module/zfs/zpl_super.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright (c) 2011, Lawrence Livermore National Security, LLC.
  23  */
  24
  25
  26 #include <sys/zfs_vfsops.h>
  27 #include <sys/zfs_vnops.h>
  28 #include <sys/zfs_znode.h>
  29 #include <sys/zfs_ctldir.h>
  30 #include <sys/zpl.h>
  31
  32
  33 static struct inode *
  34 zpl_inode_alloc(struct super_block *sb)
  35 {
  36         struct inode *ip;
  37
  38         VERIFY3S(zfs_inode_alloc(sb, &ip), ==, 0);
  39         ip->i_version = 1;
  40
  41         return (ip);
  42 }
  43
  44 static void
  45 zpl_inode_destroy(struct inode *ip)
  46 {
  47         ASSERT(atomic_read(&ip->i_count) == 0);
  48         zfs_inode_destroy(ip);
  49 }
  50
  51 /*
  52  * Called from __mark_inode_dirty() to reflect that something in the
  53  * inode has changed.  We use it to ensure the znode system attributes
  54  * are always strictly update to date with respect to the inode.
  55  */
  56 #ifdef HAVE_DIRTY_INODE_WITH_FLAGS
  57 static void
  58 zpl_dirty_inode(struct inode *ip, int flags)
  59 {
  60         zfs_dirty_inode(ip, flags);
  61 }
  62 #else
  63 static void
  64 zpl_dirty_inode(struct inode *ip)
  65 {
  66         zfs_dirty_inode(ip, 0);
  67 }
  68 #endif /* HAVE_DIRTY_INODE_WITH_FLAGS */
  69
  70 /*
  71  * When ->drop_inode() is called its return value indicates if the
  72  * inode should be evicted from the inode cache.  If the inode is
  73  * unhashed and has no links the default policy is to evict it
  74  * immediately.
  75  *
  76  * Prior to 2.6.36 this eviction was accomplished by the vfs calling
  77  * ->delete_inode().  It was ->delete_inode()'s responsibility to
  78  * truncate the inode pages and call clear_inode().  The call to
  79  * clear_inode() synchronously invalidates all the buffers and
  80  * calls ->clear_inode().  It was ->clear_inode()'s responsibility
  81  * to cleanup and filesystem specific data before freeing the inode.
  82  *
  83  * This elaborate mechanism was replaced by ->evict_inode() which
  84  * does the job of both ->delete_inode() and ->clear_inode().  It
  85  * will be called exactly once, and when it returns the inode must
  86  * be in a state where it can simply be freed.i
  87  *
  88  * The ->evict_inode() callback must minimally truncate the inode pages,
  89  * and call clear_inode().  For 2.6.35 and later kernels this will
  90  * simply update the inode state, with the sync occurring before the
  91  * truncate in evict().  For earlier kernels clear_inode() maps to
  92  * end_writeback() which is responsible for completing all outstanding
  93  * write back.  In either case, once this is done it is safe to cleanup
  94  * any remaining inode specific data via zfs_inactive().
  95  * remaining filesystem specific data.
  96  */
  97 #ifdef HAVE_EVICT_INODE
  98 static void
  99 zpl_evict_inode(struct inode *ip)
 100 {
 101         fstrans_cookie_t cookie;
 102
 103         cookie = spl_fstrans_mark();
 104         truncate_setsize(ip, 0);
 105         clear_inode(ip);
 106         zfs_inactive(ip);
 107         spl_fstrans_unmark(cookie);
 108 }
 109
 110 #else
 111
 112 static void
 113 zpl_drop_inode(struct inode *ip)
 114 {
 115         generic_delete_inode(ip);
 116 }
 117
 118 static void
 119 zpl_clear_inode(struct inode *ip)
 120 {
 121         fstrans_cookie_t cookie;
 122
 123         cookie = spl_fstrans_mark();
 124         zfs_inactive(ip);
 125         spl_fstrans_unmark(cookie);
 126 }
 127
 128 static void
 129 zpl_inode_delete(struct inode *ip)
 130 {
 131         truncate_setsize(ip, 0);
 132         clear_inode(ip);
 133 }
 134 #endif /* HAVE_EVICT_INODE */
 135
 136 static void
 137 zpl_put_super(struct super_block *sb)
 138 {
 139         fstrans_cookie_t cookie;
 140         int error;
 141
 142         cookie = spl_fstrans_mark();
 143         error = -zfs_umount(sb);
 144         spl_fstrans_unmark(cookie);
 145         ASSERT3S(error, <=, 0);
 146 }
 147
 148 static int
 149 zpl_sync_fs(struct super_block *sb, int wait)
 150 {
 151         fstrans_cookie_t cookie;
 152         cred_t *cr = CRED();
 153         int error;
 154
 155         crhold(cr);
 156         cookie = spl_fstrans_mark();
 157         error = -zfs_sync(sb, wait, cr);
 158         spl_fstrans_unmark(cookie);
 159         crfree(cr);
 160         ASSERT3S(error, <=, 0);
 161
 162         return (error);
 163 }
 164
 165 static int
 166 zpl_statfs(struct dentry *dentry, struct kstatfs *statp)
 167 {
 168         fstrans_cookie_t cookie;
 169         int error;
 170
 171         cookie = spl_fstrans_mark();
 172         error = -zfs_statvfs(dentry, statp);
 173         spl_fstrans_unmark(cookie);
 174         ASSERT3S(error, <=, 0);
 175
 176         return (error);
 177 }
 178
 179 static int
 180 zpl_remount_fs(struct super_block *sb, int *flags, char *data)
 181 {
 182         fstrans_cookie_t cookie;
 183         int error;
 184
 185         cookie = spl_fstrans_mark();
 186         error = -zfs_remount(sb, flags, data);
 187         spl_fstrans_unmark(cookie);
 188         ASSERT3S(error, <=, 0);
 189
 190         return (error);
 191 }
 192
 193 static void
 194 zpl_umount_begin(struct super_block *sb)
 195 {
 196         zfs_sb_t *zsb = sb->s_fs_info;
 197         int count;
 198
 199         /*
 200          * Best effort to unmount snapshots in .zfs/snapshot/.  Normally this
 201          * isn't required because snapshots have the MNT_SHRINKABLE flag set.
 202          */
 203         if (zsb->z_ctldir)
 204                 (void) zfsctl_unmount_snapshots(zsb, MNT_FORCE, &count);
 205 }
 206
 207 /*
 208  * ZFS specific features must be explicitly handled here, the VFS will
 209  * automatically handled the following generic functionality.
 210  *
 211  *   MNT_NOSUID,
 212  *   MNT_NODEV,
 213  *   MNT_NOEXEC,
 214  *   MNT_NOATIME,
 215  *   MNT_NODIRATIME,
 216  *   MNT_READONLY,
 217  *   MNT_STRICTATIME,
 218  *   MS_SYNCHRONOUS,
 219  *   MS_DIRSYNC,
 220  *   MS_MANDLOCK.
 221  */
 222 static int
 223 __zpl_show_options(struct seq_file *seq, zfs_sb_t *zsb)
 224 {
 225         seq_printf(seq, ",%s", zsb->z_flags & ZSB_XATTR ? "xattr" : "noxattr");
 226
 227 #ifdef CONFIG_FS_POSIX_ACL
 228         switch (zsb->z_acl_type) {
 229         case ZFS_ACLTYPE_POSIXACL:
 230                 seq_puts(seq, ",posixacl");
 231                 break;
 232         default:
 233                 seq_puts(seq, ",noacl");
 234                 break;
 235         }
 236 #endif /* CONFIG_FS_POSIX_ACL */
 237
 238         return (0);
 239 }
 240
 241 #ifdef HAVE_SHOW_OPTIONS_WITH_DENTRY
 242 static int
 243 zpl_show_options(struct seq_file *seq, struct dentry *root)
 244 {
 245         return (__zpl_show_options(seq, root->d_sb->s_fs_info));
 246 }
 247 #else
 248 static int
 249 zpl_show_options(struct seq_file *seq, struct vfsmount *vfsp)
 250 {
 251         return (__zpl_show_options(seq, vfsp->mnt_sb->s_fs_info));
 252 }
 253 #endif /* HAVE_SHOW_OPTIONS_WITH_DENTRY */
 254
 255 static int
 256 zpl_fill_super(struct super_block *sb, void *data, int silent)
 257 {
 258         fstrans_cookie_t cookie;
 259         int error;
 260
 261         cookie = spl_fstrans_mark();
 262         error = -zfs_domount(sb, data, silent);
 263         spl_fstrans_unmark(cookie);
 264         ASSERT3S(error, <=, 0);
 265
 266         return (error);
 267 }
 268
 269 #ifdef HAVE_MOUNT_NODEV
 270 static struct dentry *
 271 zpl_mount(struct file_system_type *fs_type, int flags,
 272     const char *osname, void *data)
 273 {
 274         zpl_mount_data_t zmd = { osname, data };
 275
 276         return (mount_nodev(fs_type, flags, &zmd, zpl_fill_super));
 277 }
 278 #else
 279 static int
 280 zpl_get_sb(struct file_system_type *fs_type, int flags,
 281     const char *osname, void *data, struct vfsmount *mnt)
 282 {
 283         zpl_mount_data_t zmd = { osname, data };
 284
 285         return (get_sb_nodev(fs_type, flags, &zmd, zpl_fill_super, mnt));
 286 }
 287 #endif /* HAVE_MOUNT_NODEV */
 288
 289 static void
 290 zpl_kill_sb(struct super_block *sb)
 291 {
 292         zfs_preumount(sb);
 293         kill_anon_super(sb);
 294
 295 #ifdef HAVE_S_INSTANCES_LIST_HEAD
 296         sb->s_instances.next = &(zpl_fs_type.fs_supers);
 297 #endif /* HAVE_S_INSTANCES_LIST_HEAD */
 298 }
 299
 300 void
 301 zpl_prune_sb(int64_t nr_to_scan, void *arg)
 302 {
 303         struct super_block *sb = (struct super_block *)arg;
 304         int objects = 0;
 305
 306         (void) -zfs_sb_prune(sb, nr_to_scan, &objects);
 307 }
 308
 309 #ifdef HAVE_NR_CACHED_OBJECTS
 310 static int
 311 zpl_nr_cached_objects(struct super_block *sb)
 312 {
 313         zfs_sb_t *zsb = sb->s_fs_info;
 314         int nr;
 315
 316         mutex_enter(&zsb->z_znodes_lock);
 317         nr = zsb->z_nr_znodes;
 318         mutex_exit(&zsb->z_znodes_lock);
 319
 320         return (nr);
 321 }
 322 #endif /* HAVE_NR_CACHED_OBJECTS */
 323
 324 #ifdef HAVE_FREE_CACHED_OBJECTS
 325 /*
 326  * Attempt to evict some meta data from the cache.  The ARC operates in
 327  * terms of bytes while the Linux VFS uses objects.  Now because this is
 328  * just a best effort eviction and the exact values aren't critical so we
 329  * extrapolate from an object count to a byte size using the znode_t size.
 330  */
 331 static void
 332 zpl_free_cached_objects(struct super_block *sb, int nr_to_scan)
 333 {
 334         /* noop */
 335 }
 336 #endif /* HAVE_FREE_CACHED_OBJECTS */
 337
 338 const struct super_operations zpl_super_operations = {
 339         .alloc_inode            = zpl_inode_alloc,
 340         .destroy_inode          = zpl_inode_destroy,
 341         .dirty_inode            = zpl_dirty_inode,
 342         .write_inode            = NULL,
 343 #ifdef HAVE_EVICT_INODE
 344         .evict_inode            = zpl_evict_inode,
 345 #else
 346         .drop_inode             = zpl_drop_inode,
 347         .clear_inode            = zpl_clear_inode,
 348         .delete_inode           = zpl_inode_delete,
 349 #endif /* HAVE_EVICT_INODE */
 350         .put_super              = zpl_put_super,
 351         .sync_fs                = zpl_sync_fs,
 352         .statfs                 = zpl_statfs,
 353         .remount_fs             = zpl_remount_fs,
 354         .umount_begin           = zpl_umount_begin,
 355         .show_options           = zpl_show_options,
 356         .show_stats             = NULL,
 357 #ifdef HAVE_NR_CACHED_OBJECTS
 358         .nr_cached_objects      = zpl_nr_cached_objects,
 359 #endif /* HAVE_NR_CACHED_OBJECTS */
 360 #ifdef HAVE_FREE_CACHED_OBJECTS
 361         .free_cached_objects    = zpl_free_cached_objects,
 362 #endif /* HAVE_FREE_CACHED_OBJECTS */
 363 };
 364
 365 struct file_system_type zpl_fs_type = {
 366         .owner                  = THIS_MODULE,
 367         .name                   = ZFS_DRIVER,
 368 #ifdef HAVE_MOUNT_NODEV
 369         .mount                  = zpl_mount,
 370 #else
 371         .get_sb                 = zpl_get_sb,
 372 #endif /* HAVE_MOUNT_NODEV */
 373         .kill_sb                = zpl_kill_sb,
 374 };