dba1d70566
The iterate_supers_type() function which was introduced in the 3.0 kernel was supposed to provide a safe way to call an arbitrary function on all super blocks of a specific type. Unfortunately, because a list_head was used a bug was introduced which made it possible for iterate_supers_type() to get stuck spinning on a super block which was just deactivated. This can occur because when the list head is removed from the fs_supers list it is reinitialized to point to itself. If the iterate_supers_type() function happened to be processing the removed list_head it will get stuck spinning on that list_head. The bug was fixed in the 3.3 kernel by converting the list_head to an hlist_node. However, to resolve the issue for existing 3.0 - 3.2 kernels we detect when a list_head is used. Then to prevent the spinning from occurring the .next pointer is set to the fs_supers list_head which ensures the iterate_supers_type() function will always terminate. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #1045 Closes #861 Closes #790
366 lines
9.0 KiB
C
366 lines
9.0 KiB
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);
|
|
}
|
|
|
|
/*
|
|
* 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_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);
|
|
|
|
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 = 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,
|
|
};
|