sys.c

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/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU General Public License version 2.
 */

#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/module.h>
#include <linux/kobject.h>
#include <asm/uaccess.h>
#include <linux/gfs2_ondisk.h>
#include <linux/genhd.h>

#include "gfs2.h"
#include "incore.h"
#include "sys.h"
#include "super.h"
#include "glock.h"
#include "quota.h"
#include "util.h"
#include "glops.h"
#include "recovery.h"

struct gfs2_attr {
    struct attribute attr;
    ssize_t (*show)(struct gfs2_sbd *, char *);
    ssize_t (*store)(struct gfs2_sbd *, const char *, size_t);
};

static ssize_t gfs2_attr_show(struct kobject *kobj, struct attribute *attr,
                  char *buf)
{
    struct gfs2_sbd *sdp = container_of(kobj, struct gfs2_sbd, sd_kobj);
    struct gfs2_attr *a = container_of(attr, struct gfs2_attr, attr);
    return a->show ? a->show(sdp, buf) : 0;
}

static ssize_t gfs2_attr_store(struct kobject *kobj, struct attribute *attr,
                   const char *buf, size_t len)
{
    struct gfs2_sbd *sdp = container_of(kobj, struct gfs2_sbd, sd_kobj);
    struct gfs2_attr *a = container_of(attr, struct gfs2_attr, attr);
    return a->store ? a->store(sdp, buf, len) : len;
}

static const struct sysfs_ops gfs2_attr_ops = {
    .show  = gfs2_attr_show,
    .store = gfs2_attr_store,
};


static struct kset *gfs2_kset;

static ssize_t id_show(struct gfs2_sbd *sdp, char *buf)
{
    return snprintf(buf, PAGE_SIZE, "%u:%u\n",
            MAJOR(sdp->sd_vfs->s_dev), MINOR(sdp->sd_vfs->s_dev));
}

static ssize_t fsname_show(struct gfs2_sbd *sdp, char *buf)
{
    return snprintf(buf, PAGE_SIZE, "%s\n", sdp->sd_fsname);
}

static int gfs2_uuid_valid(const u8 *uuid)
{
    int i;

    for (i = 0; i < 16; i++) {
        if (uuid[i])
            return 1;
    }
    return 0;
}

static ssize_t uuid_show(struct gfs2_sbd *sdp, char *buf)
{
    struct super_block *s = sdp->sd_vfs;
    const u8 *uuid = s->s_uuid;
    buf[0] = '\0';
    if (!gfs2_uuid_valid(uuid))
        return 0;
    return snprintf(buf, PAGE_SIZE, "%pUB\n", uuid);
}

static ssize_t freeze_show(struct gfs2_sbd *sdp, char *buf)
{
    unsigned int count;

    mutex_lock(&sdp->sd_freeze_lock);
    count = sdp->sd_freeze_count;
    mutex_unlock(&sdp->sd_freeze_lock);

    return snprintf(buf, PAGE_SIZE, "%u\n", count);
}

static ssize_t freeze_store(struct gfs2_sbd *sdp, const char *buf, size_t len)
{
    ssize_t ret = len;
    int error = 0;
    int n = simple_strtol(buf, NULL, 0);

    if (!capable(CAP_SYS_ADMIN))
        return -EACCES;

    switch (n) {
    case 0:
        gfs2_unfreeze_fs(sdp);
        break;
    case 1:
        error = gfs2_freeze_fs(sdp);
        break;
    default:
        ret = -EINVAL;
    }

    if (error)
        fs_warn(sdp, "freeze %d error %d", n, error);

    return ret;
}

static ssize_t withdraw_show(struct gfs2_sbd *sdp, char *buf)
{
    unsigned int b = test_bit(SDF_SHUTDOWN, &sdp->sd_flags);
    return snprintf(buf, PAGE_SIZE, "%u\n", b);
}

static ssize_t withdraw_store(struct gfs2_sbd *sdp, const char *buf, size_t len)
{
    if (!capable(CAP_SYS_ADMIN))
        return -EACCES;

    if (simple_strtol(buf, NULL, 0) != 1)
        return -EINVAL;

    gfs2_lm_withdraw(sdp,
        "GFS2: fsid=%s: withdrawing from cluster at user's request\n",
        sdp->sd_fsname);
    return len;
}

static ssize_t statfs_sync_store(struct gfs2_sbd *sdp, const char *buf,
                 size_t len)
{
    if (!capable(CAP_SYS_ADMIN))
        return -EACCES;

    if (simple_strtol(buf, NULL, 0) != 1)
        return -EINVAL;

    gfs2_statfs_sync(sdp->sd_vfs, 0);
    return len;
}

static ssize_t quota_sync_store(struct gfs2_sbd *sdp, const char *buf,
                size_t len)
{
    if (!capable(CAP_SYS_ADMIN))
        return -EACCES;

    if (simple_strtol(buf, NULL, 0) != 1)
        return -EINVAL;

    gfs2_quota_sync(sdp->sd_vfs, 0);
    return len;
}

static ssize_t quota_refresh_user_store(struct gfs2_sbd *sdp, const char *buf,
                    size_t len)
{
    int error;
    u32 id;

    if (!capable(CAP_SYS_ADMIN))
        return -EACCES;

    id = simple_strtoul(buf, NULL, 0);

    error = gfs2_quota_refresh(sdp, 1, id);
    return error ? error : len;
}

static ssize_t quota_refresh_group_store(struct gfs2_sbd *sdp, const char *buf,
                     size_t len)
{
    int error;
    u32 id;

    if (!capable(CAP_SYS_ADMIN))
        return -EACCES;

    id = simple_strtoul(buf, NULL, 0);

    error = gfs2_quota_refresh(sdp, 0, id);
    return error ? error : len;
}

static ssize_t demote_rq_store(struct gfs2_sbd *sdp, const char *buf, size_t len)
{
    struct gfs2_glock *gl;
    const struct gfs2_glock_operations *glops;
    unsigned int glmode;
    unsigned int gltype;
    unsigned long long glnum;
    char mode[16];
    int rv;

    if (!capable(CAP_SYS_ADMIN))
        return -EACCES;

    rv = sscanf(buf, "%u:%llu %15s", &gltype, &glnum,
            mode);
    if (rv != 3)
        return -EINVAL;

    if (strcmp(mode, "EX") == 0)
        glmode = LM_ST_UNLOCKED;
    else if ((strcmp(mode, "CW") == 0) || (strcmp(mode, "DF") == 0))
        glmode = LM_ST_DEFERRED;
    else if ((strcmp(mode, "PR") == 0) || (strcmp(mode, "SH") == 0))
        glmode = LM_ST_SHARED;
    else
        return -EINVAL;

    if (gltype > LM_TYPE_JOURNAL)
        return -EINVAL;
    if (gltype == LM_TYPE_NONDISK && glnum == GFS2_TRANS_LOCK)
        glops = &gfs2_trans_glops;
    else
        glops = gfs2_glops_list[gltype];
    if (glops == NULL)
        return -EINVAL;
    if (!test_and_set_bit(SDF_DEMOTE, &sdp->sd_flags))
        fs_info(sdp, "demote interface used\n");
    rv = gfs2_glock_get(sdp, glnum, glops, 0, &gl);
    if (rv)
        return rv;
    gfs2_glock_cb(gl, glmode);
    gfs2_glock_put(gl);
    return len;
}


#define GFS2_ATTR(name, mode, show, store) \
static struct gfs2_attr gfs2_attr_##name = __ATTR(name, mode, show, store)

GFS2_ATTR(id,                  0444, id_show,       NULL);
GFS2_ATTR(fsname,              0444, fsname_show,   NULL);
GFS2_ATTR(uuid,                0444, uuid_show,     NULL);
GFS2_ATTR(freeze,              0644, freeze_show,   freeze_store);
GFS2_ATTR(withdraw,            0644, withdraw_show, withdraw_store);
GFS2_ATTR(statfs_sync,         0200, NULL,          statfs_sync_store);
GFS2_ATTR(quota_sync,          0200, NULL,          quota_sync_store);
GFS2_ATTR(quota_refresh_user,  0200, NULL,          quota_refresh_user_store);
GFS2_ATTR(quota_refresh_group, 0200, NULL,          quota_refresh_group_store);
GFS2_ATTR(demote_rq,           0200, NULL,      demote_rq_store);

static struct attribute *gfs2_attrs[] = {
    &gfs2_attr_id.attr,
    &gfs2_attr_fsname.attr,
    &gfs2_attr_uuid.attr,
    &gfs2_attr_freeze.attr,
    &gfs2_attr_withdraw.attr,
    &gfs2_attr_statfs_sync.attr,
    &gfs2_attr_quota_sync.attr,
    &gfs2_attr_quota_refresh_user.attr,
    &gfs2_attr_quota_refresh_group.attr,
    &gfs2_attr_demote_rq.attr,
    NULL,
};

static void gfs2_sbd_release(struct kobject *kobj)
{
    struct gfs2_sbd *sdp = container_of(kobj, struct gfs2_sbd, sd_kobj);

    kfree(sdp);
}

static struct kobj_type gfs2_ktype = {
    .release = gfs2_sbd_release,
    .default_attrs = gfs2_attrs,
    .sysfs_ops     = &gfs2_attr_ops,
};


/*
 * lock_module. Originally from lock_dlm
 */

static ssize_t proto_name_show(struct gfs2_sbd *sdp, char *buf)
{
    const struct lm_lockops *ops = sdp->sd_lockstruct.ls_ops;
    return sprintf(buf, "%s\n", ops->lm_proto_name);
}

static ssize_t block_show(struct gfs2_sbd *sdp, char *buf)
{
    struct lm_lockstruct *ls = &sdp->sd_lockstruct;
    ssize_t ret;
    int val = 0;

    if (test_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags))
        val = 1;
    ret = sprintf(buf, "%d\n", val);
    return ret;
}

static ssize_t block_store(struct gfs2_sbd *sdp, const char *buf, size_t len)
{
    struct lm_lockstruct *ls = &sdp->sd_lockstruct;
    ssize_t ret = len;
    int val;

    val = simple_strtol(buf, NULL, 0);

    if (val == 1)
        set_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags);
    else if (val == 0) {
        clear_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags);
        smp_mb__after_clear_bit();
        gfs2_glock_thaw(sdp);
    } else {
        ret = -EINVAL;
    }
    return ret;
}

static ssize_t lkfirst_show(struct gfs2_sbd *sdp, char *buf)
{
    struct lm_lockstruct *ls = &sdp->sd_lockstruct;
    return sprintf(buf, "%d\n", ls->ls_first);
}

static ssize_t lkfirst_store(struct gfs2_sbd *sdp, const char *buf, size_t len)
{
    unsigned first;
    int rv;

    rv = sscanf(buf, "%u", &first);
    if (rv != 1 || first > 1)
        return -EINVAL;
    rv = wait_for_completion_killable(&sdp->sd_locking_init);
    if (rv)
        return rv;
    spin_lock(&sdp->sd_jindex_spin);
    rv = -EBUSY;
    if (test_bit(SDF_NOJOURNALID, &sdp->sd_flags) == 0)
        goto out;
    rv = -EINVAL;
    if (sdp->sd_args.ar_spectator)
        goto out;
    if (sdp->sd_lockstruct.ls_ops->lm_mount == NULL)
        goto out;
    sdp->sd_lockstruct.ls_first = first;
    rv = 0;
out:
        spin_unlock(&sdp->sd_jindex_spin);
        return rv ? rv : len;
}

static ssize_t first_done_show(struct gfs2_sbd *sdp, char *buf)
{
    struct lm_lockstruct *ls = &sdp->sd_lockstruct;
    return sprintf(buf, "%d\n", !!test_bit(DFL_FIRST_MOUNT_DONE, &ls->ls_recover_flags));
}

int gfs2_recover_set(struct gfs2_sbd *sdp, unsigned jid)
{
    struct gfs2_jdesc *jd;
    int rv;

    spin_lock(&sdp->sd_jindex_spin);
    rv = -EBUSY;
    if (sdp->sd_jdesc->jd_jid == jid)
        goto out;
    rv = -ENOENT;
    list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
        if (jd->jd_jid != jid)
            continue;
        rv = gfs2_recover_journal(jd, false);
        break;
    }
out:
    spin_unlock(&sdp->sd_jindex_spin);
    return rv;
}

static ssize_t recover_store(struct gfs2_sbd *sdp, const char *buf, size_t len)
{
    unsigned jid;
    int rv;

    rv = sscanf(buf, "%u", &jid);
    if (rv != 1)
        return -EINVAL;

    if (test_bit(SDF_NORECOVERY, &sdp->sd_flags)) {
        rv = -ESHUTDOWN;
        goto out;
    }

    rv = gfs2_recover_set(sdp, jid);
out:
    return rv ? rv : len;
}

static ssize_t recover_done_show(struct gfs2_sbd *sdp, char *buf)
{
    struct lm_lockstruct *ls = &sdp->sd_lockstruct;
    return sprintf(buf, "%d\n", ls->ls_recover_jid_done);
}

static ssize_t recover_status_show(struct gfs2_sbd *sdp, char *buf)
{
    struct lm_lockstruct *ls = &sdp->sd_lockstruct;
    return sprintf(buf, "%d\n", ls->ls_recover_jid_status);
}

static ssize_t jid_show(struct gfs2_sbd *sdp, char *buf)
{
    return sprintf(buf, "%d\n", sdp->sd_lockstruct.ls_jid);
}

static ssize_t jid_store(struct gfs2_sbd *sdp, const char *buf, size_t len)
{
        int jid;
    int rv;

    rv = sscanf(buf, "%d", &jid);
    if (rv != 1)
        return -EINVAL;
    rv = wait_for_completion_killable(&sdp->sd_locking_init);
    if (rv)
        return rv;
    spin_lock(&sdp->sd_jindex_spin);
    rv = -EINVAL;
    if (sdp->sd_lockstruct.ls_ops->lm_mount == NULL)
        goto out;
    rv = -EBUSY;
    if (test_bit(SDF_NOJOURNALID, &sdp->sd_flags) == 0)
        goto out;
    rv = 0;
    if (sdp->sd_args.ar_spectator && jid > 0)
        rv = jid = -EINVAL;
    sdp->sd_lockstruct.ls_jid = jid;
    clear_bit(SDF_NOJOURNALID, &sdp->sd_flags);
    smp_mb__after_clear_bit();
    wake_up_bit(&sdp->sd_flags, SDF_NOJOURNALID);
out:
    spin_unlock(&sdp->sd_jindex_spin);
    return rv ? rv : len;
}

#define GDLM_ATTR(_name,_mode,_show,_store) \
static struct gfs2_attr gdlm_attr_##_name = __ATTR(_name,_mode,_show,_store)

GDLM_ATTR(proto_name,       0444, proto_name_show,      NULL);
GDLM_ATTR(block,        0644, block_show,       block_store);
GDLM_ATTR(withdraw,     0644, withdraw_show,        withdraw_store);
GDLM_ATTR(jid,          0644, jid_show,         jid_store);
GDLM_ATTR(first,        0644, lkfirst_show,     lkfirst_store);
GDLM_ATTR(first_done,       0444, first_done_show,      NULL);
GDLM_ATTR(recover,      0600, NULL,         recover_store);
GDLM_ATTR(recover_done,     0444, recover_done_show,    NULL);
GDLM_ATTR(recover_status,   0444, recover_status_show,  NULL);

static struct attribute *lock_module_attrs[] = {
    &gdlm_attr_proto_name.attr,
    &gdlm_attr_block.attr,
    &gdlm_attr_withdraw.attr,
    &gdlm_attr_jid.attr,
    &gdlm_attr_first.attr,
    &gdlm_attr_first_done.attr,
    &gdlm_attr_recover.attr,
    &gdlm_attr_recover_done.attr,
    &gdlm_attr_recover_status.attr,
    NULL,
};

/*
 * get and set struct gfs2_tune fields
 */

static ssize_t quota_scale_show(struct gfs2_sbd *sdp, char *buf)
{
    return snprintf(buf, PAGE_SIZE, "%u %u\n",
            sdp->sd_tune.gt_quota_scale_num,
            sdp->sd_tune.gt_quota_scale_den);
}

static ssize_t quota_scale_store(struct gfs2_sbd *sdp, const char *buf,
                 size_t len)
{
    struct gfs2_tune *gt = &sdp->sd_tune;
    unsigned int x, y;

    if (!capable(CAP_SYS_ADMIN))
        return -EACCES;

    if (sscanf(buf, "%u %u", &x, &y) != 2 || !y)
        return -EINVAL;

    spin_lock(&gt->gt_spin);
    gt->gt_quota_scale_num = x;
    gt->gt_quota_scale_den = y;
    spin_unlock(&gt->gt_spin);
    return len;
}

static ssize_t tune_set(struct gfs2_sbd *sdp, unsigned int *field,
            int check_zero, const char *buf, size_t len)
{
    struct gfs2_tune *gt = &sdp->sd_tune;
    unsigned int x;

    if (!capable(CAP_SYS_ADMIN))
        return -EACCES;

    x = simple_strtoul(buf, NULL, 0);

    if (check_zero && !x)
        return -EINVAL;

    spin_lock(&gt->gt_spin);
    *field = x;
    spin_unlock(&gt->gt_spin);
    return len;
}

#define TUNE_ATTR_3(name, show, store)                                        \
static struct gfs2_attr tune_attr_##name = __ATTR(name, 0644, show, store)

#define TUNE_ATTR_2(name, store)                                              \
static ssize_t name##_show(struct gfs2_sbd *sdp, char *buf)                   \
{                                                                             \
    return snprintf(buf, PAGE_SIZE, "%u\n", sdp->sd_tune.gt_##name);      \
}                                                                             \
TUNE_ATTR_3(name, name##_show, store)

#define TUNE_ATTR(name, check_zero)                                           \
static ssize_t name##_store(struct gfs2_sbd *sdp, const char *buf, size_t len)\
{                                                                             \
    return tune_set(sdp, &sdp->sd_tune.gt_##name, check_zero, buf, len);  \
}                                                                             \
TUNE_ATTR_2(name, name##_store)

TUNE_ATTR(quota_warn_period, 0);
TUNE_ATTR(quota_quantum, 0);
TUNE_ATTR(max_readahead, 0);
TUNE_ATTR(complain_secs, 0);
TUNE_ATTR(statfs_slow, 0);
TUNE_ATTR(new_files_jdata, 0);
TUNE_ATTR(quota_simul_sync, 1);
TUNE_ATTR(statfs_quantum, 1);
TUNE_ATTR_3(quota_scale, quota_scale_show, quota_scale_store);

static struct attribute *tune_attrs[] = {
    &tune_attr_quota_warn_period.attr,
    &tune_attr_quota_quantum.attr,
    &tune_attr_max_readahead.attr,
    &tune_attr_complain_secs.attr,
    &tune_attr_statfs_slow.attr,
    &tune_attr_quota_simul_sync.attr,
    &tune_attr_statfs_quantum.attr,
    &tune_attr_quota_scale.attr,
    &tune_attr_new_files_jdata.attr,
    NULL,
};

static struct attribute_group tune_group = {
    .name = "tune",
    .attrs = tune_attrs,
};

static struct attribute_group lock_module_group = {
    .name = "lock_module",
    .attrs = lock_module_attrs,
};

int gfs2_sys_fs_add(struct gfs2_sbd *sdp)
{
    struct super_block *sb = sdp->sd_vfs;
    int error;
    char ro[20];
    char spectator[20];
    char *envp[] = { ro, spectator, NULL };
    int sysfs_frees_sdp = 0;

    sprintf(ro, "RDONLY=%d", (sb->s_flags & MS_RDONLY) ? 1 : 0);
    sprintf(spectator, "SPECTATOR=%d", sdp->sd_args.ar_spectator ? 1 : 0);

    sdp->sd_kobj.kset = gfs2_kset;
    error = kobject_init_and_add(&sdp->sd_kobj, &gfs2_ktype, NULL,
                     "%s", sdp->sd_table_name);
    if (error)
        goto fail_reg;

    sysfs_frees_sdp = 1; /* Freeing sdp is now done by sysfs calling
                function gfs2_sbd_release. */
    error = sysfs_create_group(&sdp->sd_kobj, &tune_group);
    if (error)
        goto fail_reg;

    error = sysfs_create_group(&sdp->sd_kobj, &lock_module_group);
    if (error)
        goto fail_tune;

    error = sysfs_create_link(&sdp->sd_kobj,
                  &disk_to_dev(sb->s_bdev->bd_disk)->kobj,
                  "device");
    if (error)
        goto fail_lock_module;

    kobject_uevent_env(&sdp->sd_kobj, KOBJ_ADD, envp);
    return 0;

fail_lock_module:
    sysfs_remove_group(&sdp->sd_kobj, &lock_module_group);
fail_tune:
    sysfs_remove_group(&sdp->sd_kobj, &tune_group);
fail_reg:
    free_percpu(sdp->sd_lkstats);
    fs_err(sdp, "error %d adding sysfs files", error);
    if (sysfs_frees_sdp)
        kobject_put(&sdp->sd_kobj);
    else
        kfree(sdp);
    sb->s_fs_info = NULL;
    return error;
}

void gfs2_sys_fs_del(struct gfs2_sbd *sdp)
{
    sysfs_remove_link(&sdp->sd_kobj, "device");
    sysfs_remove_group(&sdp->sd_kobj, &tune_group);
    sysfs_remove_group(&sdp->sd_kobj, &lock_module_group);
    kobject_put(&sdp->sd_kobj);
}

static int gfs2_uevent(struct kset *kset, struct kobject *kobj,
               struct kobj_uevent_env *env)
{
    struct gfs2_sbd *sdp = container_of(kobj, struct gfs2_sbd, sd_kobj);
    struct super_block *s = sdp->sd_vfs;
    const u8 *uuid = s->s_uuid;

    add_uevent_var(env, "LOCKTABLE=%s", sdp->sd_table_name);
    add_uevent_var(env, "LOCKPROTO=%s", sdp->sd_proto_name);
    if (!test_bit(SDF_NOJOURNALID, &sdp->sd_flags))
        add_uevent_var(env, "JOURNALID=%d", sdp->sd_lockstruct.ls_jid);
    if (gfs2_uuid_valid(uuid))
        add_uevent_var(env, "UUID=%pUB", uuid);
    return 0;
}

static const struct kset_uevent_ops gfs2_uevent_ops = {
    .uevent = gfs2_uevent,
};

int gfs2_sys_init(void)
{
    gfs2_kset = kset_create_and_add("gfs2", &gfs2_uevent_ops, fs_kobj);
    if (!gfs2_kset)
        return -ENOMEM;
    return 0;
}

void gfs2_sys_uninit(void)
{
    kset_unregister(gfs2_kset);
}