mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-05-10 05:39:42 -04:00
ce6915f534
The disk layout and volume information of a DASD reside in the first two tracks of cylinder 0. When a DASD is set online, currently the first three tracks are read and analysed to confirm an expected layout. For CDL (Compatible Disk Layout) only count area data of the first track is evaluated and checked against expected key and data lengths. For LDL (Linux Disk Layout) the first and third track is evaluated. However, an LDL formatted volume is expected to be in the same format across all tracks. Checking the third track therefore doesn't have any more value than checking any other track at random. Now, an Extent Space Efficient (ESE) DASD is initialised by only formatting the first two tracks, as those tracks always contain all information necessarry. Checking the third track on an ESE volume will therefore most likely fail with a record not found error, as the third track will be empty. This in turn leads to the device being recognised with a volume size of 0. Attempts to write volume information on the first two tracks then fail with "no space left on device" errors. Initialising the first three tracks for an ESE volume is not a viable solution, because the third track is already a regular track and could contain user data. With that there is potential for data corruption. Instead, always only analyse the first two tracks, as it is sufficiant for both CDL and LDL, and allow ESE volumes to be recognised as well. Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com> Reviewed-by: Stefan Haberland <sth@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.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.