Dan Magenheimer | 077b1f8 | 2011-05-26 10:01:36 -0600 | [diff] [blame] | 1 | /* |
| 2 | * Cleancache frontend |
| 3 | * |
| 4 | * This code provides the generic "frontend" layer to call a matching |
| 5 | * "backend" driver implementation of cleancache. See |
| 6 | * Documentation/vm/cleancache.txt for more information. |
| 7 | * |
| 8 | * Copyright (C) 2009-2010 Oracle Corp. All rights reserved. |
| 9 | * Author: Dan Magenheimer |
| 10 | * |
| 11 | * This work is licensed under the terms of the GNU GPL, version 2. |
| 12 | */ |
| 13 | |
| 14 | #include <linux/module.h> |
| 15 | #include <linux/fs.h> |
| 16 | #include <linux/exportfs.h> |
| 17 | #include <linux/mm.h> |
| 18 | #include <linux/cleancache.h> |
| 19 | |
| 20 | /* |
| 21 | * This global enablement flag may be read thousands of times per second |
Dan Magenheimer | 3167760 | 2011-09-21 11:56:28 -0400 | [diff] [blame] | 22 | * by cleancache_get/put/invalidate even on systems where cleancache_ops |
Dan Magenheimer | 077b1f8 | 2011-05-26 10:01:36 -0600 | [diff] [blame] | 23 | * is not claimed (e.g. cleancache is config'ed on but remains |
| 24 | * disabled), so is preferred to the slower alternative: a function |
| 25 | * call that checks a non-global. |
| 26 | */ |
| 27 | int cleancache_enabled; |
| 28 | EXPORT_SYMBOL(cleancache_enabled); |
| 29 | |
| 30 | /* |
| 31 | * cleancache_ops is set by cleancache_ops_register to contain the pointers |
| 32 | * to the cleancache "backend" implementation functions. |
| 33 | */ |
| 34 | static struct cleancache_ops cleancache_ops; |
| 35 | |
| 36 | /* useful stats available in /sys/kernel/mm/cleancache */ |
| 37 | static unsigned long cleancache_succ_gets; |
| 38 | static unsigned long cleancache_failed_gets; |
| 39 | static unsigned long cleancache_puts; |
| 40 | static unsigned long cleancache_flushes; |
| 41 | |
| 42 | /* |
| 43 | * register operations for cleancache, returning previous thus allowing |
| 44 | * detection of multiple backends and possible nesting |
| 45 | */ |
| 46 | struct cleancache_ops cleancache_register_ops(struct cleancache_ops *ops) |
| 47 | { |
| 48 | struct cleancache_ops old = cleancache_ops; |
| 49 | |
| 50 | cleancache_ops = *ops; |
| 51 | cleancache_enabled = 1; |
| 52 | return old; |
| 53 | } |
| 54 | EXPORT_SYMBOL(cleancache_register_ops); |
| 55 | |
| 56 | /* Called by a cleancache-enabled filesystem at time of mount */ |
| 57 | void __cleancache_init_fs(struct super_block *sb) |
| 58 | { |
| 59 | sb->cleancache_poolid = (*cleancache_ops.init_fs)(PAGE_SIZE); |
| 60 | } |
| 61 | EXPORT_SYMBOL(__cleancache_init_fs); |
| 62 | |
| 63 | /* Called by a cleancache-enabled clustered filesystem at time of mount */ |
| 64 | void __cleancache_init_shared_fs(char *uuid, struct super_block *sb) |
| 65 | { |
| 66 | sb->cleancache_poolid = |
| 67 | (*cleancache_ops.init_shared_fs)(uuid, PAGE_SIZE); |
| 68 | } |
| 69 | EXPORT_SYMBOL(__cleancache_init_shared_fs); |
| 70 | |
| 71 | /* |
| 72 | * If the filesystem uses exportable filehandles, use the filehandle as |
| 73 | * the key, else use the inode number. |
| 74 | */ |
| 75 | static int cleancache_get_key(struct inode *inode, |
| 76 | struct cleancache_filekey *key) |
| 77 | { |
| 78 | int (*fhfn)(struct dentry *, __u32 *fh, int *, int); |
| 79 | int len = 0, maxlen = CLEANCACHE_KEY_MAX; |
| 80 | struct super_block *sb = inode->i_sb; |
| 81 | |
| 82 | key->u.ino = inode->i_ino; |
| 83 | if (sb->s_export_op != NULL) { |
| 84 | fhfn = sb->s_export_op->encode_fh; |
| 85 | if (fhfn) { |
| 86 | struct dentry d; |
| 87 | d.d_inode = inode; |
| 88 | len = (*fhfn)(&d, &key->u.fh[0], &maxlen, 0); |
| 89 | if (len <= 0 || len == 255) |
| 90 | return -1; |
| 91 | if (maxlen > CLEANCACHE_KEY_MAX) |
| 92 | return -1; |
| 93 | } |
| 94 | } |
| 95 | return 0; |
| 96 | } |
| 97 | |
| 98 | /* |
| 99 | * "Get" data from cleancache associated with the poolid/inode/index |
| 100 | * that were specified when the data was put to cleanache and, if |
| 101 | * successful, use it to fill the specified page with data and return 0. |
| 102 | * The pageframe is unchanged and returns -1 if the get fails. |
| 103 | * Page must be locked by caller. |
| 104 | */ |
| 105 | int __cleancache_get_page(struct page *page) |
| 106 | { |
| 107 | int ret = -1; |
| 108 | int pool_id; |
| 109 | struct cleancache_filekey key = { .u.key = { 0 } }; |
| 110 | |
| 111 | VM_BUG_ON(!PageLocked(page)); |
| 112 | pool_id = page->mapping->host->i_sb->cleancache_poolid; |
| 113 | if (pool_id < 0) |
| 114 | goto out; |
| 115 | |
| 116 | if (cleancache_get_key(page->mapping->host, &key) < 0) |
| 117 | goto out; |
| 118 | |
| 119 | ret = (*cleancache_ops.get_page)(pool_id, key, page->index, page); |
| 120 | if (ret == 0) |
| 121 | cleancache_succ_gets++; |
| 122 | else |
| 123 | cleancache_failed_gets++; |
| 124 | out: |
| 125 | return ret; |
| 126 | } |
| 127 | EXPORT_SYMBOL(__cleancache_get_page); |
| 128 | |
| 129 | /* |
| 130 | * "Put" data from a page to cleancache and associate it with the |
| 131 | * (previously-obtained per-filesystem) poolid and the page's, |
| 132 | * inode and page index. Page must be locked. Note that a put_page |
| 133 | * always "succeeds", though a subsequent get_page may succeed or fail. |
| 134 | */ |
| 135 | void __cleancache_put_page(struct page *page) |
| 136 | { |
| 137 | int pool_id; |
| 138 | struct cleancache_filekey key = { .u.key = { 0 } }; |
| 139 | |
| 140 | VM_BUG_ON(!PageLocked(page)); |
| 141 | pool_id = page->mapping->host->i_sb->cleancache_poolid; |
| 142 | if (pool_id >= 0 && |
| 143 | cleancache_get_key(page->mapping->host, &key) >= 0) { |
| 144 | (*cleancache_ops.put_page)(pool_id, key, page->index, page); |
| 145 | cleancache_puts++; |
| 146 | } |
| 147 | } |
| 148 | EXPORT_SYMBOL(__cleancache_put_page); |
| 149 | |
| 150 | /* |
Dan Magenheimer | 3167760 | 2011-09-21 11:56:28 -0400 | [diff] [blame] | 151 | * Invalidate any data from cleancache associated with the poolid and the |
Dan Magenheimer | 077b1f8 | 2011-05-26 10:01:36 -0600 | [diff] [blame] | 152 | * page's inode and page index so that a subsequent "get" will fail. |
| 153 | */ |
Dan Magenheimer | 3167760 | 2011-09-21 11:56:28 -0400 | [diff] [blame] | 154 | void __cleancache_invalidate_page(struct address_space *mapping, |
| 155 | struct page *page) |
Dan Magenheimer | 077b1f8 | 2011-05-26 10:01:36 -0600 | [diff] [blame] | 156 | { |
| 157 | /* careful... page->mapping is NULL sometimes when this is called */ |
| 158 | int pool_id = mapping->host->i_sb->cleancache_poolid; |
| 159 | struct cleancache_filekey key = { .u.key = { 0 } }; |
| 160 | |
| 161 | if (pool_id >= 0) { |
| 162 | VM_BUG_ON(!PageLocked(page)); |
| 163 | if (cleancache_get_key(mapping->host, &key) >= 0) { |
Dan Magenheimer | 91c6cc9 | 2012-01-12 14:03:25 -0500 | [diff] [blame^] | 164 | (*cleancache_ops.invalidate_page)(pool_id, |
| 165 | key, page->index); |
Dan Magenheimer | 077b1f8 | 2011-05-26 10:01:36 -0600 | [diff] [blame] | 166 | cleancache_flushes++; |
| 167 | } |
| 168 | } |
| 169 | } |
Dan Magenheimer | 3167760 | 2011-09-21 11:56:28 -0400 | [diff] [blame] | 170 | EXPORT_SYMBOL(__cleancache_invalidate_page); |
Dan Magenheimer | 077b1f8 | 2011-05-26 10:01:36 -0600 | [diff] [blame] | 171 | |
| 172 | /* |
Dan Magenheimer | 3167760 | 2011-09-21 11:56:28 -0400 | [diff] [blame] | 173 | * Invalidate all data from cleancache associated with the poolid and the |
Dan Magenheimer | 077b1f8 | 2011-05-26 10:01:36 -0600 | [diff] [blame] | 174 | * mappings's inode so that all subsequent gets to this poolid/inode |
| 175 | * will fail. |
| 176 | */ |
Dan Magenheimer | 3167760 | 2011-09-21 11:56:28 -0400 | [diff] [blame] | 177 | void __cleancache_invalidate_inode(struct address_space *mapping) |
Dan Magenheimer | 077b1f8 | 2011-05-26 10:01:36 -0600 | [diff] [blame] | 178 | { |
| 179 | int pool_id = mapping->host->i_sb->cleancache_poolid; |
| 180 | struct cleancache_filekey key = { .u.key = { 0 } }; |
| 181 | |
| 182 | if (pool_id >= 0 && cleancache_get_key(mapping->host, &key) >= 0) |
Dan Magenheimer | 91c6cc9 | 2012-01-12 14:03:25 -0500 | [diff] [blame^] | 183 | (*cleancache_ops.invalidate_inode)(pool_id, key); |
Dan Magenheimer | 077b1f8 | 2011-05-26 10:01:36 -0600 | [diff] [blame] | 184 | } |
Dan Magenheimer | 3167760 | 2011-09-21 11:56:28 -0400 | [diff] [blame] | 185 | EXPORT_SYMBOL(__cleancache_invalidate_inode); |
Dan Magenheimer | 077b1f8 | 2011-05-26 10:01:36 -0600 | [diff] [blame] | 186 | |
| 187 | /* |
| 188 | * Called by any cleancache-enabled filesystem at time of unmount; |
| 189 | * note that pool_id is surrendered and may be reutrned by a subsequent |
| 190 | * cleancache_init_fs or cleancache_init_shared_fs |
| 191 | */ |
Dan Magenheimer | 3167760 | 2011-09-21 11:56:28 -0400 | [diff] [blame] | 192 | void __cleancache_invalidate_fs(struct super_block *sb) |
Dan Magenheimer | 077b1f8 | 2011-05-26 10:01:36 -0600 | [diff] [blame] | 193 | { |
| 194 | if (sb->cleancache_poolid >= 0) { |
| 195 | int old_poolid = sb->cleancache_poolid; |
| 196 | sb->cleancache_poolid = -1; |
Dan Magenheimer | 91c6cc9 | 2012-01-12 14:03:25 -0500 | [diff] [blame^] | 197 | (*cleancache_ops.invalidate_fs)(old_poolid); |
Dan Magenheimer | 077b1f8 | 2011-05-26 10:01:36 -0600 | [diff] [blame] | 198 | } |
| 199 | } |
Dan Magenheimer | 3167760 | 2011-09-21 11:56:28 -0400 | [diff] [blame] | 200 | EXPORT_SYMBOL(__cleancache_invalidate_fs); |
Dan Magenheimer | 077b1f8 | 2011-05-26 10:01:36 -0600 | [diff] [blame] | 201 | |
| 202 | #ifdef CONFIG_SYSFS |
| 203 | |
| 204 | /* see Documentation/ABI/xxx/sysfs-kernel-mm-cleancache */ |
| 205 | |
| 206 | #define CLEANCACHE_SYSFS_RO(_name) \ |
| 207 | static ssize_t cleancache_##_name##_show(struct kobject *kobj, \ |
| 208 | struct kobj_attribute *attr, char *buf) \ |
| 209 | { \ |
| 210 | return sprintf(buf, "%lu\n", cleancache_##_name); \ |
| 211 | } \ |
| 212 | static struct kobj_attribute cleancache_##_name##_attr = { \ |
| 213 | .attr = { .name = __stringify(_name), .mode = 0444 }, \ |
| 214 | .show = cleancache_##_name##_show, \ |
| 215 | } |
| 216 | |
| 217 | CLEANCACHE_SYSFS_RO(succ_gets); |
| 218 | CLEANCACHE_SYSFS_RO(failed_gets); |
| 219 | CLEANCACHE_SYSFS_RO(puts); |
| 220 | CLEANCACHE_SYSFS_RO(flushes); |
| 221 | |
| 222 | static struct attribute *cleancache_attrs[] = { |
| 223 | &cleancache_succ_gets_attr.attr, |
| 224 | &cleancache_failed_gets_attr.attr, |
| 225 | &cleancache_puts_attr.attr, |
| 226 | &cleancache_flushes_attr.attr, |
| 227 | NULL, |
| 228 | }; |
| 229 | |
| 230 | static struct attribute_group cleancache_attr_group = { |
| 231 | .attrs = cleancache_attrs, |
| 232 | .name = "cleancache", |
| 233 | }; |
| 234 | |
| 235 | #endif /* CONFIG_SYSFS */ |
| 236 | |
| 237 | static int __init init_cleancache(void) |
| 238 | { |
| 239 | #ifdef CONFIG_SYSFS |
| 240 | int err; |
| 241 | |
| 242 | err = sysfs_create_group(mm_kobj, &cleancache_attr_group); |
| 243 | #endif /* CONFIG_SYSFS */ |
| 244 | return 0; |
| 245 | } |
| 246 | module_init(init_cleancache) |