Managing a file system to avoid unnecessary replay of a transaction log

Patent metadata

Field	Value
Publication number	US-9542396-B1
Application number	US-201213728324-A
Country	US
Kind code	B1
Filing date	Dec 27, 2012
Priority date	Dec 27, 2012
Publication date	Jan 10, 2017
Grant date	Jan 10, 2017

Abstract

Managing a file system to avoid unnecessary replay of a transaction log. The file system may reside on a non-volatile storage medium having an associated transaction log residing on a non-volatile storage medium, the transaction log including a plurality of log entries, and each log entry representing one or more changes to metadata of the file system. The file system may include a first data structure including a status parameter, a value of which is indicative of whether to replay the transaction log when the file system is initialized. It may be determined whether the one or more changes to metadata represented by each of the plurality of log entries have been written in place in the file system. In response to the determination, the status parameter may be set to a value indicative of the determination.

First claim

What is claimed is:

1. For a file system residing on a non-volatile storage medium having an associated transaction log residing on a non-volatile storage medium, the transaction log including a plurality of log entries, each log entry representing one or more changes to metadata of the file system, the file system including a first data structure including a status parameter, a value of which is indicative of whether to replay the transaction log when the file system is initialized, a method comprising:
determining whether the one or more changes to metadata represented by each of the plurality of log entries have been written in place in the file system; and
in response to the determination, setting the status parameter to a value indicative of the determination.

2. The method of claim 1 , wherein the act of determining includes determining that the one or more changes to metadata represented by each of the plurality of log entries have been written in place in the file system,
wherein the act of setting includes setting the status parameter to a first value indicating to not replay the transaction log when the file system is initialized, and
wherein the method further comprises, during an initializing of the file system, refraining from replaying any portion of the metadata transaction log based on the first value.

3. The method of claim 1 , further comprising:
logging a first of the plurality of log entries in the transaction log,
wherein the act of determining includes determining, based at least in part on the logging, that the one or more changes to metadata represented by each of the plurality of log entries have not been written in place in the file system, and
wherein the act of setting includes setting the status parameter to a second value indicating to replay the transaction log when the file system is initialized.

4. The method of claim 3 , wherein the transaction log includes a plurality of sectors,
wherein the method further comprises providing a log use map including a plurality of map entries, each map entry corresponding to a respective one of the sectors, and each map entry having a value indicative of whether the respective sector has at least a portion of a log entry stored thereon for which the one or more metadata changes represented by the log entry have been written in place in the file system, a first of the plurality of map entries corresponding to a first of the plurality of sectors, the first sector having stored thereon at least a portion of the first log entry,
wherein the method further comprises, based at least in part on the logging, setting the first map entry to the second value, and
wherein the act of determining includes accessing the log use map.

5. The method of claim 3 , further comprising, after performing the acts of logging, determining and setting:
writing the one or more metadata changes corresponding to the first log entry in place in the file system;
based at least in part on the writing, determining that the one or more changes to metadata represented by each of the plurality of log entries have been written in place in the file system; and
setting the status parameter to a first value indicating to not replay the transaction log if the file system is initialized.

6. The method of claim 1 , further comprising:
writing the one or more metadata changes corresponding to a first of the plurality of log entries in place in the file system,
wherein the act of determining includes determining, based at least in part on the writing, that the one or more changes to metadata represented by each of the plurality of log entries have been written in place in the file system, and
wherein the act of setting includes setting the status parameter to a first value indicating to not replay the transaction log if the file system is initialized.

7. The method of claim 6 , wherein the transaction log includes a plurality of sectors,
wherein the method further comprises providing a log use map including a plurality of map entries, each map entry corresponding to a respective one of the sectors, and each map entry having a value indicative of whether the respective sector has at least a portion of a log entry stored thereon for which the one or more metadata changes represented by the log entry have been written in place in the file system, a first of the plurality of map entries corresponding to a first of the plurality of sectors, the first sector having stored thereon at least a portion of the first log entry,
wherein the method further comprises, based at least in part on the writing, setting the first map entry to the first value, and
wherein the act of determining includes accessing the log use map.

8. The method of claim 1 , further comprising:
providing a log use map indicating whether the transaction log includes one or more log entries for which the corresponding one or more metadata changes have not been written in place in the file system,
wherein the act of determining includes accessing the log use map.

9. The method of claim 8 , wherein the transaction log includes a plurality of sectors, and
wherein providing the log use map includes providing a plurality of map entries, each map entry corresponding to a respective one of the sectors, and each map entry having a value indicative of whether the respective sector has at least a portion of a log entry stored thereon for which the one or more metadata changes represented by the log entry have been written in place in the file system.

10. For a file system residing on a non-volatile storage medium having an associated transaction log residing on a non-volatile storage medium, the transaction log including a plurality of log entries, each log entry representing one or more changes to metadata of the file system, the file system including a first data structure including a status parameter, a value of which is indicative of whether to replay the transaction log when the file system is initialized, a system comprising:
first logic to determine whether the one or more changes to metadata represented by each of the plurality of log entries have been written in place in the file system; and
second logic to set the status parameter to a value indicative of the determination in response to the determination.

11. The system of claim 10 , wherein the first logic includes logic to determine that the one or more changes to metadata represented by each of the plurality of log entries have been written in place in the file system,
wherein the second logic includes logic to set the status parameter to a first value indicating to not replay the transaction log when the file system is initialized, and
wherein the system further comprises third logic to refrain from replaying any portion of the metadata transaction log based on the first value during an initializing of the file system.

12. The system of claim 10 , further comprising:
third logic to log a first of the plurality of log entries in the transaction log,
wherein the first logic includes logic to determine that the one or more changes to metadata represented by each of the plurality of log entries have not been written in place in the file system based at least in part on the logging, and
wherein the second logic includes setting the status parameter to a second value indicating to replay the transaction log when the file system is initialized.

13. The system of claim 12 , wherein the transaction log includes a plurality of sectors,
wherein the system further comprises a log use map including a plurality of map entries, each map entry corresponding to a respective one of the sectors, and ea

Assignees

• Emc Corp
• Emc Ip Holding Co Llc

Inventors

• Pawar Sitaram
• Bono Jean-Pierre
• Wang Yubing
• Kanteti Kumar V K H
• Sethi Pranit

Classifications

• G06F11/14

  Error detection or correction of the data by redundancy in operations (error detection or correction of the data by redundancy in hardware G06F11/16) · CPC title

• G06F11/1435

  using file system or storage system metadata · CPC title

• G06F11/1471

  involving logging of persistent data for recovery · CPC title

• G06F16/2358 Primary

  Change logging, detection, and notification (replication G06F16/27) · CPC title

• G06F17/30368

  Physics · mapped topic