Jeff Mahoney 5c06147128 btrfs: fix error handling in btrfs_dev_replace_start
When we fail to start a transaction in btrfs_dev_replace_start, we leave
dev_replace->replace_start set to STARTED but clear ->srcdev and
->tgtdev.  Later, that can result in an Oops in
btrfs_dev_replace_progress when having state set to STARTED or SUSPENDED
implies that ->srcdev is valid.

Also fix error handling when the state is already STARTED or SUSPENDED
while starting.  That, too, will clear ->srcdev and ->tgtdev even though
it doesn't own them.  This should be an impossible case to hit since we
should be protected by the BTRFS_FS_EXCL_OP bit being set.  Let's add an
ASSERT there while we're at it.

Fixes: e93c89c1aa (Btrfs: add new sources for device replace code)
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-10-15 17:23:31 +02:00
2018-10-15 07:20:24 +02:00

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 Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

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.
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