[mirror_zfs.git] / module / zfs / zpl_super.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 2011, Lawrence Livermore National Security, LLC.
 */


#include <sys/zfs_vfsops.h>
#include <sys/zfs_vnops.h>
#include <sys/zfs_znode.h>
#include <sys/zfs_ctldir.h>
#include <sys/zpl.h>


static struct inode *
zpl_inode_alloc(struct super_block *sb)
{
	struct inode *ip;

	VERIFY3S(zfs_inode_alloc(sb, &ip), ==, 0);
	ip->i_version = 1;

	return (ip);
}

static void
zpl_inode_destroy(struct inode *ip)
{
	ASSERT(atomic_read(&ip->i_count) == 0);
	zfs_inode_destroy(ip);
}

/*
 * Called from __mark_inode_dirty() to reflect that something in the
 * inode has changed.  We use it to ensure the znode system attributes
 * are always strictly update to date with respect to the inode.
 */
#ifdef HAVE_DIRTY_INODE_WITH_FLAGS
static void
zpl_dirty_inode(struct inode *ip, int flags)
{
	zfs_dirty_inode(ip, flags);
}
#else
static void
zpl_dirty_inode(struct inode *ip)
{
	zfs_dirty_inode(ip, 0);
}
#endif /* HAVE_DIRTY_INODE_WITH_FLAGS */

/*
 * When ->drop_inode() is called its return value indicates if the
 * inode should be evicted from the inode cache.  If the inode is
 * unhashed and has no links the default policy is to evict it
 * immediately.
 *
 * Prior to 2.6.36 this eviction was accomplished by the vfs calling
 * ->delete_inode().  It was ->delete_inode()'s responsibility to
 * truncate the inode pages and call clear_inode().  The call to
 * clear_inode() synchronously invalidates all the buffers and
 * calls ->clear_inode().  It was ->clear_inode()'s responsibility
 * to cleanup and filesystem specific data before freeing the inode.
 *
 * This elaborate mechanism was replaced by ->evict_inode() which
 * does the job of both ->delete_inode() and ->clear_inode().  It
 * will be called exactly once, and when it returns the inode must
 * be in a state where it can simply be freed.i
 *
 * The ->evict_inode() callback must minimally truncate the inode pages,
 * and call clear_inode().  For 2.6.35 and later kernels this will
 * simply update the inode state, with the sync occurring before the
 * truncate in evict().  For earlier kernels clear_inode() maps to
 * end_writeback() which is responsible for completing all outstanding
 * write back.  In either case, once this is done it is safe to cleanup
 * any remaining inode specific data via zfs_inactive().
 * remaining filesystem specific data.
 */
#ifdef HAVE_EVICT_INODE
static void
zpl_evict_inode(struct inode *ip)
{
	truncate_setsize(ip, 0);
	clear_inode(ip);
	zfs_inactive(ip);
}

#else

static void
zpl_clear_inode(struct inode *ip)
{
	zfs_inactive(ip);
}

static void
zpl_inode_delete(struct inode *ip)
{
	truncate_setsize(ip, 0);
	clear_inode(ip);
}

#endif /* HAVE_EVICT_INODE */

static void
zpl_put_super(struct super_block *sb)
{
	int error;

	error = -zfs_umount(sb);
	ASSERT3S(error, <=, 0);
}

static int
zpl_sync_fs(struct super_block *sb, int wait)
{
	cred_t *cr = CRED();
	int error;

	crhold(cr);
	error = -zfs_sync(sb, wait, cr);
	crfree(cr);
	ASSERT3S(error, <=, 0);

	return (error);
}

static int
zpl_statfs(struct dentry *dentry, struct kstatfs *statp)
{
	int error;

	error = -zfs_statvfs(dentry, statp);
	ASSERT3S(error, <=, 0);

	return (error);
}

static int
zpl_remount_fs(struct super_block *sb, int *flags, char *data)
{
	int error;
	error = -zfs_remount(sb, flags, data);
	ASSERT3S(error, <=, 0);

	return (error);
}

static void
zpl_umount_begin(struct super_block *sb)
{
	zfs_sb_t *zsb = sb->s_fs_info;
	int count;

	/*
	 * Best effort to unmount snapshots in .zfs/snapshot/.  Normally this
	 * isn't required because snapshots have the MNT_SHRINKABLE flag set.
	 */
	if (zsb->z_ctldir)
		(void) zfsctl_unmount_snapshots(zsb, MNT_FORCE, &count);
}

/*
 * ZFS specific features must be explicitly handled here, the VFS will
 * automatically handled the following generic functionality.
 *
 *   MNT_NOSUID,
 *   MNT_NODEV,
 *   MNT_NOEXEC,
 *   MNT_NOATIME,
 *   MNT_NODIRATIME,
 *   MNT_READONLY,
 *   MNT_STRICTATIME,
 *   MS_SYNCHRONOUS,
 *   MS_DIRSYNC,
 *   MS_MANDLOCK.
 */
static int
__zpl_show_options(struct seq_file *seq, zfs_sb_t *zsb)
{
	seq_printf(seq, ",%s", zsb->z_flags & ZSB_XATTR ? "xattr" : "noxattr");

#ifdef CONFIG_FS_POSIX_ACL
	switch (zsb->z_acl_type) {
	case ZFS_ACLTYPE_POSIXACL:
		seq_puts(seq, ",posixacl");
		break;
	default:
		seq_puts(seq, ",noacl");
		break;
	}
#endif /* CONFIG_FS_POSIX_ACL */

	return (0);
}

#ifdef HAVE_SHOW_OPTIONS_WITH_DENTRY
static int
zpl_show_options(struct seq_file *seq, struct dentry *root)
{
	return (__zpl_show_options(seq, root->d_sb->s_fs_info));
}
#else
static int
zpl_show_options(struct seq_file *seq, struct vfsmount *vfsp)
{
	return (__zpl_show_options(seq, vfsp->mnt_sb->s_fs_info));
}
#endif /* HAVE_SHOW_OPTIONS_WITH_DENTRY */

static int
zpl_fill_super(struct super_block *sb, void *data, int silent)
{
	int error;

	error = -zfs_domount(sb, data, silent);
	ASSERT3S(error, <=, 0);

	return (error);
}

#ifdef HAVE_MOUNT_NODEV
static struct dentry *
zpl_mount(struct file_system_type *fs_type, int flags,
    const char *osname, void *data)
{
	zpl_mount_data_t zmd = { osname, data };

	return (mount_nodev(fs_type, flags, &zmd, zpl_fill_super));
}
#else
static int
zpl_get_sb(struct file_system_type *fs_type, int flags,
    const char *osname, void *data, struct vfsmount *mnt)
{
	zpl_mount_data_t zmd = { osname, data };

	return (get_sb_nodev(fs_type, flags, &zmd, zpl_fill_super, mnt));
}
#endif /* HAVE_MOUNT_NODEV */

static void
zpl_kill_sb(struct super_block *sb)
{
	zfs_preumount(sb);
	kill_anon_super(sb);

#ifdef HAVE_S_INSTANCES_LIST_HEAD
	sb->s_instances.next = &(zpl_fs_type.fs_supers);
#endif /* HAVE_S_INSTANCES_LIST_HEAD */
}

#ifdef HAVE_SHRINK
/*
 * Linux 3.1 - 3.x API
 *
 * The Linux 3.1 API introduced per-sb cache shrinkers to replace the
 * global ones.  This allows us a mechanism to cleanly target a specific
 * zfs file system when the dnode and inode caches grow too large.
 *
 * In addition, the 3.0 kernel added the iterate_supers_type() helper
 * function which is used to safely walk all of the zfs file systems.
 */
static void
zpl_prune_sb(struct super_block *sb, void *arg)
{
	int objects = 0;
	int error;

	error = -zfs_sb_prune(sb, *(unsigned long *)arg, &objects);
	ASSERT3S(error, <=, 0);
}

void
zpl_prune_sbs(int64_t bytes_to_scan, void *private)
{
	unsigned long nr_to_scan = (bytes_to_scan / sizeof (znode_t));

	iterate_supers_type(&zpl_fs_type, zpl_prune_sb, &nr_to_scan);
	kmem_reap();
}
#else
/*
 * Linux 2.6.x - 3.0 API
 *
 * These are best effort interfaces are provided by the SPL to induce
 * the Linux VM subsystem to reclaim a fraction of the both dnode and
 * inode caches.  Ideally, we want to just target the zfs file systems
 * however our only option is to reclaim from them all.
 */
void
zpl_prune_sbs(int64_t bytes_to_scan, void *private)
{
	unsigned long nr_to_scan = (bytes_to_scan / sizeof (znode_t));

	shrink_dcache_memory(nr_to_scan, GFP_KERNEL);
	shrink_icache_memory(nr_to_scan, GFP_KERNEL);
	kmem_reap();
}
#endif /* HAVE_SHRINK */

#ifdef HAVE_NR_CACHED_OBJECTS
static int
zpl_nr_cached_objects(struct super_block *sb)
{
	zfs_sb_t *zsb = sb->s_fs_info;
	int nr;

	mutex_enter(&zsb->z_znodes_lock);
	nr = zsb->z_nr_znodes;
	mutex_exit(&zsb->z_znodes_lock);

	return (nr);
}
#endif /* HAVE_NR_CACHED_OBJECTS */

#ifdef HAVE_FREE_CACHED_OBJECTS
/*
 * Attempt to evict some meta data from the cache.  The ARC operates in
 * terms of bytes while the Linux VFS uses objects.  Now because this is
 * just a best effort eviction and the exact values aren't critical so we
 * extrapolate from an object count to a byte size using the znode_t size.
 */
static void
zpl_free_cached_objects(struct super_block *sb, int nr_to_scan)
{
	arc_adjust_meta(nr_to_scan * sizeof (znode_t), B_FALSE);
}
#endif /* HAVE_FREE_CACHED_OBJECTS */

const struct super_operations zpl_super_operations = {
	.alloc_inode		= zpl_inode_alloc,
	.destroy_inode		= zpl_inode_destroy,
	.dirty_inode		= zpl_dirty_inode,
	.write_inode		= NULL,
	.drop_inode		= NULL,
#ifdef HAVE_EVICT_INODE
	.evict_inode		= zpl_evict_inode,
#else
	.clear_inode		= zpl_clear_inode,
	.delete_inode		= zpl_inode_delete,
#endif /* HAVE_EVICT_INODE */
	.put_super		= zpl_put_super,
	.sync_fs		= zpl_sync_fs,
	.statfs			= zpl_statfs,
	.remount_fs		= zpl_remount_fs,
	.umount_begin		= zpl_umount_begin,
	.show_options		= zpl_show_options,
	.show_stats		= NULL,
#ifdef HAVE_NR_CACHED_OBJECTS
	.nr_cached_objects	= zpl_nr_cached_objects,
#endif /* HAVE_NR_CACHED_OBJECTS */
#ifdef HAVE_FREE_CACHED_OBJECTS
	.free_cached_objects	= zpl_free_cached_objects,
#endif /* HAVE_FREE_CACHED_OBJECTS */
};

struct file_system_type zpl_fs_type = {
	.owner			= THIS_MODULE,
	.name			= ZFS_DRIVER,
#ifdef HAVE_MOUNT_NODEV
	.mount			= zpl_mount,
#else
	.get_sb			= zpl_get_sb,
#endif /* HAVE_MOUNT_NODEV */
	.kill_sb		= zpl_kill_sb,
};
Commit	Line	Data
51f0bbe4 BB	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>
ebe7e575	29	#include <sys/zfs_ctldir.h>
51f0bbe4 BB	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	{
d1d7e268	47	ASSERT(atomic_read(&ip->i_count) == 0);
51f0bbe4 BB	48	zfs_inode_destroy(ip);
	49	}
	50
8780c539 BB	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
2c395def BB	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
739a1a82 RY	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().
2c395def BB	95	* remaining filesystem specific data.
	96	*/
	97	#ifdef HAVE_EVICT_INODE
51f0bbe4	98	static void
2c395def	99	zpl_evict_inode(struct inode *ip)
51f0bbe4	100	{
b3129792	101	truncate_setsize(ip, 0);
739a1a82	102	clear_inode(ip);
2c395def	103	zfs_inactive(ip);
51f0bbe4 BB	104	}
51f0bbe4 BB	105
2c395def BB	106	#else
2c395def BB	107
51f0bbe4	108	static void
2c395def	109	zpl_clear_inode(struct inode *ip)
51f0bbe4 BB	110	{
	111	zfs_inactive(ip);
	112	}
	113
2c395def BB	114	static void
	115	zpl_inode_delete(struct inode *ip)
	116	{
b3129792	117	truncate_setsize(ip, 0);
2c395def BB	118	clear_inode(ip);
	119	}
	120
	121	#endif /* HAVE_EVICT_INODE */
	122
51f0bbe4 BB	123	static void
	124	zpl_put_super(struct super_block *sb)
	125	{
	126	int error;
	127
	128	error = -zfs_umount(sb);
	129	ASSERT3S(error, <=, 0);
	130	}
	131
03f9ba9d BB	132	static int
	133	zpl_sync_fs(struct super_block *sb, int wait)
	134	{
0d3ac5e7	135	cred_t *cr = CRED();
03f9ba9d BB	136	int error;
03f9ba9d BB	137
0d3ac5e7	138	crhold(cr);
03f9ba9d	139	error = -zfs_sync(sb, wait, cr);
0d3ac5e7	140	crfree(cr);
03f9ba9d BB	141	ASSERT3S(error, <=, 0);
	142
	143	return (error);
	144	}
	145
51f0bbe4 BB	146	static int
	147	zpl_statfs(struct dentry dentry, struct kstatfs statp)
	148	{
	149	int error;
	150
	151	error = -zfs_statvfs(dentry, statp);
	152	ASSERT3S(error, <=, 0);
	153
	154	return (error);
	155	}
	156
0de19dad BB	157	static int
	158	zpl_remount_fs(struct super_block sb, int flags, char *data)
	159	{
	160	int error;
	161	error = -zfs_remount(sb, flags, data);
	162	ASSERT3S(error, <=, 0);
	163
	164	return (error);
	165	}
	166
ebe7e575 BB	167	static void
	168	zpl_umount_begin(struct super_block *sb)
	169	{
	170	zfs_sb_t *zsb = sb->s_fs_info;
	171	int count;
	172
	173	/*
	174	* Best effort to unmount snapshots in .zfs/snapshot/. Normally this
	175	* isn't required because snapshots have the MNT_SHRINKABLE flag set.
	176	*/
	177	if (zsb->z_ctldir)
	178	(void) zfsctl_unmount_snapshots(zsb, MNT_FORCE, &count);
	179	}
	180
47621f3d	181	/*
023699cd MM	182	* ZFS specific features must be explicitly handled here, the VFS will
	183	* automatically handled the following generic functionality.
	184	*
	185	* MNT_NOSUID,
	186	* MNT_NODEV,
	187	* MNT_NOEXEC,
	188	* MNT_NOATIME,
	189	* MNT_NODIRATIME,
	190	* MNT_READONLY,
	191	* MNT_STRICTATIME,
	192	* MS_SYNCHRONOUS,
	193	* MS_DIRSYNC,
	194	* MS_MANDLOCK.
47621f3d	195	*/
51f0bbe4	196	static int
023699cd	197	__zpl_show_options(struct seq_file seq, zfs_sb_t zsb)
51f0bbe4	198	{
47621f3d BB	199	seq_printf(seq, ",%s", zsb->z_flags & ZSB_XATTR ? "xattr" : "noxattr");
47621f3d BB	200
b695c34e	201	#ifdef CONFIG_FS_POSIX_ACL
023699cd MM	202	switch (zsb->z_acl_type) {
	203	case ZFS_ACLTYPE_POSIXACL:
	204	seq_puts(seq, ",posixacl");
	205	break;
	206	default:
	207	seq_puts(seq, ",noacl");
	208	break;
	209	}
b695c34e	210	#endif /* CONFIG_FS_POSIX_ACL */
023699cd	211
47621f3d BB	212	return (0);
47621f3d BB	213	}
023699cd MM	214
	215	#ifdef HAVE_SHOW_OPTIONS_WITH_DENTRY
	216	static int
	217	zpl_show_options(struct seq_file seq, struct dentry root)
	218	{
d1d7e268	219	return (__zpl_show_options(seq, root->d_sb->s_fs_info));
023699cd	220	}
47621f3d BB	221	#else
	222	static int
	223	zpl_show_options(struct seq_file seq, struct vfsmount vfsp)
	224	{
d1d7e268	225	return (__zpl_show_options(seq, vfsp->mnt_sb->s_fs_info));
51f0bbe4	226	}
47621f3d	227	#endif /* HAVE_SHOW_OPTIONS_WITH_DENTRY */
51f0bbe4 BB	228
	229	static int
	230	zpl_fill_super(struct super_block sb, void data, int silent)
	231	{
	232	int error;
	233
	234	error = -zfs_domount(sb, data, silent);
	235	ASSERT3S(error, <=, 0);
	236
	237	return (error);
	238	}
	239
2cf7f52b BB	240	#ifdef HAVE_MOUNT_NODEV
	241	static struct dentry *
	242	zpl_mount(struct file_system_type *fs_type, int flags,
	243	const char osname, void data)
	244	{
	245	zpl_mount_data_t zmd = { osname, data };
	246
d1d7e268	247	return (mount_nodev(fs_type, flags, &zmd, zpl_fill_super));
2cf7f52b BB	248	}
2cf7f52b BB	249	#else
51f0bbe4 BB	250	static int
	251	zpl_get_sb(struct file_system_type *fs_type, int flags,
	252	const char osname, void data, struct vfsmount *mnt)
	253	{
2cf7f52b	254	zpl_mount_data_t zmd = { osname, data };
51f0bbe4	255
d1d7e268	256	return (get_sb_nodev(fs_type, flags, &zmd, zpl_fill_super, mnt));
51f0bbe4	257	}
2cf7f52b	258	#endif /* HAVE_MOUNT_NODEV */
51f0bbe4 BB	259
	260	static void
	261	zpl_kill_sb(struct super_block *sb)
	262	{
ebe7e575	263	zfs_preumount(sb);
51f0bbe4	264	kill_anon_super(sb);
dba1d705 BB	265
	266	#ifdef HAVE_S_INSTANCES_LIST_HEAD
	267	sb->s_instances.next = &(zpl_fs_type.fs_supers);
	268	#endif /* HAVE_S_INSTANCES_LIST_HEAD */
51f0bbe4 BB	269	}
51f0bbe4 BB	270
ab26409d BB	271	#ifdef HAVE_SHRINK
	272	/*
	273	* Linux 3.1 - 3.x API
	274	*
	275	* The Linux 3.1 API introduced per-sb cache shrinkers to replace the
	276	* global ones. This allows us a mechanism to cleanly target a specific
	277	* zfs file system when the dnode and inode caches grow too large.
	278	*
	279	* In addition, the 3.0 kernel added the iterate_supers_type() helper
	280	* function which is used to safely walk all of the zfs file systems.
	281	*/
	282	static void
	283	zpl_prune_sb(struct super_block sb, void arg)
	284	{
	285	int objects = 0;
	286	int error;
	287
	288	error = -zfs_sb_prune(sb, (unsigned long )arg, &objects);
	289	ASSERT3S(error, <=, 0);
ab26409d BB	290	}
	291
	292	void
	293	zpl_prune_sbs(int64_t bytes_to_scan, void *private)
	294	{
d1d7e268	295	unsigned long nr_to_scan = (bytes_to_scan / sizeof (znode_t));
ab26409d BB	296
	297	iterate_supers_type(&zpl_fs_type, zpl_prune_sb, &nr_to_scan);
	298	kmem_reap();
	299	}
	300	#else
	301	/*
	302	* Linux 2.6.x - 3.0 API
	303	*
	304	* These are best effort interfaces are provided by the SPL to induce
	305	* the Linux VM subsystem to reclaim a fraction of the both dnode and
	306	* inode caches. Ideally, we want to just target the zfs file systems
	307	* however our only option is to reclaim from them all.
	308	*/
	309	void
	310	zpl_prune_sbs(int64_t bytes_to_scan, void *private)
	311	{
d1d7e268	312	unsigned long nr_to_scan = (bytes_to_scan / sizeof (znode_t));
ab26409d	313
d1d7e268 MK	314	shrink_dcache_memory(nr_to_scan, GFP_KERNEL);
	315	shrink_icache_memory(nr_to_scan, GFP_KERNEL);
	316	kmem_reap();
ab26409d BB	317	}
	318	#endif /* HAVE_SHRINK */
	319
	320	#ifdef HAVE_NR_CACHED_OBJECTS
	321	static int
	322	zpl_nr_cached_objects(struct super_block *sb)
	323	{
	324	zfs_sb_t *zsb = sb->s_fs_info;
	325	int nr;
	326
	327	mutex_enter(&zsb->z_znodes_lock);
	328	nr = zsb->z_nr_znodes;
	329	mutex_exit(&zsb->z_znodes_lock);
	330
	331	return (nr);
	332	}
	333	#endif /* HAVE_NR_CACHED_OBJECTS */
	334
	335	#ifdef HAVE_FREE_CACHED_OBJECTS
	336	/*
	337	* Attempt to evict some meta data from the cache. The ARC operates in
	338	* terms of bytes while the Linux VFS uses objects. Now because this is
	339	* just a best effort eviction and the exact values aren't critical so we
	340	* extrapolate from an object count to a byte size using the znode_t size.
	341	*/
	342	static void
	343	zpl_free_cached_objects(struct super_block *sb, int nr_to_scan)
	344	{
d1d7e268	345	arc_adjust_meta(nr_to_scan * sizeof (znode_t), B_FALSE);
ab26409d BB	346	}
	347	#endif /* HAVE_FREE_CACHED_OBJECTS */
	348
51f0bbe4	349	const struct super_operations zpl_super_operations = {
ab26409d BB	350	.alloc_inode = zpl_inode_alloc,
ab26409d BB	351	.destroy_inode = zpl_inode_destroy,
8780c539	352	.dirty_inode = zpl_dirty_inode,
ab26409d BB	353	.write_inode = NULL,
ab26409d BB	354	.drop_inode = NULL,
2c395def	355	#ifdef HAVE_EVICT_INODE
ab26409d	356	.evict_inode = zpl_evict_inode,
2c395def	357	#else
ab26409d BB	358	.clear_inode = zpl_clear_inode,
ab26409d BB	359	.delete_inode = zpl_inode_delete,
2c395def	360	#endif /* HAVE_EVICT_INODE */
ab26409d	361	.put_super = zpl_put_super,
ab26409d BB	362	.sync_fs = zpl_sync_fs,
	363	.statfs = zpl_statfs,
	364	.remount_fs = zpl_remount_fs,
ebe7e575	365	.umount_begin = zpl_umount_begin,
ab26409d BB	366	.show_options = zpl_show_options,
	367	.show_stats = NULL,
	368	#ifdef HAVE_NR_CACHED_OBJECTS
	369	.nr_cached_objects = zpl_nr_cached_objects,
	370	#endif /* HAVE_NR_CACHED_OBJECTS */
	371	#ifdef HAVE_FREE_CACHED_OBJECTS
	372	.free_cached_objects = zpl_free_cached_objects,
	373	#endif /* HAVE_FREE_CACHED_OBJECTS */
51f0bbe4 BB	374	};
51f0bbe4 BB	375
51f0bbe4	376	struct file_system_type zpl_fs_type = {
ab26409d BB	377	.owner = THIS_MODULE,
ab26409d BB	378	.name = ZFS_DRIVER,
2cf7f52b	379	#ifdef HAVE_MOUNT_NODEV
ab26409d	380	.mount = zpl_mount,
2cf7f52b	381	#else
ab26409d	382	.get_sb = zpl_get_sb,
2cf7f52b	383	#endif /* HAVE_MOUNT_NODEV */
ab26409d	384	.kill_sb = zpl_kill_sb,
51f0bbe4	385	};