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> |
| 16 | #include <linux/eventpoll.h> |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 17 | #include <linux/rcupdate.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 18 | #include <linux/mount.h> |
Randy Dunlap | 16f7e0f | 2006-01-11 12:17:46 -0800 | [diff] [blame] | 19 | #include <linux/capability.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | #include <linux/cdev.h> |
Robert Love | 0eeca28 | 2005-07-12 17:06:03 -0400 | [diff] [blame] | 21 | #include <linux/fsnotify.h> |
Dipankar Sarma | 529bf6b | 2006-03-07 21:55:35 -0800 | [diff] [blame] | 22 | #include <linux/sysctl.h> |
| 23 | #include <linux/percpu_counter.h> |
| 24 | |
| 25 | #include <asm/atomic.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 26 | |
| 27 | /* sysctl tunables... */ |
| 28 | struct files_stat_struct files_stat = { |
| 29 | .max_files = NR_FILE |
| 30 | }; |
| 31 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 32 | /* public. Not pretty! */ |
Dipankar Sarma | 529bf6b | 2006-03-07 21:55:35 -0800 | [diff] [blame] | 33 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(files_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | |
Dipankar Sarma | 529bf6b | 2006-03-07 21:55:35 -0800 | [diff] [blame] | 35 | static struct percpu_counter nr_files __cacheline_aligned_in_smp; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 36 | |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 37 | static inline void file_free_rcu(struct rcu_head *head) |
| 38 | { |
Eric Dumazet | 2f51201 | 2005-10-30 15:02:16 -0800 | [diff] [blame] | 39 | struct file *f = container_of(head, struct file, f_u.fu_rcuhead); |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 40 | kmem_cache_free(filp_cachep, f); |
| 41 | } |
| 42 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | static inline void file_free(struct file *f) |
| 44 | { |
Dipankar Sarma | 529bf6b | 2006-03-07 21:55:35 -0800 | [diff] [blame] | 45 | percpu_counter_dec(&nr_files); |
Dave Hansen | ad775f5 | 2008-02-15 14:38:01 -0800 | [diff] [blame] | 46 | file_check_state(f); |
Eric Dumazet | 2f51201 | 2005-10-30 15:02:16 -0800 | [diff] [blame] | 47 | call_rcu(&f->f_u.fu_rcuhead, file_free_rcu); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 48 | } |
| 49 | |
Dipankar Sarma | 529bf6b | 2006-03-07 21:55:35 -0800 | [diff] [blame] | 50 | /* |
| 51 | * Return the total number of open files in the system |
| 52 | */ |
| 53 | static int get_nr_files(void) |
| 54 | { |
| 55 | return percpu_counter_read_positive(&nr_files); |
| 56 | } |
| 57 | |
| 58 | /* |
| 59 | * Return the maximum number of open files in the system |
| 60 | */ |
| 61 | int get_max_files(void) |
| 62 | { |
| 63 | return files_stat.max_files; |
| 64 | } |
| 65 | EXPORT_SYMBOL_GPL(get_max_files); |
| 66 | |
| 67 | /* |
| 68 | * Handle nr_files sysctl |
| 69 | */ |
| 70 | #if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS) |
| 71 | int proc_nr_files(ctl_table *table, int write, struct file *filp, |
| 72 | void __user *buffer, size_t *lenp, loff_t *ppos) |
| 73 | { |
| 74 | files_stat.nr_files = get_nr_files(); |
| 75 | return proc_dointvec(table, write, filp, buffer, lenp, ppos); |
| 76 | } |
| 77 | #else |
| 78 | int proc_nr_files(ctl_table *table, int write, struct file *filp, |
| 79 | void __user *buffer, size_t *lenp, loff_t *ppos) |
| 80 | { |
| 81 | return -ENOSYS; |
| 82 | } |
| 83 | #endif |
| 84 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 85 | /* Find an unused file structure and return a pointer to it. |
| 86 | * Returns NULL, if there are no more free file structures or |
| 87 | * we run out of memory. |
Dave Hansen | 430e285 | 2008-02-15 14:37:26 -0800 | [diff] [blame] | 88 | * |
| 89 | * Be very careful using this. You are responsible for |
| 90 | * getting write access to any mount that you might assign |
| 91 | * to this filp, if it is opened for write. If this is not |
| 92 | * done, you will imbalance int the mount's writer count |
| 93 | * and a warning at __fput() time. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 94 | */ |
| 95 | struct file *get_empty_filp(void) |
| 96 | { |
Benjamin LaHaise | 5a6b7951 | 2006-03-23 03:01:03 -0800 | [diff] [blame] | 97 | struct task_struct *tsk; |
Kirill Korotaev | af4d2ec | 2005-06-23 00:09:50 -0700 | [diff] [blame] | 98 | static int old_max; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 99 | struct file * f; |
| 100 | |
| 101 | /* |
| 102 | * Privileged users can go above max_files |
| 103 | */ |
Dipankar Sarma | 529bf6b | 2006-03-07 21:55:35 -0800 | [diff] [blame] | 104 | if (get_nr_files() >= files_stat.max_files && !capable(CAP_SYS_ADMIN)) { |
| 105 | /* |
| 106 | * percpu_counters are inaccurate. Do an expensive check before |
| 107 | * we go and fail. |
| 108 | */ |
Peter Zijlstra | 52d9f3b | 2007-10-16 23:25:44 -0700 | [diff] [blame] | 109 | if (percpu_counter_sum_positive(&nr_files) >= files_stat.max_files) |
Dipankar Sarma | 529bf6b | 2006-03-07 21:55:35 -0800 | [diff] [blame] | 110 | goto over; |
| 111 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 112 | |
Denis Cheng | 4975e45 | 2007-10-16 23:26:19 -0700 | [diff] [blame] | 113 | f = kmem_cache_zalloc(filp_cachep, GFP_KERNEL); |
Kirill Korotaev | af4d2ec | 2005-06-23 00:09:50 -0700 | [diff] [blame] | 114 | if (f == NULL) |
| 115 | goto fail; |
| 116 | |
Dipankar Sarma | 529bf6b | 2006-03-07 21:55:35 -0800 | [diff] [blame] | 117 | percpu_counter_inc(&nr_files); |
Kirill Korotaev | af4d2ec | 2005-06-23 00:09:50 -0700 | [diff] [blame] | 118 | if (security_file_alloc(f)) |
| 119 | goto fail_sec; |
| 120 | |
Benjamin LaHaise | 5a6b7951 | 2006-03-23 03:01:03 -0800 | [diff] [blame] | 121 | tsk = current; |
Eric Dumazet | 2f51201 | 2005-10-30 15:02:16 -0800 | [diff] [blame] | 122 | INIT_LIST_HEAD(&f->f_u.fu_list); |
Al Viro | 516e0cc | 2008-07-26 00:39:17 -0400 | [diff] [blame] | 123 | atomic_long_set(&f->f_count, 1); |
Benjamin LaHaise | 5a6b7951 | 2006-03-23 03:01:03 -0800 | [diff] [blame] | 124 | rwlock_init(&f->f_owner.lock); |
| 125 | f->f_uid = tsk->fsuid; |
| 126 | f->f_gid = tsk->fsgid; |
| 127 | eventpoll_init_file(f); |
| 128 | /* f->f_version: 0 */ |
Kirill Korotaev | af4d2ec | 2005-06-23 00:09:50 -0700 | [diff] [blame] | 129 | return f; |
| 130 | |
| 131 | over: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 132 | /* Ran out of filps - report that */ |
Dipankar Sarma | 529bf6b | 2006-03-07 21:55:35 -0800 | [diff] [blame] | 133 | if (get_nr_files() > old_max) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 134 | printk(KERN_INFO "VFS: file-max limit %d reached\n", |
Dipankar Sarma | 529bf6b | 2006-03-07 21:55:35 -0800 | [diff] [blame] | 135 | get_max_files()); |
| 136 | old_max = get_nr_files(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 137 | } |
Kirill Korotaev | af4d2ec | 2005-06-23 00:09:50 -0700 | [diff] [blame] | 138 | goto fail; |
| 139 | |
| 140 | fail_sec: |
| 141 | file_free(f); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 142 | fail: |
| 143 | return NULL; |
| 144 | } |
| 145 | |
| 146 | EXPORT_SYMBOL(get_empty_filp); |
| 147 | |
Dave Hansen | ce8d2cd | 2007-10-16 23:31:13 -0700 | [diff] [blame] | 148 | /** |
| 149 | * alloc_file - allocate and initialize a 'struct file' |
| 150 | * @mnt: the vfsmount on which the file will reside |
| 151 | * @dentry: the dentry representing the new file |
| 152 | * @mode: the mode with which the new file will be opened |
| 153 | * @fop: the 'struct file_operations' for the new file |
| 154 | * |
| 155 | * Use this instead of get_empty_filp() to get a new |
| 156 | * 'struct file'. Do so because of the same initialization |
| 157 | * pitfalls reasons listed for init_file(). This is a |
| 158 | * preferred interface to using init_file(). |
| 159 | * |
| 160 | * If all the callers of init_file() are eliminated, its |
| 161 | * code should be moved into this function. |
| 162 | */ |
| 163 | struct file *alloc_file(struct vfsmount *mnt, struct dentry *dentry, |
Al Viro | aeb5d72 | 2008-09-02 15:28:45 -0400 | [diff] [blame] | 164 | fmode_t mode, const struct file_operations *fop) |
Dave Hansen | ce8d2cd | 2007-10-16 23:31:13 -0700 | [diff] [blame] | 165 | { |
| 166 | struct file *file; |
| 167 | struct path; |
| 168 | |
| 169 | file = get_empty_filp(); |
| 170 | if (!file) |
| 171 | return NULL; |
| 172 | |
| 173 | init_file(file, mnt, dentry, mode, fop); |
| 174 | return file; |
| 175 | } |
| 176 | EXPORT_SYMBOL(alloc_file); |
| 177 | |
| 178 | /** |
| 179 | * init_file - initialize a 'struct file' |
| 180 | * @file: the already allocated 'struct file' to initialized |
| 181 | * @mnt: the vfsmount on which the file resides |
| 182 | * @dentry: the dentry representing this file |
| 183 | * @mode: the mode the file is opened with |
| 184 | * @fop: the 'struct file_operations' for this file |
| 185 | * |
| 186 | * Use this instead of setting the members directly. Doing so |
| 187 | * avoids making mistakes like forgetting the mntget() or |
| 188 | * forgetting to take a write on the mnt. |
| 189 | * |
| 190 | * Note: This is a crappy interface. It is here to make |
| 191 | * merging with the existing users of get_empty_filp() |
| 192 | * who have complex failure logic easier. All users |
| 193 | * of this should be moving to alloc_file(). |
| 194 | */ |
| 195 | int init_file(struct file *file, struct vfsmount *mnt, struct dentry *dentry, |
Al Viro | aeb5d72 | 2008-09-02 15:28:45 -0400 | [diff] [blame] | 196 | fmode_t mode, const struct file_operations *fop) |
Dave Hansen | ce8d2cd | 2007-10-16 23:31:13 -0700 | [diff] [blame] | 197 | { |
| 198 | int error = 0; |
| 199 | file->f_path.dentry = dentry; |
| 200 | file->f_path.mnt = mntget(mnt); |
| 201 | file->f_mapping = dentry->d_inode->i_mapping; |
| 202 | file->f_mode = mode; |
| 203 | file->f_op = fop; |
Dave Hansen | 4a3fd21 | 2008-02-15 14:37:48 -0800 | [diff] [blame] | 204 | |
| 205 | /* |
| 206 | * These mounts don't really matter in practice |
| 207 | * for r/o bind mounts. They aren't userspace- |
| 208 | * visible. We do this for consistency, and so |
| 209 | * that we can do debugging checks at __fput() |
| 210 | */ |
| 211 | if ((mode & FMODE_WRITE) && !special_file(dentry->d_inode->i_mode)) { |
Dave Hansen | ad775f5 | 2008-02-15 14:38:01 -0800 | [diff] [blame] | 212 | file_take_write(file); |
Dave Hansen | 4a3fd21 | 2008-02-15 14:37:48 -0800 | [diff] [blame] | 213 | error = mnt_want_write(mnt); |
| 214 | WARN_ON(error); |
| 215 | } |
Dave Hansen | ce8d2cd | 2007-10-16 23:31:13 -0700 | [diff] [blame] | 216 | return error; |
| 217 | } |
| 218 | EXPORT_SYMBOL(init_file); |
| 219 | |
Harvey Harrison | fc9b52c | 2008-02-08 04:19:52 -0800 | [diff] [blame] | 220 | void fput(struct file *file) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 221 | { |
Al Viro | 516e0cc | 2008-07-26 00:39:17 -0400 | [diff] [blame] | 222 | if (atomic_long_dec_and_test(&file->f_count)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 223 | __fput(file); |
| 224 | } |
| 225 | |
| 226 | EXPORT_SYMBOL(fput); |
| 227 | |
Dave Hansen | aceaf78 | 2008-02-15 14:37:31 -0800 | [diff] [blame] | 228 | /** |
| 229 | * drop_file_write_access - give up ability to write to a file |
| 230 | * @file: the file to which we will stop writing |
| 231 | * |
| 232 | * This is a central place which will give up the ability |
| 233 | * to write to @file, along with access to write through |
| 234 | * its vfsmount. |
| 235 | */ |
| 236 | void drop_file_write_access(struct file *file) |
| 237 | { |
Dave Hansen | 4a3fd21 | 2008-02-15 14:37:48 -0800 | [diff] [blame] | 238 | struct vfsmount *mnt = file->f_path.mnt; |
Dave Hansen | aceaf78 | 2008-02-15 14:37:31 -0800 | [diff] [blame] | 239 | struct dentry *dentry = file->f_path.dentry; |
| 240 | struct inode *inode = dentry->d_inode; |
| 241 | |
| 242 | put_write_access(inode); |
Dave Hansen | ad775f5 | 2008-02-15 14:38:01 -0800 | [diff] [blame] | 243 | |
| 244 | if (special_file(inode->i_mode)) |
| 245 | return; |
| 246 | if (file_check_writeable(file) != 0) |
| 247 | return; |
| 248 | mnt_drop_write(mnt); |
| 249 | file_release_write(file); |
Dave Hansen | aceaf78 | 2008-02-15 14:37:31 -0800 | [diff] [blame] | 250 | } |
| 251 | EXPORT_SYMBOL_GPL(drop_file_write_access); |
| 252 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 253 | /* __fput is called from task context when aio completion releases the last |
| 254 | * last use of a struct file *. Do not use otherwise. |
| 255 | */ |
Harvey Harrison | fc9b52c | 2008-02-08 04:19:52 -0800 | [diff] [blame] | 256 | void __fput(struct file *file) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 257 | { |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 258 | struct dentry *dentry = file->f_path.dentry; |
| 259 | struct vfsmount *mnt = file->f_path.mnt; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 260 | struct inode *inode = dentry->d_inode; |
| 261 | |
| 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); |
| 270 | locks_remove_flock(file); |
| 271 | |
| 272 | if (file->f_op && file->f_op->release) |
| 273 | file->f_op->release(inode, file); |
| 274 | security_file_free(file); |
Theodore Ts'o | 577c4eb | 2006-09-27 01:50:49 -0700 | [diff] [blame] | 275 | if (unlikely(S_ISCHR(inode->i_mode) && inode->i_cdev != NULL)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 276 | cdev_put(inode->i_cdev); |
| 277 | fops_put(file->f_op); |
Eric W. Biederman | 609d7fa | 2006-10-02 02:17:15 -0700 | [diff] [blame] | 278 | put_pid(file->f_owner.pid); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 279 | file_kill(file); |
Dave Hansen | aceaf78 | 2008-02-15 14:37:31 -0800 | [diff] [blame] | 280 | if (file->f_mode & FMODE_WRITE) |
| 281 | drop_file_write_access(file); |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 282 | file->f_path.dentry = NULL; |
| 283 | file->f_path.mnt = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 284 | file_free(file); |
| 285 | dput(dentry); |
| 286 | mntput(mnt); |
| 287 | } |
| 288 | |
Harvey Harrison | fc9b52c | 2008-02-08 04:19:52 -0800 | [diff] [blame] | 289 | struct file *fget(unsigned int fd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 290 | { |
| 291 | struct file *file; |
| 292 | struct files_struct *files = current->files; |
| 293 | |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 294 | rcu_read_lock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 295 | file = fcheck_files(files, fd); |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 296 | if (file) { |
Al Viro | 516e0cc | 2008-07-26 00:39:17 -0400 | [diff] [blame] | 297 | if (!atomic_long_inc_not_zero(&file->f_count)) { |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 298 | /* File object ref couldn't be taken */ |
| 299 | rcu_read_unlock(); |
| 300 | return NULL; |
| 301 | } |
| 302 | } |
| 303 | rcu_read_unlock(); |
| 304 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 305 | return file; |
| 306 | } |
| 307 | |
| 308 | EXPORT_SYMBOL(fget); |
| 309 | |
| 310 | /* |
| 311 | * Lightweight file lookup - no refcnt increment if fd table isn't shared. |
| 312 | * You can use this only if it is guranteed that the current task already |
| 313 | * holds a refcnt to that file. That check has to be done at fget() only |
| 314 | * and a flag is returned to be passed to the corresponding fput_light(). |
| 315 | * There must not be a cloning between an fget_light/fput_light pair. |
| 316 | */ |
Harvey Harrison | fc9b52c | 2008-02-08 04:19:52 -0800 | [diff] [blame] | 317 | struct file *fget_light(unsigned int fd, int *fput_needed) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 318 | { |
| 319 | struct file *file; |
| 320 | struct files_struct *files = current->files; |
| 321 | |
| 322 | *fput_needed = 0; |
| 323 | if (likely((atomic_read(&files->count) == 1))) { |
| 324 | file = fcheck_files(files, fd); |
| 325 | } else { |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 326 | rcu_read_lock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 327 | file = fcheck_files(files, fd); |
| 328 | if (file) { |
Al Viro | 516e0cc | 2008-07-26 00:39:17 -0400 | [diff] [blame] | 329 | if (atomic_long_inc_not_zero(&file->f_count)) |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 330 | *fput_needed = 1; |
| 331 | else |
| 332 | /* Didn't get the reference, someone's freed */ |
| 333 | file = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 334 | } |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 335 | rcu_read_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 336 | } |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 337 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 338 | return file; |
| 339 | } |
| 340 | |
| 341 | |
| 342 | void put_filp(struct file *file) |
| 343 | { |
Al Viro | 516e0cc | 2008-07-26 00:39:17 -0400 | [diff] [blame] | 344 | if (atomic_long_dec_and_test(&file->f_count)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 345 | security_file_free(file); |
| 346 | file_kill(file); |
| 347 | file_free(file); |
| 348 | } |
| 349 | } |
| 350 | |
| 351 | void file_move(struct file *file, struct list_head *list) |
| 352 | { |
| 353 | if (!list) |
| 354 | return; |
| 355 | file_list_lock(); |
Eric Dumazet | 2f51201 | 2005-10-30 15:02:16 -0800 | [diff] [blame] | 356 | list_move(&file->f_u.fu_list, list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 357 | file_list_unlock(); |
| 358 | } |
| 359 | |
| 360 | void file_kill(struct file *file) |
| 361 | { |
Eric Dumazet | 2f51201 | 2005-10-30 15:02:16 -0800 | [diff] [blame] | 362 | if (!list_empty(&file->f_u.fu_list)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 363 | file_list_lock(); |
Eric Dumazet | 2f51201 | 2005-10-30 15:02:16 -0800 | [diff] [blame] | 364 | list_del_init(&file->f_u.fu_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 365 | file_list_unlock(); |
| 366 | } |
| 367 | } |
| 368 | |
| 369 | int fs_may_remount_ro(struct super_block *sb) |
| 370 | { |
Matthias Kaehlcke | cfdaf9e | 2007-10-18 23:39:56 -0700 | [diff] [blame] | 371 | struct file *file; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 372 | |
| 373 | /* Check that no files are currently opened for writing. */ |
| 374 | file_list_lock(); |
Matthias Kaehlcke | cfdaf9e | 2007-10-18 23:39:56 -0700 | [diff] [blame] | 375 | list_for_each_entry(file, &sb->s_files, f_u.fu_list) { |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 376 | struct inode *inode = file->f_path.dentry->d_inode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 377 | |
| 378 | /* File with pending delete? */ |
| 379 | if (inode->i_nlink == 0) |
| 380 | goto too_bad; |
| 381 | |
| 382 | /* Writeable file? */ |
| 383 | if (S_ISREG(inode->i_mode) && (file->f_mode & FMODE_WRITE)) |
| 384 | goto too_bad; |
| 385 | } |
| 386 | file_list_unlock(); |
| 387 | return 1; /* Tis' cool bro. */ |
| 388 | too_bad: |
| 389 | file_list_unlock(); |
| 390 | return 0; |
| 391 | } |
| 392 | |
| 393 | void __init files_init(unsigned long mempages) |
| 394 | { |
| 395 | int n; |
| 396 | /* One file with associated inode and dcache is very roughly 1K. |
| 397 | * Per default don't use more than 10% of our memory for files. |
| 398 | */ |
| 399 | |
| 400 | n = (mempages * (PAGE_SIZE / 1024)) / 10; |
| 401 | files_stat.max_files = n; |
| 402 | if (files_stat.max_files < NR_FILE) |
| 403 | files_stat.max_files = NR_FILE; |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 404 | files_defer_init(); |
Mingming Cao | 0216bfc | 2006-06-23 02:05:41 -0700 | [diff] [blame] | 405 | percpu_counter_init(&nr_files, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 406 | } |