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/zpl.h>
  30
  31
  32 static struct inode *
  33 zpl_inode_alloc(struct super_block *sb)
  34 {
  35         struct inode *ip;
  36
  37         VERIFY3S(zfs_inode_alloc(sb, &ip), ==, 0);
  38         ip->i_version = 1;
  39
  40         return (ip);
  41 }
  42
  43 static void
  44 zpl_inode_destroy(struct inode *ip)
  45 {
  46         ASSERT(atomic_read(&ip->i_count) == 0);
  47         zfs_inode_destroy(ip);
  48 }
  49
  50 /*
  51  * When ->drop_inode() is called its return value indicates if the
  52  * inode should be evicted from the inode cache.  If the inode is
  53  * unhashed and has no links the default policy is to evict it
  54  * immediately.
  55  *
  56  * Prior to 2.6.36 this eviction was accomplished by the vfs calling
  57  * ->delete_inode().  It was ->delete_inode()'s responsibility to
  58  * truncate the inode pages and call clear_inode().  The call to
  59  * clear_inode() synchronously invalidates all the buffers and
  60  * calls ->clear_inode().  It was ->clear_inode()'s responsibility
  61  * to cleanup and filesystem specific data before freeing the inode.
  62  *
  63  * This elaborate mechanism was replaced by ->evict_inode() which
  64  * does the job of both ->delete_inode() and ->clear_inode().  It
  65  * will be called exactly once, and when it returns the inode must
  66  * be in a state where it can simply be freed.  The ->evict_inode()
  67  * callback must minimally truncate the inode pages, and call
  68  * end_writeback() to complete all outstanding writeback for the
  69  * inode.  After this is complete evict inode can cleanup any
  70  * remaining filesystem specific data.
  71  */
  72 #ifdef HAVE_EVICT_INODE
  73 static void
  74 zpl_evict_inode(struct inode *ip)
  75 {
  76         truncate_setsize(ip, 0);
  77         end_writeback(ip);
  78         zfs_inactive(ip);
  79 }
  80
  81 #else
  82
  83 static void
  84 zpl_clear_inode(struct inode *ip)
  85 {
  86         zfs_inactive(ip);
  87 }
  88
  89 static void
  90 zpl_inode_delete(struct inode *ip)
  91 {
  92         truncate_setsize(ip, 0);
  93         clear_inode(ip);
  94 }
  95
  96 #endif /* HAVE_EVICT_INODE */
  97
  98 static void
  99 zpl_put_super(struct super_block *sb)
 100 {
 101         int error;
 102
 103         error = -zfs_umount(sb);
 104         ASSERT3S(error, <=, 0);
 105 }
 106
 107 static int
 108 zpl_sync_fs(struct super_block *sb, int wait)
 109 {
 110         cred_t *cr = CRED();
 111         int error;
 112
 113         crhold(cr);
 114         error = -zfs_sync(sb, wait, cr);
 115         crfree(cr);
 116         ASSERT3S(error, <=, 0);
 117
 118         return (error);
 119 }
 120
 121 static int
 122 zpl_statfs(struct dentry *dentry, struct kstatfs *statp)
 123 {
 124         int error;
 125
 126         error = -zfs_statvfs(dentry, statp);
 127         ASSERT3S(error, <=, 0);
 128
 129         return (error);
 130 }
 131
 132 static int
 133 zpl_remount_fs(struct super_block *sb, int *flags, char *data)
 134 {
 135         int error;
 136         error = -zfs_remount(sb, flags, data);
 137         ASSERT3S(error, <=, 0);
 138
 139         return (error);
 140 }
 141
 142 static int
 143 zpl_show_options(struct seq_file *seq, struct vfsmount *vfsp)
 144 {
 145         struct super_block *sb = vfsp->mnt_sb;
 146         zfs_sb_t *zsb = sb->s_fs_info;
 147
 148         /*
 149          * The Linux VFS automatically handles the following flags:
 150          * MNT_NOSUID, MNT_NODEV, MNT_NOEXEC, MNT_NOATIME, MNT_READONLY
 151          */
 152
 153         if (zsb->z_flags & ZSB_XATTR_USER)
 154                 seq_printf(seq, ",%s", "xattr");
 155
 156         return (0);
 157 }
 158
 159 static int
 160 zpl_fill_super(struct super_block *sb, void *data, int silent)
 161 {
 162         int error;
 163
 164         error = -zfs_domount(sb, data, silent);
 165         ASSERT3S(error, <=, 0);
 166
 167         return (error);
 168 }
 169
 170 static int
 171 zpl_get_sb(struct file_system_type *fs_type, int flags,
 172     const char *osname, void *data, struct vfsmount *mnt)
 173 {
 174         zpl_mount_data_t zmd = { osname, data, mnt };
 175
 176         return get_sb_nodev(fs_type, flags, &zmd, zpl_fill_super, mnt);
 177 }
 178
 179 static void
 180 zpl_kill_sb(struct super_block *sb)
 181 {
 182 #ifdef HAVE_SNAPSHOT
 183         zfs_sb_t *zsb = sb->s_fs_info;
 184
 185         if (zsb && dmu_objset_is_snapshot(zsb->z_os))
 186                 zfs_snap_destroy(zsb);
 187 #endif /* HAVE_SNAPSHOT */
 188
 189         kill_anon_super(sb);
 190 }
 191
 192 const struct super_operations zpl_super_operations = {
 193         .alloc_inode    = zpl_inode_alloc,
 194         .destroy_inode  = zpl_inode_destroy,
 195         .dirty_inode    = NULL,
 196         .write_inode    = NULL,
 197         .drop_inode     = NULL,
 198 #ifdef HAVE_EVICT_INODE
 199         .evict_inode    = zpl_evict_inode,
 200 #else
 201         .clear_inode    = zpl_clear_inode,
 202         .delete_inode   = zpl_inode_delete,
 203 #endif /* HAVE_EVICT_INODE */
 204         .put_super      = zpl_put_super,
 205         .write_super    = NULL,
 206         .sync_fs        = zpl_sync_fs,
 207         .statfs         = zpl_statfs,
 208         .remount_fs     = zpl_remount_fs,
 209         .show_options   = zpl_show_options,
 210         .show_stats     = NULL,
 211 };
 212
 213 struct file_system_type zpl_fs_type = {
 214         .owner          = THIS_MODULE,
 215         .name           = ZFS_DRIVER,
 216         .get_sb         = zpl_get_sb,
 217         .kill_sb        = zpl_kill_sb,
 218 };