diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/file_table.c |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'fs/file_table.c')
-rw-r--r-- | fs/file_table.c | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/fs/file_table.c b/fs/file_table.c new file mode 100644 index 000000000000..03d83cb686b1 --- /dev/null +++ b/fs/file_table.c | |||
@@ -0,0 +1,255 @@ | |||
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> | ||
11 | #include <linux/init.h> | ||
12 | #include <linux/module.h> | ||
13 | #include <linux/smp_lock.h> | ||
14 | #include <linux/fs.h> | ||
15 | #include <linux/security.h> | ||
16 | #include <linux/eventpoll.h> | ||
17 | #include <linux/mount.h> | ||
18 | #include <linux/cdev.h> | ||
19 | |||
20 | /* sysctl tunables... */ | ||
21 | struct files_stat_struct files_stat = { | ||
22 | .max_files = NR_FILE | ||
23 | }; | ||
24 | |||
25 | EXPORT_SYMBOL(files_stat); /* Needed by unix.o */ | ||
26 | |||
27 | /* public. Not pretty! */ | ||
28 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(files_lock); | ||
29 | |||
30 | static DEFINE_SPINLOCK(filp_count_lock); | ||
31 | |||
32 | /* slab constructors and destructors are called from arbitrary | ||
33 | * context and must be fully threaded - use a local spinlock | ||
34 | * to protect files_stat.nr_files | ||
35 | */ | ||
36 | void filp_ctor(void * objp, struct kmem_cache_s *cachep, unsigned long cflags) | ||
37 | { | ||
38 | if ((cflags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == | ||
39 | SLAB_CTOR_CONSTRUCTOR) { | ||
40 | unsigned long flags; | ||
41 | spin_lock_irqsave(&filp_count_lock, flags); | ||
42 | files_stat.nr_files++; | ||
43 | spin_unlock_irqrestore(&filp_count_lock, flags); | ||
44 | } | ||
45 | } | ||
46 | |||
47 | void filp_dtor(void * objp, struct kmem_cache_s *cachep, unsigned long dflags) | ||
48 | { | ||
49 | unsigned long flags; | ||
50 | spin_lock_irqsave(&filp_count_lock, flags); | ||
51 | files_stat.nr_files--; | ||
52 | spin_unlock_irqrestore(&filp_count_lock, flags); | ||
53 | } | ||
54 | |||
55 | static inline void file_free(struct file *f) | ||
56 | { | ||
57 | kmem_cache_free(filp_cachep, f); | ||
58 | } | ||
59 | |||
60 | /* Find an unused file structure and return a pointer to it. | ||
61 | * Returns NULL, if there are no more free file structures or | ||
62 | * we run out of memory. | ||
63 | */ | ||
64 | struct file *get_empty_filp(void) | ||
65 | { | ||
66 | static int old_max; | ||
67 | struct file * f; | ||
68 | |||
69 | /* | ||
70 | * Privileged users can go above max_files | ||
71 | */ | ||
72 | if (files_stat.nr_files < files_stat.max_files || | ||
73 | capable(CAP_SYS_ADMIN)) { | ||
74 | f = kmem_cache_alloc(filp_cachep, GFP_KERNEL); | ||
75 | if (f) { | ||
76 | memset(f, 0, sizeof(*f)); | ||
77 | if (security_file_alloc(f)) { | ||
78 | file_free(f); | ||
79 | goto fail; | ||
80 | } | ||
81 | eventpoll_init_file(f); | ||
82 | atomic_set(&f->f_count, 1); | ||
83 | f->f_uid = current->fsuid; | ||
84 | f->f_gid = current->fsgid; | ||
85 | rwlock_init(&f->f_owner.lock); | ||
86 | /* f->f_version: 0 */ | ||
87 | INIT_LIST_HEAD(&f->f_list); | ||
88 | f->f_maxcount = INT_MAX; | ||
89 | return f; | ||
90 | } | ||
91 | } | ||
92 | |||
93 | /* Ran out of filps - report that */ | ||
94 | if (files_stat.max_files >= old_max) { | ||
95 | printk(KERN_INFO "VFS: file-max limit %d reached\n", | ||
96 | files_stat.max_files); | ||
97 | old_max = files_stat.max_files; | ||
98 | } else { | ||
99 | /* Big problems... */ | ||
100 | printk(KERN_WARNING "VFS: filp allocation failed\n"); | ||
101 | } | ||
102 | fail: | ||
103 | return NULL; | ||
104 | } | ||
105 | |||
106 | EXPORT_SYMBOL(get_empty_filp); | ||
107 | |||
108 | void fastcall fput(struct file *file) | ||
109 | { | ||
110 | if (atomic_dec_and_test(&file->f_count)) | ||
111 | __fput(file); | ||
112 | } | ||
113 | |||
114 | EXPORT_SYMBOL(fput); | ||
115 | |||
116 | /* __fput is called from task context when aio completion releases the last | ||
117 | * last use of a struct file *. Do not use otherwise. | ||
118 | */ | ||
119 | void fastcall __fput(struct file *file) | ||
120 | { | ||
121 | struct dentry *dentry = file->f_dentry; | ||
122 | struct vfsmount *mnt = file->f_vfsmnt; | ||
123 | struct inode *inode = dentry->d_inode; | ||
124 | |||
125 | might_sleep(); | ||
126 | /* | ||
127 | * The function eventpoll_release() should be the first called | ||
128 | * in the file cleanup chain. | ||
129 | */ | ||
130 | eventpoll_release(file); | ||
131 | locks_remove_flock(file); | ||
132 | |||
133 | if (file->f_op && file->f_op->release) | ||
134 | file->f_op->release(inode, file); | ||
135 | security_file_free(file); | ||
136 | if (unlikely(inode->i_cdev != NULL)) | ||
137 | cdev_put(inode->i_cdev); | ||
138 | fops_put(file->f_op); | ||
139 | if (file->f_mode & FMODE_WRITE) | ||
140 | put_write_access(inode); | ||
141 | file_kill(file); | ||
142 | file->f_dentry = NULL; | ||
143 | file->f_vfsmnt = NULL; | ||
144 | file_free(file); | ||
145 | dput(dentry); | ||
146 | mntput(mnt); | ||
147 | } | ||
148 | |||
149 | struct file fastcall *fget(unsigned int fd) | ||
150 | { | ||
151 | struct file *file; | ||
152 | struct files_struct *files = current->files; | ||
153 | |||
154 | spin_lock(&files->file_lock); | ||
155 | file = fcheck_files(files, fd); | ||
156 | if (file) | ||
157 | get_file(file); | ||
158 | spin_unlock(&files->file_lock); | ||
159 | return file; | ||
160 | } | ||
161 | |||
162 | EXPORT_SYMBOL(fget); | ||
163 | |||
164 | /* | ||
165 | * Lightweight file lookup - no refcnt increment if fd table isn't shared. | ||
166 | * You can use this only if it is guranteed that the current task already | ||
167 | * holds a refcnt to that file. That check has to be done at fget() only | ||
168 | * and a flag is returned to be passed to the corresponding fput_light(). | ||
169 | * There must not be a cloning between an fget_light/fput_light pair. | ||
170 | */ | ||
171 | struct file fastcall *fget_light(unsigned int fd, int *fput_needed) | ||
172 | { | ||
173 | struct file *file; | ||
174 | struct files_struct *files = current->files; | ||
175 | |||
176 | *fput_needed = 0; | ||
177 | if (likely((atomic_read(&files->count) == 1))) { | ||
178 | file = fcheck_files(files, fd); | ||
179 | } else { | ||
180 | spin_lock(&files->file_lock); | ||
181 | file = fcheck_files(files, fd); | ||
182 | if (file) { | ||
183 | get_file(file); | ||
184 | *fput_needed = 1; | ||
185 | } | ||
186 | spin_unlock(&files->file_lock); | ||
187 | } | ||
188 | return file; | ||
189 | } | ||
190 | |||
191 | |||
192 | void put_filp(struct file *file) | ||
193 | { | ||
194 | if (atomic_dec_and_test(&file->f_count)) { | ||
195 | security_file_free(file); | ||
196 | file_kill(file); | ||
197 | file_free(file); | ||
198 | } | ||
199 | } | ||
200 | |||
201 | void file_move(struct file *file, struct list_head *list) | ||
202 | { | ||
203 | if (!list) | ||
204 | return; | ||
205 | file_list_lock(); | ||
206 | list_move(&file->f_list, list); | ||
207 | file_list_unlock(); | ||
208 | } | ||
209 | |||
210 | void file_kill(struct file *file) | ||
211 | { | ||
212 | if (!list_empty(&file->f_list)) { | ||
213 | file_list_lock(); | ||
214 | list_del_init(&file->f_list); | ||
215 | file_list_unlock(); | ||
216 | } | ||
217 | } | ||
218 | |||
219 | int fs_may_remount_ro(struct super_block *sb) | ||
220 | { | ||
221 | struct list_head *p; | ||
222 | |||
223 | /* Check that no files are currently opened for writing. */ | ||
224 | file_list_lock(); | ||
225 | list_for_each(p, &sb->s_files) { | ||
226 | struct file *file = list_entry(p, struct file, f_list); | ||
227 | struct inode *inode = file->f_dentry->d_inode; | ||
228 | |||
229 | /* File with pending delete? */ | ||
230 | if (inode->i_nlink == 0) | ||
231 | goto too_bad; | ||
232 | |||
233 | /* Writeable file? */ | ||
234 | if (S_ISREG(inode->i_mode) && (file->f_mode & FMODE_WRITE)) | ||
235 | goto too_bad; | ||
236 | } | ||
237 | file_list_unlock(); | ||
238 | return 1; /* Tis' cool bro. */ | ||
239 | too_bad: | ||
240 | file_list_unlock(); | ||
241 | return 0; | ||
242 | } | ||
243 | |||
244 | void __init files_init(unsigned long mempages) | ||
245 | { | ||
246 | int n; | ||
247 | /* One file with associated inode and dcache is very roughly 1K. | ||
248 | * Per default don't use more than 10% of our memory for files. | ||
249 | */ | ||
250 | |||
251 | n = (mempages * (PAGE_SIZE / 1024)) / 10; | ||
252 | files_stat.max_files = n; | ||
253 | if (files_stat.max_files < NR_FILE) | ||
254 | files_stat.max_files = NR_FILE; | ||
255 | } | ||