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linux/Documentation/ABI/testing/pstore

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pstore: Create a convenient mount point for pstore Using /dev/pstore as a mount point for the pstore filesystem is slightly awkward. We don't normally mount filesystems in /dev/ and the /dev/pstore file isn't created automatically by anything. While this method will still work, we can create a persistent mount point in sysfs. This will put pstore on par with things like cgroups and efivarfs. Signed-off-by: Josh Boyer <jwboyer@redhat.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Tony Luck <tony.luck@intel.com>
2013-02-13 05:07:22 +08:00
Where: /sys/fs/pstore/... (or /dev/pstore/...)
pstore: use mount option instead sysfs to tweak kmsg_bytes /sys/fs is a somewhat strange way to tweak what could more obviously be tuned with a mount option. Suggested-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-19 06:33:43 +08:00
Date: March 2011
Kernel Version: 2.6.39
pstore: new filesystem interface to platform persistent storage Some platforms have a small amount of non-volatile storage that can be used to store information useful to diagnose the cause of a system crash. This is the generic part of a file system interface that presents information from the crash as a series of files in /dev/pstore. Once the information has been seen, the underlying storage is freed by deleting the files. Signed-off-by: Tony Luck <tony.luck@intel.com>
2010-12-29 06:25:21 +08:00
Contact: tony.luck@intel.com
Description: Generic interface to platform dependent persistent storage.
Platforms that provide a mechanism to preserve some data
across system reboots can register with this driver to
provide a generic interface to show records captured in
the dying moments. In the case of a panic the last part
of the console log is captured, but other interesting
data can also be saved.
pstore: Create a convenient mount point for pstore Using /dev/pstore as a mount point for the pstore filesystem is slightly awkward. We don't normally mount filesystems in /dev/ and the /dev/pstore file isn't created automatically by anything. While this method will still work, we can create a persistent mount point in sysfs. This will put pstore on par with things like cgroups and efivarfs. Signed-off-by: Josh Boyer <jwboyer@redhat.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Tony Luck <tony.luck@intel.com>
2013-02-13 05:07:22 +08:00
# mount -t pstore -o kmsg_bytes=8000 - /sys/fs/pstore
pstore: new filesystem interface to platform persistent storage Some platforms have a small amount of non-volatile storage that can be used to store information useful to diagnose the cause of a system crash. This is the generic part of a file system interface that presents information from the crash as a series of files in /dev/pstore. Once the information has been seen, the underlying storage is freed by deleting the files. Signed-off-by: Tony Luck <tony.luck@intel.com>
2010-12-29 06:25:21 +08:00
pstore: Create a convenient mount point for pstore Using /dev/pstore as a mount point for the pstore filesystem is slightly awkward. We don't normally mount filesystems in /dev/ and the /dev/pstore file isn't created automatically by anything. While this method will still work, we can create a persistent mount point in sysfs. This will put pstore on par with things like cgroups and efivarfs. Signed-off-by: Josh Boyer <jwboyer@redhat.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Tony Luck <tony.luck@intel.com>
2013-02-13 05:07:22 +08:00
$ ls -l /sys/fs/pstore/
pstore: new filesystem interface to platform persistent storage Some platforms have a small amount of non-volatile storage that can be used to store information useful to diagnose the cause of a system crash. This is the generic part of a file system interface that presents information from the crash as a series of files in /dev/pstore. Once the information has been seen, the underlying storage is freed by deleting the files. Signed-off-by: Tony Luck <tony.luck@intel.com>
2010-12-29 06:25:21 +08:00
total 0
-r--r--r-- 1 root root 7896 Nov 30 15:38 dmesg-erst-1
Different users of this interface will result in different
filename prefixes. Currently two are defined:
"dmesg" - saved console log
"mce" - architecture dependent data from fatal h/w error
Once the information in a file has been read, removing
the file will signal to the underlying persistent storage
device that it can reclaim the space for later re-use.
pstore: Create a convenient mount point for pstore Using /dev/pstore as a mount point for the pstore filesystem is slightly awkward. We don't normally mount filesystems in /dev/ and the /dev/pstore file isn't created automatically by anything. While this method will still work, we can create a persistent mount point in sysfs. This will put pstore on par with things like cgroups and efivarfs. Signed-off-by: Josh Boyer <jwboyer@redhat.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Tony Luck <tony.luck@intel.com>
2013-02-13 05:07:22 +08:00
$ rm /sys/fs/pstore/dmesg-erst-1
pstore: new filesystem interface to platform persistent storage Some platforms have a small amount of non-volatile storage that can be used to store information useful to diagnose the cause of a system crash. This is the generic part of a file system interface that presents information from the crash as a series of files in /dev/pstore. Once the information has been seen, the underlying storage is freed by deleting the files. Signed-off-by: Tony Luck <tony.luck@intel.com>
2010-12-29 06:25:21 +08:00
pstore: Create a convenient mount point for pstore Using /dev/pstore as a mount point for the pstore filesystem is slightly awkward. We don't normally mount filesystems in /dev/ and the /dev/pstore file isn't created automatically by anything. While this method will still work, we can create a persistent mount point in sysfs. This will put pstore on par with things like cgroups and efivarfs. Signed-off-by: Josh Boyer <jwboyer@redhat.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Tony Luck <tony.luck@intel.com>
2013-02-13 05:07:22 +08:00
The expectation is that all files in /sys/fs/pstore/
pstore: new filesystem interface to platform persistent storage Some platforms have a small amount of non-volatile storage that can be used to store information useful to diagnose the cause of a system crash. This is the generic part of a file system interface that presents information from the crash as a series of files in /dev/pstore. Once the information has been seen, the underlying storage is freed by deleting the files. Signed-off-by: Tony Luck <tony.luck@intel.com>
2010-12-29 06:25:21 +08:00
will be saved elsewhere and erased from persistent store
soon after boot to free up space ready for the next
catastrophe.
pstore: use mount option instead sysfs to tweak kmsg_bytes /sys/fs is a somewhat strange way to tweak what could more obviously be tuned with a mount option. Suggested-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-19 06:33:43 +08:00
The 'kmsg_bytes' mount option changes the target amount of
data saved on each oops/panic. Pstore saves (possibly
multiple) files based on the record size of the underlying
persistent storage until at least this amount is reached.
Default is 10 Kbytes.
pstore: Allow the user to explicitly choose a backend pstore only allows one backend to be registered at present, but the system may provide several. Add a parameter to allow the user to choose which backend will be used rather than just relying on load order. Signed-off-by: Matthew Garrett <mjg@redhat.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
2011-07-22 04:57:55 +08:00
Pstore only supports one backend at a time. If multiple
backends are available, the preferred backend may be
set by passing the pstore.backend= argument to the kernel at
boot time.