Method and device for file system log
Embodiments of the present disclosure provide a method and device for a file system log. In some embodiments, there is provided a computer-implemented method. The method comprises: in response to receiving a write request for metadata associated with a first transaction, determining at least one zone associated with the first transaction from a plurality of zones of the metadata, the plurality of zones being formed by striping the metadata; requesting a resource slice for the at least one zone from a resource pool of a logging system; and recording to the resource slice a log that the first transaction modifies the at least one zone.
1. A computer-implemented method, comprising:
in response to receiving a write request for metadata associated with a first transaction, determining at least a first zone and a second zone associated with the first transaction from a plurality of zones of the metadata, the plurality of zones being formed by striping the metadata;
requesting at least one resource slice for the at least one zone from a resource pool of a logging system; and
recording to the at least one resource slice at least one log indicating that the first transaction modifies the first zone and the second zone, wherein recording to the at least one resource slice the at least one log includes:
in response to determining that there is no buffer queue of logs to be recorded in a first resource slice associated with the first zone and there is a buffer queue of logs to be recorded in a second resource slice associated with the second zone,
recording both a first log associated with the first zone and a second log associated with the second zone to the first resource slice,
generating a first dummy for the second log, wherein the first dummy indicates that the first transaction modified the second zone, exists only in memory, and specifies modifications to the second zone made by the first transaction, and
adding the first dummy into the buffer queue associated with the second resource slice.
2. The method of claim 1 , wherein recording to the resource slice the log comprises:
determining a size of the log to be stored; and
in response to the size of the log being smaller than a predetermined threshold, adding the log into a buffer queue associated with the resource slice.
3. The method of claim 2 , further comprising:
determining whether a total size of logs to be recorded included in the buffer queue reaches the threshold; and
in response to the total size reaching the threshold, recording the logs to be recorded in the buffer queue to the resource slice.
4. The method of claim 1 , wherein the at least one zone at least comprises a first zone and a second zone, and wherein recording to the resource slice the log includes:
receiving a write request for metadata associated with a second transaction, the second transaction having a larger transaction sequence number than the first transaction; and
in response to a buffer queue of logs to be recorded in the first resource slice including the log and a second dummy indicating that the second transaction modified the first zone, and to presence of the first dummy in a buffer queue of logs to be recorded in the second resource slice and a log indicating the second transaction modified the first and second zones, recording to the first resource slice a part of a buffer queue of logs to be recorded in the first resource slice excluding the second dummy.
5. The method of claim 1 , further comprising:
releasing the resource slice by flushing the log recorded to the resource slice to a solid-state storage device.
6. The method of claim 1 , wherein the at least one zone has an allocated incremental super block, the incremental super block recording usage of a respective disk zone, the method further comprising:
in response to a modification of the at least one zone by the first transaction, modifying the incremental super block; and
flushing the incremental super block into a base super block associated with the plurality of zones at a predetermined time interval.
7. An electronic device, comprising:
at least one processor; and
a memory coupled to the at least one processor and having instructions stored thereon, the instructions, when executed by the at least one processor, causing the device to perform acts comprising:
in response to receiving a write request for metadata associated with a first transaction, determining at least a first zone and a second zone associated with the first transaction from a plurality of zones of the metadata, the plurality of zones being formed by striping the metadata;
requesting at least one resource slice for the at least one zone from a resource pool of a logging system; and
recording to the at least one resource slice at least one log indicating that the first transaction modifies the first zone and the second zone, wherein recording to the at least one resource slice the at least one log includes:
in response to determining that there is no buffer queue of logs to be recorded in a first resource slice associated with the first zone and there is a buffer queue of logs to be recorded in a second resource slice associated with the second zone,
recording both a first log associated with the first zone and a second log associated with the second zone to the first resource slice,
generating a first dummy for the second log, wherein the first dummy indicates that the first transaction modified the second zone, exists only in memory, and specifies modifications to the second zone made by the first transaction, and
adding the first dummy into the buffer queue associated with the second resource slice.
8. The device of claim 7 , wherein recording the log to the resource slice comprises:
determining a size of the log to be stored; and
in response to the size of the log being smaller than a predetermined threshold, adding the log into a buffer queue associated with the resource slice.
9. The device of claim 8 , wherein the acts further comprise:
determining whether a total size of logs to be recorded included in the buffer queue reaches the threshold; and
in response to the total size reaching the threshold, recording the logs to be recorded in the buffer queue to the resource slice.
10. The device of claim 7 , wherein the at least one zone at least comprises a first zone and a second zone, and wherein recording to the resource slice the log includes:
receiving a write request for metadata associated with a second transaction, the second transaction having a larger transaction sequence number than the first transaction; and
in response to a buffer queue of logs to be recorded in the first resource slice including the log and a second dummy indicating that the second transaction modified the first zone, and to presence of the first dummy in a buffer queue of logs to be recorded in the second resource slice and a log indicating the second transaction modified the first and second zones, recording to the first resource slice a part of a buffer queue of logs to be recorded in the first resource slice excluding the second dummy.
11. The device of claim 7 , wherein the acts further comprise:
releasing the resource slice by flushing the log recorded to the resource slice to a solid-state storage device.
12. The device of claim 7 , wherein the at least one zone has an allocated incremental super block, the incremental super block recording usage of a respective disk zone, wherein the acts further comprise:
in response to a modification of the at least one zone by the first transaction, modifying the incremental super block; and
flushing the incremental super block into a base super block associated with the plurality of zones at a predetermined time interval.
13. A computer program product, comprising:
a non-transitory computer readable medium encoded with computer-executable code, the code configured for the execution of:
in response to receiving a write request for metadata associated with a first transaction, determining at least a first zone and a second zone associated with the first transaction from a plurality of zones of the metadata, the plurality of zones being formed by striping the metadata;
requesting at least one resource slice for the at least one zone from a resource pool of a logging system; and
recording to the at least one resource slice at least one log indicating that the first transaction modifies the first zone and the second zone, wherein recording to the at least one resource slice the at least one log includes:
in response to determining that there is no buffer queue of logs to be recorded in a first resource slice associated with the first zone and there is a buffer queue of logs to be recorded in a second resource slice associated with the second zone,
recording both a first log associated with the first zone and a second log associated with the second zone to the first resource slice,
generating a first dummy for the second log, wherein the first dummy indicates that the first transaction modified the second zone, exists only in memory, and specifies modifications to the second zone made by the first transaction, and
adding the first dummy into the buffer queue associated with the second resource slice.
14. The computer program product of claim 13 , wherein recording the log to the resource slice comprises:
determining a size of the log to be stored; and
in response to the size of the log being smaller than a predetermined threshold, adding the log into a buffer queue associated with the resource slice.
15. The method of claim 1 , further comprising:
wherein the plurality of zones are formed by striping the metadata according to file system block number; and
wherein determining the first zone and the second zone associated with the first transaction includes determining that the first transaction modifies both at least one file system block number in the first zone and at least one file system block number in the second zone.