mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-04-30 20:30:32 -04:00
d9e14a4eb9
bcachefs grabs s_umount and sets SB_RDONLY when the fs is shutdown via the ioctl() interface. This has a couple issues related to interactions between shutdown and freeze: 1. The flags == FSOP_GOING_FLAGS_DEFAULT case is a deadlock vector because freeze_bdev() calls into freeze_super(), which also acquires s_umount. 2. If an explicit shutdown occurs while the sb is frozen, SB_RDONLY alters the thaw path as if the sb was read-only at freeze time. This effectively leaks the frozen state and leaves the sb frozen indefinitely. The usage of SB_RDONLY here goes back to the initial bcachefs commit and AFAICT is simply historical behavior. This behavior is unique to bcachefs relative to the handful of other filesystems that support the shutdown ioctl(). Typically, SB_RDONLY is reserved for the proper remount path, which itself is restricted from modifying frozen superblocks in reconfigure_super(). Drop the unnecessary sb lock and flags update bch2_ioc_goingdown() to address both of these issues. Signed-off-by: Brian Foster <bfoster@redhat.com> 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 Restructured Text 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.