*
* (this comment should be rewritten !)
* jfs uses only "after" log records (only a single writer is allowed
*
* (this comment should be rewritten !)
* jfs uses only "after" log records (only a single writer is allowed
* if they must be written to disk before commit, and i/o is
* scheduled for modified pages to their home location after
* the log records containing the after values and the commit
* if they must be written to disk before commit, and i/o is
* scheduled for modified pages to their home location after
* the log records containing the after values and the commit
*
* a log record consists of a data area of variable length followed by
* a descriptor of fixed size LOGRDSIZE bytes.
*
* a log record consists of a data area of variable length followed by
* a descriptor of fixed size LOGRDSIZE bytes.
* must be no longer than LOGPSIZE.
* the descriptor is of size of multiple of 4-bytes and aligned on a
* 4-byte boundary.
* must be no longer than LOGPSIZE.
* the descriptor is of size of multiple of 4-bytes and aligned on a
* 4-byte boundary.
*
* do not apply after-image records which precede this record
* in the log with the same page block number to this page.
*
* do not apply after-image records which precede this record
* in the log with the same page block number to this page.
*
* do not apply after-image records which precede this
* record in the log with the any of the 4 page block
*
* do not apply after-image records which precede this
* record in the log with the any of the 4 page block
*
* free specified extent(s) from block allocation map
* N.B.: nextents should be length of data/sizeof(xad_t)
*
* free specified extent(s) from block allocation map
* N.B.: nextents should be length of data/sizeof(xad_t)