diff options
| -rw-r--r-- | fs/nfs/dir.c | 47 |
1 files changed, 32 insertions, 15 deletions
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 2b68a14982c8..07a7be27182e 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -1803,9 +1803,10 @@ __nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags, if (parent != READ_ONCE(dentry->d_parent)) return -ECHILD; } else { - /* Wait for unlink to complete */ + /* Wait for unlink to complete - see unblock_revalidate() */ wait_var_event(&dentry->d_fsdata, - dentry->d_fsdata != NFS_FSDATA_BLOCKED); + smp_load_acquire(&dentry->d_fsdata) + != NFS_FSDATA_BLOCKED); parent = dget_parent(dentry); ret = reval(d_inode(parent), dentry, flags); dput(parent); @@ -1818,6 +1819,29 @@ static int nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags) return __nfs_lookup_revalidate(dentry, flags, nfs_do_lookup_revalidate); } +static void block_revalidate(struct dentry *dentry) +{ + /* old devname - just in case */ + kfree(dentry->d_fsdata); + + /* Any new reference that could lead to an open + * will take ->d_lock in lookup_open() -> d_lookup(). + * Holding this lock ensures we cannot race with + * __nfs_lookup_revalidate() and removes and need + * for further barriers. + */ + lockdep_assert_held(&dentry->d_lock); + + dentry->d_fsdata = NFS_FSDATA_BLOCKED; +} + +static void unblock_revalidate(struct dentry *dentry) +{ + /* store_release ensures wait_var_event() sees the update */ + smp_store_release(&dentry->d_fsdata, NULL); + wake_up_var(&dentry->d_fsdata); +} + /* * A weaker form of d_revalidate for revalidating just the d_inode(dentry) * when we don't really care about the dentry name. This is called when a @@ -2551,15 +2575,12 @@ int nfs_unlink(struct inode *dir, struct dentry *dentry) spin_unlock(&dentry->d_lock); goto out; } - /* old devname */ - kfree(dentry->d_fsdata); - dentry->d_fsdata = NFS_FSDATA_BLOCKED; + block_revalidate(dentry); spin_unlock(&dentry->d_lock); error = nfs_safe_remove(dentry); nfs_dentry_remove_handle_error(dir, dentry, error); - dentry->d_fsdata = NULL; - wake_up_var(&dentry->d_fsdata); + unblock_revalidate(dentry); out: trace_nfs_unlink_exit(dir, dentry, error); return error; @@ -2666,8 +2687,7 @@ nfs_unblock_rename(struct rpc_task *task, struct nfs_renamedata *data) { struct dentry *new_dentry = data->new_dentry; - new_dentry->d_fsdata = NULL; - wake_up_var(&new_dentry->d_fsdata); + unblock_revalidate(new_dentry); } /* @@ -2729,11 +2749,6 @@ int nfs_rename(struct mnt_idmap *idmap, struct inode *old_dir, if (WARN_ON(new_dentry->d_flags & DCACHE_NFSFS_RENAMED) || WARN_ON(new_dentry->d_fsdata == NFS_FSDATA_BLOCKED)) goto out; - if (new_dentry->d_fsdata) { - /* old devname */ - kfree(new_dentry->d_fsdata); - new_dentry->d_fsdata = NULL; - } spin_lock(&new_dentry->d_lock); if (d_count(new_dentry) > 2) { @@ -2755,7 +2770,7 @@ int nfs_rename(struct mnt_idmap *idmap, struct inode *old_dir, new_dentry = dentry; new_inode = NULL; } else { - new_dentry->d_fsdata = NFS_FSDATA_BLOCKED; + block_revalidate(new_dentry); must_unblock = true; spin_unlock(&new_dentry->d_lock); } @@ -2767,6 +2782,8 @@ int nfs_rename(struct mnt_idmap *idmap, struct inode *old_dir, task = nfs_async_rename(old_dir, new_dir, old_dentry, new_dentry, must_unblock ? nfs_unblock_rename : NULL); if (IS_ERR(task)) { + if (must_unblock) + unblock_revalidate(new_dentry); error = PTR_ERR(task); goto out; } |