16 Commits

Author SHA1 Message Date
David Howells
b64a331498 cachefiles: Trace active-mark failure
Add a tracepoint to log failure to apply an active mark to a file in
addition to tracing successfully setting and unsetting the mark.

Also include the backing file inode number in the message logged to dmesg.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/164251404666.3435901.17331742792401482190.stgit@warthog.procyon.org.uk/ # v1
2022-01-21 21:36:28 +00:00
David Howells
8c39b8bc82 cachefiles: Make some tracepoint adjustments
Make some adjustments to tracepoints to make the tracing a bit more
followable:

 (1) Standardise on displaying the backing inode number as "B=<hex>" with
     no leading zeros.

 (2) Make the cachefiles_lookup tracepoint log the directory inode number
     as well as the looked-up inode number.

 (3) Add a cachefiles_lookup tracepoint into cachefiles_get_directory() to
     log directory lookup.

 (4) Add a new cachefiles_mkdir tracepoint and use that to log a successful
     mkdir from cachefiles_get_directory().

 (5) Make the cachefiles_unlink and cachefiles_rename tracepoints log the
     inode number of the affected file/dir rather than dentry struct
     pointers.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/164251403694.3435901.9797725381831316715.stgit@warthog.procyon.org.uk/ # v1
2022-01-21 21:36:28 +00:00
David Howells
32e150037d fscache, cachefiles: Store the volume coherency data
Store the volume coherency data in an xattr and check it when we rebind the
volume.  If it doesn't match the cache volume is moved to the graveyard and
rebuilt anew.

Changes
=======
ver #4:
 - Remove a couple of debugging prints.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/163967164397.1823006.2950539849831291830.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021563138.640689.15851092065380543119.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 13:43:03 +00:00
David Howells
047487c947 cachefiles: Implement the I/O routines
Implement the I/O routines for cachefiles.  There are two sets of routines
here: preparation and actual I/O.

Preparation for read involves looking to see whether there is data present,
and how much.  Netfslib tells us what it wants us to do and we have the
option of adjusting shrinking and telling it whether to read from the
cache, download from the server or simply clear a region.

Preparation for write involves checking for space and defending against
possibly running short of space, if necessary punching out a hole in the
file so that we don't leave old data in the cache if we update the
coherency information.

Then there's a read routine and a write routine.  They wait for the cookie
state to move to something appropriate and then start a potentially
asynchronous direct I/O operation upon it.

Changes
=======
ver #2:
 - Fix a misassigned variable[1].

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1]
Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 13:42:58 +00:00
David Howells
72b957856b cachefiles: Implement metadata/coherency data storage in xattrs
Use an xattr on each backing file in the cache to store some metadata, such
as the content type and the coherency data.

Five content types are defined:

 (0) No content stored.

 (1) The file contains a single monolithic blob and must be all or nothing.
     This would be used for something like an AFS directory or a symlink.

 (2) The file is populated with content completely up to a point with
     nothing beyond that.

 (3) The file has a map attached and is sparsely populated.  This would be
     stored in one or more additional xattrs.

 (4) The file is dirty, being in the process of local modification and the
     contents are not necessarily represented correctly by the metadata.
     The file should be deleted if this is seen on binding.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819641320.215744.16346770087799536862.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906942248.143852.5423738045012094252.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967151734.1823006.9301249989443622576.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021550471.640689.553853918307994335.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 13:42:24 +00:00
David Howells
df98e87f20 cachefiles: Implement object lifecycle funcs
Implement allocate, get, see and put functions for the cachefiles_object
struct.  The members of the struct we're going to need are also added.

Additionally, implement a lifecycle tracepoint.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819639457.215744.4600093239395728232.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906939569.143852.3594314410666551982.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967148857.1823006.6332962598220464364.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021547762.640689.8422781599594931000.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 13:42:08 +00:00
David Howells
13871bad1e cachefiles: Add tracepoints for calls to the VFS
Add tracepoints in cachefiles to monitor when it does various VFS
operations, such as mkdir.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819638517.215744.12773133137536579766.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906938316.143852.17227990869551737803.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967147139.1823006.4909879317496543392.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021546287.640689.3501604495002415631.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 13:41:59 +00:00
David Howells
1bd9c4e4f0 vfs, cachefiles: Mark a backing file in use with an inode flag
Use an inode flag, S_KERNEL_FILE, to mark that a backing file is in use by
the kernel to prevent cachefiles or other kernel services from interfering
with that file.

Alter rmdir to reject attempts to remove a directory marked with this flag.
This is used by cachefiles to prevent cachefilesd from removing them.

Using S_SWAPFILE instead isn't really viable as that has other effects in
the I/O paths.

Changes
=======
ver #3:
 - Check for the object pointer being NULL in the tracepoints rather than
   the caller.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819630256.215744.4815885535039369574.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906931596.143852.8642051223094013028.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967141000.1823006.12920680657559677789.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021541207.640689.564689725898537127.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 13:41:32 +00:00
David Howells
ecf5a6ce15 cachefiles: Add a couple of tracepoints for logging errors
Add two trace points to log errors, one for vfs operations like mkdir or
create, and one for I/O operations, like read, write or truncate.

Also add the beginnings of a struct that is going to represent a data file
and place a debugging ID in it for the tracepoints to record.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819625632.215744.17907340966178411033.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906926297.143852.18267924605548658911.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967135390.1823006.2512120406360156424.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021534029.640689.1875723624947577095.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 13:41:01 +00:00
David Howells
77443f6171 cachefiles: Introduce rewritten driver
Introduce basic skeleton of the rewritten cachefiles driver including
config options so that it can be enabled for compilation.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819622766.215744.9108359326983195047.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906923341.143852.3856498104256721447.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967130320.1823006.15791456613198441566.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021528993.640689.9069695476048171884.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 13:40:39 +00:00
David Howells
850cba069c cachefiles: Delete the cachefiles driver pending rewrite
Delete the code from the cachefiles driver to make it easier to rewrite and
resubmit in a logical manner.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819577641.215744.12718114397770666596.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906883770.143852.4149714614981373410.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967076066.1823006.7175712134577687753.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021483619.640689.7586546280515844702.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
Dave Wysochanski
a0e25f0a0d cachefiles: Fix oops with cachefiles_cull() due to NULL object
When cachefiles_cull() calls cachefiles_bury_object(), it passes
a NULL object.  When this occurs, either trace_cachefiles_unlink()
or trace_cachefiles_rename() may oops due to the NULL object.
Check for NULL object in the tracepoint and if so, set debug_id
to MAX_UINT as was done in 2908f5e101e3.

The following oops was seen with xfstests generic/100.
BUG: kernel NULL pointer dereference, address: 0000000000000010
...
RIP: 0010:trace_event_raw_event_cachefiles_unlink+0x4e/0xa0 [cachefiles]
...
 Call Trace:
   cachefiles_bury_object+0x242/0x430 [cachefiles]
   ? __vfs_removexattr_locked+0x10f/0x150
   ? vfs_removexattr+0x51/0xd0
   cachefiles_cull+0x84/0x120 [cachefiles]
   cachefiles_daemon_cull+0xd1/0x120 [cachefiles]
   cachefiles_daemon_write+0x158/0x190 [cachefiles]
   vfs_write+0xbc/0x260
   ksys_write+0x4f/0xc0
   do_syscall_64+0x3b/0x90

The following oops was seen with xfstests generic/290.
BUG: kernel NULL pointer dereference, address: 0000000000000010
...
RIP: 0010:trace_event_raw_event_cachefiles_rename+0x54/0xa0 [cachefiles]
...
Call Trace:
  cachefiles_bury_object+0x35c/0x430 [cachefiles]
  cachefiles_cull+0x84/0x120 [cachefiles]
  cachefiles_daemon_cull+0xd1/0x120 [cachefiles]
  cachefiles_daemon_write+0x158/0x190 [cachefiles]
  vfs_write+0xbc/0x260
  ksys_write+0x4f/0xc0
  do_syscall_64+0x3b/0x90

Fixes: 2908f5e101e3 ("fscache: Add a cookie debug ID and use that in traces")
Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://listman.redhat.com/archives/linux-cachefs/2021-October/msg00009.html
2021-10-05 11:22:06 +01:00
Dave Wysochanski
6e9bfdcf0a cachefiles: Fix oops in trace_cachefiles_mark_buried due to NULL object
In cachefiles_mark_object_buried, the dentry in question may not have an
owner, and thus our cachefiles_object pointer may be NULL when calling
the tracepoint, in which case we will also not have a valid debug_id to
print in the tracepoint.

Check for NULL object in the tracepoint and if so, just set debug_id to
MAX_UINT as was done in 2908f5e101e3 ("fscache: Add a cookie debug ID
and use that in traces").

This fixes the following oops:

    FS-Cache: Cache "mycache" added (type cachefiles)
    CacheFiles: File cache on vdc registered
    ...
    Workqueue: fscache_object fscache_object_work_func [fscache]
    RIP: 0010:trace_event_raw_event_cachefiles_mark_buried+0x4e/0xa0 [cachefiles]
    ....
    Call Trace:
     cachefiles_mark_object_buried+0xa5/0xb0 [cachefiles]
     cachefiles_bury_object+0x270/0x430 [cachefiles]
     cachefiles_walk_to_object+0x195/0x9c0 [cachefiles]
     cachefiles_lookup_object+0x5a/0xc0 [cachefiles]
     fscache_look_up_object+0xd7/0x160 [fscache]
     fscache_object_work_func+0xb2/0x340 [fscache]
     process_one_work+0x1f1/0x390
     worker_thread+0x53/0x3e0
     kthread+0x127/0x150

Fixes: 2908f5e101e3 ("fscache: Add a cookie debug ID and use that in traces")
Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-02 10:03:28 -07:00
David Howells
2908f5e101 fscache: Add a cookie debug ID and use that in traces
Add a cookie debug ID and use that in traces and in procfiles rather than
displaying the (hashed) pointer to the cookie.  This is easier to correlate
and we don't lose anything when interpreting oops output since that shows
unhashed addresses and registers that aren't comparable to the hashed
values.

Changes:

ver #2:
 - Fix the fscache_op tracepoint to handle a NULL cookie pointer.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/158861210988.340223.11688464116498247790.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/159465769844.1376105.14119502774019865432.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/160588459097.3465195.1273313637721852165.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/162431193544.2908479.17556704572948300790.stgit@warthog.procyon.org.uk/
2021-08-27 13:24:46 +01:00
Thomas Gleixner
b4d0d230cc treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public licence as published by
  the free software foundation either version 2 of the licence or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 114 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520170857.552531963@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-24 17:27:11 +02:00
David Howells
a18feb5576 fscache: Add tracepoints
Add some tracepoints to fscache:

 (*) fscache_cookie - Tracks a cookie's usage count.

 (*) fscache_netfs - Logs registration of a network filesystem, including
     the pointer to the cookie allocated.

 (*) fscache_acquire - Logs cookie acquisition.

 (*) fscache_relinquish - Logs cookie relinquishment.

 (*) fscache_enable - Logs enablement of a cookie.

 (*) fscache_disable - Logs disablement of a cookie.

 (*) fscache_osm - Tracks execution of states in the object state machine.

and cachefiles:

 (*) cachefiles_ref - Tracks a cachefiles object's usage count.

 (*) cachefiles_lookup - Logs result of lookup_one_len().

 (*) cachefiles_mkdir - Logs result of vfs_mkdir().

 (*) cachefiles_create - Logs result of vfs_create().

 (*) cachefiles_unlink - Logs calls to vfs_unlink().

 (*) cachefiles_rename - Logs calls to vfs_rename().

 (*) cachefiles_mark_active - Logs an object becoming active.

 (*) cachefiles_wait_active - Logs a wait for an old object to be
     destroyed.

 (*) cachefiles_mark_inactive - Logs an object becoming inactive.

 (*) cachefiles_mark_buried - Logs the burial of an object.

Signed-off-by: David Howells <dhowells@redhat.com>
2018-04-04 13:41:27 +01:00