mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-04-09 18:11:32 -04:00
c6e8d51b37
Don't mark btree nodes for rewrites, if they are or would be degraded, if journal replay hasn't finished, to avoid a deadlock. This is because btree node rewrites generate more updates for the interior updates (alloc, backpointers), and if those updates touch new nodes and generate more rewrites - we can only have so many interior btree updates in flight before we deadlock on open_buckets. The biggest cause is that we don't use the btree write buffer (for the backpointer updates - this needs some real thought on locking in order to fix. The problem with this workaround (not doing the rewrite for degraded nodes in journal replay) is that those degraded nodes persist, and we don't want that (this is a real bug when a btree node write completes with fewer replicas than we wanted and leaves a degraded node due to device _removal_, i.e. the device went away mid write). It's less of a bug here, but still a problem because we don't yet have a way of tracking degraded data - we another index (all extents/btree nodes, by replicas entry) in order to fix properly (re-replicate degraded data at the earliest possible time). Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.