Release 4.7 fs/super.c
/*
* linux/fs/super.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* super.c contains code to handle: - mount structures
* - super-block tables
* - filesystem drivers list
* - mount system call
* - umount system call
* - ustat system call
*
* GK 2/5/95 - Changed to support mounting the root fs via NFS
*
* Added kerneld support: Jacques Gelinas and Bjorn Ekwall
* Added change_root: Werner Almesberger & Hans Lermen, Feb '96
* Added options to /proc/mounts:
* Torbjörn Lindh (torbjorn.lindh@gopta.se), April 14, 1996.
* Added devfs support: Richard Gooch <rgooch@atnf.csiro.au>, 13-JAN-1998
* Heavily rewritten for 'one fs - one tree' dcache architecture. AV, Mar 2000
*/
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/blkdev.h>
#include <linux/mount.h>
#include <linux/security.h>
#include <linux/writeback.h> /* for the emergency remount stuff */
#include <linux/idr.h>
#include <linux/mutex.h>
#include <linux/backing-dev.h>
#include <linux/rculist_bl.h>
#include <linux/cleancache.h>
#include <linux/fsnotify.h>
#include <linux/lockdep.h>
#include "internal.h"
static LIST_HEAD(super_blocks);
static DEFINE_SPINLOCK(sb_lock);
static char *sb_writers_name[SB_FREEZE_LEVELS] = {
"sb_writers",
"sb_pagefaults",
"sb_internal",
};
/*
* One thing we have to be careful of with a per-sb shrinker is that we don't
* drop the last active reference to the superblock from within the shrinker.
* If that happens we could trigger unregistering the shrinker from within the
* shrinker path and that leads to deadlock on the shrinker_rwsem. Hence we
* take a passive reference to the superblock to avoid this from occurring.
*/
static unsigned long super_cache_scan(struct shrinker *shrink,
struct shrink_control *sc)
{
struct super_block *sb;
long fs_objects = 0;
long total_objects;
long freed = 0;
long dentries;
long inodes;
sb = container_of(shrink, struct super_block, s_shrink);
/*
* Deadlock avoidance. We may hold various FS locks, and we don't want
* to recurse into the FS that called us in clear_inode() and friends..
*/
if (!(sc->gfp_mask & __GFP_FS))
return SHRINK_STOP;
if (!trylock_super(sb))
return SHRINK_STOP;
if (sb->s_op->nr_cached_objects)
fs_objects = sb->s_op->nr_cached_objects(sb, sc);
inodes = list_lru_shrink_count(&sb->s_inode_lru, sc);
dentries = list_lru_shrink_count(&sb->s_dentry_lru, sc);
total_objects = dentries + inodes + fs_objects + 1;
if (!total_objects)
total_objects = 1;
/* proportion the scan between the caches */
dentries = mult_frac(sc->nr_to_scan, dentries, total_objects);
inodes = mult_frac(sc->nr_to_scan, inodes, total_objects);
fs_objects = mult_frac(sc->nr_to_scan, fs_objects, total_objects);
/*
* prune the dcache first as the icache is pinned by it, then
* prune the icache, followed by the filesystem specific caches
*
* Ensure that we always scan at least one object - memcg kmem
* accounting uses this to fully empty the caches.
*/
sc->nr_to_scan = dentries + 1;
freed = prune_dcache_sb(sb, sc);
sc->nr_to_scan = inodes + 1;
freed += prune_icache_sb(sb, sc);
if (fs_objects) {
sc->nr_to_scan = fs_objects + 1;
freed += sb->s_op->free_cached_objects(sb, sc);
}
up_read(&sb->s_umount);
return freed;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
dave chinner | dave chinner | 197 | 76.95% | 6 | 50.00% |
vladimir davydov | vladimir davydov | 35 | 13.67% | 3 | 25.00% |
glauber costa | glauber costa | 10 | 3.91% | 1 | 8.33% |
tetsuo handa | tetsuo handa | 9 | 3.52% | 1 | 8.33% |
konstantin khlebnikov | konstantin khlebnikov | 5 | 1.95% | 1 | 8.33% |
| Total | 256 | 100.00% | 12 | 100.00% |
static unsigned long super_cache_count(struct shrinker *shrink,
struct shrink_control *sc)
{
struct super_block *sb;
long total_objects = 0;
sb = container_of(shrink, struct super_block, s_shrink);
/*
* Don't call trylock_super as it is a potential
* scalability bottleneck. The counts could get updated
* between super_cache_count and super_cache_scan anyway.
* Call to super_cache_count with shrinker_rwsem held
* ensures the safety of call to list_lru_shrink_count() and
* s_op->nr_cached_objects().
*/
if (sb->s_op && sb->s_op->nr_cached_objects)
total_objects = sb->s_op->nr_cached_objects(sb, sc);
total_objects += list_lru_shrink_count(&sb->s_dentry_lru, sc);
total_objects += list_lru_shrink_count(&sb->s_inode_lru, sc);
total_objects = vfs_pressure_ratio(total_objects);
return total_objects;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
dave chinner | dave chinner | 93 | 93.94% | 6 | 66.67% |
glauber costa | glauber costa | 3 | 3.03% | 1 | 11.11% |
vladimir davydov | vladimir davydov | 2 | 2.02% | 1 | 11.11% |
konstantin khlebnikov | konstantin khlebnikov | 1 | 1.01% | 1 | 11.11% |
| Total | 99 | 100.00% | 9 | 100.00% |
static void destroy_super_work(struct work_struct *work)
{
struct super_block *s = container_of(work, struct super_block,
destroy_work);
int i;
for (i = 0; i < SB_FREEZE_LEVELS; i++)
percpu_free_rwsem(&s->s_writers.rw_sem[i]);
kfree(s);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
jan kara | jan kara | 30 | 50.00% | 1 | 25.00% |
oleg nesterov | oleg nesterov | 26 | 43.33% | 2 | 50.00% |
al viro | al viro | 4 | 6.67% | 1 | 25.00% |
| Total | 60 | 100.00% | 4 | 100.00% |
static void destroy_super_rcu(struct rcu_head *head)
{
struct super_block *s = container_of(head, struct super_block, rcu);
INIT_WORK(&s->destroy_work, destroy_super_work);
schedule_work(&s->destroy_work);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
oleg nesterov | oleg nesterov | 44 | 100.00% | 1 | 100.00% |
| Total | 44 | 100.00% | 1 | 100.00% |
/**
* destroy_super - frees a superblock
* @s: superblock to free
*
* Frees a superblock.
*/
static void destroy_super(struct super_block *s)
{
list_lru_destroy(&s->s_dentry_lru);
list_lru_destroy(&s->s_inode_lru);
security_sb_free(s);
WARN_ON(!list_empty(&s->s_mounts));
kfree(s->s_subtype);
kfree(s->s_options);
call_rcu(&s->rcu, destroy_super_rcu);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
oleg nesterov | oleg nesterov | 31 | 45.59% | 1 | 25.00% |
jan kara | jan kara | 25 | 36.76% | 1 | 25.00% |
al viro | al viro | 12 | 17.65% | 2 | 50.00% |
| Total | 68 | 100.00% | 4 | 100.00% |
/**
* alloc_super - create new superblock
* @type: filesystem type superblock should belong to
* @flags: the mount flags
*
* Allocates and initializes a new &struct super_block. alloc_super()
* returns a pointer new superblock or %NULL if allocation had failed.
*/
static struct super_block *alloc_super(struct file_system_type *type, int flags)
{
struct super_block *s = kzalloc(sizeof(struct super_block), GFP_USER);
static const struct super_operations default_op;
int i;
if (!s)
return NULL;
INIT_LIST_HEAD(&s->s_mounts);
if (security_sb_alloc(s))
goto fail;
for (i = 0; i < SB_FREEZE_LEVELS; i++) {
if (__percpu_init_rwsem(&s->s_writers.rw_sem[i],
sb_writers_name[i],
&type->s_writers_key[i]))
goto fail;
}
init_waitqueue_head(&s->s_writers.wait_unfrozen);
s->s_bdi = &noop_backing_dev_info;
s->s_flags = flags;
INIT_HLIST_NODE(&s->s_instances);
INIT_HLIST_BL_HEAD(&s->s_anon);
mutex_init(&s->s_sync_lock);
INIT_LIST_HEAD(&s->s_inodes);
spin_lock_init(&s->s_inode_list_lock);
if (list_lru_init_memcg(&s->s_dentry_lru))
goto fail;
if (list_lru_init_memcg(&s->s_inode_lru))
goto fail;
init_rwsem(&s->s_umount);
lockdep_set_class(&s->s_umount, &type->s_umount_key);
/*
* sget() can have s_umount recursion.
*
* When it cannot find a suitable sb, it allocates a new
* one (this one), and tries again to find a suitable old
* one.
*
* In case that succeeds, it will acquire the s_umount
* lock of the old one. Since these are clearly distrinct
* locks, and this object isn't exposed yet, there's no
* risk of deadlocks.
*
* Annotate this by putting this lock in a different
* subclass.
*/
down_write_nested(&s->s_umount, SINGLE_DEPTH_NESTING);
s->s_count = 1;
atomic_set(&s->s_active, 1);
mutex_init(&s->s_vfs_rename_mutex);
lockdep_set_class(&s->s_vfs_rename_mutex, &type->s_vfs_rename_key);
mutex_init(&s->s_dquot.dqio_mutex);
mutex_init(&s->s_dquot.dqonoff_mutex);
s->s_maxbytes = MAX_NON_LFS;
s->s_op = &default_op;
s->s_time_gran = 1000000000;
s->cleancache_poolid = CLEANCACHE_NO_POOL;
s->s_shrink.seeks = DEFAULT_SEEKS;
s->s_shrink.scan_objects = super_cache_scan;
s->s_shrink.count_objects = super_cache_count;
s->s_shrink.batch = 1024;
s->s_shrink.flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE;
return s;
fail:
destroy_super(s);
return NULL;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
linus torvalds | linus torvalds | 91 | 24.53% | 4 | 9.09% |
al viro | al viro | 63 | 16.98% | 3 | 6.82% |
dave chinner | dave chinner | 62 | 16.71% | 7 | 15.91% |
andrew morton | andrew morton | 18 | 4.85% | 2 | 4.55% |
arjan van de ven | arjan van de ven | 15 | 4.04% | 2 | 4.55% |
roland dreier | roland dreier | 13 | 3.50% | 1 | 2.27% |
vladimir davydov | vladimir davydov | 13 | 3.50% | 3 | 6.82% |
glauber costa | glauber costa | 10 | 2.70% | 1 | 2.27% |
ingo molnar | ingo molnar | 8 | 2.16% | 2 | 4.55% |
william lee irwin iii | william lee irwin iii | 8 | 2.16% | 1 | 2.27% |
stephen d. smalley | stephen d. smalley | 8 | 2.16% | 1 | 2.27% |
david howells | david howells | 7 | 1.89% | 1 | 2.27% |
neil brown | neil brown | 7 | 1.89% | 1 | 2.27% |
christoph hellwig | christoph hellwig | 6 | 1.62% | 2 | 4.55% |
kentaro makita | kentaro makita | 6 | 1.62% | 1 | 2.27% |
oleg nesterov | oleg nesterov | 6 | 1.62% | 1 | 2.27% |
jan kara | jan kara | 6 | 1.62% | 2 | 4.55% |
andi kleen | andi kleen | 6 | 1.62% | 1 | 2.27% |
dan magenheimer | dan magenheimer | 5 | 1.35% | 1 | 2.27% |
jens axboe | jens axboe | 4 | 1.08% | 1 | 2.27% |
peter zijlstra | peter zijlstra | 3 | 0.81% | 1 | 2.27% |
miklos szeredi | miklos szeredi | 2 | 0.54% | 1 | 2.27% |
nick piggin | nick piggin | 1 | 0.27% | 1 | 2.27% |
alexey dobriyan | alexey dobriyan | 1 | 0.27% | 1 | 2.27% |
greg kroah-hartman | greg kroah-hartman | 1 | 0.27% | 1 | 2.27% |
oliver neukum | oliver neukum | 1 | 0.27% | 1 | 2.27% |
| Total | 371 | 100.00% | 44 | 100.00% |
/* Superblock refcounting */
/*
* Drop a superblock's refcount. The caller must hold sb_lock.
*/
static void __put_super(struct super_block *sb)
{
if (!--sb->s_count) {
list_del_init(&sb->s_list);
destroy_super(sb);
}
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
andrew morton | andrew morton | 22 | 64.71% | 1 | 20.00% |
al viro | al viro | 10 | 29.41% | 3 | 60.00% |
kirill korotaev | kirill korotaev | 2 | 5.88% | 1 | 20.00% |
| Total | 34 | 100.00% | 5 | 100.00% |
/**
* put_super - drop a temporary reference to superblock
* @sb: superblock in question
*
* Drops a temporary reference, frees superblock if there's no
* references left.
*/
static void put_super(struct super_block *sb)
{
spin_lock(&sb_lock);
__put_super(sb);
spin_unlock(&sb_lock);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
linus torvalds | linus torvalds | 18 | 64.29% | 2 | 40.00% |
al viro | al viro | 7 | 25.00% | 2 | 40.00% |
andrew morton | andrew morton | 3 | 10.71% | 1 | 20.00% |
| Total | 28 | 100.00% | 5 | 100.00% |
/**
* deactivate_locked_super - drop an active reference to superblock
* @s: superblock to deactivate
*
* Drops an active reference to superblock, converting it into a temporary
* one if there is no other active references left. In that case we
* tell fs driver to shut it down and drop the temporary reference we
* had just acquired.
*
* Caller holds exclusive lock on superblock; that lock is released.
*/
void deactivate_locked_super(struct super_block *s)
{
struct file_system_type *fs = s->s_type;
if (atomic_dec_and_test(&s->s_active)) {
cleancache_invalidate_fs(s);
unregister_shrinker(&s->s_shrink);
fs->kill_sb(s);
/*
* Since list_lru_destroy() may sleep, we cannot call it from
* put_super(), where we hold the sb_lock. Therefore we destroy
* the lru lists right now.
*/
list_lru_destroy(&s->s_dentry_lru);
list_lru_destroy(&s->s_inode_lru);
put_filesystem(fs);
put_super(s);
} else {
up_write(&s->s_umount);
}
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
al viro | al viro | 40 | 44.94% | 3 | 27.27% |
vladimir davydov | vladimir davydov | 17 | 19.10% | 1 | 9.09% |
linus torvalds | linus torvalds | 12 | 13.48% | 3 | 27.27% |
dave chinner | dave chinner | 8 | 8.99% | 1 | 9.09% |
david chinner | david chinner | 7 | 7.87% | 1 | 9.09% |
dan magenheimer | dan magenheimer | 5 | 5.62% | 2 | 18.18% |
| Total | 89 | 100.00% | 11 | 100.00% |
EXPORT_SYMBOL(deactivate_locked_super);
/**
* deactivate_super - drop an active reference to superblock
* @s: superblock to deactivate
*
* Variant of deactivate_locked_super(), except that superblock is *not*
* locked by caller. If we are going to drop the final active reference,
* lock will be acquired prior to that.
*/
void deactivate_super(struct super_block *s)
{
if (!atomic_add_unless(&s->s_active, -1, 1)) {
down_write(&s->s_umount);
deactivate_locked_super(s);
}
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
al viro | al viro | 41 | 100.00% | 2 | 100.00% |
| Total | 41 | 100.00% | 2 | 100.00% |
EXPORT_SYMBOL(deactivate_super);
/**
* grab_super - acquire an active reference
* @s: reference we are trying to make active
*
* Tries to acquire an active reference. grab_super() is used when we
* had just found a superblock in super_blocks or fs_type->fs_supers
* and want to turn it into a full-blown active reference. grab_super()
* is called with sb_lock held and drops it. Returns 1 in case of
* success, 0 if we had failed (superblock contents was already dead or
* dying when grab_super() had been called). Note that this is only
* called for superblocks not in rundown mode (== ones still on ->fs_supers
* of their type), so increment of ->s_count is OK here.
*/
static int grab_super(struct super_block *s) __releases(sb_lock)
{
s->s_count++;
spin_unlock(&sb_lock);
down_write(&s->s_umount);
if ((s->s_flags & MS_BORN) && atomic_inc_not_zero(&s->s_active)) {
put_super(s);
return 1;
}
up_write(&s->s_umount);
put_super(s);
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
linus torvalds | linus torvalds | 41 | 52.56% | 1 | 25.00% |
al viro | al viro | 33 | 42.31% | 2 | 50.00% |
josh triplett | josh triplett | 4 | 5.13% | 1 | 25.00% |
| Total | 78 | 100.00% | 4 | 100.00% |
/*
* trylock_super - try to grab ->s_umount shared
* @sb: reference we are trying to grab
*
* Try to prevent fs shutdown. This is used in places where we
* cannot take an active reference but we need to ensure that the
* filesystem is not shut down while we are working on it. It returns
* false if we cannot acquire s_umount or if we lose the race and
* filesystem already got into shutdown, and returns true with the s_umount
* lock held in read mode in case of success. On successful return,
* the caller must drop the s_umount lock when done.
*
* Note that unlike get_super() et.al. this one does *not* bump ->s_count.
* The reason why it's safe is that we are OK with doing trylock instead
* of down_read(). There's a couple of places that are OK with that, but
* it's very much not a general-purpose interface.
*/
bool trylock_super(struct super_block *sb)
{
if (down_read_trylock(&sb->s_umount)) {
if (!hlist_unhashed(&sb->s_instances) &&
sb->s_root && (sb->s_flags & MS_BORN))
return true;
up_read(&sb->s_umount);
}
return false;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
dave chinner | dave chinner | 44 | 74.58% | 1 | 33.33% |
al viro | al viro | 8 | 13.56% | 1 | 33.33% |
konstantin khlebnikov | konstantin khlebnikov | 7 | 11.86% | 1 | 33.33% |
| Total | 59 | 100.00% | 3 | 100.00% |
/**
* generic_shutdown_super - common helper for ->kill_sb()
* @sb: superblock to kill
*
* generic_shutdown_super() does all fs-independent work on superblock
* shutdown. Typical ->kill_sb() should pick all fs-specific objects
* that need destruction out of superblock, call generic_shutdown_super()
* and release aforementioned objects. Note: dentries and inodes _are_
* taken care of and do not need specific handling.
*
* Upon calling this function, the filesystem may no longer alter or
* rearrange the set of dentries belonging to this super_block, nor may it
* change the attachments of dentries to inodes.
*/
void generic_shutdown_super(struct super_block *sb)
{
const struct super_operations *sop = sb->s_op;
if (sb->s_root) {
shrink_dcache_for_umount(sb);
sync_filesystem(sb);
sb->s_flags &= ~MS_ACTIVE;
fsnotify_unmount_inodes(sb);
cgroup_writeback_umount();
evict_inodes(sb);
if (sb->s_dio_done_wq) {
destroy_workqueue(sb->s_dio_done_wq);
sb->s_dio_done_wq = NULL;
}
if (sop->put_super)
sop->put_super(sb);
if (!list_empty(&sb->s_inodes)) {
printk("VFS: Busy inodes after unmount of %s. "
"Self-destruct in 5 seconds. Have a nice day...\n",
sb->s_id);
}
}
spin_lock(&sb_lock);
/* should be initialized for __put_super_and_need_restart() */
hlist_del_init(&sb->s_instances);
spin_unlock(&sb_lock);
up_write(&sb->s_umount);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
al viro | al viro | 105 | 72.92% | 4 | 33.33% |
christoph hellwig | christoph hellwig | 21 | 14.58% | 1 | 8.33% |
dave jones | dave jones | 5 | 3.47% | 1 | 8.33% |
neil brown | neil brown | 4 | 2.78% | 1 | 8.33% |
tejun heo | tejun heo | 3 | 2.08% | 1 | 8.33% |
david howells | david howells | 3 | 2.08% | 1 | 8.33% |
kirill korotaev | kirill korotaev | 1 | 0.69% | 1 | 8.33% |
jan kara | jan kara | 1 | 0.69% | 1 | 8.33% |
josef 'jeff' sipek | josef 'jeff' sipek | 1 | 0.69% | 1 | 8.33% |
| Total | 144 | 100.00% | 12 | 100.00% |
EXPORT_SYMBOL(generic_shutdown_super);
/**
* sget - find or create a superblock
* @type: filesystem type superblock should belong to
* @test: comparison callback
* @set: setup callback
* @flags: mount flags
* @data: argument to each of them
*/
struct super_block *sget(struct file_system_type *type,
int (*test)(struct super_block *,void *),
int (*set)(struct super_block *,void *),
int flags,
void *data)
{
struct super_block *s = NULL;
struct super_block *old;
int err;
retry:
spin_lock(&sb_lock);
if (test) {
hlist_for_each_entry(old, &type->fs_supers, s_instances) {
if (!test(old, data))
continue;
if (!grab_super(old))
goto retry;
if (s) {
up_write(&s->s_umount);
destroy_super(s);
s = NULL;
}
return old;
}
}
if (!s) {
spin_unlock(&sb_lock);
s = alloc_super(type, flags);
if (!s)
return ERR_PTR(-ENOMEM);
goto retry;
}
err = set(s, data);
if (err) {
spin_unlock(&sb_lock);
up_write(&s->s_umount);
destroy_super(s);
return ERR_PTR(err);
}
s->s_type = type;
strlcpy(s->s_id, type->name, sizeof(s->s_id));
list_add_tail(&s->s_list, &super_blocks);
hlist_add_head(&s->s_instances, &type->fs_supers);
spin_unlock(&sb_lock);
get_filesystem(type);
register_shrinker(&s->s_shrink);
return s;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
al viro | al viro | 220 | 78.29% | 5 | 41.67% |
andrew morton | andrew morton | 18 | 6.41% | 1 | 8.33% |
li zefan | li zefan | 18 | 6.41% | 1 | 8.33% |
dave chinner | dave chinner | 8 | 2.85% | 1 | 8.33% |
matthias kaehlcke | matthias kaehlcke | 7 | 2.49% | 1 | 8.33% |
david howells | david howells | 5 | 1.78% | 1 | 8.33% |
ingo molnar | ingo molnar | 3 | 1.07% | 1 | 8.33% |
kirill korotaev | kirill korotaev | 2 | 0.71% | 1 | 8.33% |
| Total | 281 | 100.00% | 12 | 100.00% |
EXPORT_SYMBOL(sget);
void drop_super(struct super_block *sb)
{
up_read(&sb->s_umount);
put_super(sb);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
linus torvalds | linus torvalds | 23 | 100.00% | 4 | 100.00% |
| Total | 23 | 100.00% | 4 | 100.00% |
EXPORT_SYMBOL(drop_super);
/**
* iterate_supers - call function for all active superblocks
* @f: function to call
* @arg: argument to pass to it
*
* Scans the superblock list and calls given function, passing it
* locked superblock and given argument.
*/
void iterate_supers(void (*f)(struct super_block *, void *), void *arg)
{
struct super_block *sb, *p = NULL;
spin_lock(&sb_lock);
list_for_each_entry(sb, &super_blocks, s_list) {
if (hlist_unhashed(&sb->s_instances))
continue;
sb->s_count++;
spin_unlock(&sb_lock);
down_read(&sb->s_umount);
if (sb->s_root && (sb->s_flags & MS_BORN))
f(sb, arg);
up_read(&sb->s_umount);
spin_lock(&sb_lock);
if (p)
__put_super(p);
p = sb;
}
if (p)
__put_super(p);
spin_unlock(&sb_lock);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
al viro | al viro | 139 | 97.89% | 4 | 80.00% |
nick piggin | nick piggin | 3 | 2.11% | 1 | 20.00% |
| Total | 142 | 100.00% | 5 | 100.00% |
/**
* iterate_supers_type - call function for superblocks of given type
* @type: fs type
* @f: function to call
* @arg: argument to pass to it
*
* Scans the superblock list and calls given function, passing it
* locked superblock and given argument.
*/
void iterate_supers_type(struct file_system_type *type,
void (*f)(struct super_block *, void *), void *arg)
{
struct super_block *sb, *p = NULL;
spin_lock(&sb_lock);
hlist_for_each_entry(sb, &type->fs_supers, s_instances) {
sb->s_count++;
spin_unlock(&sb_lock);
down_read(&sb->s_umount);
if (sb->s_root && (sb->s_flags & MS_BORN))
f(sb, arg);
up_read(&sb->s_umount);
spin_lock(&sb_lock);
if (p)
__put_super(p);
p = sb;
}
if (p)
__put_super(p);
spin_unlock(&sb_lock);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
al viro | al viro | 136 | 100.00% | 3 | 100.00% |
| Total | 136 | 100.00% | 3 | 100.00% |
EXPORT_SYMBOL(iterate_supers_type);
/**
* get_super - get the superblock of a device
* @bdev: device to get the superblock for
*
* Scans the superblock list and finds the superblock of the file system
* mounted on the device given. %NULL is returned if no match is found.
*/
struct super_block *get_super(struct block_device *bdev)
{
struct super_block *sb;
if (!bdev)
return NULL;
spin_lock(&sb_lock);
rescan:
list_for_each_entry(sb, &super_blocks, s_list) {
if (hlist_unhashed(&sb->s_instances))
continue;
if (sb->s_bdev == bdev) {
sb->s_count++;
spin_unlock(&sb_lock);
down_read(&sb->s_umount);
/* still alive? */
if (sb->s_root && (sb->s_flags & MS_BORN))
return sb;
up_read(&sb->s_umount);
/* nope, got unmounted */
spin_lock(&sb_lock);
__put_super(sb);
goto rescan;
}
}
spin_unlock(&sb_lock);
return NULL;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
al viro | al viro | 73 | 54.89% | 5 | 41.67% |
kirill korotaev | kirill korotaev | 27 | 20.30% | 1 | 8.33% |
linus torvalds | linus torvalds | 25 | 18.80% | 4 | 33.33% |
pre-git | pre-git | 8 | 6.02% | 2 | 16.67% |
| Total | 133 | 100.00% | 12 | 100.00% |
EXPORT_SYMBOL(get_super);
/**
* get_super_thawed - get thawed superblock of a device
* @bdev: device to get the superblock for
*
* Scans the superblock list and finds the superblock of the file system
* mounted on the device. The superblock is returned once it is thawed
* (or immediately if it was not frozen). %NULL is returned if no match
* is found.
*/
struct super_block *get_super_thawed(struct block_device *bdev)
{
while (1) {
struct super_block *s = get_super(bdev);
if (!s || s->s_writers.frozen == SB_UNFROZEN)
return s;
up_read(&s->s_umount);
wait_event(s->s_writers.wait_unfrozen,
s->s_writers.frozen == SB_UNFROZEN);
put_super(s);
}
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
jan kara | jan kara | 74 | 100.00% | 2 | 100.00% |
| Total | 74 | 100.00% | 2 | 100.00% |
EXPORT_SYMBOL(get_super_thawed);
/**
* get_active_super - get an active reference to the superblock of a device
* @bdev: device to get the superblock for
*
* Scans the superblock list and finds the superblock of the file system
* mounted on the device given. Returns the superblock with an active
* reference or %NULL if none was found.
*/
struct super_block *get_active_super(struct block_device *bdev)
{
struct super_block *sb;
if (!bdev)
return NULL;
restart:
spin_lock(&sb_lock);
list_for_each_entry(sb, &super_blocks, s_list) {
if (hlist_unhashed(&sb->s_instances))
continue;
if (sb->s_bdev == bdev) {
if (!grab_super(sb))
goto restart;
up_write(&sb->s_umount);
return sb;
}
}
spin_unlock(&sb_lock);
return NULL;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
christoph hellwig | christoph hellwig | 62 | 65.26% | 1 | 16.67% |
al viro | al viro | 33 | 34.74% | 5 | 83.33% |
| Total | 95 | 100.00% | 6 | 100.00% |
struct super_block *user_get_super(dev_t dev)
{
struct super_block *sb;
spin_lock(&sb_lock);
rescan:
list_for_each_entry(sb, &super_blocks, s_list) {
if (hlist_unhashed(&sb->s_instances))
continue;
if (sb->s_dev == dev) {
sb->s_count++;
spin_unlock(&sb_lock);
down_read(&sb->s_umount);
/* still alive? */
if (sb->s_root && (sb->s_flags & MS_BORN))
return sb;
up_read(&sb->s_umount);
/* nope, got unmounted */
spin_lock(&sb_lock);
__put_super(sb);
goto rescan;
}
}
spin_unlock(&sb_lock);
return NULL;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
al viro | al viro | 74 | 60.16% | 5 | 41.67% |
kirill korotaev | kirill korotaev | 27 | 21.95% | 1 | 8.33% |
linus torvalds | linus torvalds | 12 | 9.76% | 3 | 25.00% |
pre-git | pre-git | 10 | 8.13% | 3 | 25.00% |
| Total | 123 | 100.00% | 12 | 100.00% |
/**
* do_remount_sb - asks filesystem to change mount options.
* @sb: superblock in question
* @flags: numeric part of options
* @data: the rest of options
* @force: whether or not to force the change
*
* Alters the mount options of a mounted file system.
*/
int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
{
int retval;
int remount_ro;
if (sb->s_writers.frozen != SB_UNFROZEN)
return -EBUSY;
#ifdef CONFIG_BLOCK
if (!(flags & MS_RDONLY) && bdev_read_only(sb->s_bdev))
return -EACCES;
#endif
remount_ro = (flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY);
if (remount_ro) {
if (!hlist_empty(&sb->s_pins)) {
up_write(&sb->s_umount);
group_pin_kill(&sb->s_pins);
down_write(&sb->s_umount);
if (!sb->s_root)
return 0;
if (sb->s_writers.frozen != SB_UNFROZEN)
return -EBUSY;
remount_ro = (flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY);
}
}
shrink_dcache_sb(sb);
/* If we are remounting RDONLY and current sb is read/write,
make sure there are no rw files opened */
if (remount_ro) {
if (force) {
sb->s_readonly_remount = 1;
smp_wmb();
} else {
retval = sb_prepare_remount_readonly(sb);
if (retval)
return retval;
}
}
if (sb->s_op->remount_fs) {
retval = sb->s_op->remount_fs(sb, &flags, data);
if (retval) {
if (!force)
goto cancel_readonly;
/* If forced remount, go ahead despite any errors */
WARN(1, "forced remount of a %s fs returned %i\n",
sb->s_type->name, retval);
}
}
sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK);
/* Needs to be ordered wrt mnt_is_readonly() */
smp_wmb();
sb->s_readonly_remount = 0;
/*
* Some filesystems modify their metadata via some other path than the
* bdev buffer cache (eg. use a private mapping, or directories in
* pagecache, etc). Also file data modifications go via their own
* mappings. So If we try to mount readonly then copy the filesystem
* from bdev, we could get stale data, so invalidate it to give a best
* effort at coherency.
*/
if (remount_ro && sb->s_bdev)
invalidate_bdev(sb->s_bdev);
return 0;
cancel_readonly:
sb->s_readonly_remount = 0;
return retval;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
linus torvalds | linus torvalds | 107 | 32.92% | 2 | 10.00% |
al viro | al viro | 86 | 26.46% | 4 | 20.00% |
miklos szeredi | miklos szeredi | 66 | 20.31% | 2 | 10.00% |
nick piggin | nick piggin | 24 | 7.38% | 1 | 5.00% |
andrew morton | andrew morton | 11 | 3.38% | 1 | 5.00% |
christoph hellwig | christoph hellwig | 11 | 3.38% | 1 | 5.00% |
pre-git | pre-git | 10 | 3.08% | 6 | 30.00% |
david howells | david howells | 5 | 1.54% | 1 | 5.00% |
jan kara | jan kara | 5 | 1.54% | 2 | 10.00% |
| Total | 325 | 100.00% | 20 | 100.00% |
static void do_emergency_remount(struct work_struct *work)
{
struct super_block *sb, *p = NULL;
spin_lock(&sb_lock);
list_for_each_entry(sb, &super_blocks, s_list) {
if (hlist_unhashed(&sb->s_instances))
continue;
sb->s_count++;
spin_unlock(&sb_lock);
down_write(&sb->s_umount);
if (sb->s_root && sb->s_bdev && (sb->s_flags & MS_BORN) &&
!(sb->s_flags & MS_RDONLY)) {