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/*
* 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);
}
/*
* 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);
}
/*
* The Linux VFS automatically handles the following flags:
* MNT_NOSUID, MNT_NODEV, MNT_NOEXEC, MNT_NOATIME, MNT_READONLY
*/
#ifdef HAVE_SHOW_OPTIONS_WITH_DENTRY
static int
zpl_show_options(struct seq_file *seq, struct dentry *root)
{
zfs_sb_t *zsb = root->d_sb->s_fs_info;
seq_printf(seq, ",%s", zsb->z_flags & ZSB_XATTR ? "xattr" : "noxattr");
return (0);
}
#else
static int
zpl_show_options(struct seq_file *seq, struct vfsmount *vfsp)
{
zfs_sb_t *zsb = vfsp->mnt_sb->s_fs_info;
seq_printf(seq, ",%s", zsb->z_flags & ZSB_XATTR ? "xattr" : "noxattr");
return (0);
}
#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_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);
return;
}
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 = NULL,
.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,
#ifdef HAVE_WRITE_SUPER
.write_super = NULL,
#endif
.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,
};
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