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[130.117.225.111]) by mx.google.com with ESMTPS id ffacd0b85a97d-485883b8e2asi38636850f8f.55.2026.09.09.14.35.42 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 09 Sep 2026 14:35:42 -0700 (PDT) Received-SPF: pass (google.com: domain of vladimir.riabchun@virtuozzo.com designates 130.117.225.111 as permitted sender) client-ip=130.117.225.111; Authentication-Results: mx.google.com; dkim=pass header.i=@virtuozzo.com header.s=relay header.b="U/H5tsmX"; spf=pass (google.com: domain of vladimir.riabchun@virtuozzo.com designates 130.117.225.111 as permitted sender) smtp.mailfrom=vladimir.riabchun@virtuozzo.com; dmarc=pass (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=virtuozzo.com DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=virtuozzo.com; s=relay; h=MIME-Version:Message-ID:Date:Subject:From: Content-Type; bh=VxVEif2vvhE6qXT9BV/E4iDbF9fgowD02hYF8Wl+0ko=; b=U/H5tsmX28O4 K98V4/COh/xF/SNuIHrBusPVO5HJDytlW5dntEdOQFDVyfoME529C0ITgtDhoEE4gd0CbT7KJWxX+ jPVwYqthk1LluyUnBlGWWBmvSJSHKoUvF1La9Cs2mygg/xtXDUh0NDgXoNvCuRgNRuLEQ3dbb94v3 ArUIOoVvmf687KtOmTuWtz2n137D65Vn9Cf8tz1hyMIj4Fgt1O/skWCa1qFyzNvsvj5qpvJetbsE+ WLyuG4cFxnndBV1k3ubIIJ9u/CYR3kUAC/cRwl0tEE1oCzHtI7Ohiz+NEqGpkfBgLyQczc2+8xe6F ye2bRmygKgI36Snp05OZOQ==; Received: from [130.117.225.5] (helo=dev012.aci.vzint.dev) by relay.virtuozzo.com with esmtps (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1x4Pug-00DVmc-0X; Wed, 09 Sep 2026 23:35:41 +0200 From: Vladimir Riabchun To: devel@openvz.org Date: Wed, 9 Sep 2026 21:35:24 +0000 Message-ID: <281dbe6b90a8b894dbd63d9368f11e9b5f855888.1788989664.git.vladimir.riabchun@virtuozzo.com> X-Mailer: git-send-email 2.47.1 In-Reply-To: References: MIME-Version: 1.0 X-OZ-Fwd: true Subject: [Devel] [PATCH VZ10 v8 2/7] ve/fs: Rework per-ve mount count X-BeenThere: devel@openvz.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: OpenVZ development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: devel-bounces@openvz.org Errors-To: devel-bounces@openvz.org Previous approach with current mounts counter had an issue: there was a gap between ve_mount_allowed check and ve_mount_nr_inc, which could allow CT to have more mounts than expected. Fix this by tracking the number of available mounts instead of current ones. This also makes resources accounting more consistent - we are using ***_avail_nr approach more. One more issue with inconsistent ve value is fixed: ve_mount_allowed always used ve from get_exec_env, but ve_mount_nr_inc operated with owner_ve. Now actual ve value is calculated in the beginning of alloc_vfsmnt. To avoid incorrect accounting when is_pseudosuper is changed, update avail_nr count without > 0 check if VE is ve0 or pseudosuper. This also simplifies ve_mount_put, since increment is now unconditional. https://virtuozzo.atlassian.net/browse/VSTOR-135520 Feature: per-ve failcounters Signed-off-by: Vladimir Riabchun --- fs/namespace.c | 78 ++++++++++++++++++++++++++++------------------ include/linux/ve.h | 2 +- kernel/ve/ve.c | 12 +++---- 3 files changed, 54 insertions(+), 38 deletions(-) diff --git a/fs/namespace.c b/fs/namespace.c index 4adc1db84b4c..1d6e66cd7174 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -317,19 +317,22 @@ int mnt_get_count(struct mount *mnt) #endif } -static inline int ve_mount_allowed(void); -static inline void ve_mount_nr_inc(struct mount *mnt, struct ve_struct *ve); -static inline void ve_mount_nr_dec(struct mount *mnt); +static inline int ve_try_reserve_mount(struct ve_struct *ve); +static inline void ve_mount_put(struct mount *mnt, struct ve_struct *ve); static inline void ve_mount_reown(struct mount *mnt, struct ve_struct *ve); static struct mount *alloc_vfsmnt(const char *name, struct ve_struct *owner_ve) { struct mount *mnt; + struct ve_struct *ve = owner_ve; - if (!ve_mount_allowed()) { + if (!ve) + ve = get_exec_env(); + + if (!ve_try_reserve_mount(ve)) { pr_warn_ratelimited( "CT#%s reached the limit on mounts.\n", - ve_name(get_exec_env())); + ve_name(ve)); return NULL; } @@ -337,6 +340,14 @@ static struct mount *alloc_vfsmnt(const char *name, struct ve_struct *owner_ve) if (mnt) { int err; +#ifdef CONFIG_VE + /* + * Got ve reference in ve_try_reserve_mount, set mnt ve data + * here, so in case of error ve_mount_put sees correct info. + */ + mnt->ve_owner = ve; +#endif + err = mnt_alloc_id(mnt); if (err) goto out_free_cache; @@ -371,7 +382,8 @@ static struct mount *alloc_vfsmnt(const char *name, struct ve_struct *owner_ve) INIT_LIST_HEAD(&mnt->mnt_umounting); INIT_HLIST_HEAD(&mnt->mnt_stuck_children); mnt->mnt.mnt_idmap = &nop_mnt_idmap; - ve_mount_nr_inc(mnt, owner_ve); + } else { + ve_mount_put(mnt, ve); } return mnt; @@ -382,6 +394,8 @@ static struct mount *alloc_vfsmnt(const char *name, struct ve_struct *owner_ve) out_free_id: mnt_free_id(mnt); out_free_cache: + /* Got ve reference in ve_try_reserve_mount */ + ve_mount_put(mnt, ve); kmem_cache_free(mnt_cache, mnt); return NULL; } @@ -751,7 +765,9 @@ int sb_prepare_remount_readonly(struct super_block *sb) static void free_vfsmnt(struct mount *mnt) { mnt_idmap_put(mnt_idmap(&mnt->mnt)); - ve_mount_nr_dec(mnt); +#ifdef CONFIG_VE + ve_mount_put(mnt, mnt->ve_owner); +#endif kfree_const(mnt->mnt_devname); #ifdef CONFIG_SMP free_percpu(mnt->mnt_pcp); @@ -3214,7 +3230,7 @@ int ve_devmnt_process(struct ve_struct *ve, dev_t dev, void **data_pp, int remou if (devmnt->dev == dev) { err = ve_devmnt_check(data, devmnt->allowed_options); /* - * In case of @is_pseudouser set, ie restore procedure, + * In case of @is_pseudosuper set, ie restore procedure, * we don't check for allowed options filtering, since * restore mode is special. */ @@ -3353,30 +3369,30 @@ int ve_devmnt_verify(struct ve_struct *ve, dev_t dev, char *opts, bool new_mount return err; } -static inline int ve_mount_allowed(void) -{ - struct ve_struct *ve = get_exec_env(); - - return ve_is_super(ve) || ve->is_pseudosuper || - atomic_read(&ve->mnt_nr) < (int)sysctl_ve_mount_nr; -} - -static inline void ve_mount_nr_inc(struct mount *mnt, struct ve_struct *ve) +static inline int ve_try_reserve_mount(struct ve_struct *ve) { - if (!ve) - ve = get_exec_env(); + int ret = ve_is_super(ve) || ve->is_pseudosuper; + /* Ignore limits in ve0 and pseudosuper cases, but still count. */ + if (ret) + atomic_dec(&ve->mnt_avail_nr); + else + ret = atomic_dec_if_positive(&ve->mnt_avail_nr) >= 0; - mnt->ve_owner = get_ve(ve); - atomic_inc(&ve->mnt_nr); + if (ret) + get_ve(ve); + return ret; } -static inline void ve_mount_nr_dec(struct mount *mnt) +static inline void ve_mount_put(struct mount *mnt, struct ve_struct *ve) { - struct ve_struct *ve = mnt->ve_owner; - - atomic_dec(&ve->mnt_nr); + /* + * ve argument is needed to reuse this function in alloc_vfsmnt error path. + * Other users should pass mnt->ve_owner value. + */ + atomic_inc(&ve->mnt_avail_nr); put_ve(ve); - mnt->ve_owner = NULL; + if (mnt) + mnt->ve_owner = NULL; } /* @@ -3397,9 +3413,9 @@ static inline void ve_mount_reown(struct mount *mnt, struct ve_struct *ve) if (old == ve) return; - atomic_inc(&ve->mnt_nr); + atomic_dec(&ve->mnt_avail_nr); WRITE_ONCE(mnt->ve_owner, get_ve(ve)); - atomic_dec(&old->mnt_nr); + atomic_inc(&old->mnt_avail_nr); put_ve(old); } @@ -3422,10 +3438,10 @@ bool is_sb_ve_accessible(struct ve_struct *ve, struct super_block *sb) #else /* CONFIG_VE */ -static inline int ve_mount_allowed(void) { return 1; } -static inline void ve_mount_nr_inc(struct mount *mnt, struct ve_struct *ve) { } -static inline void ve_mount_nr_dec(struct mount *mnt) { } +static inline int ve_try_reserve_mount(struct ve_struct *ve) { return 1; } +static inline void ve_mount_put(struct mount *mnt, struct ve_struct *ve) { } static inline void ve_mount_reown(struct mount *mnt, struct ve_struct *ve) { } + #endif /* CONFIG_VE */ /* diff --git a/include/linux/ve.h b/include/linux/ve.h index f946abe4d859..65c058c0f34d 100644 --- a/include/linux/ve.h +++ b/include/linux/ve.h @@ -96,7 +96,7 @@ struct ve_struct { atomic_t nd_neigh_nr; unsigned long meminfo_val; - atomic_t mnt_nr; /* number of present VE mounts */ + atomic_t mnt_avail_nr; /* number of available VE mounts */ #ifdef CONFIG_COREDUMP char core_pattern[CORENAME_MAX_SIZE]; diff --git a/kernel/ve/ve.c b/kernel/ve/ve.c index 2d2934e1ec10..58a0c4b8e36e 100644 --- a/kernel/ve/ve.c +++ b/kernel/ve/ve.c @@ -82,7 +82,7 @@ struct ve_struct ve0 = { .arp_neigh_nr = ATOMIC_INIT(0), .nd_neigh_nr = ATOMIC_INIT(0), - .mnt_nr = ATOMIC_INIT(0), + .mnt_avail_nr = ATOMIC_INIT(INT_MAX), .meminfo_val = VE_MEMINFO_SYSTEM, #ifdef CONFIG_X86 .umh_running_helpers = ATOMIC_INIT(0), @@ -787,7 +787,7 @@ static struct cgroup_subsys_state *ve_create(struct cgroup_subsys_state *parent_ atomic_set(&ve->arp_neigh_nr, 0); atomic_set(&ve->nd_neigh_nr, 0); - atomic_set(&ve->mnt_nr, 0); + atomic_set(&ve->mnt_avail_nr, sysctl_ve_mount_nr); #ifdef CONFIG_COREDUMP strcpy(ve->core_pattern, "core"); @@ -1063,9 +1063,9 @@ static u64 ve_netns_avail_nr_read(struct cgroup_subsys_state *css, struct cftype return atomic_read(&css_to_ve(css)->netns_avail_nr); } -static u64 ve_mnt_nr_read(struct cgroup_subsys_state *css, struct cftype *cft) +static s64 ve_mnt_avail_nr_read(struct cgroup_subsys_state *css, struct cftype *cft) { - return atomic_read(&css_to_ve(css)->mnt_nr); + return atomic_read(&css_to_ve(css)->mnt_avail_nr); } static u64 ve_netif_max_nr_read(struct cgroup_subsys_state *css, struct cftype *cft) @@ -1627,8 +1627,8 @@ static struct cftype ve_cftypes[] = { .read_u64 = ve_netns_avail_nr_read, }, { - .name = "mnt_nr", - .read_u64 = ve_mnt_nr_read, + .name = "mnt_avail_nr", + .read_s64 = ve_mnt_avail_nr_read, }, { .name = "netif_max_nr", -- 2.47.1 _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel