tree 79304e6bba22764bc3d9b8ec6aa8339e535aea5f
parent c4c2250c2160c5b1a9fe08cb96adf0396745aecf
author Konstantin Khlebnikov <khlebnikov@yandex-team.ru> 1573379346 +0300
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1578141650 +0100

fs/quota: handle overflows of sysctl fs.quota.* and report as unsigned long

[ Upstream commit 6fcbcec9cfc7b3c6a2c1f1a23ebacedff7073e0a ]

Quota statistics counted as 64-bit per-cpu counter. Reading sums per-cpu
fractions as signed 64-bit int, filters negative values and then reports
lower half as signed 32-bit int.

Result may looks like:

fs.quota.allocated_dquots = 22327
fs.quota.cache_hits = -489852115
fs.quota.drops = -487288718
fs.quota.free_dquots = 22083
fs.quota.lookups = -486883485
fs.quota.reads = 22327
fs.quota.syncs = 335064
fs.quota.writes = 3088689

Values bigger than 2^31-1 reported as negative.

All counters except "allocated_dquots" and "free_dquots" are monotonic,
thus they should be reported as is without filtering negative values.

Kernel doesn't have generic helper for 64-bit sysctl yet,
let's use at least unsigned long.

Link: https://lore.kernel.org/r/157337934693.2078.9842146413181153727.stgit@buzz
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>