4 * A snap shot file system.
8 #define DEBUG_SUBSYSTEM S_SNAP
10 #include <linux/kmod.h>
11 #include <linux/init.h>
13 #include <linux/slab.h>
14 #include <linux/jbd.h>
15 #include <linux/ext3_fs.h>
16 #include <linux/string.h>
17 #include <linux/snap.h>
18 #include "snapfs_internal.h"
21 extern int currentfs_remount(struct super_block * sb, int *flags, char *data);
23 /* XXX PJB: this is exactly what we need to put things under
24 filters - we don't want the ext2 methods hardcoded, we want them
25 in the filter (in read_super) and then call those methods.
26 See how InterMezzo gets the journal operations .
29 extern void currentfs_dotsnap_read_inode(struct snap_cache *, struct inode *);
31 static kmem_cache_t *filter_info_cache = NULL;
33 void cleanup_filter_info_cache()
35 kmem_cache_destroy(filter_info_cache);
38 int init_filter_info_cache()
40 filter_info_cache = kmem_cache_create("snapfs_filter_info",
41 sizeof(struct filter_inode_info),
43 if (!filter_info_cache) {
44 CERROR("unable to create snap_inode info cache\n");
51 void init_filter_data(struct inode *inode,
54 struct filter_inode_info *i;
55 struct snap_cache *cache;
56 struct snapshot_operations *snapops;
58 if (inode->i_filterdata || inode->i_ino & 0xF0000000)
60 cache = snap_find_cache(inode->i_dev);
62 CERROR("currentfs_read_inode: cannot find cache\n");
63 make_bad_inode(inode);
66 snapops = filter_c2csnapops(cache->cache_filter);
68 inode->i_filterdata = (struct filter_inode_info *) \
69 kmem_cache_alloc(filter_info_cache, SLAB_KERNEL);
70 i = inode->i_filterdata;
71 i -> generation = snapops->get_generation(inode);
75 void set_filter_ops(struct snap_cache *cache, struct inode *inode)
77 /* XXX now set the correct snap_{file,dir,sym}_iops */
78 if (S_ISDIR(inode->i_mode)) {
79 inode->i_op = filter_c2udiops(cache->cache_filter);
80 inode->i_fop = filter_c2udfops(cache->cache_filter);
81 } else if (S_ISREG(inode->i_mode)) {
82 if ( !filter_c2cfiops(cache->cache_filter) ) {
83 filter_setup_file_ops(cache->cache_filter, inode,
86 ¤tfs_file_aops);
88 CDEBUG(D_INODE, "inode %lu, i_op at %p\n",
89 inode->i_ino, inode->i_op);
90 inode->i_fop = filter_c2uffops(cache->cache_filter);
91 inode->i_op = filter_c2ufiops(cache->cache_filter);
93 inode->i_mapping->a_ops = filter_c2ufaops(cache->cache_filter);
96 else if (S_ISLNK(inode->i_mode)) {
97 if ( !filter_c2csiops(cache->cache_filter) ) {
98 filter_setup_symlink_ops(cache->cache_filter, inode,
99 ¤tfs_sym_iops, ¤tfs_sym_fops);
101 inode->i_op = filter_c2usiops(cache->cache_filter);
102 inode->i_fop = filter_c2usfops(cache->cache_filter);
103 CDEBUG(D_INODE, "inode %lu, i_op at %p\n",
104 inode->i_ino, inode->i_op);
108 /* Superblock operations. */
109 static void currentfs_read_inode(struct inode *inode)
111 struct snap_cache *cache;
117 CDEBUG(D_INODE, "read_inode ino %lu\n", inode->i_ino);
119 cache = snap_find_cache(inode->i_dev);
121 CERROR("currentfs_read_inode: cannot find cache\n");
122 make_bad_inode(inode);
126 if (inode->i_ino & 0xF0000000) {
127 currentfs_dotsnap_read_inode(cache, inode);
131 if(filter_c2csops(cache->cache_filter))
132 filter_c2csops(cache->cache_filter)->read_inode(inode);
134 set_filter_ops(cache, inode);
135 /*init filter_data struct
136 * FIXME flag should be set future*/
137 init_filter_data(inode, 0);
141 static void currentfs_put_super(struct super_block *sb)
144 struct snap_cache *cache;
147 CDEBUG(D_SUPER, "sb %lx, sb->u.generic_sbp: %lx\n",
148 (ulong) sb, (ulong) sb->u.generic_sbp);
149 cache = snap_find_cache(sb->s_dev);
154 /* handle COMPAT_FEATUREs */
155 #ifdef CONFIG_SNAPFS_EXT2
156 else if( cache->cache_type == FILTER_FS_EXT2 ){
157 if( !EXT2_HAS_COMPAT_FEATURE(sb, EXT2_FEATURE_COMPAT_SNAPFS) ){
158 sb->u.ext2_sb.s_feature_compat &=
159 ~EXT2_FEATURE_COMPAT_BLOCKCOW;
160 sb->u.ext2_sb.s_es->s_feature_compat &=
161 cpu_to_le32(~EXT2_FEATURE_COMPAT_BLOCKCOW);
165 #ifdef CONFIG_SNAPFS_EXT3
166 else if( cache->cache_type == FILTER_FS_EXT3 ){
167 if( !EXT3_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_SNAPFS) ){
168 sb->u.ext3_sb.s_es->s_feature_compat &=
169 cpu_to_le32(~EXT3_FEATURE_COMPAT_BLOCKCOW);
174 * If there is a saved 'put_super' function for the underlying
177 if (cache->cache_filter->o_caops.cache_sops->put_super) {
178 cache->cache_filter->o_caops.cache_sops->put_super(sb);
181 if (!list_empty(&cache->cache_clone_list)) {
182 CWARN("snap_put_super: clones exist!\n");
185 list_del(&cache->cache_chain);
186 snap_free_cache(cache);
188 CDEBUG(D_SUPER, "sb %lx, sb->u.generic_sbp: %lx\n",
189 (ulong) sb, (ulong) sb->u.generic_sbp);
194 static void currentfs_clear_inode(struct inode *inode)
196 struct snap_cache *cache;
197 struct super_operations *sops;
199 cache = snap_find_cache(inode->i_dev);
201 CDEBUG(D_INODE, "inode has invalid dev\n");
205 if (inode->i_filterdata) {
206 kmem_cache_free(filter_info_cache, inode->i_filterdata);
207 inode->i_filterdata = NULL;
210 sops = filter_c2csops(cache->cache_filter);
211 if (sops && sops->clear_inode)
212 sops->clear_inode(inode);
215 struct super_operations currentfs_super_ops = {
216 read_inode: currentfs_read_inode,
217 put_super: currentfs_put_super,
218 clear_inode: currentfs_clear_inode,