fs/quota: handle overflows of sysctl fs.quota.* and report as unsigned long
[ Upstream commit 6fcbcec9cf
]
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>
This commit is contained in:
parent
e44850bd42
commit
19f612e6cc
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@ -2861,68 +2861,73 @@ EXPORT_SYMBOL(dquot_quotactl_sysfile_ops);
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static int do_proc_dqstats(struct ctl_table *table, int write,
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void __user *buffer, size_t *lenp, loff_t *ppos)
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{
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unsigned int type = (int *)table->data - dqstats.stat;
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unsigned int type = (unsigned long *)table->data - dqstats.stat;
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s64 value = percpu_counter_sum(&dqstats.counter[type]);
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/* Filter negative values for non-monotonic counters */
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if (value < 0 && (type == DQST_ALLOC_DQUOTS ||
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type == DQST_FREE_DQUOTS))
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value = 0;
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/* Update global table */
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dqstats.stat[type] =
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percpu_counter_sum_positive(&dqstats.counter[type]);
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return proc_dointvec(table, write, buffer, lenp, ppos);
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dqstats.stat[type] = value;
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return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
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}
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static struct ctl_table fs_dqstats_table[] = {
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{
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.procname = "lookups",
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.data = &dqstats.stat[DQST_LOOKUPS],
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.maxlen = sizeof(int),
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.maxlen = sizeof(unsigned long),
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.mode = 0444,
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.proc_handler = do_proc_dqstats,
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},
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{
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.procname = "drops",
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.data = &dqstats.stat[DQST_DROPS],
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.maxlen = sizeof(int),
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.maxlen = sizeof(unsigned long),
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.mode = 0444,
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.proc_handler = do_proc_dqstats,
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},
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{
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.procname = "reads",
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.data = &dqstats.stat[DQST_READS],
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.maxlen = sizeof(int),
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.maxlen = sizeof(unsigned long),
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.mode = 0444,
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.proc_handler = do_proc_dqstats,
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},
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{
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.procname = "writes",
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.data = &dqstats.stat[DQST_WRITES],
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.maxlen = sizeof(int),
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.maxlen = sizeof(unsigned long),
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.mode = 0444,
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.proc_handler = do_proc_dqstats,
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},
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{
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.procname = "cache_hits",
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.data = &dqstats.stat[DQST_CACHE_HITS],
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.maxlen = sizeof(int),
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.maxlen = sizeof(unsigned long),
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.mode = 0444,
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.proc_handler = do_proc_dqstats,
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},
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{
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.procname = "allocated_dquots",
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.data = &dqstats.stat[DQST_ALLOC_DQUOTS],
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.maxlen = sizeof(int),
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.maxlen = sizeof(unsigned long),
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.mode = 0444,
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.proc_handler = do_proc_dqstats,
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},
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{
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.procname = "free_dquots",
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.data = &dqstats.stat[DQST_FREE_DQUOTS],
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.maxlen = sizeof(int),
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.maxlen = sizeof(unsigned long),
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.mode = 0444,
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.proc_handler = do_proc_dqstats,
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},
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{
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.procname = "syncs",
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.data = &dqstats.stat[DQST_SYNCS],
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.maxlen = sizeof(int),
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.maxlen = sizeof(unsigned long),
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.mode = 0444,
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.proc_handler = do_proc_dqstats,
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},
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@ -263,7 +263,7 @@ enum {
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};
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struct dqstats {
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int stat[_DQST_DQSTAT_LAST];
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unsigned long stat[_DQST_DQSTAT_LAST];
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struct percpu_counter counter[_DQST_DQSTAT_LAST];
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};
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