ebe7e575ea
Add support for the .zfs control directory. This was accomplished
by leveraging as much of the existing ZFS infrastructure as posible
and updating it for Linux as required. The bulk of the core
functionality is now all there with the following limitations.
*) The .zfs/snapshot directory automount support requires a 2.6.37
or newer kernel. The exception is RHEL6.2 which has backported
the d_automount patches.
*) Creating/destroying/renaming snapshots with mkdir/rmdir/mv
in the .zfs/snapshot directory works as expected. However,
this functionality is only available to root until zfs
delegations are finished.
* mkdir - create a snapshot
* rmdir - destroy a snapshot
* mv - rename a snapshot
The following issues are known defeciences, but we expect them to
be addressed by future commits.
*) Add automount support for kernels older the 2.6.37. This should
be possible using follow_link() which is what Linux did before.
*) Accessing the .zfs/snapshot directory via NFS is not yet possible.
The majority of the ground work for this is complete. However,
finishing this work will require resolving some lingering
integration issues with the Linux NFS kernel server.
*) The .zfs/shares directory exists but no futher smb functionality
has yet been implemented.
Contributions-by: Rohan Puri <rohan.puri15@gmail.com>
Contributiobs-by: Andrew Barnes <barnes333@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #173
339 lines
8.2 KiB
C
339 lines
8.2 KiB
C
/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License (the "License").
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* You may not use this file except in compliance with the License.
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*
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* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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* or http://www.opensolaris.org/os/licensing.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information: Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*/
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/*
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* Copyright (c) 2011, Lawrence Livermore National Security, LLC.
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*/
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#include <sys/zfs_vfsops.h>
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#include <sys/zfs_vnops.h>
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#include <sys/zfs_znode.h>
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#include <sys/zfs_ctldir.h>
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#include <sys/zpl.h>
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static struct inode *
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zpl_inode_alloc(struct super_block *sb)
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{
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struct inode *ip;
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VERIFY3S(zfs_inode_alloc(sb, &ip), ==, 0);
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ip->i_version = 1;
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return (ip);
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}
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static void
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zpl_inode_destroy(struct inode *ip)
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{
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ASSERT(atomic_read(&ip->i_count) == 0);
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zfs_inode_destroy(ip);
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}
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/*
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* When ->drop_inode() is called its return value indicates if the
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* inode should be evicted from the inode cache. If the inode is
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* unhashed and has no links the default policy is to evict it
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* immediately.
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*
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* Prior to 2.6.36 this eviction was accomplished by the vfs calling
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* ->delete_inode(). It was ->delete_inode()'s responsibility to
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* truncate the inode pages and call clear_inode(). The call to
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* clear_inode() synchronously invalidates all the buffers and
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* calls ->clear_inode(). It was ->clear_inode()'s responsibility
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* to cleanup and filesystem specific data before freeing the inode.
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*
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* This elaborate mechanism was replaced by ->evict_inode() which
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* does the job of both ->delete_inode() and ->clear_inode(). It
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* will be called exactly once, and when it returns the inode must
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* be in a state where it can simply be freed. The ->evict_inode()
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* callback must minimally truncate the inode pages, and call
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* end_writeback() to complete all outstanding writeback for the
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* inode. After this is complete evict inode can cleanup any
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* remaining filesystem specific data.
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*/
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#ifdef HAVE_EVICT_INODE
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static void
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zpl_evict_inode(struct inode *ip)
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{
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truncate_setsize(ip, 0);
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end_writeback(ip);
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zfs_inactive(ip);
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}
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#else
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static void
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zpl_clear_inode(struct inode *ip)
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{
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zfs_inactive(ip);
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}
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static void
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zpl_inode_delete(struct inode *ip)
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{
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truncate_setsize(ip, 0);
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clear_inode(ip);
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}
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#endif /* HAVE_EVICT_INODE */
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static void
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zpl_put_super(struct super_block *sb)
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{
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int error;
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error = -zfs_umount(sb);
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ASSERT3S(error, <=, 0);
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}
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static int
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zpl_sync_fs(struct super_block *sb, int wait)
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{
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cred_t *cr = CRED();
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int error;
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crhold(cr);
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error = -zfs_sync(sb, wait, cr);
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crfree(cr);
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ASSERT3S(error, <=, 0);
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return (error);
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}
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static int
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zpl_statfs(struct dentry *dentry, struct kstatfs *statp)
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{
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int error;
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error = -zfs_statvfs(dentry, statp);
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ASSERT3S(error, <=, 0);
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return (error);
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}
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static int
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zpl_remount_fs(struct super_block *sb, int *flags, char *data)
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{
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int error;
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error = -zfs_remount(sb, flags, data);
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ASSERT3S(error, <=, 0);
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return (error);
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}
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static void
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zpl_umount_begin(struct super_block *sb)
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{
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zfs_sb_t *zsb = sb->s_fs_info;
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int count;
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/*
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* Best effort to unmount snapshots in .zfs/snapshot/. Normally this
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* isn't required because snapshots have the MNT_SHRINKABLE flag set.
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*/
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if (zsb->z_ctldir)
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(void) zfsctl_unmount_snapshots(zsb, MNT_FORCE, &count);
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}
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/*
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* The Linux VFS automatically handles the following flags:
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* MNT_NOSUID, MNT_NODEV, MNT_NOEXEC, MNT_NOATIME, MNT_READONLY
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*/
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#ifdef HAVE_SHOW_OPTIONS_WITH_DENTRY
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static int
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zpl_show_options(struct seq_file *seq, struct dentry *root)
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{
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zfs_sb_t *zsb = root->d_sb->s_fs_info;
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seq_printf(seq, ",%s", zsb->z_flags & ZSB_XATTR ? "xattr" : "noxattr");
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return (0);
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}
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#else
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static int
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zpl_show_options(struct seq_file *seq, struct vfsmount *vfsp)
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{
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zfs_sb_t *zsb = vfsp->mnt_sb->s_fs_info;
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seq_printf(seq, ",%s", zsb->z_flags & ZSB_XATTR ? "xattr" : "noxattr");
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return (0);
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}
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#endif /* HAVE_SHOW_OPTIONS_WITH_DENTRY */
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static int
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zpl_fill_super(struct super_block *sb, void *data, int silent)
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{
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int error;
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error = -zfs_domount(sb, data, silent);
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ASSERT3S(error, <=, 0);
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return (error);
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}
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#ifdef HAVE_MOUNT_NODEV
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static struct dentry *
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zpl_mount(struct file_system_type *fs_type, int flags,
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const char *osname, void *data)
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{
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zpl_mount_data_t zmd = { osname, data };
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return mount_nodev(fs_type, flags, &zmd, zpl_fill_super);
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}
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#else
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static int
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zpl_get_sb(struct file_system_type *fs_type, int flags,
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const char *osname, void *data, struct vfsmount *mnt)
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{
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zpl_mount_data_t zmd = { osname, data };
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return get_sb_nodev(fs_type, flags, &zmd, zpl_fill_super, mnt);
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}
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#endif /* HAVE_MOUNT_NODEV */
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static void
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zpl_kill_sb(struct super_block *sb)
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{
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zfs_preumount(sb);
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kill_anon_super(sb);
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}
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#ifdef HAVE_SHRINK
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/*
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* Linux 3.1 - 3.x API
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*
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* The Linux 3.1 API introduced per-sb cache shrinkers to replace the
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* global ones. This allows us a mechanism to cleanly target a specific
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* zfs file system when the dnode and inode caches grow too large.
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*
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* In addition, the 3.0 kernel added the iterate_supers_type() helper
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* function which is used to safely walk all of the zfs file systems.
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*/
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static void
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zpl_prune_sb(struct super_block *sb, void *arg)
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{
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int objects = 0;
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int error;
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error = -zfs_sb_prune(sb, *(unsigned long *)arg, &objects);
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ASSERT3S(error, <=, 0);
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return;
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}
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void
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zpl_prune_sbs(int64_t bytes_to_scan, void *private)
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{
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unsigned long nr_to_scan = (bytes_to_scan / sizeof(znode_t));
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iterate_supers_type(&zpl_fs_type, zpl_prune_sb, &nr_to_scan);
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kmem_reap();
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}
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#else
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/*
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* Linux 2.6.x - 3.0 API
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*
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* These are best effort interfaces are provided by the SPL to induce
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* the Linux VM subsystem to reclaim a fraction of the both dnode and
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* inode caches. Ideally, we want to just target the zfs file systems
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* however our only option is to reclaim from them all.
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*/
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void
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zpl_prune_sbs(int64_t bytes_to_scan, void *private)
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{
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unsigned long nr_to_scan = (bytes_to_scan / sizeof(znode_t));
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shrink_dcache_memory(nr_to_scan, GFP_KERNEL);
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shrink_icache_memory(nr_to_scan, GFP_KERNEL);
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kmem_reap();
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}
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#endif /* HAVE_SHRINK */
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#ifdef HAVE_NR_CACHED_OBJECTS
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static int
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zpl_nr_cached_objects(struct super_block *sb)
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{
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zfs_sb_t *zsb = sb->s_fs_info;
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int nr;
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mutex_enter(&zsb->z_znodes_lock);
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nr = zsb->z_nr_znodes;
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mutex_exit(&zsb->z_znodes_lock);
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return (nr);
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}
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#endif /* HAVE_NR_CACHED_OBJECTS */
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#ifdef HAVE_FREE_CACHED_OBJECTS
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/*
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* Attempt to evict some meta data from the cache. The ARC operates in
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* terms of bytes while the Linux VFS uses objects. Now because this is
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* just a best effort eviction and the exact values aren't critical so we
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* extrapolate from an object count to a byte size using the znode_t size.
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*/
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static void
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zpl_free_cached_objects(struct super_block *sb, int nr_to_scan)
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{
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arc_adjust_meta(nr_to_scan * sizeof(znode_t), B_FALSE);
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}
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#endif /* HAVE_FREE_CACHED_OBJECTS */
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const struct super_operations zpl_super_operations = {
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.alloc_inode = zpl_inode_alloc,
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.destroy_inode = zpl_inode_destroy,
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.dirty_inode = NULL,
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.write_inode = NULL,
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.drop_inode = NULL,
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#ifdef HAVE_EVICT_INODE
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.evict_inode = zpl_evict_inode,
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#else
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.clear_inode = zpl_clear_inode,
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.delete_inode = zpl_inode_delete,
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#endif /* HAVE_EVICT_INODE */
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.put_super = zpl_put_super,
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.write_super = NULL,
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.sync_fs = zpl_sync_fs,
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.statfs = zpl_statfs,
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.remount_fs = zpl_remount_fs,
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.umount_begin = zpl_umount_begin,
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.show_options = zpl_show_options,
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.show_stats = NULL,
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#ifdef HAVE_NR_CACHED_OBJECTS
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.nr_cached_objects = zpl_nr_cached_objects,
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#endif /* HAVE_NR_CACHED_OBJECTS */
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#ifdef HAVE_FREE_CACHED_OBJECTS
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.free_cached_objects = zpl_free_cached_objects,
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#endif /* HAVE_FREE_CACHED_OBJECTS */
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};
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struct file_system_type zpl_fs_type = {
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.owner = THIS_MODULE,
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.name = ZFS_DRIVER,
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#ifdef HAVE_MOUNT_NODEV
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.mount = zpl_mount,
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#else
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.get_sb = zpl_get_sb,
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#endif /* HAVE_MOUNT_NODEV */
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.kill_sb = zpl_kill_sb,
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};
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