kernel.git/fs/fscache/cookie.c, branch linux-5.16.y

fscache: Use refcount_t for the cookie refcount instead of atomic_t

2021-08-27T12:34:03Z

Use refcount_t for the fscache_cookie refcount instead of atomic_t and rename the 'usage' member to 'ref' in such cases. The tracepoints that reference it change from showing "u=%d" to "r=%d". Signed-off-by: David Howells Reviewed-by: Jeff Layton cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/162431204358.2908479.8006938388213098079.stgit@warthog.procyon.org.uk/

fscache: Fix fscache_cookie_put() to not deref after dec

2021-08-27T12:34:02Z

fscache_cookie_put() accesses the cookie it has just put inside the tracepoint that monitors the change - but this is something it's not allowed to do if we didn't reduce the count to zero. Fix this by dropping most of those values from the tracepoint and grabbing the cookie debug ID before doing the dec. Also take the opportunity to switch over the usage and where arguments on the tracepoint to put the reason last. Fixes: a18feb55769b ("fscache: Add tracepoints") Signed-off-by: David Howells Reviewed-by: Jeff Layton cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/162431203107.2908479.3259582550347000088.stgit@warthog.procyon.org.uk/

fscache: Fix cookie key hashing

2021-08-27T12:34:02Z

The current hash algorithm used for hashing cookie keys is really bad, producing almost no dispersion (after a test kernel build, ~30000 files were split over just 18 out of the 32768 hash buckets). Borrow the full_name_hash() hash function into fscache to do the hashing for cookie keys and, in the future, volume keys. I don't want to use full_name_hash() as-is because I want the hash value to be consistent across arches and over time as the hash value produced may get used on disk. I can also optimise parts of it away as the key will always be a padded array of aligned 32-bit words. Fixes: ec0328e46d6e ("fscache: Maintain a catalogue of allocated cookies") Signed-off-by: David Howells Reviewed-by: Jeff Layton cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/162431201844.2908479.8293647220901514696.stgit@warthog.procyon.org.uk/

fscache: Change %p in format strings to something else

2021-08-27T12:34:02Z

Change plain %p in format strings in fscache code to something more useful, since %p is now hashed before printing and thus no longer matches the contents of an oops register dump. Signed-off-by: David Howells Reviewed-by: Jeff Layton cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/160588474843.3465195.5446072310069374803.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/162431199509.2908479.2950631488219944294.stgit@warthog.procyon.org.uk/

fscache: Remove the object list procfile

2021-08-27T12:34:02Z

Remove the object list procfile from fscache as objects will become entirely internal to the cache. Signed-off-by: David Howells Reviewed-by: Jeff Layton cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/162431198332.2908479.5847286163455099669.stgit@warthog.procyon.org.uk/

fscache: Procfile to display cookies

2021-08-27T12:34:02Z

Add /proc/fs/fscache/cookies to display active cookies. Signed-off-by: David Howells Reviewed-by: Jeff Layton cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/158861211871.340223.7223853943667440807.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/159465771021.1376105.6933857529128238020.stgit@warthog.procyon.org.uk/ Link: https://lore.kernel.org/r/160588460994.3465195.16963417803501149328.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/162431194785.2908479.786917990782538164.stgit@warthog.procyon.org.uk/

fscache: Add a cookie debug ID and use that in traces

2021-08-27T12:24:46Z

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 Reviewed-by: Jeff Layton 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/

docs: filesystems: caching/netfs-api.txt: convert it to ReST

2020-05-05T15:22:20Z

- Add a SPDX header; - Adjust document and section titles; - Some whitespace fixes and new line breaks; - Mark literal blocks as such; - Add it to filesystems/caching/index.rst. Signed-off-by: Mauro Carvalho Chehab Link: https://lore.kernel.org/r/cfe4cb1bf8e1f0093d44c30801ec42e74721e543.1588021877.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

2019-05-30T18:26:32Z

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 license as published by the free software foundation either version 2 of the license 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 3029 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman

fscache: Fix out of bound read in long cookie keys

2018-10-18T09:32:21Z

fscache_set_key() can incur an out-of-bounds read, reported by KASAN: BUG: KASAN: slab-out-of-bounds in fscache_alloc_cookie+0x5b3/0x680 [fscache] Read of size 4 at addr ffff88084ff056d4 by task mount.nfs/32615 and also reported by syzbot at https://lkml.org/lkml/2018/7/8/236 BUG: KASAN: slab-out-of-bounds in fscache_set_key fs/fscache/cookie.c:120 [inline] BUG: KASAN: slab-out-of-bounds in fscache_alloc_cookie+0x7a9/0x880 fs/fscache/cookie.c:171 Read of size 4 at addr ffff8801d3cc8bb4 by task syz-executor907/4466 This happens for any index_key_len which is not divisible by 4 and is larger than the size of the inline key, because the code allocates exactly index_key_len for the key buffer, but the hashing loop is stepping through it 4 bytes (u32) at a time in the buf[] array. Fix this by calculating how many u32 buffers we'll need by using DIV_ROUND_UP, and then using kcalloc() to allocate a precleared allocation buffer to hold the index_key, then using that same count as the hashing index limit. Fixes: ec0328e46d6e ("fscache: Maintain a catalogue of allocated cookies") Reported-by: syzbot+a95b989b2dde8e806af8@syzkaller.appspotmail.com Signed-off-by: Eric Sandeen Cc: stable Signed-off-by: David Howells Signed-off-by: Greg Kroah-Hartman