#include <asm/div64.h>
#include <linux/blkdev.h> /* sector_div */
#include <linux/pid_namespace.h>
+#include <linux/fs_pin.h>
/*
* These constants control the amount of freespace that suspend and
/*
* External references and all of the globals.
*/
-static void do_acct_process(struct bsd_acct_struct *acct,
- struct pid_namespace *ns, struct file *);
+static void do_acct_process(struct bsd_acct_struct *acct);
-/*
- * This structure is used so that all the data protected by lock
- * can be placed in the same cache line as the lock. This primes
- * the cache line to have the data after getting the lock.
- */
struct bsd_acct_struct {
+ struct fs_pin pin;
+ struct mutex lock;
int active;
unsigned long needcheck;
struct file *file;
struct pid_namespace *ns;
- struct list_head list;
+ struct work_struct work;
+ struct completion done;
};
-static DEFINE_SPINLOCK(acct_lock);
-static LIST_HEAD(acct_list);
-
/*
* Check the amount of free space and suspend/resume accordingly.
*/
-static int check_free_space(struct bsd_acct_struct *acct, struct file *file)
+static int check_free_space(struct bsd_acct_struct *acct)
{
struct kstatfs sbuf;
- int res;
- int act;
- u64 resume;
- u64 suspend;
-
- spin_lock(&acct_lock);
- res = acct->active;
- if (!file || time_is_before_jiffies(acct->needcheck))
+
+ if (time_is_before_jiffies(acct->needcheck))
goto out;
- spin_unlock(&acct_lock);
/* May block */
- if (vfs_statfs(&file->f_path, &sbuf))
- return res;
- suspend = sbuf.f_blocks * SUSPEND;
- resume = sbuf.f_blocks * RESUME;
-
- do_div(suspend, 100);
- do_div(resume, 100);
-
- if (sbuf.f_bavail <= suspend)
- act = -1;
- else if (sbuf.f_bavail >= resume)
- act = 1;
- else
- act = 0;
-
- /*
- * If some joker switched acct->file under us we'ld better be
- * silent and _not_ touch anything.
- */
- spin_lock(&acct_lock);
- if (file != acct->file) {
- if (act)
- res = act > 0;
+ if (vfs_statfs(&acct->file->f_path, &sbuf))
goto out;
- }
if (acct->active) {
- if (act < 0) {
+ u64 suspend = sbuf.f_blocks * SUSPEND;
+ do_div(suspend, 100);
+ if (sbuf.f_bavail <= suspend) {
acct->active = 0;
- printk(KERN_INFO "Process accounting paused\n");
+ pr_info("Process accounting paused\n");
}
} else {
- if (act > 0) {
+ u64 resume = sbuf.f_blocks * RESUME;
+ do_div(resume, 100);
+ if (sbuf.f_bavail >= resume) {
acct->active = 1;
- printk(KERN_INFO "Process accounting resumed\n");
+ pr_info("Process accounting resumed\n");
}
}
acct->needcheck = jiffies + ACCT_TIMEOUT*HZ;
- res = acct->active;
out:
- spin_unlock(&acct_lock);
+ return acct->active;
+}
+
+static struct bsd_acct_struct *acct_get(struct pid_namespace *ns)
+{
+ struct bsd_acct_struct *res;
+again:
+ smp_rmb();
+ rcu_read_lock();
+ res = ACCESS_ONCE(ns->bacct);
+ if (!res) {
+ rcu_read_unlock();
+ return NULL;
+ }
+ if (!atomic_long_inc_not_zero(&res->pin.count)) {
+ rcu_read_unlock();
+ cpu_relax();
+ goto again;
+ }
+ rcu_read_unlock();
+ mutex_lock(&res->lock);
+ if (!res->ns) {
+ mutex_unlock(&res->lock);
+ pin_put(&res->pin);
+ goto again;
+ }
return res;
}
-/*
- * Close the old accounting file (if currently open) and then replace
- * it with file (if non-NULL).
- *
- * NOTE: acct_lock MUST be held on entry and exit.
- */
-static void acct_file_reopen(struct bsd_acct_struct *acct, struct file *file,
- struct pid_namespace *ns)
+static void close_work(struct work_struct *work)
+{
+ struct bsd_acct_struct *acct = container_of(work, struct bsd_acct_struct, work);
+ struct file *file = acct->file;
+ if (file->f_op->flush)
+ file->f_op->flush(file, NULL);
+ __fput_sync(file);
+ complete(&acct->done);
+}
+
+static void acct_kill(struct bsd_acct_struct *acct,
+ struct bsd_acct_struct *new)
{
- struct file *old_acct = NULL;
- struct pid_namespace *old_ns = NULL;
-
- if (acct->file) {
- old_acct = acct->file;
- old_ns = acct->ns;
- acct->active = 0;
- acct->file = NULL;
+ if (acct) {
+ struct pid_namespace *ns = acct->ns;
+ do_acct_process(acct);
+ INIT_WORK(&acct->work, close_work);
+ init_completion(&acct->done);
+ schedule_work(&acct->work);
+ wait_for_completion(&acct->done);
+ pin_remove(&acct->pin);
+ ns->bacct = new;
acct->ns = NULL;
- list_del(&acct->list);
+ atomic_long_dec(&acct->pin.count);
+ mutex_unlock(&acct->lock);
+ pin_put(&acct->pin);
}
- if (file) {
- acct->file = file;
- acct->ns = ns;
- acct->needcheck = jiffies + ACCT_TIMEOUT*HZ;
- acct->active = 1;
- list_add(&acct->list, &acct_list);
- }
- if (old_acct) {
- mnt_unpin(old_acct->f_path.mnt);
- spin_unlock(&acct_lock);
- do_acct_process(acct, old_ns, old_acct);
- filp_close(old_acct, NULL);
- spin_lock(&acct_lock);
+}
+
+static void acct_pin_kill(struct fs_pin *pin)
+{
+ struct bsd_acct_struct *acct;
+ acct = container_of(pin, struct bsd_acct_struct, pin);
+ mutex_lock(&acct->lock);
+ if (!acct->ns) {
+ mutex_unlock(&acct->lock);
+ pin_put(pin);
+ acct = NULL;
}
+ acct_kill(acct, NULL);
}
static int acct_on(struct filename *pathname)
{
struct file *file;
- struct vfsmount *mnt;
- struct pid_namespace *ns;
- struct bsd_acct_struct *acct = NULL;
+ struct vfsmount *mnt, *internal;
+ struct pid_namespace *ns = task_active_pid_ns(current);
+ struct bsd_acct_struct *acct, *old;
+ int err;
+
+ acct = kzalloc(sizeof(struct bsd_acct_struct), GFP_KERNEL);
+ if (!acct)
+ return -ENOMEM;
/* Difference from BSD - they don't do O_APPEND */
file = file_open_name(pathname, O_WRONLY|O_APPEND|O_LARGEFILE, 0);
- if (IS_ERR(file))
+ if (IS_ERR(file)) {
+ kfree(acct);
return PTR_ERR(file);
+ }
if (!S_ISREG(file_inode(file)->i_mode)) {
+ kfree(acct);
filp_close(file, NULL);
return -EACCES;
}
if (!file->f_op->write) {
+ kfree(acct);
filp_close(file, NULL);
return -EIO;
}
-
- ns = task_active_pid_ns(current);
- if (ns->bacct == NULL) {
- acct = kzalloc(sizeof(struct bsd_acct_struct), GFP_KERNEL);
- if (acct == NULL) {
- filp_close(file, NULL);
- return -ENOMEM;
- }
+ internal = mnt_clone_internal(&file->f_path);
+ if (IS_ERR(internal)) {
+ kfree(acct);
+ filp_close(file, NULL);
+ return PTR_ERR(internal);
}
-
- spin_lock(&acct_lock);
- if (ns->bacct == NULL) {
- ns->bacct = acct;
- acct = NULL;
+ err = mnt_want_write(internal);
+ if (err) {
+ mntput(internal);
+ kfree(acct);
+ filp_close(file, NULL);
+ return err;
}
-
mnt = file->f_path.mnt;
- mnt_pin(mnt);
- acct_file_reopen(ns->bacct, file, ns);
- spin_unlock(&acct_lock);
-
- mntput(mnt); /* it's pinned, now give up active reference */
- kfree(acct);
-
+ file->f_path.mnt = internal;
+
+ atomic_long_set(&acct->pin.count, 1);
+ acct->pin.kill = acct_pin_kill;
+ acct->file = file;
+ acct->needcheck = jiffies;
+ acct->ns = ns;
+ mutex_init(&acct->lock);
+ mutex_lock_nested(&acct->lock, 1); /* nobody has seen it yet */
+ pin_insert(&acct->pin, mnt);
+
+ old = acct_get(ns);
+ if (old)
+ acct_kill(old, acct);
+ else
+ ns->bacct = acct;
+ mutex_unlock(&acct->lock);
+ mnt_drop_write(mnt);
+ mntput(mnt);
return 0;
}
+static DEFINE_MUTEX(acct_on_mutex);
+
/**
* sys_acct - enable/disable process accounting
* @name: file name for accounting records or NULL to shutdown accounting
if (name) {
struct filename *tmp = getname(name);
+
if (IS_ERR(tmp))
return PTR_ERR(tmp);
+ mutex_lock(&acct_on_mutex);
error = acct_on(tmp);
+ mutex_unlock(&acct_on_mutex);
putname(tmp);
} else {
- struct bsd_acct_struct *acct;
-
- acct = task_active_pid_ns(current)->bacct;
- if (acct == NULL)
- return 0;
-
- spin_lock(&acct_lock);
- acct_file_reopen(acct, NULL, NULL);
- spin_unlock(&acct_lock);
+ acct_kill(acct_get(task_active_pid_ns(current)), NULL);
}
return error;
}
-/**
- * acct_auto_close - turn off a filesystem's accounting if it is on
- * @m: vfsmount being shut down
- *
- * If the accounting is turned on for a file in the subtree pointed to
- * to by m, turn accounting off. Done when m is about to die.
- */
-void acct_auto_close_mnt(struct vfsmount *m)
-{
- struct bsd_acct_struct *acct;
-
- spin_lock(&acct_lock);
-restart:
- list_for_each_entry(acct, &acct_list, list)
- if (acct->file && acct->file->f_path.mnt == m) {
- acct_file_reopen(acct, NULL, NULL);
- goto restart;
- }
- spin_unlock(&acct_lock);
-}
-
-/**
- * acct_auto_close - turn off a filesystem's accounting if it is on
- * @sb: super block for the filesystem
- *
- * If the accounting is turned on for a file in the filesystem pointed
- * to by sb, turn accounting off.
- */
-void acct_auto_close(struct super_block *sb)
-{
- struct bsd_acct_struct *acct;
-
- spin_lock(&acct_lock);
-restart:
- list_for_each_entry(acct, &acct_list, list)
- if (acct->file && acct->file->f_path.dentry->d_sb == sb) {
- acct_file_reopen(acct, NULL, NULL);
- goto restart;
- }
- spin_unlock(&acct_lock);
-}
-
void acct_exit_ns(struct pid_namespace *ns)
{
- struct bsd_acct_struct *acct = ns->bacct;
-
- if (acct == NULL)
- return;
-
- spin_lock(&acct_lock);
- if (acct->file != NULL)
- acct_file_reopen(acct, NULL, NULL);
- spin_unlock(&acct_lock);
-
- kfree(acct);
+ acct_kill(acct_get(ns), NULL);
}
/*
return exp;
}
-#if ACCT_VERSION==1 || ACCT_VERSION==2
+#if ACCT_VERSION == 1 || ACCT_VERSION == 2
/*
* encode an u64 into a comp2_t (24 bits)
*
#define MANTSIZE2 20 /* 20 bit mantissa. */
#define EXPSIZE2 5 /* 5 bit base 2 exponent. */
#define MAXFRACT2 ((1ul << MANTSIZE2) - 1) /* Maximum fractional value. */
-#define MAXEXP2 ((1 <<EXPSIZE2) - 1) /* Maximum exponent. */
+#define MAXEXP2 ((1 << EXPSIZE2) - 1) /* Maximum exponent. */
static comp2_t encode_comp2_t(u64 value)
{
}
#endif
-#if ACCT_VERSION==3
+#if ACCT_VERSION == 3
/*
* encode an u64 into a 32 bit IEEE float
*/
unsigned exp = 190;
unsigned u;
- if (value==0) return 0;
- while ((s64)value > 0){
+ if (value == 0)
+ return 0;
+ while ((s64)value > 0) {
value <<= 1;
exp--;
}
* do_exit() or when switching to a different output file.
*/
-/*
- * do_acct_process does all actual work. Caller holds the reference to file.
- */
-static void do_acct_process(struct bsd_acct_struct *acct,
- struct pid_namespace *ns, struct file *file)
+static void fill_ac(acct_t *ac)
{
struct pacct_struct *pacct = ¤t->signal->pacct;
- acct_t ac;
- mm_segment_t fs;
- unsigned long flim;
u64 elapsed, run_time;
struct tty_struct *tty;
- const struct cred *orig_cred;
-
- /* Perform file operations on behalf of whoever enabled accounting */
- orig_cred = override_creds(file->f_cred);
-
- /*
- * First check to see if there is enough free_space to continue
- * the process accounting system.
- */
- if (!check_free_space(acct, file))
- goto out;
/*
* Fill the accounting struct with the needed info as recorded
* by the different kernel functions.
*/
- memset(&ac, 0, sizeof(acct_t));
+ memset(ac, 0, sizeof(acct_t));
- ac.ac_version = ACCT_VERSION | ACCT_BYTEORDER;
- strlcpy(ac.ac_comm, current->comm, sizeof(ac.ac_comm));
+ ac->ac_version = ACCT_VERSION | ACCT_BYTEORDER;
+ strlcpy(ac->ac_comm, current->comm, sizeof(ac->ac_comm));
/* calculate run_time in nsec*/
run_time = ktime_get_ns();
run_time -= current->group_leader->start_time;
/* convert nsec -> AHZ */
elapsed = nsec_to_AHZ(run_time);
-#if ACCT_VERSION==3
- ac.ac_etime = encode_float(elapsed);
+#if ACCT_VERSION == 3
+ ac->ac_etime = encode_float(elapsed);
#else
- ac.ac_etime = encode_comp_t(elapsed < (unsigned long) -1l ?
- (unsigned long) elapsed : (unsigned long) -1l);
+ ac->ac_etime = encode_comp_t(elapsed < (unsigned long) -1l ?
+ (unsigned long) elapsed : (unsigned long) -1l);
#endif
-#if ACCT_VERSION==1 || ACCT_VERSION==2
+#if ACCT_VERSION == 1 || ACCT_VERSION == 2
{
/* new enlarged etime field */
comp2_t etime = encode_comp2_t(elapsed);
- ac.ac_etime_hi = etime >> 16;
- ac.ac_etime_lo = (u16) etime;
+
+ ac->ac_etime_hi = etime >> 16;
+ ac->ac_etime_lo = (u16) etime;
}
#endif
do_div(elapsed, AHZ);
- ac.ac_btime = get_seconds() - elapsed;
+ ac->ac_btime = get_seconds() - elapsed;
+#if ACCT_VERSION==2
+ ac->ac_ahz = AHZ;
+#endif
+
+ spin_lock_irq(¤t->sighand->siglock);
+ tty = current->signal->tty; /* Safe as we hold the siglock */
+ ac->ac_tty = tty ? old_encode_dev(tty_devnum(tty)) : 0;
+ ac->ac_utime = encode_comp_t(jiffies_to_AHZ(cputime_to_jiffies(pacct->ac_utime)));
+ ac->ac_stime = encode_comp_t(jiffies_to_AHZ(cputime_to_jiffies(pacct->ac_stime)));
+ ac->ac_flag = pacct->ac_flag;
+ ac->ac_mem = encode_comp_t(pacct->ac_mem);
+ ac->ac_minflt = encode_comp_t(pacct->ac_minflt);
+ ac->ac_majflt = encode_comp_t(pacct->ac_majflt);
+ ac->ac_exitcode = pacct->ac_exitcode;
+ spin_unlock_irq(¤t->sighand->siglock);
+}
+/*
+ * do_acct_process does all actual work. Caller holds the reference to file.
+ */
+static void do_acct_process(struct bsd_acct_struct *acct)
+{
+ acct_t ac;
+ unsigned long flim;
+ const struct cred *orig_cred;
+ struct pid_namespace *ns = acct->ns;
+ struct file *file = acct->file;
+
+ /*
+ * Accounting records are not subject to resource limits.
+ */
+ flim = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
+ current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
+ /* Perform file operations on behalf of whoever enabled accounting */
+ orig_cred = override_creds(file->f_cred);
+
+ /*
+ * First check to see if there is enough free_space to continue
+ * the process accounting system.
+ */
+ if (!check_free_space(acct))
+ goto out;
+
+ fill_ac(&ac);
/* we really need to bite the bullet and change layout */
ac.ac_uid = from_kuid_munged(file->f_cred->user_ns, orig_cred->uid);
ac.ac_gid = from_kgid_munged(file->f_cred->user_ns, orig_cred->gid);
-#if ACCT_VERSION==2
- ac.ac_ahz = AHZ;
-#endif
-#if ACCT_VERSION==1 || ACCT_VERSION==2
+#if ACCT_VERSION == 1 || ACCT_VERSION == 2
/* backward-compatible 16 bit fields */
ac.ac_uid16 = ac.ac_uid;
ac.ac_gid16 = ac.ac_gid;
#endif
-#if ACCT_VERSION==3
+#if ACCT_VERSION == 3
ac.ac_pid = task_tgid_nr_ns(current, ns);
rcu_read_lock();
ac.ac_ppid = task_tgid_nr_ns(rcu_dereference(current->real_parent), ns);
rcu_read_unlock();
#endif
-
- spin_lock_irq(¤t->sighand->siglock);
- tty = current->signal->tty; /* Safe as we hold the siglock */
- ac.ac_tty = tty ? old_encode_dev(tty_devnum(tty)) : 0;
- ac.ac_utime = encode_comp_t(jiffies_to_AHZ(cputime_to_jiffies(pacct->ac_utime)));
- ac.ac_stime = encode_comp_t(jiffies_to_AHZ(cputime_to_jiffies(pacct->ac_stime)));
- ac.ac_flag = pacct->ac_flag;
- ac.ac_mem = encode_comp_t(pacct->ac_mem);
- ac.ac_minflt = encode_comp_t(pacct->ac_minflt);
- ac.ac_majflt = encode_comp_t(pacct->ac_majflt);
- ac.ac_exitcode = pacct->ac_exitcode;
- spin_unlock_irq(¤t->sighand->siglock);
- ac.ac_io = encode_comp_t(0 /* current->io_usage */); /* %% */
- ac.ac_rw = encode_comp_t(ac.ac_io / 1024);
- ac.ac_swaps = encode_comp_t(0);
-
/*
* Get freeze protection. If the fs is frozen, just skip the write
* as we could deadlock the system otherwise.
*/
- if (!file_start_write_trylock(file))
- goto out;
- /*
- * Kernel segment override to datasegment and write it
- * to the accounting file.
- */
- fs = get_fs();
- set_fs(KERNEL_DS);
- /*
- * Accounting records are not subject to resource limits.
- */
- flim = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
- current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
- file->f_op->write(file, (char *)&ac,
- sizeof(acct_t), &file->f_pos);
- current->signal->rlim[RLIMIT_FSIZE].rlim_cur = flim;
- set_fs(fs);
- file_end_write(file);
+ if (file_start_write_trylock(file)) {
+ /* it's been opened O_APPEND, so position is irrelevant */
+ loff_t pos = 0;
+ __kernel_write(file, (char *)&ac, sizeof(acct_t), &pos);
+ file_end_write(file);
+ }
out:
+ current->signal->rlim[RLIMIT_FSIZE].rlim_cur = flim;
revert_creds(orig_cred);
}
if (group_dead && current->mm) {
struct vm_area_struct *vma;
+
down_read(¤t->mm->mmap_sem);
vma = current->mm->mmap;
while (vma) {
spin_unlock_irq(¤t->sighand->siglock);
}
-static void acct_process_in_ns(struct pid_namespace *ns)
+static void slow_acct_process(struct pid_namespace *ns)
{
- struct file *file = NULL;
- struct bsd_acct_struct *acct;
-
- acct = ns->bacct;
- /*
- * accelerate the common fastpath:
- */
- if (!acct || !acct->file)
- return;
-
- spin_lock(&acct_lock);
- file = acct->file;
- if (unlikely(!file)) {
- spin_unlock(&acct_lock);
- return;
+ for ( ; ns; ns = ns->parent) {
+ struct bsd_acct_struct *acct = acct_get(ns);
+ if (acct) {
+ do_acct_process(acct);
+ mutex_unlock(&acct->lock);
+ pin_put(&acct->pin);
+ }
}
- get_file(file);
- spin_unlock(&acct_lock);
-
- do_acct_process(acct, ns, file);
- fput(file);
}
/**
- * acct_process - now just a wrapper around acct_process_in_ns,
- * which in turn is a wrapper around do_acct_process.
+ * acct_process
*
* handles process accounting for an exiting task
*/
* alive and holds its namespace, which in turn holds
* its parent.
*/
- for (ns = task_active_pid_ns(current); ns != NULL; ns = ns->parent)
- acct_process_in_ns(ns);
+ for (ns = task_active_pid_ns(current); ns != NULL; ns = ns->parent) {
+ if (ns->bacct)
+ break;
+ }
+ if (unlikely(ns))
+ slow_acct_process(ns);
}
git.samba.org / sfrench / cifs-2.6.git / blobdiff