8e9800f9f2
While running generic/050 with an external log, I observed this warning in dmesg: Trying to write to read-only block-device sda4 (partno 4) WARNING: CPU: 2 PID: 215677 at block/blk-core.c:704 submit_bio_checks+0x256/0x510 Call Trace: submit_bio_noacct+0x2c/0x430 _xfs_buf_ioapply+0x283/0x3c0 [xfs] __xfs_buf_submit+0x6a/0x210 [xfs] xfs_buf_delwri_submit_buffers+0xf8/0x270 [xfs] xfsaild+0x2db/0xc50 [xfs] kthread+0x14b/0x170 I think this happened because we tried to cover the log after a readonly mount, and the AIL tried to write the primary superblock to the data device. The test marks the data device readonly, but it doesn't do the same to the external log device. Therefore, XFS thinks that the log is writable, even though AIL writes whine to dmesg because the data device is read only. Fix this by amending xfs_log_writable to prevent writes when the AIL can't possible write anything into the filesystem. Note: As for the external log or the rt devices being readonly-- xfs_blkdev_get will complain about that if we aren't doing a norecovery mount. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Brian Foster <bfoster@redhat.com>
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.