use bios directly in the log code v2

Christoph Hellwig
2019-06-03T17:29:49Z

Hi all,

this series switches the log writing and log recovery code to use bios
directly, and remove various special cases from the buffer cache code.
Note that I have developed it on top of the previous series of log item
related cleanups, so if you don't have that applied there is a small
conflict. To make life easier I have pushed out a git branche here:

git://git.infradead.org/users/hch/xfs.git xfs-log-bio

Gitweb:

http://git.infradead.org/users/hch/xfs.git/shortlog/refs/heads/xfs-log-bio

Changes since v2:
- rename the 'flush' flag to 'need_flush'
- spelling fixes
- minor cleanups

Changes since v1:
- rebased to not required the log item series first
- split the bio-related code out of xfs_log_recover.c into a new file
to ease using xfs_log_recover.c in xfsprogs
- use kmem_alloc_large instead of vmalloc to allocate the buffer
- additional minor cleanups