diff options
Diffstat (limited to '')
-rw-r--r-- | fs/afs/dir_silly.c | 282 |
1 files changed, 282 insertions, 0 deletions
diff --git a/fs/afs/dir_silly.c b/fs/afs/dir_silly.c new file mode 100644 index 000000000..bb5807e87 --- /dev/null +++ b/fs/afs/dir_silly.c @@ -0,0 +1,282 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* AFS silly rename handling + * + * Copyright (C) 2019 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * - Derived from NFS's sillyrename. + */ + +#include <linux/kernel.h> +#include <linux/fs.h> +#include <linux/namei.h> +#include <linux/fsnotify.h> +#include "internal.h" + +static void afs_silly_rename_success(struct afs_operation *op) +{ + _enter("op=%08x", op->debug_id); + + afs_check_dir_conflict(op, &op->file[0]); + afs_vnode_commit_status(op, &op->file[0]); +} + +static void afs_silly_rename_edit_dir(struct afs_operation *op) +{ + struct afs_vnode_param *dvp = &op->file[0]; + struct afs_vnode *dvnode = dvp->vnode; + struct afs_vnode *vnode = AFS_FS_I(d_inode(op->dentry)); + struct dentry *old = op->dentry; + struct dentry *new = op->dentry_2; + + spin_lock(&old->d_lock); + old->d_flags |= DCACHE_NFSFS_RENAMED; + spin_unlock(&old->d_lock); + if (dvnode->silly_key != op->key) { + key_put(dvnode->silly_key); + dvnode->silly_key = key_get(op->key); + } + + down_write(&dvnode->validate_lock); + if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags) && + dvnode->status.data_version == dvp->dv_before + dvp->dv_delta) { + afs_edit_dir_remove(dvnode, &old->d_name, + afs_edit_dir_for_silly_0); + afs_edit_dir_add(dvnode, &new->d_name, + &vnode->fid, afs_edit_dir_for_silly_1); + } + up_write(&dvnode->validate_lock); +} + +static const struct afs_operation_ops afs_silly_rename_operation = { + .issue_afs_rpc = afs_fs_rename, + .issue_yfs_rpc = yfs_fs_rename, + .success = afs_silly_rename_success, + .edit_dir = afs_silly_rename_edit_dir, +}; + +/* + * Actually perform the silly rename step. + */ +static int afs_do_silly_rename(struct afs_vnode *dvnode, struct afs_vnode *vnode, + struct dentry *old, struct dentry *new, + struct key *key) +{ + struct afs_operation *op; + + _enter("%pd,%pd", old, new); + + op = afs_alloc_operation(key, dvnode->volume); + if (IS_ERR(op)) + return PTR_ERR(op); + + afs_op_set_vnode(op, 0, dvnode); + afs_op_set_vnode(op, 1, dvnode); + op->file[0].dv_delta = 1; + op->file[1].dv_delta = 1; + op->file[0].modification = true; + op->file[1].modification = true; + op->file[0].update_ctime = true; + op->file[1].update_ctime = true; + + op->dentry = old; + op->dentry_2 = new; + op->ops = &afs_silly_rename_operation; + + trace_afs_silly_rename(vnode, false); + return afs_do_sync_operation(op); +} + +/* + * Perform silly-rename of a dentry. + * + * AFS is stateless and the server doesn't know when the client is holding a + * file open. To prevent application problems when a file is unlinked while + * it's still open, the client performs a "silly-rename". That is, it renames + * the file to a hidden file in the same directory, and only performs the + * unlink once the last reference to it is put. + * + * The final cleanup is done during dentry_iput. + */ +int afs_sillyrename(struct afs_vnode *dvnode, struct afs_vnode *vnode, + struct dentry *dentry, struct key *key) +{ + static unsigned int sillycounter; + struct dentry *sdentry = NULL; + unsigned char silly[16]; + int ret = -EBUSY; + + _enter(""); + + /* We don't allow a dentry to be silly-renamed twice. */ + if (dentry->d_flags & DCACHE_NFSFS_RENAMED) + return -EBUSY; + + sdentry = NULL; + do { + int slen; + + dput(sdentry); + sillycounter++; + + /* Create a silly name. Note that the ".__afs" prefix is + * understood by the salvager and must not be changed. + */ + slen = scnprintf(silly, sizeof(silly), ".__afs%04X", sillycounter); + sdentry = lookup_one_len(silly, dentry->d_parent, slen); + + /* N.B. Better to return EBUSY here ... it could be dangerous + * to delete the file while it's in use. + */ + if (IS_ERR(sdentry)) + goto out; + } while (!d_is_negative(sdentry)); + + ihold(&vnode->netfs.inode); + + ret = afs_do_silly_rename(dvnode, vnode, dentry, sdentry, key); + switch (ret) { + case 0: + /* The rename succeeded. */ + set_bit(AFS_VNODE_SILLY_DELETED, &vnode->flags); + d_move(dentry, sdentry); + break; + case -ERESTARTSYS: + /* The result of the rename is unknown. Play it safe by forcing + * a new lookup. + */ + d_drop(dentry); + d_drop(sdentry); + } + + iput(&vnode->netfs.inode); + dput(sdentry); +out: + _leave(" = %d", ret); + return ret; +} + +static void afs_silly_unlink_success(struct afs_operation *op) +{ + _enter("op=%08x", op->debug_id); + afs_check_dir_conflict(op, &op->file[0]); + afs_vnode_commit_status(op, &op->file[0]); + afs_vnode_commit_status(op, &op->file[1]); + afs_update_dentry_version(op, &op->file[0], op->dentry); +} + +static void afs_silly_unlink_edit_dir(struct afs_operation *op) +{ + struct afs_vnode_param *dvp = &op->file[0]; + struct afs_vnode *dvnode = dvp->vnode; + + _enter("op=%08x", op->debug_id); + down_write(&dvnode->validate_lock); + if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags) && + dvnode->status.data_version == dvp->dv_before + dvp->dv_delta) + afs_edit_dir_remove(dvnode, &op->dentry->d_name, + afs_edit_dir_for_unlink); + up_write(&dvnode->validate_lock); +} + +static const struct afs_operation_ops afs_silly_unlink_operation = { + .issue_afs_rpc = afs_fs_remove_file, + .issue_yfs_rpc = yfs_fs_remove_file, + .success = afs_silly_unlink_success, + .aborted = afs_check_for_remote_deletion, + .edit_dir = afs_silly_unlink_edit_dir, +}; + +/* + * Tell the server to remove a sillyrename file. + */ +static int afs_do_silly_unlink(struct afs_vnode *dvnode, struct afs_vnode *vnode, + struct dentry *dentry, struct key *key) +{ + struct afs_operation *op; + + _enter(""); + + op = afs_alloc_operation(NULL, dvnode->volume); + if (IS_ERR(op)) + return PTR_ERR(op); + + afs_op_set_vnode(op, 0, dvnode); + afs_op_set_vnode(op, 1, vnode); + op->file[0].dv_delta = 1; + op->file[0].modification = true; + op->file[0].update_ctime = true; + op->file[1].op_unlinked = true; + op->file[1].update_ctime = true; + + op->dentry = dentry; + op->ops = &afs_silly_unlink_operation; + + trace_afs_silly_rename(vnode, true); + afs_begin_vnode_operation(op); + afs_wait_for_operation(op); + + /* If there was a conflict with a third party, check the status of the + * unlinked vnode. + */ + if (op->error == 0 && (op->flags & AFS_OPERATION_DIR_CONFLICT)) { + op->file[1].update_ctime = false; + op->fetch_status.which = 1; + op->ops = &afs_fetch_status_operation; + afs_begin_vnode_operation(op); + afs_wait_for_operation(op); + } + + return afs_put_operation(op); +} + +/* + * Remove sillyrename file on iput. + */ +int afs_silly_iput(struct dentry *dentry, struct inode *inode) +{ + struct afs_vnode *dvnode = AFS_FS_I(d_inode(dentry->d_parent)); + struct afs_vnode *vnode = AFS_FS_I(inode); + struct dentry *alias; + int ret; + + DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); + + _enter("%p{%pd},%llx", dentry, dentry, vnode->fid.vnode); + + down_read(&dvnode->rmdir_lock); + + alias = d_alloc_parallel(dentry->d_parent, &dentry->d_name, &wq); + if (IS_ERR(alias)) { + up_read(&dvnode->rmdir_lock); + return 0; + } + + if (!d_in_lookup(alias)) { + /* We raced with lookup... See if we need to transfer the + * sillyrename information to the aliased dentry. + */ + ret = 0; + spin_lock(&alias->d_lock); + if (d_really_is_positive(alias) && + !(alias->d_flags & DCACHE_NFSFS_RENAMED)) { + alias->d_flags |= DCACHE_NFSFS_RENAMED; + ret = 1; + } + spin_unlock(&alias->d_lock); + up_read(&dvnode->rmdir_lock); + dput(alias); + return ret; + } + + /* Stop lock-release from complaining. */ + spin_lock(&vnode->lock); + vnode->lock_state = AFS_VNODE_LOCK_DELETED; + trace_afs_flock_ev(vnode, NULL, afs_flock_silly_delete, 0); + spin_unlock(&vnode->lock); + + afs_do_silly_unlink(dvnode, vnode, dentry, dvnode->silly_key); + up_read(&dvnode->rmdir_lock); + d_lookup_done(alias); + dput(alias); + return 1; +} |