Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/fs/file_table.c |
| 3 | * |
| 4 | * Copyright (C) 1991, 1992 Linus Torvalds |
| 5 | * Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu) |
| 6 | */ |
| 7 | |
| 8 | #include <linux/string.h> |
| 9 | #include <linux/slab.h> |
| 10 | #include <linux/file.h> |
Al Viro | 9f3acc3 | 2008-04-24 07:44:08 -0400 | [diff] [blame] | 11 | #include <linux/fdtable.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 12 | #include <linux/init.h> |
| 13 | #include <linux/module.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 14 | #include <linux/fs.h> |
| 15 | #include <linux/security.h> |
Ingo Molnar | 5b825c3 | 2017-02-02 17:54:15 +0100 | [diff] [blame] | 16 | #include <linux/cred.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 17 | #include <linux/eventpoll.h> |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 18 | #include <linux/rcupdate.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 19 | #include <linux/mount.h> |
Randy Dunlap | 16f7e0f | 2006-01-11 12:17:46 -0800 | [diff] [blame] | 20 | #include <linux/capability.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 21 | #include <linux/cdev.h> |
Robert Love | 0eeca28 | 2005-07-12 17:06:03 -0400 | [diff] [blame] | 22 | #include <linux/fsnotify.h> |
Dipankar Sarma | 529bf6b | 2006-03-07 21:55:35 -0800 | [diff] [blame] | 23 | #include <linux/sysctl.h> |
| 24 | #include <linux/percpu_counter.h> |
Nick Piggin | 6416ccb | 2010-08-18 04:37:38 +1000 | [diff] [blame] | 25 | #include <linux/percpu.h> |
Al Viro | 4a9d4b0 | 2012-06-24 09:56:45 +0400 | [diff] [blame] | 26 | #include <linux/task_work.h> |
Al Viro | 0552f87 | 2009-12-16 04:53:03 -0500 | [diff] [blame] | 27 | #include <linux/ima.h> |
Mel Gorman | 4248b0d | 2015-08-06 15:46:20 -0700 | [diff] [blame] | 28 | #include <linux/swap.h> |
Dipankar Sarma | 529bf6b | 2006-03-07 21:55:35 -0800 | [diff] [blame] | 29 | |
Arun Sharma | 60063497 | 2011-07-26 16:09:06 -0700 | [diff] [blame] | 30 | #include <linux/atomic.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 31 | |
Eric Paris | e81e3f4 | 2009-12-04 15:47:36 -0500 | [diff] [blame] | 32 | #include "internal.h" |
| 33 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | /* sysctl tunables... */ |
| 35 | struct files_stat_struct files_stat = { |
| 36 | .max_files = NR_FILE |
| 37 | }; |
| 38 | |
Eric Dumazet | b6b3fde | 2008-12-10 09:35:45 -0800 | [diff] [blame] | 39 | /* SLAB cache for file structures */ |
| 40 | static struct kmem_cache *filp_cachep __read_mostly; |
| 41 | |
Dipankar Sarma | 529bf6b | 2006-03-07 21:55:35 -0800 | [diff] [blame] | 42 | static struct percpu_counter nr_files __cacheline_aligned_in_smp; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | |
Al Viro | 5c33b18 | 2012-07-20 23:05:59 +0400 | [diff] [blame] | 44 | static void file_free_rcu(struct rcu_head *head) |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 45 | { |
David Howells | d76b0d9 | 2008-11-14 10:39:25 +1100 | [diff] [blame] | 46 | struct file *f = container_of(head, struct file, f_u.fu_rcuhead); |
| 47 | |
| 48 | put_cred(f->f_cred); |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 49 | kmem_cache_free(filp_cachep, f); |
| 50 | } |
| 51 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 52 | static inline void file_free(struct file *f) |
| 53 | { |
Al Viro | e8cff84 | 2018-07-09 11:24:21 -0400 | [diff] [blame] | 54 | security_file_free(f); |
Miklos Szeredi | d3b1084 | 2018-07-18 15:44:40 +0200 | [diff] [blame] | 55 | if (!(f->f_mode & FMODE_NOACCOUNT)) |
| 56 | percpu_counter_dec(&nr_files); |
Eric Dumazet | 2f51201 | 2005-10-30 15:02:16 -0800 | [diff] [blame] | 57 | call_rcu(&f->f_u.fu_rcuhead, file_free_rcu); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 58 | } |
| 59 | |
Dipankar Sarma | 529bf6b | 2006-03-07 21:55:35 -0800 | [diff] [blame] | 60 | /* |
| 61 | * Return the total number of open files in the system |
| 62 | */ |
Eric Dumazet | 518de9b | 2010-10-26 14:22:44 -0700 | [diff] [blame] | 63 | static long get_nr_files(void) |
Dipankar Sarma | 529bf6b | 2006-03-07 21:55:35 -0800 | [diff] [blame] | 64 | { |
| 65 | return percpu_counter_read_positive(&nr_files); |
| 66 | } |
| 67 | |
| 68 | /* |
| 69 | * Return the maximum number of open files in the system |
| 70 | */ |
Eric Dumazet | 518de9b | 2010-10-26 14:22:44 -0700 | [diff] [blame] | 71 | unsigned long get_max_files(void) |
Dipankar Sarma | 529bf6b | 2006-03-07 21:55:35 -0800 | [diff] [blame] | 72 | { |
| 73 | return files_stat.max_files; |
| 74 | } |
| 75 | EXPORT_SYMBOL_GPL(get_max_files); |
| 76 | |
| 77 | /* |
| 78 | * Handle nr_files sysctl |
| 79 | */ |
| 80 | #if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS) |
Joe Perches | 1f7e061 | 2014-06-06 14:38:05 -0700 | [diff] [blame] | 81 | int proc_nr_files(struct ctl_table *table, int write, |
Dipankar Sarma | 529bf6b | 2006-03-07 21:55:35 -0800 | [diff] [blame] | 82 | void __user *buffer, size_t *lenp, loff_t *ppos) |
| 83 | { |
| 84 | files_stat.nr_files = get_nr_files(); |
Eric Dumazet | 518de9b | 2010-10-26 14:22:44 -0700 | [diff] [blame] | 85 | return proc_doulongvec_minmax(table, write, buffer, lenp, ppos); |
Dipankar Sarma | 529bf6b | 2006-03-07 21:55:35 -0800 | [diff] [blame] | 86 | } |
| 87 | #else |
Joe Perches | 1f7e061 | 2014-06-06 14:38:05 -0700 | [diff] [blame] | 88 | int proc_nr_files(struct ctl_table *table, int write, |
Dipankar Sarma | 529bf6b | 2006-03-07 21:55:35 -0800 | [diff] [blame] | 89 | void __user *buffer, size_t *lenp, loff_t *ppos) |
| 90 | { |
| 91 | return -ENOSYS; |
| 92 | } |
| 93 | #endif |
| 94 | |
Miklos Szeredi | d3b1084 | 2018-07-18 15:44:40 +0200 | [diff] [blame] | 95 | static struct file *__alloc_file(int flags, const struct cred *cred) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 96 | { |
Al Viro | 1afc99b | 2013-02-14 20:41:04 -0500 | [diff] [blame] | 97 | struct file *f; |
| 98 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 99 | |
Denis Cheng | 4975e45 | 2007-10-16 23:26:19 -0700 | [diff] [blame] | 100 | f = kmem_cache_zalloc(filp_cachep, GFP_KERNEL); |
Al Viro | 1afc99b | 2013-02-14 20:41:04 -0500 | [diff] [blame] | 101 | if (unlikely(!f)) |
| 102 | return ERR_PTR(-ENOMEM); |
Kirill Korotaev | af4d2ec | 2005-06-23 00:09:50 -0700 | [diff] [blame] | 103 | |
Tetsuo Handa | 78d2978 | 2011-02-04 18:13:24 +0000 | [diff] [blame] | 104 | f->f_cred = get_cred(cred); |
Al Viro | 1afc99b | 2013-02-14 20:41:04 -0500 | [diff] [blame] | 105 | error = security_file_alloc(f); |
| 106 | if (unlikely(error)) { |
Al Viro | e8cff84 | 2018-07-09 11:24:21 -0400 | [diff] [blame] | 107 | file_free_rcu(&f->f_u.fu_rcuhead); |
Al Viro | 1afc99b | 2013-02-14 20:41:04 -0500 | [diff] [blame] | 108 | return ERR_PTR(error); |
| 109 | } |
Kirill Korotaev | af4d2ec | 2005-06-23 00:09:50 -0700 | [diff] [blame] | 110 | |
Al Viro | 516e0cc | 2008-07-26 00:39:17 -0400 | [diff] [blame] | 111 | atomic_long_set(&f->f_count, 1); |
Benjamin LaHaise | 5a6b795 | 2006-03-23 03:01:03 -0800 | [diff] [blame] | 112 | rwlock_init(&f->f_owner.lock); |
Jonathan Corbet | 6849991 | 2009-02-06 13:52:43 -0700 | [diff] [blame] | 113 | spin_lock_init(&f->f_lock); |
Linus Torvalds | 9c225f2 | 2014-03-03 09:36:58 -0800 | [diff] [blame] | 114 | mutex_init(&f->f_pos_lock); |
Benjamin LaHaise | 5a6b795 | 2006-03-23 03:01:03 -0800 | [diff] [blame] | 115 | eventpoll_init_file(f); |
Al Viro | ea73ea7 | 2018-07-11 15:00:04 -0400 | [diff] [blame] | 116 | f->f_flags = flags; |
| 117 | f->f_mode = OPEN_FMODE(flags); |
Benjamin LaHaise | 5a6b795 | 2006-03-23 03:01:03 -0800 | [diff] [blame] | 118 | /* f->f_version: 0 */ |
Miklos Szeredi | d3b1084 | 2018-07-18 15:44:40 +0200 | [diff] [blame] | 119 | |
| 120 | return f; |
| 121 | } |
| 122 | |
| 123 | /* Find an unused file structure and return a pointer to it. |
| 124 | * Returns an error pointer if some error happend e.g. we over file |
| 125 | * structures limit, run out of memory or operation is not permitted. |
| 126 | * |
| 127 | * Be very careful using this. You are responsible for |
| 128 | * getting write access to any mount that you might assign |
| 129 | * to this filp, if it is opened for write. If this is not |
| 130 | * done, you will imbalance int the mount's writer count |
| 131 | * and a warning at __fput() time. |
| 132 | */ |
| 133 | struct file *alloc_empty_file(int flags, const struct cred *cred) |
| 134 | { |
| 135 | static long old_max; |
| 136 | struct file *f; |
| 137 | |
| 138 | /* |
| 139 | * Privileged users can go above max_files |
| 140 | */ |
| 141 | if (get_nr_files() >= files_stat.max_files && !capable(CAP_SYS_ADMIN)) { |
| 142 | /* |
| 143 | * percpu_counters are inaccurate. Do an expensive check before |
| 144 | * we go and fail. |
| 145 | */ |
| 146 | if (percpu_counter_sum_positive(&nr_files) >= files_stat.max_files) |
| 147 | goto over; |
| 148 | } |
| 149 | |
| 150 | f = __alloc_file(flags, cred); |
| 151 | if (!IS_ERR(f)) |
| 152 | percpu_counter_inc(&nr_files); |
| 153 | |
Kirill Korotaev | af4d2ec | 2005-06-23 00:09:50 -0700 | [diff] [blame] | 154 | return f; |
| 155 | |
| 156 | over: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 157 | /* Ran out of filps - report that */ |
Dipankar Sarma | 529bf6b | 2006-03-07 21:55:35 -0800 | [diff] [blame] | 158 | if (get_nr_files() > old_max) { |
Eric Dumazet | 518de9b | 2010-10-26 14:22:44 -0700 | [diff] [blame] | 159 | pr_info("VFS: file-max limit %lu reached\n", get_max_files()); |
Dipankar Sarma | 529bf6b | 2006-03-07 21:55:35 -0800 | [diff] [blame] | 160 | old_max = get_nr_files(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 161 | } |
Al Viro | 1afc99b | 2013-02-14 20:41:04 -0500 | [diff] [blame] | 162 | return ERR_PTR(-ENFILE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 163 | } |
| 164 | |
Miklos Szeredi | d3b1084 | 2018-07-18 15:44:40 +0200 | [diff] [blame] | 165 | /* |
| 166 | * Variant of alloc_empty_file() that doesn't check and modify nr_files. |
| 167 | * |
| 168 | * Should not be used unless there's a very good reason to do so. |
| 169 | */ |
| 170 | struct file *alloc_empty_file_noaccount(int flags, const struct cred *cred) |
| 171 | { |
| 172 | struct file *f = __alloc_file(flags, cred); |
| 173 | |
| 174 | if (!IS_ERR(f)) |
| 175 | f->f_mode |= FMODE_NOACCOUNT; |
| 176 | |
| 177 | return f; |
| 178 | } |
| 179 | |
Dave Hansen | ce8d2cd | 2007-10-16 23:31:13 -0700 | [diff] [blame] | 180 | /** |
| 181 | * alloc_file - allocate and initialize a 'struct file' |
Eric Biggers | a457606 | 2014-10-12 14:29:29 -0500 | [diff] [blame] | 182 | * |
| 183 | * @path: the (dentry, vfsmount) pair for the new file |
Al Viro | c9c554f | 2018-07-11 14:19:04 -0400 | [diff] [blame] | 184 | * @flags: O_... flags with which the new file will be opened |
Dave Hansen | ce8d2cd | 2007-10-16 23:31:13 -0700 | [diff] [blame] | 185 | * @fop: the 'struct file_operations' for the new file |
Dave Hansen | ce8d2cd | 2007-10-16 23:31:13 -0700 | [diff] [blame] | 186 | */ |
Al Viro | ee1904b | 2018-06-17 14:21:27 -0400 | [diff] [blame] | 187 | static struct file *alloc_file(const struct path *path, int flags, |
Al Viro | 2c48b9c | 2009-08-09 00:52:35 +0400 | [diff] [blame] | 188 | const struct file_operations *fop) |
Dave Hansen | ce8d2cd | 2007-10-16 23:31:13 -0700 | [diff] [blame] | 189 | { |
| 190 | struct file *file; |
Dave Hansen | ce8d2cd | 2007-10-16 23:31:13 -0700 | [diff] [blame] | 191 | |
Al Viro | ea73ea7 | 2018-07-11 15:00:04 -0400 | [diff] [blame] | 192 | file = alloc_empty_file(flags, current_cred()); |
Al Viro | 1afc99b | 2013-02-14 20:41:04 -0500 | [diff] [blame] | 193 | if (IS_ERR(file)) |
Anatol Pomozov | 39b65252 | 2012-09-12 20:11:55 -0700 | [diff] [blame] | 194 | return file; |
Dave Hansen | ce8d2cd | 2007-10-16 23:31:13 -0700 | [diff] [blame] | 195 | |
Al Viro | 2c48b9c | 2009-08-09 00:52:35 +0400 | [diff] [blame] | 196 | file->f_path = *path; |
Al Viro | dd37978 | 2013-03-01 19:48:30 -0500 | [diff] [blame] | 197 | file->f_inode = path->dentry->d_inode; |
Al Viro | 2c48b9c | 2009-08-09 00:52:35 +0400 | [diff] [blame] | 198 | file->f_mapping = path->dentry->d_inode->i_mapping; |
Jeff Layton | 5660e13 | 2017-07-06 07:02:25 -0400 | [diff] [blame] | 199 | file->f_wb_err = filemap_sample_wb_err(file->f_mapping); |
Al Viro | c9c554f | 2018-07-11 14:19:04 -0400 | [diff] [blame] | 200 | if ((file->f_mode & FMODE_READ) && |
Al Viro | 8436318 | 2015-04-04 01:14:53 -0400 | [diff] [blame] | 201 | likely(fop->read || fop->read_iter)) |
Al Viro | c9c554f | 2018-07-11 14:19:04 -0400 | [diff] [blame] | 202 | file->f_mode |= FMODE_CAN_READ; |
| 203 | if ((file->f_mode & FMODE_WRITE) && |
Al Viro | 8436318 | 2015-04-04 01:14:53 -0400 | [diff] [blame] | 204 | likely(fop->write || fop->write_iter)) |
Al Viro | c9c554f | 2018-07-11 14:19:04 -0400 | [diff] [blame] | 205 | file->f_mode |= FMODE_CAN_WRITE; |
Al Viro | f5d1140 | 2018-07-09 02:35:08 -0400 | [diff] [blame] | 206 | file->f_mode |= FMODE_OPENED; |
Dave Hansen | ce8d2cd | 2007-10-16 23:31:13 -0700 | [diff] [blame] | 207 | file->f_op = fop; |
Al Viro | c9c554f | 2018-07-11 14:19:04 -0400 | [diff] [blame] | 208 | if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) |
Mimi Zohar | 890275b5 | 2010-11-02 10:13:07 -0400 | [diff] [blame] | 209 | i_readcount_inc(path->dentry->d_inode); |
Al Viro | 3d1e463 | 2009-08-08 23:56:29 +0400 | [diff] [blame] | 210 | return file; |
Dave Hansen | ce8d2cd | 2007-10-16 23:31:13 -0700 | [diff] [blame] | 211 | } |
Dave Hansen | ce8d2cd | 2007-10-16 23:31:13 -0700 | [diff] [blame] | 212 | |
Al Viro | d93aa9d | 2018-06-09 09:40:05 -0400 | [diff] [blame] | 213 | struct file *alloc_file_pseudo(struct inode *inode, struct vfsmount *mnt, |
| 214 | const char *name, int flags, |
| 215 | const struct file_operations *fops) |
| 216 | { |
| 217 | static const struct dentry_operations anon_ops = { |
| 218 | .d_dname = simple_dname |
| 219 | }; |
| 220 | struct qstr this = QSTR_INIT(name, strlen(name)); |
| 221 | struct path path; |
| 222 | struct file *file; |
| 223 | |
| 224 | path.dentry = d_alloc_pseudo(mnt->mnt_sb, &this); |
| 225 | if (!path.dentry) |
| 226 | return ERR_PTR(-ENOMEM); |
| 227 | if (!mnt->mnt_sb->s_d_op) |
| 228 | d_set_d_op(path.dentry, &anon_ops); |
| 229 | path.mnt = mntget(mnt); |
| 230 | d_instantiate(path.dentry, inode); |
| 231 | file = alloc_file(&path, flags, fops); |
| 232 | if (IS_ERR(file)) { |
| 233 | ihold(inode); |
| 234 | path_put(&path); |
| 235 | } |
| 236 | return file; |
| 237 | } |
| 238 | EXPORT_SYMBOL(alloc_file_pseudo); |
| 239 | |
Al Viro | 183266f | 2018-06-17 14:15:10 -0400 | [diff] [blame] | 240 | struct file *alloc_file_clone(struct file *base, int flags, |
| 241 | const struct file_operations *fops) |
| 242 | { |
| 243 | struct file *f = alloc_file(&base->f_path, flags, fops); |
| 244 | if (!IS_ERR(f)) { |
| 245 | path_get(&f->f_path); |
| 246 | f->f_mapping = base->f_mapping; |
| 247 | } |
| 248 | return f; |
| 249 | } |
| 250 | |
Al Viro | d7065da | 2010-05-26 15:13:55 -0400 | [diff] [blame] | 251 | /* the real guts of fput() - releasing the last reference to file |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 252 | */ |
Al Viro | d7065da | 2010-05-26 15:13:55 -0400 | [diff] [blame] | 253 | static void __fput(struct file *file) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 254 | { |
Josef "Jeff" Sipek | 0f7fc9e4 | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 255 | struct dentry *dentry = file->f_path.dentry; |
| 256 | struct vfsmount *mnt = file->f_path.mnt; |
David Howells | c77cece | 2013-06-13 23:37:49 +0100 | [diff] [blame] | 257 | struct inode *inode = file->f_inode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 258 | |
Al Viro | 4d27f32 | 2018-07-09 11:14:39 -0400 | [diff] [blame] | 259 | if (unlikely(!(file->f_mode & FMODE_OPENED))) |
| 260 | goto out; |
| 261 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 262 | might_sleep(); |
Robert Love | 0eeca28 | 2005-07-12 17:06:03 -0400 | [diff] [blame] | 263 | |
| 264 | fsnotify_close(file); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 265 | /* |
| 266 | * The function eventpoll_release() should be the first called |
| 267 | * in the file cleanup chain. |
| 268 | */ |
| 269 | eventpoll_release(file); |
Jeff Layton | 78ed8a1 | 2014-02-03 12:13:08 -0500 | [diff] [blame] | 270 | locks_remove_file(file); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 271 | |
Mimi Zohar | bb02b18 | 2017-06-21 21:13:18 -0400 | [diff] [blame] | 272 | ima_file_free(file); |
Al Viro | 233e70f | 2008-10-31 23:28:30 +0000 | [diff] [blame] | 273 | if (unlikely(file->f_flags & FASYNC)) { |
Al Viro | 72c2d53 | 2013-09-22 16:27:52 -0400 | [diff] [blame] | 274 | if (file->f_op->fasync) |
Al Viro | 233e70f | 2008-10-31 23:28:30 +0000 | [diff] [blame] | 275 | file->f_op->fasync(-1, file, 0); |
| 276 | } |
Al Viro | 72c2d53 | 2013-09-22 16:27:52 -0400 | [diff] [blame] | 277 | if (file->f_op->release) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 278 | file->f_op->release(inode, file); |
Miklos Szeredi | 60ed8cf | 2011-03-16 18:17:54 +0100 | [diff] [blame] | 279 | if (unlikely(S_ISCHR(inode->i_mode) && inode->i_cdev != NULL && |
| 280 | !(file->f_mode & FMODE_PATH))) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 281 | cdev_put(inode->i_cdev); |
Miklos Szeredi | 60ed8cf | 2011-03-16 18:17:54 +0100 | [diff] [blame] | 282 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 283 | fops_put(file->f_op); |
Eric W. Biederman | 609d7fa | 2006-10-02 02:17:15 -0700 | [diff] [blame] | 284 | put_pid(file->f_owner.pid); |
Mimi Zohar | 890275b5 | 2010-11-02 10:13:07 -0400 | [diff] [blame] | 285 | if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) |
| 286 | i_readcount_dec(inode); |
Al Viro | 83f936c | 2014-03-14 12:02:47 -0400 | [diff] [blame] | 287 | if (file->f_mode & FMODE_WRITER) { |
| 288 | put_write_access(inode); |
| 289 | __mnt_drop_write(mnt); |
| 290 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 291 | dput(dentry); |
| 292 | mntput(mnt); |
Al Viro | 4d27f32 | 2018-07-09 11:14:39 -0400 | [diff] [blame] | 293 | out: |
| 294 | file_free(file); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 295 | } |
| 296 | |
Oleg Nesterov | 4f5e65a | 2013-07-08 14:24:16 -0700 | [diff] [blame] | 297 | static LLIST_HEAD(delayed_fput_list); |
Al Viro | 4a9d4b0 | 2012-06-24 09:56:45 +0400 | [diff] [blame] | 298 | static void delayed_fput(struct work_struct *unused) |
| 299 | { |
Oleg Nesterov | 4f5e65a | 2013-07-08 14:24:16 -0700 | [diff] [blame] | 300 | struct llist_node *node = llist_del_all(&delayed_fput_list); |
Byungchul Park | b9ea557 | 2017-08-07 17:45:39 +0900 | [diff] [blame] | 301 | struct file *f, *t; |
Oleg Nesterov | 4f5e65a | 2013-07-08 14:24:16 -0700 | [diff] [blame] | 302 | |
Byungchul Park | b9ea557 | 2017-08-07 17:45:39 +0900 | [diff] [blame] | 303 | llist_for_each_entry_safe(f, t, node, f_u.fu_llist) |
| 304 | __fput(f); |
Al Viro | 4a9d4b0 | 2012-06-24 09:56:45 +0400 | [diff] [blame] | 305 | } |
| 306 | |
| 307 | static void ____fput(struct callback_head *work) |
| 308 | { |
| 309 | __fput(container_of(work, struct file, f_u.fu_rcuhead)); |
| 310 | } |
| 311 | |
| 312 | /* |
| 313 | * If kernel thread really needs to have the final fput() it has done |
| 314 | * to complete, call this. The only user right now is the boot - we |
| 315 | * *do* need to make sure our writes to binaries on initramfs has |
| 316 | * not left us with opened struct file waiting for __fput() - execve() |
| 317 | * won't work without that. Please, don't add more callers without |
| 318 | * very good reasons; in particular, never call that with locks |
| 319 | * held and never call that from a thread that might need to do |
| 320 | * some work on any kind of umount. |
| 321 | */ |
| 322 | void flush_delayed_fput(void) |
| 323 | { |
| 324 | delayed_fput(NULL); |
| 325 | } |
| 326 | |
Al Viro | c7314d7 | 2013-10-20 08:44:39 -0400 | [diff] [blame] | 327 | static DECLARE_DELAYED_WORK(delayed_fput_work, delayed_fput); |
Al Viro | 4a9d4b0 | 2012-06-24 09:56:45 +0400 | [diff] [blame] | 328 | |
Jens Axboe | 091141a | 2018-11-21 10:32:39 -0700 | [diff] [blame] | 329 | void fput_many(struct file *file, unsigned int refs) |
Al Viro | d7065da | 2010-05-26 15:13:55 -0400 | [diff] [blame] | 330 | { |
Jens Axboe | 091141a | 2018-11-21 10:32:39 -0700 | [diff] [blame] | 331 | if (atomic_long_sub_and_test(refs, &file->f_count)) { |
Al Viro | 4a9d4b0 | 2012-06-24 09:56:45 +0400 | [diff] [blame] | 332 | struct task_struct *task = current; |
Oleg Nesterov | e7b2c40 | 2013-06-14 21:09:47 +0200 | [diff] [blame] | 333 | |
Oleg Nesterov | e7b2c40 | 2013-06-14 21:09:47 +0200 | [diff] [blame] | 334 | if (likely(!in_interrupt() && !(task->flags & PF_KTHREAD))) { |
| 335 | init_task_work(&file->f_u.fu_rcuhead, ____fput); |
| 336 | if (!task_work_add(task, &file->f_u.fu_rcuhead, true)) |
| 337 | return; |
Andrew Morton | 6437250 | 2013-07-08 14:24:15 -0700 | [diff] [blame] | 338 | /* |
| 339 | * After this task has run exit_task_work(), |
Andrew Morton | be49b30 | 2013-09-11 14:24:34 -0700 | [diff] [blame] | 340 | * task_work_add() will fail. Fall through to delayed |
Andrew Morton | 6437250 | 2013-07-08 14:24:15 -0700 | [diff] [blame] | 341 | * fput to avoid leaking *file. |
| 342 | */ |
Al Viro | 4a9d4b0 | 2012-06-24 09:56:45 +0400 | [diff] [blame] | 343 | } |
Oleg Nesterov | 4f5e65a | 2013-07-08 14:24:16 -0700 | [diff] [blame] | 344 | |
| 345 | if (llist_add(&file->f_u.fu_llist, &delayed_fput_list)) |
Al Viro | c7314d7 | 2013-10-20 08:44:39 -0400 | [diff] [blame] | 346 | schedule_delayed_work(&delayed_fput_work, 1); |
Al Viro | 4a9d4b0 | 2012-06-24 09:56:45 +0400 | [diff] [blame] | 347 | } |
| 348 | } |
| 349 | |
Jens Axboe | 091141a | 2018-11-21 10:32:39 -0700 | [diff] [blame] | 350 | void fput(struct file *file) |
| 351 | { |
| 352 | fput_many(file, 1); |
| 353 | } |
| 354 | |
Al Viro | 4a9d4b0 | 2012-06-24 09:56:45 +0400 | [diff] [blame] | 355 | /* |
| 356 | * synchronous analog of fput(); for kernel threads that might be needed |
| 357 | * in some umount() (and thus can't use flush_delayed_fput() without |
| 358 | * risking deadlocks), need to wait for completion of __fput() and know |
| 359 | * for this specific struct file it won't involve anything that would |
| 360 | * need them. Use only if you really need it - at the very least, |
| 361 | * don't blindly convert fput() by kernel thread to that. |
| 362 | */ |
| 363 | void __fput_sync(struct file *file) |
| 364 | { |
| 365 | if (atomic_long_dec_and_test(&file->f_count)) { |
| 366 | struct task_struct *task = current; |
Al Viro | 4a9d4b0 | 2012-06-24 09:56:45 +0400 | [diff] [blame] | 367 | BUG_ON(!(task->flags & PF_KTHREAD)); |
Al Viro | d7065da | 2010-05-26 15:13:55 -0400 | [diff] [blame] | 368 | __fput(file); |
Al Viro | 4a9d4b0 | 2012-06-24 09:56:45 +0400 | [diff] [blame] | 369 | } |
Al Viro | d7065da | 2010-05-26 15:13:55 -0400 | [diff] [blame] | 370 | } |
| 371 | |
| 372 | EXPORT_SYMBOL(fput); |
| 373 | |
Mel Gorman | 4248b0d | 2015-08-06 15:46:20 -0700 | [diff] [blame] | 374 | void __init files_init(void) |
Byungchul Park | b9ea557 | 2017-08-07 17:45:39 +0900 | [diff] [blame] | 375 | { |
Eric Dumazet | b6b3fde | 2008-12-10 09:35:45 -0800 | [diff] [blame] | 376 | filp_cachep = kmem_cache_create("filp", sizeof(struct file), 0, |
Shakeel Butt | f3f7c09 | 2017-11-15 17:35:44 -0800 | [diff] [blame] | 377 | SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT, NULL); |
Tejun Heo | 908c7f1 | 2014-09-08 09:51:29 +0900 | [diff] [blame] | 378 | percpu_counter_init(&nr_files, 0, GFP_KERNEL); |
Mel Gorman | 4248b0d | 2015-08-06 15:46:20 -0700 | [diff] [blame] | 379 | } |
| 380 | |
| 381 | /* |
| 382 | * One file with associated inode and dcache is very roughly 1K. Per default |
| 383 | * do not use more than 10% of our memory for files. |
| 384 | */ |
| 385 | void __init files_maxfiles_init(void) |
| 386 | { |
| 387 | unsigned long n; |
Arun KS | ca79b0c | 2018-12-28 00:34:29 -0800 | [diff] [blame] | 388 | unsigned long nr_pages = totalram_pages(); |
Arun KS | 3d6357d | 2018-12-28 00:34:20 -0800 | [diff] [blame] | 389 | unsigned long memreserve = (nr_pages - nr_free_pages()) * 3/2; |
Mel Gorman | 4248b0d | 2015-08-06 15:46:20 -0700 | [diff] [blame] | 390 | |
Arun KS | 3d6357d | 2018-12-28 00:34:20 -0800 | [diff] [blame] | 391 | memreserve = min(memreserve, nr_pages - 1); |
| 392 | n = ((nr_pages - memreserve) * (PAGE_SIZE / 1024)) / 10; |
Mel Gorman | 4248b0d | 2015-08-06 15:46:20 -0700 | [diff] [blame] | 393 | |
| 394 | files_stat.max_files = max_t(unsigned long, n, NR_FILE); |
Byungchul Park | b9ea557 | 2017-08-07 17:45:39 +0900 | [diff] [blame] | 395 | } |