An interrupted rename will leave the old dentry behind if the rename
succeeds. Fix this by forcing a lookup the next time through
->d_revalidate.
A previous attempt at solving this problem took the approach to complete
the work of the rename asynchronously, however that approach was wrong
since it would allow the d_move() to occur after the directory's i_mutex
had been dropped by the original process.
v2: Add memory barrier, hold directory i_locks while revalidating, specify
single-bit field width for cancelled flag.
Signed-off-by: Benjamin Coddington <bcodding@xxxxxxxxxx>
---
fs/nfs/dir.c | 5 ++++-
fs/nfs/unlink.c | 11 +++++++++++
include/linux/nfs_xdr.h | 1 +
3 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 1faf337b316f..94b05d0eec06 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -2035,7 +2035,10 @@ int nfs_rename(struct inode *old_dir, struct dentry *old_dentry,
}
error = rpc_wait_for_completion_task(task);
- if (error == 0)
+ if (error != 0) {
+ ((struct nfs_renamedata *)task->tk_calldata)->cancelled = 1;
+ smp_wmb();
+ } else
error = task->tk_status;
rpc_put_task(task);
nfs_mark_for_revalidate(old_inode);
diff --git a/fs/nfs/unlink.c b/fs/nfs/unlink.c
index 191aa577dd1f..28628dde38b9 100644
--- a/fs/nfs/unlink.c
+++ b/fs/nfs/unlink.c
@@ -288,6 +288,17 @@ static void nfs_async_rename_release(void *calldata)
if (d_really_is_positive(data->old_dentry))
nfs_mark_for_revalidate(d_inode(data->old_dentry));
+ /* The result of the rename is unknown. Play it safe by
+ * forcing a new lookup */
+ if (data->cancelled) {
+ spin_lock(&data->old_dir->i_lock);
+ nfs_force_lookup_revalidate(data->old_dir);
+ spin_unlock(&data->old_dir->i_lock);
+ spin_lock(&data->new_dir->i_lock);
+ nfs_force_lookup_revalidate(data->new_dir);
+ spin_unlock(&data->new_dir->i_lock);
+ }
+
dput(data->old_dentry);
dput(data->new_dentry);
iput(data->old_dir);
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index b28c83475ee8..0c32443d29a7 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -1533,6 +1533,7 @@ struct nfs_renamedata {
struct nfs_fattr new_fattr;
void (*complete)(struct rpc_task *, struct nfs_renamedata *);
long timeout;
+ unsigned int cancelled : 1;
};
struct nfs_access_entry;
--
2.9.3
--
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