cregit-Linux how code gets into the kernel

Release 4.13 fs/super.c

Directory: fs
/*
 *  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 <linux/user_namespace.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

PersonTokensPropCommitsCommitProp
Dave Chinner19776.95%650.00%
Vladimir Davydov3513.67%325.00%
Glauber de Oliveira Costa103.91%18.33%
Tetsuo Handa93.52%18.33%
Konstantin Khlebnikov51.95%18.33%
Total256100.00%12100.00%


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

PersonTokensPropCommitsCommitProp
Dave Chinner9393.94%666.67%
Glauber de Oliveira Costa33.03%111.11%
Vladimir Davydov22.02%111.11%
Konstantin Khlebnikov11.01%111.11%
Total99100.00%9100.00%


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

PersonTokensPropCommitsCommitProp
Jan Kara3050.00%125.00%
Oleg Nesterov2643.33%250.00%
Al Viro46.67%125.00%
Total60100.00%4100.00%


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

PersonTokensPropCommitsCommitProp
Oleg Nesterov44100.00%1100.00%
Total44100.00%1100.00%

/** * 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)); put_user_ns(s->s_user_ns); kfree(s->s_subtype); call_rcu(&s->rcu, destroy_super_rcu); }

Contributors

PersonTokensPropCommitsCommitProp
Oleg Nesterov3145.59%120.00%
Jan Kara2029.41%120.00%
Al Viro1014.71%240.00%
Eric W. Biedermann710.29%120.00%
Total68100.00%5100.00%

/** * alloc_super - create new superblock * @type: filesystem type superblock should belong to * @flags: the mount flags * @user_ns: User namespace for the super_block * * 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 user_namespace *user_ns) { 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); s->s_user_ns = get_user_ns(user_ns); 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; if (s->s_user_ns != &init_user_ns) s->s_iflags |= SB_I_NODEV; 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); INIT_LIST_HEAD(&s->s_inodes_wb); spin_lock_init(&s->s_inode_wblist_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); 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

PersonTokensPropCommitsCommitProp
Linus Torvalds9122.41%36.67%
Dave Chinner7819.21%817.78%
Al Viro6315.52%36.67%
Eric W. Biedermann297.14%24.44%
Arjan van de Ven153.69%24.44%
Roland Dreier133.20%12.22%
Vladimir Davydov133.20%36.67%
Andrew Morton102.46%12.22%
Glauber de Oliveira Costa102.46%12.22%
Stephen D. Smalley81.97%12.22%
William Lee Irwin III81.97%12.22%
Neil Brown71.72%12.22%
David Howells71.72%12.22%
Jan Kara61.48%24.44%
Kentaro Makita61.48%12.22%
Andi Kleen61.48%12.22%
Oleg Nesterov61.48%12.22%
Ingo Molnar61.48%24.44%
Christoph Hellwig61.48%24.44%
Dan Magenheimer51.23%12.22%
Jens Axboe40.99%12.22%
Peter Zijlstra30.74%12.22%
Miklos Szeredi20.49%12.22%
Oliver Neukum10.25%12.22%
Alexey Dobriyan10.25%12.22%
Nicholas Piggin10.25%12.22%
Greg Kroah-Hartman10.25%12.22%
Total406100.00%45100.00%

/* 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

PersonTokensPropCommitsCommitProp
Andrew Morton2264.71%120.00%
Al Viro1029.41%360.00%
Kirill Korotaev25.88%120.00%
Total34100.00%5100.00%

/** * 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

PersonTokensPropCommitsCommitProp
Linus Torvalds1864.29%240.00%
Al Viro725.00%240.00%
Andrew Morton310.71%120.00%
Total28100.00%5100.00%

/** * 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

PersonTokensPropCommitsCommitProp
Al Viro4044.94%327.27%
Vladimir Davydov1719.10%19.09%
Linus Torvalds1213.48%327.27%
Dave Chinner88.99%19.09%
David Chinner77.87%19.09%
Dan Magenheimer55.62%218.18%
Total89100.00%11100.00%

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

PersonTokensPropCommitsCommitProp
Al Viro41100.00%2100.00%
Total41100.00%2100.00%

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

PersonTokensPropCommitsCommitProp
Linus Torvalds4051.28%233.33%
Al Viro3342.31%233.33%
Josh Triplett45.13%116.67%
Dave Chinner11.28%116.67%
Total78100.00%6100.00%

/* * 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

PersonTokensPropCommitsCommitProp
Dave Chinner4372.88%125.00%
Al Viro813.56%125.00%
Konstantin Khlebnikov711.86%125.00%
Linus Torvalds11.69%125.00%
Total59100.00%4100.00%

/** * 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); if (sb->s_bdi != &noop_backing_dev_info) { bdi_put(sb->s_bdi); sb->s_bdi = &noop_backing_dev_info; } }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro10562.13%428.57%
Jan Kara2615.38%321.43%
Christoph Hellwig2112.43%17.14%
Dave Jones52.96%17.14%
Neil Brown42.37%17.14%
Tejun Heo31.78%17.14%
David Howells31.78%17.14%
Kirill Korotaev10.59%17.14%
Josef 'Jeff' Sipek10.59%17.14%
Total169100.00%14100.00%

EXPORT_SYMBOL(generic_shutdown_super); /** * sget_userns - find or create a superblock * @type: filesystem type superblock should belong to * @test: comparison callback * @set: setup callback * @flags: mount flags * @user_ns: User namespace for the super_block * @data: argument to each of them */
struct super_block *sget_userns(struct file_system_type *type, int (*test)(struct super_block *,void *), int (*set)(struct super_block *,void *), int flags, struct user_namespace *user_ns, void *data) { struct super_block *s = NULL; struct super_block *old; int err; if (!(flags & (MS_KERNMOUNT|MS_SUBMOUNT)) && !(type->fs_flags & FS_USERNS_MOUNT) && !capable(CAP_SYS_ADMIN)) return ERR_PTR(-EPERM); retry: spin_lock(&sb_lock); if (test) { hlist_for_each_entry(old, &type->fs_supers, s_instances) { if (!test(old, data)) continue; if (user_ns != old->s_user_ns) { spin_unlock(&sb_lock); if (s) { up_write(&s->s_umount); destroy_super(s); } return ERR_PTR(-EBUSY); } 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 & ~MS_SUBMOUNT), user_ns); 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

PersonTokensPropCommitsCommitProp
Al Viro21959.19%533.33%
Eric W. Biedermann9024.32%320.00%
Andrew Morton184.86%16.67%
Li Zefan184.86%16.67%
Dave Chinner82.16%16.67%
Matthias Kaehlcke71.89%16.67%
David Howells51.35%16.67%
Ingo Molnar30.81%16.67%
Kirill Korotaev20.54%16.67%
Total370100.00%15100.00%

EXPORT_SYMBOL(sget_userns); /** * 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 user_namespace *user_ns = current_user_ns(); /* We don't yet pass the user namespace of the parent * mount through to here so always use &init_user_ns * until that changes. */ if (flags & MS_SUBMOUNT) user_ns = &init_user_ns; /* Ensure the requestor has permissions over the target filesystem */ if (!(flags & (MS_KERNMOUNT|MS_SUBMOUNT)) && !ns_capable(user_ns, CAP_SYS_ADMIN)) return ERR_PTR(-EPERM); return sget_userns(type, test, set, flags, user_ns, data); }

Contributors

PersonTokensPropCommitsCommitProp
Eric W. Biedermann112100.00%2100.00%
Total112100.00%2100.00%

EXPORT_SYMBOL(sget);
void drop_super(struct super_block *sb) { up_read(&sb->s_umount); put_super(sb); }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds23100.00%4100.00%
Total23100.00%4100.00%

EXPORT_SYMBOL(drop_super);
void drop_super_exclusive(struct super_block *sb) { up_write(&sb->s_umount); put_super(sb); }

Contributors

PersonTokensPropCommitsCommitProp
Jan Kara23100.00%1100.00%
Total23100.00%1100.00%

EXPORT_SYMBOL(drop_super_exclusive); /** * 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

PersonTokensPropCommitsCommitProp
Al Viro13595.07%457.14%
Nicholas Piggin32.11%114.29%
Linus Torvalds32.11%114.29%
Linus Torvalds (pre-git)10.70%114.29%
Total142100.00%7100.00%

/** * 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

PersonTokensPropCommitsCommitProp
Al Viro136100.00%3100.00%
Total136100.00%3100.00%

EXPORT_SYMBOL(iterate_supers_type);
static struct super_block *__get_super(struct block_device *bdev, bool excl) { 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); if (!excl) down_read(&sb->s_umount); else down_write(&sb->s_umount); /* still alive? */ if (sb->s_root && (sb->s_flags & MS_BORN)) return sb; if (!excl) up_read(&sb->s_umount); else up_write(&sb->s_umount); /* nope, got unmounted */ spin_lock(&sb_lock); __put_super(sb); goto rescan; } } spin_unlock(&sb_lock); return NULL; }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro7344.24%538.46%
Jan Kara3320.00%17.69%
Kirill Korotaev2716.36%17.69%
Linus Torvalds2414.55%430.77%
Linus Torvalds (pre-git)84.85%215.38%
Total165100.00%13100.00%

/** * 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) { return __get_super(bdev, false); }

Contributors

PersonTokensPropCommitsCommitProp
Jan Kara20100.00%1100.00%
Total20100.00%1100.00%

EXPORT_SYMBOL(get_super);
static struct super_block *__get_super_thawed(struct block_device *bdev, bool excl) { while (1) { struct super_block *s = __get_super(bdev, excl); if (!s || s->s_writers.frozen == SB_UNFROZEN) return s; if (!excl) up_read(&s->s_umount); else up_write(&s->s_umount); wait_event(s->s_writers.wait_unfrozen, s->s_writers.frozen == SB_UNFROZEN); put_super(s); } }

Contributors

PersonTokensPropCommitsCommitProp
Jan Kara94100.00%3100.00%
Total94100.00%3100.00%

/** * 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) { return __get_super_thawed(bdev, false); }

Contributors

PersonTokensPropCommitsCommitProp
Jan Kara20100.00%1100.00%
Total20100.00%1100.00%

EXPORT_SYMBOL(get_super_thawed); /** * get_super_exclusive_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) and s_umount semaphore is held * in exclusive mode. %NULL is returned if no match is found. */
struct super_block *get_super_exclusive_thawed(struct block_device *bdev) { return __get_super_thawed(bdev, true); }

Contributors

PersonTokensPropCommitsCommitProp
Jan Kara20100.00%1100.00%
Total20100.00%1100.00%

EXPORT_SYMBOL(get_super_exclusive_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

PersonTokensPropCommitsCommitProp
Christoph Hellwig6265.26%116.67%
Al Viro3334.74%583.33%
Total95100.00%6100.00%


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

PersonTokensPropCommitsCommitProp
Al Viro7460.16%541.67%
Kirill Korotaev2721.95%18.33%
Linus Torvalds129.76%325.00%
Linus Torvalds (pre-git)108.13%325.00%
Total123100.00%12100.00%

/** * 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

PersonTokensPropCommitsCommitProp
Linus Torvalds11736.00%17.69%
Al Viro8626.46%430.77%
Miklos Szeredi6620.31%215.38%
Nicholas Piggin247.38%17.69%
Christoph Hellwig113.38%17.69%
Andrew Morton113.38%17.69%
David Howells51.54%17.69%
Jan Kara51.54%215.38%
Total325100.00%13100.00%


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)) { /* * What lock protects sb->s_flags?? */ do_remount_sb(sb, MS_RDONLY, NULL, 1); } up_write(&sb->s_umount); spin_lock(&sb_lock); if (p) __put_super(p); p = sb; } if (p) __put_super(p); spin_unlock(&sb_lock); kfree(work); printk("Emergency Remount complete\n"); }

Contributors

PersonTokensPropCommitsCommitProp
Andrew Morton9358.12%325.00%
Al Viro5433.75%650.00%
Jens Axboe95.62%18.33%
Nicholas Piggin31.88%18.33%
Christoph Hellwig10.62%18.33%
Total160100.00%12100.00%


void emergency_remount(void) { struct work_struct *work; work = kmalloc(sizeof(*work), GFP_ATOMIC); if (work) { INIT_WORK(work, do_emergency_remount); schedule_work(work); } }

Contributors

PersonTokensPropCommitsCommitProp
Jens Axboe3274.42%150.00%
Andrew Morton1125.58%150.00%
Total43100.00%2100.00%

/* * Unnamed block devices are dummy devices used by virtual * filesystems which don't use real block-devices. -- jrs */ static DEFINE_IDA(unnamed_dev_ida); static DEFINE_SPINLOCK(unnamed_dev_lock);/* protects the above */ /* Many userspace utilities consider an FSID of 0 invalid. * Always return at least 1 from get_anon_bdev. */ static int unnamed_dev_start = 1;
int get_anon_bdev(dev_t *p) { int dev; int error; retry: if (ida_pre_get(&unnamed_dev_ida, GFP_ATOMIC) == 0) return -ENOMEM; spin_lock(&unnamed_dev_lock); error = ida_get_new_above(&unnamed_dev_ida, unnamed_dev_start, &dev); if (!error) unnamed_dev_start = dev + 1; spin_unlock(&unnamed_dev_lock); if (error == -EAGAIN) /* We raced and lost with another CPU. */ goto retry; else if (error) return -EAGAIN; if (dev >= (1 << MINORBITS)) { spin_lock(&unnamed_dev_lock); ida_remove(&unnamed_dev_ida, dev); if (unnamed_dev_start > dev) unnamed_dev_start = dev; spin_unlock(&unnamed_dev_lock); return -EMFILE; } *p = MKDEV(0, dev & MINORMASK); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Andrew Morton4328.67%211.76%
Al Viro3422.67%529.41%
Corey Minyard3422.67%15.88%
Linus Torvalds2919.33%423.53%
Alexey Dobriyan53.33%15.88%
Linus Torvalds (pre-git)42.67%317.65%
Wang YanQing10.67%15.88%
Total150100.00%17100.00%

EXPORT_SYMBOL(get_anon_bdev);
void free_anon_bdev(dev_t dev) { int slot = MINOR(dev); spin_lock(&unnamed_dev_lock); ida_remove(&unnamed_dev_ida, slot); if (slot < unnamed_dev_start) unnamed_dev_start = slot; spin_unlock(&unnamed_dev_lock); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro4291.30%466.67%
Alexey Dobriyan24.35%116.67%
Andrew Morton24.35%116.67%
Total46100.00%6100.00%

EXPORT_SYMBOL(free_anon_bdev);
int set_anon_super(struct super_block *s, void *data) { return get_anon_bdev(&s->s_dev); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro2295.65%150.00%
Christoph Hellwig14.35%150.00%
Total23100.00%2100.00%

EXPORT_SYMBOL(set_anon_super);
void kill_anon_super(struct super_block *sb) { dev_t dev = sb->s_dev; generic_shutdown_super(sb); free_anon_bdev(dev); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro27100.00%1100.00%
Total27100.00%1100.00%

EXPORT_SYMBOL(kill_anon_super);
void kill_litter_super(struct super_block *sb) { if (sb->s_root) d_genocide(sb->s_root); kill_anon_super(sb); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro28100.00%1100.00%
Total28100.00%1100.00%

EXPORT_SYMBOL(kill_litter_super);
static int ns_test_super(struct super_block *sb, void *data) { return sb->s_fs_info == data; }

Contributors

PersonTokensPropCommitsCommitProp
Serge E. Hallyn22100.00%1100.00%
Total22100.00%1100.00%


static int ns_set_super(struct super_block *sb, void *data) { sb->s_fs_info = data; return set_anon_super(sb, NULL); }

Contributors

PersonTokensPropCommitsCommitProp
Serge E. Hallyn29100.00%1100.00%
Total29100.00%1100.00%


struct dentry *mount_ns(struct file_system_type *fs_type, int flags, void *data, void *ns, struct user_namespace *user_ns, int (*fill_super)(struct super_block *, void *, int)) { struct super_block *sb; /* Don't allow mounting unless the caller has CAP_SYS_ADMIN * over the namespace. */ if (!(flags & MS_KERNMOUNT) && !ns_capable(user_ns, CAP_SYS_ADMIN)) return ERR_PTR(-EPERM); sb = sget_userns(fs_type, ns_test_super, ns_set_super, flags, user_ns, ns); if (IS_ERR(sb)) return ERR_CAST(sb); if (!sb->s_root) { int err; err = fill_super(sb, data, flags & MS_SILENT ? 1 : 0); if (err) { deactivate_locked_super(sb); return ERR_PTR(err); } sb->s_flags |= MS_ACTIVE; } return dget(sb->s_root); }

Contributors

PersonTokensPropCommitsCommitProp
Serge E. Hallyn11167.68%116.67%
Eric W. Biedermann3823.17%233.33%
Al Viro137.93%233.33%
David Howells21.22%116.67%
Total164100.00%6100.00%

EXPORT_SYMBOL(mount_ns); #ifdef CONFIG_BLOCK
static int set_bdev_super(struct super_block *s, void *data) { s->s_bdev = data; s->s_dev = s->s_bdev->bd_dev; s->s_bdi = bdi_get(s->s_bdev->bd_bdi); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro3472.34%133.33%
Jens Axboe919.15%133.33%
Jan Kara48.51%133.33%
Total47100.00%3100.00%


static int test_bdev_super(struct super_block *s, void *data) { return (void *)s->s_bdev == data; }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro26100.00%1100.00%
Total26100.00%1100.00%


struct dentry *mount_bdev(struct file_system_type *fs_type, int flags, const char *dev_name, void *data, int (*fill_super)(struct super_block *, void *, int)) { struct block_device *bdev; struct super_block *s; fmode_t mode = FMODE_READ | FMODE_EXCL; int error = 0; if (!(flags & MS_RDONLY)) mode |= FMODE_WRITE; bdev = blkdev_get_by_path(dev_name, mode, fs_type); if (IS_ERR(bdev)) return ERR_CAST(bdev); /* * once the super is inserted into the list by sget, s_umount * will protect the lockfs code from trying to start a snapshot * while we are mounting */ mutex_lock(&bdev->bd_fsfreeze_mutex); if (bdev->bd_fsfreeze_count > 0) { mutex_unlock(&bdev->bd_fsfreeze_mutex); error = -EBUSY; goto error_bdev; } s = sget(fs_type, test_bdev_super, set_bdev_super, flags | MS_NOSEC, bdev); mutex_unlock(&bdev->bd_fsfreeze_mutex); if (IS_ERR(s)) goto error_s; if (s->s_root) { if ((flags ^ s->s_flags) & MS_RDONLY) { deactivate_locked_super(s); error = -EBUSY; goto error_bdev; } /* * s_umount nests inside bd_mutex during * __invalidate_device(). blkdev_put() acquires * bd_mutex and can't be called under s_umount. Drop * s_umount temporarily. This is safe as we're * holding an active reference. */ up_write(&s->s_umount); blkdev_put(bdev, mode); down_write(&s->s_umount); } else { s->s_mode = mode; snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev); sb_set_blocksize(s, block_size(bdev)); error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); if (error) { deactivate_locked_super(s); goto error; } s->s_flags |= MS_ACTIVE; bdev->bd_super = s; } return dget(s->s_root); error_s: error = PTR_ERR(s); error_bdev: blkdev_put(bdev, mode); error: return ERR_PTR(error); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro11533.63%1127.50%
Linus Torvalds7120.76%512.50%
Christoph Hellwig3911.40%25.00%
Linus Torvalds (pre-git)349.94%1025.00%
David Howells319.06%25.00%
Tejun Heo226.43%37.50%
Andrew Morton133.80%12.50%
Theodore Y. Ts'o72.05%25.00%
Dmitriy Monakhov51.46%12.50%
Pekka J Enberg30.88%12.50%
Andries E. Brouwer10.29%12.50%
Greg Kroah-Hartman10.29%12.50%
Total342100.00%40100.00%

EXPORT_SYMBOL(mount_bdev);
void kill_block_super(struct super_block *sb) { struct block_device *bdev = sb->s_bdev; fmode_t mode = sb->s_mode; bdev->bd_super = NULL; generic_shutdown_super(sb); sync_blockdev(bdev); WARN_ON_ONCE(!(mode & FMODE_EXCL)); blkdev_put(bdev, mode | FMODE_EXCL); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro4167.21%337.50%
Tejun Heo1321.31%225.00%
Theodore Y. Ts'o58.20%112.50%
Linus Torvalds11.64%112.50%
H Hartley Sweeten11.64%112.50%
Total61100.00%8100.00%

EXPORT_SYMBOL(kill_block_super); #endif
struct dentry *mount_nodev(struct file_system_type *fs_type, int flags, void *data, int (*fill_super)(struct super_block *, void *, int)) { int error; struct super_block *s = sget(fs_type, NULL, set_anon_super, flags, NULL); if (IS_ERR(s)) return ERR_CAST(s); error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); if (error) { deactivate_locked_super(s); return ERR_PTR(error); } s->s_flags |= MS_ACTIVE; return dget(s->s_root); }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds6454.70%327.27%
Al Viro4639.32%436.36%
David Howells54.27%218.18%
Linus Torvalds (pre-git)10.85%19.09%
Theodore Y. Ts'o10.85%19.09%
Total117100.00%11100.00%

EXPORT_SYMBOL(mount_nodev);
static int compare_single(struct super_block *s, void *p) { return 1; }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds18100.00%1100.00%
Total18100.00%1100.00%


struct dentry *mount_single(struct file_system_type *fs_type, int flags, void *data, int (*fill_super)(struct super_block *, void *, int)) { struct super_block *s; int error; s = sget(fs_type, compare_single, set_anon_super, flags, NULL); if (IS_ERR(s)) return ERR_CAST(s); if (!s->s_root) { error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); if (error) { deactivate_locked_super(s); return ERR_PTR(error); } s->s_flags |= MS_ACTIVE; } else { do_remount_sb(s, flags, data, 0); } return dget(s->s_root); }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds6948.59%526.32%
Al Viro5035.21%421.05%
Linus Torvalds (pre-git)128.45%526.32%
David Howells53.52%210.53%
Kay Sievers32.11%15.26%
Andrew Morton21.41%15.26%
Theodore Y. Ts'o10.70%15.26%
Total142100.00%19100.00%

EXPORT_SYMBOL(mount_single);
struct dentry * mount_fs(struct file_system_type *type, int flags, const char *name, void *data) { struct dentry *root; struct super_block *sb; char *secdata = NULL; int error = -ENOMEM; if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) { secdata = alloc_secdata(); if (!secdata) goto out; error = security_sb_copy_data(data, secdata); if (error) goto out_free_secdata; } root = type->mount(type, flags, name, data); if (IS_ERR(root)) { error = PTR_ERR(root); goto out_free_secdata; } sb = root->d_sb; BUG_ON(!sb); WARN_ON(!sb->s_bdi); sb->s_flags |= MS_BORN; error = security_sb_kern_mount(sb, flags, secdata); if (error) goto out_sb; /* * filesystems should never set s_maxbytes larger than MAX_LFS_FILESIZE * but s_maxbytes was an unsigned long long for many releases. Throw * this warning for a little while to try and catch filesystems that * violate this rule. */ WARN((sb->s_maxbytes < 0), "%s set sb->s_maxbytes to " "negative value (%lld)\n", type->name, sb->s_maxbytes); up_write(&sb->s_umount); free_secdata(secdata); return root; out_sb: dput(root); deactivate_locked_super(sb); out_free_secdata: free_secdata(secdata); out: return ERR_PTR(error); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro7029.91%525.00%
Andrew Morton4720.09%15.00%
Linus Torvalds3314.10%15.00%
Jeff Layton218.97%210.00%
Stephen D. Smalley187.69%210.00%
David Howells125.13%15.00%
Eric Paris93.85%15.00%
Jörn Engel72.99%15.00%
Lee Schermerhorn52.14%15.00%
Gerald Schaefer52.14%15.00%
Trond Myklebust31.28%15.00%
James Morris20.85%15.00%
Linus Torvalds (pre-git)10.43%15.00%
Andries E. Brouwer10.43%15.00%
Total234100.00%20100.00%

/* * Setup private BDI for given superblock. It gets automatically cleaned up * in generic_shutdown_super(). */
int super_setup_bdi_name(struct super_block *sb, char *fmt, ...) { struct backing_dev_info *bdi; int err; va_list args; bdi = bdi_alloc(GFP_KERNEL); if (!bdi) return -ENOMEM; bdi->name = sb->s_type->name; va_start(args, fmt); err = bdi_register_va(bdi, fmt, args); va_end(args); if (err) { bdi_put(bdi); return err; } WARN_ON(sb->s_bdi != &noop_backing_dev_info); sb->s_bdi = bdi; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Jan Kara109100.00%1100.00%
Total109100.00%1100.00%

EXPORT_SYMBOL(super_setup_bdi_name); /* * Setup private BDI for given superblock. I gets automatically cleaned up * in generic_shutdown_super(). */
int super_setup_bdi(struct super_block *sb) { static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0); return super_setup_bdi_name(sb, "%.28s-%ld", sb->s_type->name, atomic_long_inc_return(&bdi_seq)); }

Contributors

PersonTokensPropCommitsCommitProp
Jan Kara39100.00%1100.00%
Total39100.00%1100.00%

EXPORT_SYMBOL(super_setup_bdi); /* * This is an internal function, please use sb_end_{write,pagefault,intwrite} * instead. */
void __sb_end_write(struct super_block *sb, int level) { percpu_up_read(sb->s_writers.rw_sem + level-1); }

Contributors

PersonTokensPropCommitsCommitProp
Jan Kara1661.54%133.33%
Josef Bacik726.92%133.33%
Oleg Nesterov311.54%133.33%
Total26100.00%3100.00%

EXPORT_SYMBOL(__sb_end_write); /* * This is an internal function, please use sb_start_{write,pagefault,intwrite} * instead. */
int __sb_start_write(struct super_block *sb, int level, bool wait) { bool force_trylock = false; int ret = 1; #ifdef CONFIG_LOCKDEP /* * We want lockdep to tell us about possible deadlocks with freezing * but it's it bit tricky to properly instrument it. Getting a freeze * protection works as getting a read lock but there are subtle * problems. XFS for example gets freeze protection on internal level * twice in some cases, which is OK only because we already hold a * freeze protection also on higher level. Due to these cases we have * to use wait == F (trylock mode) which must not fail. */ if (wait) { int i; for (i = 0; i < level - 1; i++) if (percpu_rwsem_is_held(sb->s_writers.rw_sem + i)) { force_trylock = true; break; } } #endif if (wait && !force_trylock) percpu_down_read(sb->s_writers.rw_sem + level-1); else ret = percpu_down_read_trylock(sb->s_writers.rw_sem + level-1); WARN_ON(force_trylock && !ret); return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Oleg Nesterov12299.19%266.67%
Vincent Stehlé10.81%133.33%
Total123100.00%3100.00%

EXPORT_SYMBOL(__sb_start_write); /** * sb_wait_write - wait until all writers to given file system finish * @sb: the super for which we wait * @level: type of writers we wait for (normal vs page fault) * * This function waits until there are no writers of given type to given file * system. */
static void sb_wait_write(struct super_block *sb, int level) { percpu_down_write(sb->s_writers.rw_sem + level-1); }

Contributors

PersonTokensPropCommitsCommitProp
Jan Kara2385.19%133.33%
Oleg Nesterov414.81%266.67%
Total27100.00%3100.00%

/* * We are going to return to userspace and forget about these locks, the * ownership goes to the caller of thaw_super() which does unlock(). */
static void lockdep_sb_freeze_release(struct super_block *sb) { int level; for (level = SB_FREEZE_LEVELS - 1; level >= 0; level--) percpu_rwsem_release(sb->s_writers.rw_sem + level, 0, _THIS_IP_); }

Contributors

PersonTokensPropCommitsCommitProp
Oleg Nesterov3375.00%266.67%
Jan Kara1125.00%133.33%
Total44100.00%3100.00%

/* * Tell lockdep we are holding these locks before we call ->unfreeze_fs(sb). */
static void lockdep_sb_freeze_acquire(struct super_block *sb) { int level; for (level = 0; level < SB_FREEZE_LEVELS; ++level) percpu_rwsem_acquire(sb->s_writers.rw_sem + level, 0, _THIS_IP_); }

Contributors

PersonTokensPropCommitsCommitProp
Oleg Nesterov3276.19%266.67%
Jan Kara1023.81%133.33%
Total42100.00%3100.00%


static void sb_freeze_unlock(struct super_block *sb) { int level; for (level = SB_FREEZE_LEVELS - 1; level >= 0; level--) percpu_up_write(sb->s_writers.rw_sem + level); }

Contributors

PersonTokensPropCommitsCommitProp
Oleg Nesterov2972.50%266.67%
Jan Kara1127.50%133.33%
Total40100.00%3100.00%

/** * freeze_super - lock the filesystem and force it into a consistent state * @sb: the super to lock * * Syncs the super to make sure the filesystem is consistent and calls the fs's * freeze_fs. Subsequent calls to this without first thawing the fs will return * -EBUSY. * * During this function, sb->s_writers.frozen goes through these values: * * SB_UNFROZEN: File system is normal, all writes progress as usual. * * SB_FREEZE_WRITE: The file system is in the process of being frozen. New * writes should be blocked, though page faults are still allowed. We wait for * all writes to complete and then proceed to the next stage. * * SB_FREEZE_PAGEFAULT: Freezing continues. Now also page faults are blocked * but internal fs threads can still modify the filesystem (although they * should not dirty new pages or inodes), writeback can run etc. After waiting * for all running page faults we sync the filesystem which will clean all * dirty pages and inodes (no new dirty pages or inodes can be created when * sync is running). * * SB_FREEZE_FS: The file system is frozen. Now all internal sources of fs * modification are blocked (e.g. XFS preallocation truncation on inode * reclaim). This is usually implemented by blocking new transactions for * filesystems that have them and need this additional guard. After all * internal writers are finished we call ->freeze_fs() to finish filesystem * freezing. Then we transition to SB_FREEZE_COMPLETE state. This state is * mostly auxiliary for filesystems to verify they do not modify frozen fs. * * sb->s_writers.frozen is protected by sb->s_umount. */
int freeze_super(struct super_block *sb) { int ret; atomic_inc(&sb->s_active); down_write(&sb->s_umount); if (sb->s_writers.frozen != SB_UNFROZEN) { deactivate_locked_super(sb); return -EBUSY; } if (!(sb->s_flags & MS_BORN)) { up_write(&sb->s_umount); return 0; /* sic - it's "nothing to do" */ } if (sb->s_flags & MS_RDONLY) { /* Nothing to do really... */ sb->s_writers.frozen = SB_FREEZE_COMPLETE; up_write(&sb->s_umount); return 0; } sb->s_writers.frozen = SB_FREEZE_WRITE; /* Release s_umount to preserve sb_start_write -> s_umount ordering */ up_write(&sb->s_umount); sb_wait_write(sb, SB_FREEZE_WRITE); down_write(&sb->s_umount); /* Now we go and block page faults... */ sb->s_writers.frozen = SB_FREEZE_PAGEFAULT; sb_wait_write(sb, SB_FREEZE_PAGEFAULT); /* All writers are done so after syncing there won't be dirty data */ sync_filesystem(sb); /* Now wait for internal filesystem counter */ sb->s_writers.frozen = SB_FREEZE_FS; sb_wait_write(sb, SB_FREEZE_FS); if (sb->s_op->freeze_fs) { ret = sb->s_op->freeze_fs(sb); if (ret) { printk(KERN_ERR "VFS:Filesystem freeze failed\n"); sb->s_writers.frozen = SB_UNFROZEN; sb_freeze_unlock(sb); wake_up(&sb->s_writers.wait_unfrozen); deactivate_locked_super(sb); return ret; } } /* * For debugging purposes so that fs can warn if it sees write activity * when frozen is set to SB_FREEZE_COMPLETE, and for thaw_super(). */ sb->s_writers.frozen = SB_FREEZE_COMPLETE; lockdep_sb_freeze_release(sb); up_write(&sb->s_umount); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Josef Bacik14655.30%114.29%
Jan Kara7428.03%114.29%
Al Viro259.47%114.29%
Oleg Nesterov114.17%342.86%
Kazuya Mio83.03%114.29%
Total264100.00%7100.00%

EXPORT_SYMBOL(freeze_super); /** * thaw_super -- unlock filesystem * @sb: the super to thaw * * Unlocks the filesystem and marks it writeable again after freeze_super(). */
int thaw_super(struct super_block *sb) { int error; down_write(&sb->s_umount); if (sb->s_writers.frozen != SB_FREEZE_COMPLETE) { up_write(&sb->s_umount); return -EINVAL; } if (sb->s_flags & MS_RDONLY) { sb->s_writers.frozen = SB_UNFROZEN; goto out; } lockdep_sb_freeze_acquire(sb); if (sb->s_op->unfreeze_fs) { error = sb->s_op->unfreeze_fs(sb); if (error) { printk(KERN_ERR "VFS:Filesystem thaw failed\n"); lockdep_sb_freeze_release(sb); up_write(&sb->s_umount); return error; } } sb->s_writers.frozen = SB_UNFROZEN; sb_freeze_unlock(sb); out: wake_up(&sb->s_writers.wait_unfrozen); deactivate_locked_super(sb); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Josef Bacik11675.82%120.00%
Oleg Nesterov2818.30%360.00%
Jan Kara95.88%120.00%
Total153100.00%5100.00%

EXPORT_SYMBOL(thaw_super);

Overall Contributors

PersonTokensPropCommitsCommitProp
Al Viro176529.86%5424.32%
Jan Kara66411.24%94.05%
Linus Torvalds63310.71%146.31%
Dave Chinner4297.26%125.41%
Oleg Nesterov3746.33%52.25%
Eric W. Biedermann2874.86%52.25%
Andrew Morton2834.79%114.95%
Josef Bacik2804.74%10.45%
Serge E. Hallyn1662.81%10.45%
Christoph Hellwig1442.44%73.15%
David Howells811.37%41.80%
Linus Torvalds (pre-git)781.32%177.66%
Miklos Szeredi681.15%31.35%
Vladimir Davydov671.13%73.15%
Kirill Korotaev591.00%20.90%
Jens Axboe570.96%41.80%
Arnaldo Carvalho de Melo450.76%10.45%
Tejun Heo380.64%41.80%
Corey Minyard340.58%10.45%
Nicholas Piggin340.58%31.35%
Stephen D. Smalley280.47%31.35%
Glauber de Oliveira Costa230.39%20.90%
Jeff Layton210.36%20.90%
Li Zefan180.30%10.45%
Arjan van de Ven150.25%20.90%
Theodore Y. Ts'o140.24%20.90%
Konstantin Khlebnikov140.24%10.45%
Alexey Dobriyan130.22%31.35%
Dan Magenheimer130.22%20.90%
Roland Dreier130.22%10.45%
Ingo Molnar120.20%31.35%
Neil Brown110.19%10.45%
Tetsuo Handa90.15%10.45%
Eric Paris90.15%10.45%
William Lee Irwin III80.14%10.45%
Kazuya Mio80.14%10.45%
Thomas Gleixner80.14%10.45%
David Chinner70.12%10.45%
Jörn Engel70.12%10.45%
Matthias Kaehlcke70.12%10.45%
Kentaro Makita60.10%10.45%
Andi Kleen60.10%10.45%
Dave Jones50.08%10.45%
Gerald Schaefer50.08%10.45%
Dmitriy Monakhov50.08%10.45%
Lee Schermerhorn50.08%10.45%
Josh Triplett40.07%10.45%
Kay Sievers30.05%10.45%
Pekka J Enberg30.05%10.45%
Greg Kroah-Hartman30.05%31.35%
Peter Zijlstra30.05%10.45%
Trond Myklebust30.05%10.45%
Thomas Bächler20.03%10.45%
James Morris20.03%10.45%
Andries E. Brouwer20.03%10.45%
Vincent Stehlé10.02%10.45%
Paul Gortmaker10.02%10.45%
Josef 'Jeff' Sipek10.02%10.45%
Wang YanQing10.02%10.45%
Martin Waitz10.02%10.45%
Jan Engelhardt10.02%10.45%
H Hartley Sweeten10.02%10.45%
Oliver Neukum10.02%10.45%
Masanari Iida10.02%10.45%
Total5910100.00%222100.00%
Directory: fs
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