2007-10-21 23:42:19 +00:00
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/*
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* Copyright (C) Neil Brown 2002
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* Copyright (C) Christoph Hellwig 2007
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*
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* This file contains the code mapping from inodes to NFS file handles,
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* and for mapping back from file handles to dentries.
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*
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* For details on why we do all the strange and hairy things in here
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2009-10-27 18:41:35 +00:00
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* take a look at Documentation/filesystems/nfs/Exporting.
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2007-10-21 23:42:19 +00:00
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*/
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2007-07-17 11:04:28 +00:00
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#include <linux/exportfs.h>
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2005-04-16 22:20:36 +00:00
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#include <linux/fs.h>
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#include <linux/file.h>
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#include <linux/module.h>
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2007-07-17 11:04:30 +00:00
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#include <linux/mount.h>
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2005-04-16 22:20:36 +00:00
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#include <linux/namei.h>
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2008-11-13 23:39:22 +00:00
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#include <linux/sched.h>
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2005-04-16 22:20:36 +00:00
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2007-07-17 11:04:31 +00:00
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#define dprintk(fmt, args...) do{}while(0)
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2005-04-16 22:20:36 +00:00
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2012-06-26 17:58:53 +00:00
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static int get_name(const struct path *path, char *name, struct dentry *child);
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2007-07-17 11:04:31 +00:00
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2007-10-21 23:42:19 +00:00
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static int exportfs_get_name(struct vfsmount *mnt, struct dentry *dir,
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char *name, struct dentry *child)
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2007-07-17 11:04:31 +00:00
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{
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2007-10-21 23:42:17 +00:00
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const struct export_operations *nop = dir->d_sb->s_export_op;
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2012-06-26 17:58:53 +00:00
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struct path path = {.mnt = mnt, .dentry = dir};
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2007-07-17 11:04:31 +00:00
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if (nop->get_name)
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return nop->get_name(dir, name, child);
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else
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2012-06-26 17:58:53 +00:00
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return get_name(&path, name, child);
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2007-07-17 11:04:31 +00:00
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}
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2005-04-16 22:20:36 +00:00
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2007-07-17 11:04:32 +00:00
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/*
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* Check if the dentry or any of it's aliases is acceptable.
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*/
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2006-01-19 01:43:52 +00:00
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static struct dentry *
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find_acceptable_alias(struct dentry *result,
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int (*acceptable)(void *context, struct dentry *dentry),
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void *context)
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{
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struct dentry *dentry, *toput = NULL;
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2011-01-07 06:50:06 +00:00
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struct inode *inode;
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2006-01-19 01:43:52 +00:00
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2007-07-17 11:04:32 +00:00
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if (acceptable(context, result))
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return result;
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2011-01-07 06:50:06 +00:00
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inode = result->d_inode;
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spin_lock(&inode->i_lock);
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hlist: drop the node parameter from iterators
I'm not sure why, but the hlist for each entry iterators were conceived
list_for_each_entry(pos, head, member)
The hlist ones were greedy and wanted an extra parameter:
hlist_for_each_entry(tpos, pos, head, member)
Why did they need an extra pos parameter? I'm not quite sure. Not only
they don't really need it, it also prevents the iterator from looking
exactly like the list iterator, which is unfortunate.
Besides the semantic patch, there was some manual work required:
- Fix up the actual hlist iterators in linux/list.h
- Fix up the declaration of other iterators based on the hlist ones.
- A very small amount of places were using the 'node' parameter, this
was modified to use 'obj->member' instead.
- Coccinelle didn't handle the hlist_for_each_entry_safe iterator
properly, so those had to be fixed up manually.
The semantic patch which is mostly the work of Peter Senna Tschudin is here:
@@
iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host;
type T;
expression a,c,d,e;
identifier b;
statement S;
@@
-T b;
<+... when != b
(
hlist_for_each_entry(a,
- b,
c, d) S
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hlist_for_each_entry_continue(a,
- b,
c) S
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hlist_for_each_entry_from(a,
- b,
c) S
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hlist_for_each_entry_rcu(a,
- b,
c, d) S
|
hlist_for_each_entry_rcu_bh(a,
- b,
c, d) S
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hlist_for_each_entry_continue_rcu_bh(a,
- b,
c) S
|
for_each_busy_worker(a, c,
- b,
d) S
|
ax25_uid_for_each(a,
- b,
c) S
|
ax25_for_each(a,
- b,
c) S
|
inet_bind_bucket_for_each(a,
- b,
c) S
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sctp_for_each_hentry(a,
- b,
c) S
|
sk_for_each(a,
- b,
c) S
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sk_for_each_rcu(a,
- b,
c) S
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sk_for_each_from
-(a, b)
+(a)
S
+ sk_for_each_from(a) S
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sk_for_each_safe(a,
- b,
c, d) S
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sk_for_each_bound(a,
- b,
c) S
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hlist_for_each_entry_safe(a,
- b,
c, d, e) S
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hlist_for_each_entry_continue_rcu(a,
- b,
c) S
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nr_neigh_for_each(a,
- b,
c) S
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nr_neigh_for_each_safe(a,
- b,
c, d) S
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nr_node_for_each(a,
- b,
c) S
|
nr_node_for_each_safe(a,
- b,
c, d) S
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- for_each_gfn_sp(a, c, d, b) S
+ for_each_gfn_sp(a, c, d) S
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- for_each_gfn_indirect_valid_sp(a, c, d, b) S
+ for_each_gfn_indirect_valid_sp(a, c, d) S
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for_each_host(a,
- b,
c) S
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for_each_host_safe(a,
- b,
c, d) S
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for_each_mesh_entry(a,
- b,
c, d) S
)
...+>
[akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c]
[akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c]
[akpm@linux-foundation.org: checkpatch fixes]
[akpm@linux-foundation.org: fix warnings]
[akpm@linux-foudnation.org: redo intrusive kvm changes]
Tested-by: Peter Senna Tschudin <peter.senna@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-28 01:06:00 +00:00
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hlist_for_each_entry(dentry, &inode->i_dentry, d_alias) {
|
2011-01-07 06:49:43 +00:00
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dget(dentry);
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2011-01-07 06:50:06 +00:00
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spin_unlock(&inode->i_lock);
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2006-01-19 01:43:52 +00:00
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if (toput)
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dput(toput);
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if (dentry != result && acceptable(context, dentry)) {
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dput(result);
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return dentry;
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}
|
2011-01-07 06:50:06 +00:00
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spin_lock(&inode->i_lock);
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2006-01-19 01:43:52 +00:00
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toput = dentry;
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}
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2011-01-07 06:50:06 +00:00
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spin_unlock(&inode->i_lock);
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2006-01-19 01:43:52 +00:00
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if (toput)
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dput(toput);
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return NULL;
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}
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2007-07-17 11:04:32 +00:00
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/*
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* Find root of a disconnected subtree and return a reference to it.
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*/
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static struct dentry *
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find_disconnected_root(struct dentry *dentry)
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{
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dget(dentry);
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2010-10-13 15:56:37 +00:00
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while (!IS_ROOT(dentry)) {
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struct dentry *parent = dget_parent(dentry);
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if (!(parent->d_flags & DCACHE_DISCONNECTED)) {
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dput(parent);
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break;
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}
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2007-07-17 11:04:32 +00:00
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dput(dentry);
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dentry = parent;
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}
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return dentry;
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}
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2007-07-17 11:04:33 +00:00
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/*
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* Make sure target_dir is fully connected to the dentry tree.
|
2005-04-16 22:20:36 +00:00
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*
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2007-07-17 11:04:33 +00:00
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* It may already be, as the flag isn't always updated when connection happens.
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2005-04-16 22:20:36 +00:00
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*/
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2007-07-17 11:04:33 +00:00
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static int
|
2008-08-11 16:39:47 +00:00
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reconnect_path(struct vfsmount *mnt, struct dentry *target_dir, char *nbuf)
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2005-04-16 22:20:36 +00:00
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{
|
2007-07-17 11:04:33 +00:00
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int noprogress = 0;
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int err = -ESTALE;
|
2005-04-16 22:20:36 +00:00
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/*
|
2007-07-17 11:04:33 +00:00
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* It is possible that a confused file system might not let us complete
|
2005-04-16 22:20:36 +00:00
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* the path to the root. For example, if get_parent returns a directory
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* in which we cannot find a name for the child. While this implies a
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* very sick filesystem we don't want it to cause knfsd to spin. Hence
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* the noprogress counter. If we go through the loop 10 times (2 is
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* probably enough) without getting anywhere, we just give up
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*/
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while (target_dir->d_flags & DCACHE_DISCONNECTED && noprogress++ < 10) {
|
2007-07-17 11:04:32 +00:00
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struct dentry *pd = find_disconnected_root(target_dir);
|
2005-04-16 22:20:36 +00:00
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if (!IS_ROOT(pd)) {
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/* must have found a connected parent - great */
|
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|
spin_lock(&pd->d_lock);
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|
pd->d_flags &= ~DCACHE_DISCONNECTED;
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|
spin_unlock(&pd->d_lock);
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|
noprogress = 0;
|
2007-10-21 23:42:19 +00:00
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} else if (pd == mnt->mnt_sb->s_root) {
|
2005-04-16 22:20:36 +00:00
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printk(KERN_ERR "export: Eeek filesystem root is not connected, impossible\n");
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spin_lock(&pd->d_lock);
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pd->d_flags &= ~DCACHE_DISCONNECTED;
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|
spin_unlock(&pd->d_lock);
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noprogress = 0;
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} else {
|
2007-07-17 11:04:31 +00:00
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/*
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* We have hit the top of a disconnected path, try to
|
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* find parent and connect.
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*
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* Racing with some other process renaming a directory
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* isn't much of a problem here. If someone renames
|
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* the directory, it will end up properly connected,
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* which is what we want
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*
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* Getting the parent can't be supported generically,
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* the locking is too icky.
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*
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* Instead we just return EACCES. If server reboots
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* or inodes get flushed, you lose
|
2005-04-16 22:20:36 +00:00
|
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*/
|
2007-07-17 11:04:31 +00:00
|
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struct dentry *ppd = ERR_PTR(-EACCES);
|
2005-04-16 22:20:36 +00:00
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struct dentry *npd;
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|
2006-01-09 23:59:24 +00:00
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mutex_lock(&pd->d_inode->i_mutex);
|
2007-10-21 23:42:19 +00:00
|
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|
if (mnt->mnt_sb->s_export_op->get_parent)
|
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ppd = mnt->mnt_sb->s_export_op->get_parent(pd);
|
2006-01-09 23:59:24 +00:00
|
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mutex_unlock(&pd->d_inode->i_mutex);
|
2005-04-16 22:20:36 +00:00
|
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|
|
|
if (IS_ERR(ppd)) {
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err = PTR_ERR(ppd);
|
2007-07-17 11:04:33 +00:00
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dprintk("%s: get_parent of %ld failed, err %d\n",
|
2008-04-30 07:55:09 +00:00
|
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__func__, pd->d_inode->i_ino, err);
|
2005-04-16 22:20:36 +00:00
|
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|
dput(pd);
|
|
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break;
|
|
|
|
}
|
2007-07-17 11:04:33 +00:00
|
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|
2008-04-30 07:55:09 +00:00
|
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|
dprintk("%s: find name of %lu in %lu\n", __func__,
|
2007-07-17 11:04:33 +00:00
|
|
|
pd->d_inode->i_ino, ppd->d_inode->i_ino);
|
2007-10-21 23:42:19 +00:00
|
|
|
err = exportfs_get_name(mnt, ppd, nbuf, pd);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (err) {
|
|
|
|
dput(ppd);
|
|
|
|
dput(pd);
|
|
|
|
if (err == -ENOENT)
|
|
|
|
/* some race between get_parent and
|
|
|
|
* get_name? just try again
|
|
|
|
*/
|
|
|
|
continue;
|
|
|
|
break;
|
|
|
|
}
|
2008-04-30 07:55:09 +00:00
|
|
|
dprintk("%s: found name: %s\n", __func__, nbuf);
|
2006-01-09 23:59:24 +00:00
|
|
|
mutex_lock(&ppd->d_inode->i_mutex);
|
2005-04-16 22:20:36 +00:00
|
|
|
npd = lookup_one_len(nbuf, ppd, strlen(nbuf));
|
2006-01-09 23:59:24 +00:00
|
|
|
mutex_unlock(&ppd->d_inode->i_mutex);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (IS_ERR(npd)) {
|
|
|
|
err = PTR_ERR(npd);
|
2007-07-17 11:04:33 +00:00
|
|
|
dprintk("%s: lookup failed: %d\n",
|
2008-04-30 07:55:09 +00:00
|
|
|
__func__, err);
|
2005-04-16 22:20:36 +00:00
|
|
|
dput(ppd);
|
|
|
|
dput(pd);
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
/* we didn't really want npd, we really wanted
|
|
|
|
* a side-effect of the lookup.
|
|
|
|
* hopefully, npd == pd, though it isn't really
|
|
|
|
* a problem if it isn't
|
|
|
|
*/
|
|
|
|
if (npd == pd)
|
|
|
|
noprogress = 0;
|
|
|
|
else
|
2008-04-30 07:55:09 +00:00
|
|
|
printk("%s: npd != pd\n", __func__);
|
2005-04-16 22:20:36 +00:00
|
|
|
dput(npd);
|
|
|
|
dput(ppd);
|
|
|
|
if (IS_ROOT(pd)) {
|
|
|
|
/* something went wrong, we have to give up */
|
|
|
|
dput(pd);
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
dput(pd);
|
|
|
|
}
|
|
|
|
|
|
|
|
if (target_dir->d_flags & DCACHE_DISCONNECTED) {
|
|
|
|
/* something went wrong - oh-well */
|
|
|
|
if (!err)
|
|
|
|
err = -ESTALE;
|
2007-07-17 11:04:33 +00:00
|
|
|
return err;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
2007-07-17 11:04:33 +00:00
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
struct getdents_callback {
|
2013-05-15 17:52:59 +00:00
|
|
|
struct dir_context ctx;
|
2005-04-16 22:20:36 +00:00
|
|
|
char *name; /* name that was found. It already points to a
|
|
|
|
buffer NAME_MAX+1 is size */
|
|
|
|
unsigned long ino; /* the inum we are looking for */
|
|
|
|
int found; /* inode matched? */
|
|
|
|
int sequence; /* sequence counter */
|
|
|
|
};
|
|
|
|
|
|
|
|
/*
|
|
|
|
* A rather strange filldir function to capture
|
|
|
|
* the name matching the specified inode number.
|
|
|
|
*/
|
|
|
|
static int filldir_one(void * __buf, const char * name, int len,
|
2006-10-03 08:13:46 +00:00
|
|
|
loff_t pos, u64 ino, unsigned int d_type)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
struct getdents_callback *buf = __buf;
|
|
|
|
int result = 0;
|
|
|
|
|
|
|
|
buf->sequence++;
|
|
|
|
if (buf->ino == ino) {
|
|
|
|
memcpy(buf->name, name, len);
|
|
|
|
buf->name[len] = '\0';
|
|
|
|
buf->found = 1;
|
|
|
|
result = -1;
|
|
|
|
}
|
|
|
|
return result;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* get_name - default export_operations->get_name function
|
|
|
|
* @dentry: the directory in which to find a name
|
|
|
|
* @name: a pointer to a %NAME_MAX+1 char buffer to store the name
|
|
|
|
* @child: the dentry for the child directory.
|
|
|
|
*
|
|
|
|
* calls readdir on the parent until it finds an entry with
|
|
|
|
* the same inode number as the child, and returns that.
|
|
|
|
*/
|
2012-06-26 17:58:53 +00:00
|
|
|
static int get_name(const struct path *path, char *name, struct dentry *child)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2008-11-13 23:39:22 +00:00
|
|
|
const struct cred *cred = current_cred();
|
2012-06-26 17:58:53 +00:00
|
|
|
struct inode *dir = path->dentry->d_inode;
|
2005-04-16 22:20:36 +00:00
|
|
|
int error;
|
|
|
|
struct file *file;
|
|
|
|
struct getdents_callback buffer;
|
|
|
|
|
|
|
|
error = -ENOTDIR;
|
|
|
|
if (!dir || !S_ISDIR(dir->i_mode))
|
|
|
|
goto out;
|
|
|
|
error = -EINVAL;
|
|
|
|
if (!dir->i_fop)
|
|
|
|
goto out;
|
|
|
|
/*
|
|
|
|
* Open the directory ...
|
|
|
|
*/
|
2012-06-26 17:58:53 +00:00
|
|
|
file = dentry_open(path, O_RDONLY, cred);
|
2005-04-16 22:20:36 +00:00
|
|
|
error = PTR_ERR(file);
|
|
|
|
if (IS_ERR(file))
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
error = -EINVAL;
|
2013-05-23 01:44:23 +00:00
|
|
|
if (!file->f_op->iterate)
|
2005-04-16 22:20:36 +00:00
|
|
|
goto out_close;
|
|
|
|
|
|
|
|
buffer.name = name;
|
|
|
|
buffer.ino = child->d_inode->i_ino;
|
|
|
|
buffer.found = 0;
|
|
|
|
buffer.sequence = 0;
|
2013-05-15 17:52:59 +00:00
|
|
|
buffer.ctx.actor = filldir_one;
|
2005-04-16 22:20:36 +00:00
|
|
|
while (1) {
|
|
|
|
int old_seq = buffer.sequence;
|
|
|
|
|
2013-05-15 17:52:59 +00:00
|
|
|
error = iterate_dir(file, &buffer.ctx);
|
2008-08-24 11:29:52 +00:00
|
|
|
if (buffer.found) {
|
|
|
|
error = 0;
|
|
|
|
break;
|
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
if (error < 0)
|
|
|
|
break;
|
|
|
|
|
|
|
|
error = -ENOENT;
|
|
|
|
if (old_seq == buffer.sequence)
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
out_close:
|
|
|
|
fput(file);
|
|
|
|
out:
|
|
|
|
return error;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* export_encode_fh - default export_operations->encode_fh function
|
2012-04-02 18:34:06 +00:00
|
|
|
* @inode: the object to encode
|
2005-04-16 22:20:36 +00:00
|
|
|
* @fh: where to store the file handle fragment
|
|
|
|
* @max_len: maximum length to store there
|
2012-04-02 18:34:06 +00:00
|
|
|
* @parent: parent directory inode, if wanted
|
2005-04-16 22:20:36 +00:00
|
|
|
*
|
|
|
|
* This default encode_fh function assumes that the 32 inode number
|
|
|
|
* is suitable for locating an inode, and that the generation number
|
|
|
|
* can be used to check that it is still valid. It places them in the
|
|
|
|
* filehandle fragment where export_decode_fh expects to find them.
|
|
|
|
*/
|
2012-04-02 18:34:06 +00:00
|
|
|
static int export_encode_fh(struct inode *inode, struct fid *fid,
|
|
|
|
int *max_len, struct inode *parent)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
int len = *max_len;
|
2007-10-21 23:42:03 +00:00
|
|
|
int type = FILEID_INO32_GEN;
|
2011-01-29 13:13:25 +00:00
|
|
|
|
2012-04-02 18:34:06 +00:00
|
|
|
if (parent && (len < 4)) {
|
2011-01-29 13:13:25 +00:00
|
|
|
*max_len = 4;
|
2012-08-29 14:10:10 +00:00
|
|
|
return FILEID_INVALID;
|
2011-01-29 13:13:25 +00:00
|
|
|
} else if (len < 2) {
|
|
|
|
*max_len = 2;
|
2012-08-29 14:10:10 +00:00
|
|
|
return FILEID_INVALID;
|
2011-01-29 13:13:25 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
len = 2;
|
2007-10-21 23:42:03 +00:00
|
|
|
fid->i32.ino = inode->i_ino;
|
|
|
|
fid->i32.gen = inode->i_generation;
|
2012-04-02 18:34:06 +00:00
|
|
|
if (parent) {
|
2007-10-21 23:42:03 +00:00
|
|
|
fid->i32.parent_ino = parent->i_ino;
|
|
|
|
fid->i32.parent_gen = parent->i_generation;
|
2005-04-16 22:20:36 +00:00
|
|
|
len = 4;
|
2007-10-21 23:42:03 +00:00
|
|
|
type = FILEID_INO32_GEN_PARENT;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
*max_len = len;
|
|
|
|
return type;
|
|
|
|
}
|
|
|
|
|
2012-12-18 00:05:08 +00:00
|
|
|
int exportfs_encode_inode_fh(struct inode *inode, struct fid *fid,
|
|
|
|
int *max_len, struct inode *parent)
|
|
|
|
{
|
|
|
|
const struct export_operations *nop = inode->i_sb->s_export_op;
|
|
|
|
|
|
|
|
if (nop && nop->encode_fh)
|
|
|
|
return nop->encode_fh(inode, fid->raw, max_len, parent);
|
|
|
|
|
|
|
|
return export_encode_fh(inode, fid, max_len, parent);
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(exportfs_encode_inode_fh);
|
|
|
|
|
2007-10-21 23:42:03 +00:00
|
|
|
int exportfs_encode_fh(struct dentry *dentry, struct fid *fid, int *max_len,
|
2007-07-17 11:04:30 +00:00
|
|
|
int connectable)
|
|
|
|
{
|
2007-07-17 11:04:31 +00:00
|
|
|
int error;
|
2012-04-02 18:34:06 +00:00
|
|
|
struct dentry *p = NULL;
|
|
|
|
struct inode *inode = dentry->d_inode, *parent = NULL;
|
2007-07-17 11:04:30 +00:00
|
|
|
|
2012-04-02 18:34:06 +00:00
|
|
|
if (connectable && !S_ISDIR(inode->i_mode)) {
|
|
|
|
p = dget_parent(dentry);
|
|
|
|
/*
|
|
|
|
* note that while p might've ceased to be our parent already,
|
|
|
|
* it's still pinned by and still positive.
|
|
|
|
*/
|
|
|
|
parent = p->d_inode;
|
|
|
|
}
|
2012-12-18 00:05:08 +00:00
|
|
|
|
|
|
|
error = exportfs_encode_inode_fh(inode, fid, max_len, parent);
|
2012-04-02 18:34:06 +00:00
|
|
|
dput(p);
|
2007-07-17 11:04:31 +00:00
|
|
|
|
|
|
|
return error;
|
2007-07-17 11:04:30 +00:00
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(exportfs_encode_fh);
|
|
|
|
|
2007-10-21 23:42:03 +00:00
|
|
|
struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
|
|
|
|
int fh_len, int fileid_type,
|
|
|
|
int (*acceptable)(void *, struct dentry *), void *context)
|
2007-07-17 11:04:30 +00:00
|
|
|
{
|
2007-10-21 23:42:17 +00:00
|
|
|
const struct export_operations *nop = mnt->mnt_sb->s_export_op;
|
2007-10-21 23:42:05 +00:00
|
|
|
struct dentry *result, *alias;
|
2008-08-11 16:39:47 +00:00
|
|
|
char nbuf[NAME_MAX+1];
|
2007-10-21 23:42:05 +00:00
|
|
|
int err;
|
2007-07-17 11:04:30 +00:00
|
|
|
|
2007-10-21 23:42:05 +00:00
|
|
|
/*
|
|
|
|
* Try to get any dentry for the given file handle from the filesystem.
|
|
|
|
*/
|
2011-01-29 13:13:26 +00:00
|
|
|
if (!nop || !nop->fh_to_dentry)
|
|
|
|
return ERR_PTR(-ESTALE);
|
2007-10-21 23:42:05 +00:00
|
|
|
result = nop->fh_to_dentry(mnt->mnt_sb, fid, fh_len, fileid_type);
|
2008-12-08 23:24:18 +00:00
|
|
|
if (!result)
|
|
|
|
result = ERR_PTR(-ESTALE);
|
2007-10-21 23:42:05 +00:00
|
|
|
if (IS_ERR(result))
|
|
|
|
return result;
|
|
|
|
|
|
|
|
if (S_ISDIR(result->d_inode->i_mode)) {
|
|
|
|
/*
|
|
|
|
* This request is for a directory.
|
|
|
|
*
|
|
|
|
* On the positive side there is only one dentry for each
|
|
|
|
* directory inode. On the negative side this implies that we
|
|
|
|
* to ensure our dentry is connected all the way up to the
|
|
|
|
* filesystem root.
|
|
|
|
*/
|
|
|
|
if (result->d_flags & DCACHE_DISCONNECTED) {
|
2008-08-11 16:39:47 +00:00
|
|
|
err = reconnect_path(mnt, result, nbuf);
|
2007-10-21 23:42:05 +00:00
|
|
|
if (err)
|
|
|
|
goto err_result;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (!acceptable(context, result)) {
|
|
|
|
err = -EACCES;
|
|
|
|
goto err_result;
|
|
|
|
}
|
|
|
|
|
|
|
|
return result;
|
2007-07-17 11:04:31 +00:00
|
|
|
} else {
|
2007-10-21 23:42:05 +00:00
|
|
|
/*
|
|
|
|
* It's not a directory. Life is a little more complicated.
|
|
|
|
*/
|
|
|
|
struct dentry *target_dir, *nresult;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* See if either the dentry we just got from the filesystem
|
|
|
|
* or any alias for it is acceptable. This is always true
|
|
|
|
* if this filesystem is exported without the subtreecheck
|
|
|
|
* option. If the filesystem is exported with the subtree
|
|
|
|
* check option there's a fair chance we need to look at
|
|
|
|
* the parent directory in the file handle and make sure
|
|
|
|
* it's connected to the filesystem root.
|
|
|
|
*/
|
|
|
|
alias = find_acceptable_alias(result, acceptable, context);
|
|
|
|
if (alias)
|
|
|
|
return alias;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Try to extract a dentry for the parent directory from the
|
|
|
|
* file handle. If this fails we'll have to give up.
|
|
|
|
*/
|
|
|
|
err = -ESTALE;
|
|
|
|
if (!nop->fh_to_parent)
|
|
|
|
goto err_result;
|
|
|
|
|
|
|
|
target_dir = nop->fh_to_parent(mnt->mnt_sb, fid,
|
|
|
|
fh_len, fileid_type);
|
2008-12-08 23:24:18 +00:00
|
|
|
if (!target_dir)
|
|
|
|
goto err_result;
|
2007-10-21 23:42:05 +00:00
|
|
|
err = PTR_ERR(target_dir);
|
|
|
|
if (IS_ERR(target_dir))
|
|
|
|
goto err_result;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* And as usual we need to make sure the parent directory is
|
|
|
|
* connected to the filesystem root. The VFS really doesn't
|
|
|
|
* like disconnected directories..
|
|
|
|
*/
|
2008-08-11 16:39:47 +00:00
|
|
|
err = reconnect_path(mnt, target_dir, nbuf);
|
2007-10-21 23:42:05 +00:00
|
|
|
if (err) {
|
|
|
|
dput(target_dir);
|
|
|
|
goto err_result;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Now that we've got both a well-connected parent and a
|
|
|
|
* dentry for the inode we're after, make sure that our
|
|
|
|
* inode is actually connected to the parent.
|
|
|
|
*/
|
2007-10-21 23:42:19 +00:00
|
|
|
err = exportfs_get_name(mnt, target_dir, nbuf, result);
|
2007-10-21 23:42:05 +00:00
|
|
|
if (!err) {
|
|
|
|
mutex_lock(&target_dir->d_inode->i_mutex);
|
|
|
|
nresult = lookup_one_len(nbuf, target_dir,
|
|
|
|
strlen(nbuf));
|
|
|
|
mutex_unlock(&target_dir->d_inode->i_mutex);
|
|
|
|
if (!IS_ERR(nresult)) {
|
|
|
|
if (nresult->d_inode) {
|
|
|
|
dput(result);
|
|
|
|
result = nresult;
|
|
|
|
} else
|
|
|
|
dput(nresult);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* At this point we are done with the parent, but it's pinned
|
|
|
|
* by the child dentry anyway.
|
|
|
|
*/
|
|
|
|
dput(target_dir);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* And finally make sure the dentry is actually acceptable
|
|
|
|
* to NFSD.
|
|
|
|
*/
|
|
|
|
alias = find_acceptable_alias(result, acceptable, context);
|
|
|
|
if (!alias) {
|
|
|
|
err = -EACCES;
|
|
|
|
goto err_result;
|
|
|
|
}
|
|
|
|
|
|
|
|
return alias;
|
2007-07-17 11:04:31 +00:00
|
|
|
}
|
|
|
|
|
2007-10-21 23:42:05 +00:00
|
|
|
err_result:
|
|
|
|
dput(result);
|
|
|
|
return ERR_PTR(err);
|
2007-07-17 11:04:30 +00:00
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(exportfs_decode_fh);
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
MODULE_LICENSE("GPL");
|