diff options
Diffstat (limited to 'fs/nfs')
| -rw-r--r-- | fs/nfs/dir.c | 72 |
1 files changed, 54 insertions, 18 deletions
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 7b2230297f6b..dbab3caa15ed 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -1782,6 +1782,8 @@ __nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags, int ret; if (flags & LOOKUP_RCU) { + if (dentry->d_fsdata == NFS_FSDATA_BLOCKED) + return -ECHILD; parent = READ_ONCE(dentry->d_parent); dir = d_inode_rcu(parent); if (!dir) @@ -1790,6 +1792,9 @@ __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_var_event(&dentry->d_fsdata, + dentry->d_fsdata != NFS_FSDATA_BLOCKED); parent = dget_parent(dentry); ret = reval(d_inode(parent), dentry, flags); dput(parent); @@ -2458,7 +2463,6 @@ out: int nfs_unlink(struct inode *dir, struct dentry *dentry) { int error; - int need_rehash = 0; dfprintk(VFS, "NFS: unlink(%s/%lu, %pd)\n", dir->i_sb->s_id, dir->i_ino, dentry); @@ -2473,15 +2477,25 @@ int nfs_unlink(struct inode *dir, struct dentry *dentry) error = nfs_sillyrename(dir, dentry); goto out; } - if (!d_unhashed(dentry)) { - __d_drop(dentry); - need_rehash = 1; - } + /* We must prevent any concurrent open until the unlink + * completes. ->d_revalidate will wait for ->d_fsdata + * to clear. We set it here to ensure no lookup succeeds until + * the unlink is complete on the server. + */ + error = -ETXTBSY; + if (WARN_ON(dentry->d_flags & DCACHE_NFSFS_RENAMED) || + WARN_ON(dentry->d_fsdata == NFS_FSDATA_BLOCKED)) + goto out; + if (dentry->d_fsdata) + /* old devname */ + kfree(dentry->d_fsdata); + dentry->d_fsdata = NFS_FSDATA_BLOCKED; + spin_unlock(&dentry->d_lock); error = nfs_safe_remove(dentry); nfs_dentry_remove_handle_error(dir, dentry, error); - if (need_rehash) - d_rehash(dentry); + dentry->d_fsdata = NULL; + wake_up_var(&dentry->d_fsdata); out: trace_nfs_unlink_exit(dir, dentry, error); return error; @@ -2588,6 +2602,15 @@ nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) } EXPORT_SYMBOL_GPL(nfs_link); +static void +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); +} + /* * RENAME * FIXME: Some nfsds, like the Linux user space nfsd, may generate a @@ -2618,8 +2641,9 @@ int nfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir, { struct inode *old_inode = d_inode(old_dentry); struct inode *new_inode = d_inode(new_dentry); - struct dentry *dentry = NULL, *rehash = NULL; + struct dentry *dentry = NULL; struct rpc_task *task; + bool must_unblock = false; int error = -EBUSY; if (flags) @@ -2637,18 +2661,27 @@ int nfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir, * the new target. */ if (new_inode && !S_ISDIR(new_inode->i_mode)) { - /* - * To prevent any new references to the target during the - * rename, we unhash the dentry in advance. + /* We must prevent any concurrent open until the unlink + * completes. ->d_revalidate will wait for ->d_fsdata + * to clear. We set it here to ensure no lookup succeeds until + * the unlink is complete on the server. */ - if (!d_unhashed(new_dentry)) { - d_drop(new_dentry); - rehash = new_dentry; + error = -ETXTBSY; + 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) { int err; + spin_unlock(&new_dentry->d_lock); + /* copy the target dentry's name */ dentry = d_alloc(new_dentry->d_parent, &new_dentry->d_name); @@ -2661,14 +2694,19 @@ int nfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir, goto out; new_dentry = dentry; - rehash = NULL; new_inode = NULL; + } else { + new_dentry->d_fsdata = NFS_FSDATA_BLOCKED; + must_unblock = true; + spin_unlock(&new_dentry->d_lock); } + } if (S_ISREG(old_inode->i_mode)) nfs_sync_inode(old_inode); - task = nfs_async_rename(old_dir, new_dir, old_dentry, new_dentry, NULL); + task = nfs_async_rename(old_dir, new_dir, old_dentry, new_dentry, + must_unblock ? nfs_unblock_rename : NULL); if (IS_ERR(task)) { error = PTR_ERR(task); goto out; @@ -2692,8 +2730,6 @@ int nfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir, spin_unlock(&old_inode->i_lock); } out: - if (rehash) - d_rehash(rehash); trace_nfs_rename_exit(old_dir, old_dentry, new_dir, new_dentry, error); if (!error) { |