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A mirror of the official Linux kernel repository just in case
04a6a536bc
freeze/thaw_bdev() currently use bdev->bd_fsfreeze_count to infer
whether or not bdev->bd_fsfreeze_sb is valid (it's valid iff
bd_fsfreeze_count is non-zero). thaw_bdev() doesn't nullify
bd_fsfreeze_sb.
But this means a freeze_bdev() call followed by a thaw_bdev() call can
leave bd_fsfreeze_sb with a non-null value, while bd_fsfreeze_count is
zero. If freeze_bdev() is called again, and this time
get_active_super() returns NULL (e.g. because the FS is unmounted),
we'll end up with bd_fsfreeze_count > 0, but bd_fsfreeze_sb is
*untouched* - it stays the same (now garbage) value. A subsequent
thaw_bdev() will decide that the bd_fsfreeze_sb value is legitimate
(since bd_fsfreeze_count > 0), and attempt to use it.
Fix this by always setting bd_fsfreeze_sb to NULL when
bd_fsfreeze_count is successfully decremented to 0 in thaw_sb().
Alternatively, we could set bd_fsfreeze_sb to whatever
get_active_super() returns in freeze_bdev() whenever bd_fsfreeze_count
is successfully incremented to 1 from 0 (which can be achieved cleanly
by moving the line currently setting bd_fsfreeze_sb to immediately
after the "sync:" label, but it might be a little too subtle/easily
overlooked in future).
This fixes the currently panicking xfstests generic/085.
Fixes:
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|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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.