adopts nand flash memory as kernel memory, and YAFFS2 is the log type literary composition aiming at nand flash memory design
Part system, has some characteristics different from alternative document system.Flash data logic destroys technology at present mainly zero overriding
Technology, block deleting technique, and encryption technology, but search for page to be deleted when be all not bound with file system data structure and
Memory mechanism is considering time performance.
Content of the invention
For solve above-mentioned deficiency, the present invention provide a kind of customer-centric android system data clearing method and
System.
The android system data clearing method of the customer-centric of the present invention, it includes：
Step 1, the fileinfo of the pending object of user input, all objects of inverted order scanning and this document information matches
The head page；
Step 2, judges described pending object according to the object header of described step 1 coupling：
If the type of described pending object is file, according to this document at Parent_Objectid inverted order scanning
The all page of data comprising under folder, this all page of data is the ID identical page with the object head page in described step 1
Face；Obtain block sequence number and the page physical address of described all page of data, and it is stored in respectively array block [m] and
In adress [n]；
If the type of described pending object is ordinary file, finds, with the object head page in described step 1, there is phase
With the page of Objectid, this Objectid is the unique ID number for the obj ect file belonging to identified page；Obtain described page
The block sequence number in face and page physical address, and it is stored in respectively in array block [m] and adress [n]；
Step 3, calls the write operation function of file system, and the block sequence number according to the storage of described step 2 and the page are physically
The target pages of described pending object are carried out complete zero overriding by location；
Whether step 4, have in the object block checking the described pending object after processing through step 3 and there are other files
The effectively page：
If there is effective page, by this effective page be dumped to other less than block on；
If there is not effective page, directly execution step 5；
Step 5, the garbage reclamation mechanism of triggering file system, according to the block sequence number of storage, object block is reclaimed, and should
Object block is inserted in free block chained list, waits as assignable memory space and recycling.
The android system data dump system of the customer-centric of the present invention, it includes：
Input matching module, the fileinfo of the pending object of user input, inverted order scanning and this document information matches
All object head pages；
First processing module, judges described pending object according to the object header of described input matching module coupling：
If the type of described pending object is file, according to this document at Parent_Objectid inverted order scanning
The all page of data comprising under folder, this all page of data is the ID phase with the object head page in described first processing module
The same page；Obtain block sequence number and the page physical address of described all page of data, and it is stored in respectively array block
In [m] and adress [n]；
If the type of described pending object is ordinary file, find and the object head page in described first processing module
There is the page of identical Objectid, this Objectid is the unique ID number for the obj ect file belonging to identified page；Obtain
The block sequence number of the described page and page physical address, and it is stored in respectively in array block [m] and adress [n]；
Overriding module, call the write operation function of file system, according to described first processing module storage block sequence number and
The target pages of described pending object are carried out complete zero overriding by page physical address；
Whether Second processing module, have in the object block checking the described pending object after described overriding resume module
There is effective page of other files：
If there is effective page, by this effective page be dumped to other less than block on；
If there is not effective page, directly execute recycling module；
Recycling module, the garbage reclamation mechanism of triggering file system, according to the block sequence number of storage, object block is reclaimed, and will
This object block is inserted in free block chained list, waits as assignable memory space and recycling.
The beneficial effects of the present invention is：
The memory space of energy recycle object file of the present invention, improves memory space utilization rate.
Brief description
Fig. 1 is to page of data in the android system data clearing method of customer-centric of the present invention and system
Operation chart；
Fig. 2 is the android system data clearing method flow chart of the customer-centric of the present invention；
Fig. 3 be in the android system data clearing method of customer-centric of the present invention and system file with general
The relation schematic diagram of logical file；
Fig. 4 is the android system data dump system schematic of the customer-centric of the present invention.
Specific embodiment
Fig. 2 is the android system data clearing method flow chart of the customer-centric of the present invention.As shown in Fig. 2 this
The android system data clearing method of the customer-centric of invention, it includes：
Step 1, the fileinfo of the pending object of user input, all objects of inverted order scanning and this document information matches
The head page；
Step 2, judges described pending object according to the object header of described step 1 coupling：
If the type of described pending object is file, according to this document at Parent_Objectid inverted order scanning
The all page of data comprising under folder, this all page of data is the ID identical page with the object head page in described step 1
Face；Obtain block sequence number and the page physical address of described all page of data, and it is stored in respectively array block [m] and
In adress [n]；
If the type of described pending object is ordinary file, finds, with the object head page in described step 1, there is phase
With the page of Objectid, this Objectid is used for the unique ID number of the obj ect file belonging to identified page；Obtain this page
Block sequence number and page physical address, and it is stored in respectively in array block [m] and adress [n]；
Step 3, calls the write operation function of file system, and the block sequence number according to the storage of described step 2 and the page are physically
The target pages of described pending object are carried out complete zero overriding by location；
Whether step 4, have the other literary composition of presence in the object block checking the described pending object after the overriding of described step 3
Effective page of part：
If there is effective page, by this effective page be dumped to other less than block on；
If there is not effective page, directly execution step 5；
Step 5, the garbage reclamation mechanism of triggering file system, according to block sequence number, object block is reclaimed, and by this object block
It is inserted in free block chained list, wait as assignable memory space and recycling.
Fig. 4 is the android system data dump system schematic of the customer-centric of the present invention.As shown in figure 4, this
The android system data dump system of the customer-centric of invention, it includes：
Input matching module 101, the fileinfo of the pending object of user input, inverted order scanning and this document information matches
All object head pages；
First processing module 102, judges described pending according to the object header of described input matching module 101 coupling
Object：
If the type of described pending object is file, according to this document at Parent_Objectid inverted order scanning
The all page of data comprising under folder, this all page of data is the ID with the object head page in described input matching module 101
Number identical page；Obtain block sequence number and the page physical address of described all page of data, and it is stored in respectively array
In block [m] and adress [n]；
If the type of described pending object is ordinary file, find and object head in described input matching module 101
The page has the page of identical Objectid, and this Objectid is used for the unique ID number of the obj ect file belonging to identified page；Obtain
Take block sequence number and the page physical address of this page, and it is stored in respectively in array block [m] and adress [n]；
Overriding module 103, calls the write operation function of file system, according to the block of described first processing module 102 storage
The target pages of described pending object are carried out complete zero overriding by sequence number and page physical address；
Second processing module 104, checks in the object block of the described pending object after processing through described overriding module 103
Whether there is the effective page that there are other files：
If there is effective page, by this effective page be dumped to other less than block on；
If there is not effective page, directly execute recycling module 105；
Recycling module 105, the garbage reclamation mechanism of triggering file system, according to block sequence number, object block is reclaimed, and should
Object block is inserted in free block chained list, waits as assignable memory space and recycling.
The invention provides a kind of YAFFS2 file system widely used for Android intelligent platform, from user angle
Degree sets out, and the method removing nand flash memory data, to protect user sensitive information and significant data not compromised.Different from common
Deletion action, this method combine YAFFS2 file system data structure data access method, using inverted order scanning algorithm
The file deleted to search for user to want, then calls write operation and the block erasing operation of file system, by data from flash memory
Remove it is impossible to be recovered by logical method.The file that can remove not only includes simple binary stream file, also includes
The strong jpeg file of structural comparing and pdf file etc., ensure that the security of various types of user data.
The Android data clearing method of customer-centric, mainly includes user interface, page to be deleted search, data
Removing, space reclamation Four processes.The first step, user input will delete the information of file, filename, file type.Second step,
Search for page to be deleted.Specifically searching method is：Using inverted order scanning algorithm, from the beginning of largest block sequence number, according to user input
The filename elder generation sweep object head page.The characteristic being updated due to nand flash memory strange land, the file of modified operation has difference
Old version is present on flash memory, so the file header page searching may be one or more.According in the object head page
ObjectID search all page of data of file.
The bit manipulation of nand flash memory can only be changed into 0 from 1, and the 3rd step is then that the page of data execution complete zero searching is covered
Write.After executing complete zero overriding, if storing effective page of alternative document in the block at page of data place to be deleted,
Need for active page to be dumped to other blocks, then block erasing operation is executed to object block, as shown in Figure 1.Execution erasing operation it
Afterwards, trigger the garbage reclamation mechanism of file system, object block is reclaimed, in insertion free block chained list, wait again as storage
Space utilization simultaneously distributes a new block sequence number.
Not only store substantial amounts of user data in android system, also include system itself, application program is run and produced
Data etc., page to be deleted to be searched by scanning the method for whole nand flash memory, time overhead is than larger.
Present embodiment is to load the Android intelligence of YAFFS2 file system using using nand flash memory as storage medium
As a example energy mobile phone, provide a kind of user data sweep-out method of customer-centric, and the memory space of energy recycle object file,
Improve memory space utilization rate.
Two kinds of different pages are had in YAFFS2 file system：Page of data（Data chunk）With the object head page
（Object header）, for the data content of storage object, the object head page is then used for the class of storage object to page of data
Type, file size, object name, the establishment of object, modification time etc..Corresponding data structure yaffs_ of object head
ObjectHeader includes member to be had（Only include the member for explaining the present invention）：
Yaffs_ObjectType type;The type of // explanation object（File, catalogue etc.）
int parentObjectid;No. ID of // parent directory
YCHAR name[YAFFS_MAX_NAME_lenth+1];// object name
Can judge that currently object to be dealt with is as ordinary file or file according to the type field in object head.As
Shown in Fig. 3, Fig. 3 is the relation between file and its subfile.
Page search to be deleted is to scan successively from the data BOB(beginning of block) with largest block sequence number, to each block from this block
Following page begins stepping through to first page, and concrete scanning algorithm step is as follows：
（1）Scanning BlockN；
（2）PageM in scanning current block；If PageM is first page in current block, go to（4）；
（3）M=M-1, goes to（2）；
（4）If current block block is smallest blocks in current block, the end of scan；
（5）N=N-1, goes to（1）.
User-in file name, all object head pages that inverted order scanning is mated with file name, if believe according to object head
Breath judges pending object for ordinary file, then find and have the page of identical Objectid and obtain them with the object head page
Block sequence number and Chunkid, wherein Objectid be used for identified page belonging to obj ect file unique ID number.Nand flash memory battle array
Row be divided into a series of block, each block comprises 32 or 64 or 128 pages, each page all comprise 2048kb data field and
The free area of 64kb.Initialization int type array block [m] and adress [n] are respectively intended to deposit the block sequence number getting and page
The physical address in face.If object type is file, inverted order scans for all Parent_Objectid and object in the first step
The ID identical page of the head page, the same block sequence number obtaining them and page physical address, are stored in array block respectively
[m] and adress [n], now the traversal gained page is the All Files under currently pending file.YAFFS2 file system
In data storage in strict accordance with order-assigned block sequence number, whenever one block of new distribution, block sequence number adds 1, all pages in this block
This part sequence number is shared in face.So adopting above inverted order traversal method, it is the equal of the distribution time inverted order fully according to the page
Traversal, therefore save sweep time.
Call the write operation function of file system, the block sequence number according to earlier stored and page physical address are by target pages
Carry out complete zero overriding.Because the erasing operation of YAFFS2 is executed with block for least unit, before carrying out erasing operation, should
First check in this block, whether there is the effective page belonging to other files.If having, these pages be dumped to flash memory other less than
Block on.Then just can trigger the garbage reclamation mechanism of file system, according to block sequence number, object block be reclaimed, be inserted into the free time
In block chained list, wait as assignable memory space and recycling.
Only as described above, only presently preferred embodiments of the present invention, professional who are familiar with this art such as.?
After understanding the technological means of the present invention, natural energy, according to actual needs, is changed under the teachings of the present invention.Therefore all
The equal change made according to scope of the present invention patent and modification, all should still remain within the scope of the patent.
Claims (2)
1. a kind of android system data clearing method of customer-centric is it is characterised in that include：
Step 1, the fileinfo of the pending object of user input, all object head pages of inverted order scanning and this document information matches
Face；It is distribution time inverted order traverse scanning according to the page that described inverted order scans；
Step 2, judges described pending object according to the object header of described step 1 coupling：
If the type of described pending object is file, the lower bag of this document folder is scanned according to Parent_Objectid inverted order
The all page of data containing, this all page of data is the ID identical page with the object head page in described step 1；Obtain
The block sequence number of described all page of data and page physical address, and it is stored in respectively array block [m] and adress
In [n]；
If the type of described pending object be ordinary file, find with the object head page in described step 1 have identical
The page of Objectid, this Objectid is the unique ID number for the obj ect file belonging to identified page；Obtain the described page
Block sequence number and page physical address, and it is stored in respectively in array block [m] and adress [n]；
Step 3, calls the write operation function of file system, and the block sequence number according to the storage of described step 2 and page physical address will
The target pages of described pending object carry out complete zero overriding；
Whether step 4, have the effective page that there are other files in the object block checking described pending object：
If there is effective page, by this effective page be dumped to other less than block on；
If there is not effective page, directly execution step 5；
Step 5, the garbage reclamation mechanism of triggering file system, according to the block sequence number of storage, object block is reclaimed, and by this target
Block is inserted in free block chained list, waits as assignable memory space and recycling.
2. a kind of android system data dump system of customer-centric is it is characterised in that include：
Input matching module, the fileinfo of the pending object of user input, inverted order scanning is all with this document information matches
The object head page；It is distribution time inverted order traverse scanning according to the page that described inverted order scans；
First processing module, judges described pending object according to the object header of described input matching module coupling：
If the type of described pending object is file, scanned under this document folder according to Parent_Objectid inverted order
The all page of data comprising, this all page of data is the ID identical page with the object head page in step 1；Obtain institute
State block sequence number and the page physical address of all page of data, and it is stored in respectively array block [m] and adress [n]
Interior；
If the type of described pending object be ordinary file, find with the object head page in step 1 have identical
The page of Objectid, this Objectid is the unique ID number for the obj ect file belonging to identified page；Obtain the described page
Block sequence number and page physical address, and it is stored in respectively in array block [m] and adress [n]；
Overriding module, call the write operation function of file system, according to described first processing module storage block sequence number and the page
The target pages of described pending object are carried out complete zero overriding by physical address；
Whether Second processing module, have the effective page that there are other files in the object block checking described pending object：
If there is effective page, by this effective page be dumped to other less than block on；
If there is not effective page, directly execute recycling module；
Recycling module, the garbage reclamation mechanism of triggering file system, according to the block sequence number of storage, object block is reclaimed, and by this mesh
Mark block is inserted in free block chained list, waits as assignable memory space and recycling.
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| CN107943804A (en) * | 2016-10-12 | 2018-04-20 | 中标软件有限公司 | The system and method for data is periodically deleted on mobile terminal |
| CN116860658B (en) * | 2023-06-21 | 2024-05-28 | 中国科学院软件研究所 | Efficient semi-automatic garbage collection method and system for big data processing frame |
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| CN101206656B (en) * | 2006-12-22 | 2010-05-19 | 英业达股份有限公司 | File safety deletion system and method |
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| CN101206656B (en) * | 2006-12-22 | 2010-05-19 | 英业达股份有限公司 | File safety deletion system and method |
| CN101488153A (en) * | 2009-02-12 | 2009-07-22 | 浙江大学 | Method for implementing high-capacity flash memory file system in embedded type Linux |
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Effective date of registration: 20170803 Address after: 518026 C, building 31B, electronic technology building, No. 2070 Shennan Road, Shenzhen, Guangdong, Futian District Patentee after: Shenzhen City, the number of principal Yuan Science and Technology Co Ltd Address before: 100124 Chaoyang District, Beijing Ping Park, No. 100 Patentee before: Beijing University of Technology |
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Inventor after: Zhao Bin Inventor after: Huang Na Inventor after: Zhang Yuqiang Inventor after: He Jingsha Inventor after: Liu Gongzheng Inventor after: Wan Xuejiao Inventor before: He Jingsha Inventor before: Huang Na Inventor before: Zhang Yuqiang Inventor before: Zhao Bin Inventor before: Liu Gongzheng Inventor before: Wan Xuejiao |