2cf7f52bc4
The .get_sb callback has been replaced by a .mount callback in the file_system_type structure. When using the new interface the caller must now use the mount_nodev() helper. Unfortunately, the new interface no longer passes the vfsmount down to the zfs layers. This poses a problem for the existing implementation because we currently save this pointer in the super block for latter use. It provides our only entry point in to the namespace layer for manipulating certain mount options. This needed to be done originally to allow commands like 'zfs set atime=off tank' to work properly. It also allowed me to keep more of the original Solaris code unmodified. Under Solaris there is a 1-to-1 mapping between a mount point and a file system so this is a fairly natural thing to do. However, under Linux they many be multiple entries in the namespace which reference the same filesystem. Thus keeping a back reference from the filesystem to the namespace is complicated. Rather than introduce some ugly hack to get the vfsmount and continue as before. I'm leveraging this API change to update the ZFS code to do things in a more natural way for Linux. This has the upside that is resolves the compatibility issue for the long term and fixes several other minor bugs which have been reported. This commit updates the code to remove this vfsmount back reference entirely. All modifications to filesystem mount options are now passed in to the kernel via a '-o remount'. This is the expected Linux mechanism and allows the namespace to properly handle any options which apply to it before passing them on to the file system itself. Aside from fixing the compatibility issue, removing the vfsmount has had the benefit of simplifying the code. This change which fairly involved has turned out nicely. Closes #246 Closes #217 Closes #187 Closes #248 Closes #231
120 lines
2.7 KiB
C
120 lines
2.7 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 Gunnar Beutner
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*/
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#include <sys/zfs_vnops.h>
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#include <sys/zfs_znode.h>
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#include <sys/zpl.h>
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static int
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zpl_encode_fh(struct dentry *dentry, __u32 *fh, int *max_len, int connectable)
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{
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fid_t *fid = (fid_t *)fh;
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struct inode *ip = dentry->d_inode;
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int len_bytes, rc;
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len_bytes = *max_len * sizeof (__u32);
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if (len_bytes < offsetof(fid_t, fid_data))
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return 255;
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fid->fid_len = len_bytes - offsetof(fid_t, fid_data);
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rc = zfs_fid(ip, fid);
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len_bytes = offsetof(fid_t, fid_data) + fid->fid_len;
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*max_len = roundup(len_bytes, sizeof (__u32)) / sizeof (__u32);
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return (rc == 0 ? FILEID_INO32_GEN : 255);
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}
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static struct dentry *
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zpl_dentry_obtain_alias(struct inode *ip)
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{
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struct dentry *result;
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#ifdef HAVE_D_OBTAIN_ALIAS
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result = d_obtain_alias(ip);
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#else
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result = d_alloc_anon(ip);
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if (result == NULL) {
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iput(ip);
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result = ERR_PTR(-ENOMEM);
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}
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#endif /* HAVE_D_OBTAIN_ALIAS */
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return result;
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}
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static struct dentry *
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zpl_fh_to_dentry(struct super_block *sb, struct fid *fh,
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int fh_len, int fh_type)
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{
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fid_t *fid = (fid_t *)fh;
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struct inode *ip;
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int len_bytes, rc;
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len_bytes = fh_len * sizeof (__u32);
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if (fh_type != FILEID_INO32_GEN ||
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len_bytes < offsetof(fid_t, fid_data) ||
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len_bytes < offsetof(fid_t, fid_data) + fid->fid_len)
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return ERR_PTR(-EINVAL);
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rc = zfs_vget(sb, &ip, fid);
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if (rc != 0)
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return ERR_PTR(-rc);
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ASSERT((ip != NULL) && !IS_ERR(ip));
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return zpl_dentry_obtain_alias(ip);
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}
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static struct dentry *
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zpl_get_parent(struct dentry *child)
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{
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cred_t *cr = CRED();
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struct inode *ip;
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int error;
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crhold(cr);
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error = -zfs_lookup(child->d_inode, "..", &ip, 0, cr, NULL, NULL);
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crfree(cr);
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ASSERT3S(error, <=, 0);
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if (error)
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return ERR_PTR(error);
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return zpl_dentry_obtain_alias(ip);
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}
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const struct export_operations zpl_export_operations = {
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.encode_fh = zpl_encode_fh,
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.fh_to_dentry = zpl_fh_to_dentry,
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.get_parent = zpl_get_parent
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};
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