afs: Add support for RENAME_NOREPLACE and RENAME_EXCHANGE

Add support for RENAME_NOREPLACE and RENAME_EXCHANGE, if the server
supports them.

The default is translated to YFS.Rename_Replace, falling back to
YFS.Rename; RENAME_NOREPLACE is translated to YFS.Rename_NoReplace and
RENAME_EXCHANGE to YFS.Rename_Exchange, both of which fall back to
reporting EINVAL.

Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/740476.1758718189@warthog.procyon.org.uk
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Dan Carpenter <dan.carpenter@linaro.org>
cc: linux-afs@lists.infradead.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: dhowells

fs/afs/dir.c

@@ -1823,7 +1823,8 @@ static int afs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 
 static void afs_rename_success(struct afs_operation *op)
 {
-	struct afs_vnode *vnode = AFS_FS_I(d_inode(op->dentry));
+	struct afs_vnode *vnode = op->more_files[0].vnode;
+	struct afs_vnode *new_vnode = op->more_files[1].vnode;
 
 	_enter("op=%08x", op->debug_id);
 
@@ -1834,22 +1835,40 @@ static void afs_rename_success(struct afs_operation *op)
 		op->ctime = op->file[1].scb.status.mtime_client;
 		afs_vnode_commit_status(op, &op->file[1]);
 	}
+	if (op->more_files[0].scb.have_status)
+		afs_vnode_commit_status(op, &op->more_files[0]);
+	if (op->more_files[1].scb.have_status)
+		afs_vnode_commit_status(op, &op->more_files[1]);
 
 	/* If we're moving a subdir between dirs, we need to update
 	 * its DV counter too as the ".." will be altered.
 	 */
-	if (S_ISDIR(vnode->netfs.inode.i_mode) &&
-	    op->file[0].vnode != op->file[1].vnode) {
-		u64 new_dv;
+	if (op->file[0].vnode != op->file[1].vnode) {
+		if (S_ISDIR(vnode->netfs.inode.i_mode)) {
+			u64 new_dv;
 
-		write_seqlock(&vnode->cb_lock);
+			write_seqlock(&vnode->cb_lock);
 
-		new_dv = vnode->status.data_version + 1;
-		trace_afs_set_dv(vnode, new_dv);
-		vnode->status.data_version = new_dv;
-		inode_set_iversion_raw(&vnode->netfs.inode, new_dv);
+			new_dv = vnode->status.data_version + 1;
+			trace_afs_set_dv(vnode, new_dv);
+			vnode->status.data_version = new_dv;
+			inode_set_iversion_raw(&vnode->netfs.inode, new_dv);
 
-		write_sequnlock(&vnode->cb_lock);
+			write_sequnlock(&vnode->cb_lock);
+		}
+
+		if ((op->rename.rename_flags & RENAME_EXCHANGE) &&
+		    S_ISDIR(new_vnode->netfs.inode.i_mode)) {
+			u64 new_dv;
+
+			write_seqlock(&new_vnode->cb_lock);
+
+			new_dv = new_vnode->status.data_version + 1;
+			new_vnode->status.data_version = new_dv;
+			inode_set_iversion_raw(&new_vnode->netfs.inode, new_dv);
+
+			write_sequnlock(&new_vnode->cb_lock);
+		}
 	}
 }
 
@@ -1900,8 +1919,8 @@ static void afs_rename_edit_dir(struct afs_operation *op)
 	if (S_ISDIR(vnode->netfs.inode.i_mode) &&
 	    new_dvnode != orig_dvnode &&
 	    test_bit(AFS_VNODE_DIR_VALID, &vnode->flags))
-		afs_edit_dir_update_dotdot(vnode, new_dvnode,
-					   afs_edit_dir_for_rename_sub);
+		afs_edit_dir_update(vnode, &dotdot_name, new_dvnode,
+				    afs_edit_dir_for_rename_sub);
 
 	new_inode = d_inode(new_dentry);
 	if (new_inode) {
@@ -1915,9 +1934,6 @@ static void afs_rename_edit_dir(struct afs_operation *op)
 
 	/* Now we can update d_fsdata on the dentries to reflect their
 	 * new parent's data_version.
-	 *
-	 * Note that if we ever implement RENAME_EXCHANGE, we'll have
-	 * to update both dentries with opposing dir versions.
 	 */
 	afs_update_dentry_version(op, new_dvp, op->dentry);
 	afs_update_dentry_version(op, new_dvp, op->dentry_2);
@@ -1930,6 +1946,67 @@ static void afs_rename_edit_dir(struct afs_operation *op)
 		fscache_end_operation(&new_cres);
 }
 
+static void afs_rename_exchange_edit_dir(struct afs_operation *op)
+{
+	struct afs_vnode_param *orig_dvp = &op->file[0];
+	struct afs_vnode_param *new_dvp = &op->file[1];
+	struct afs_vnode *orig_dvnode = orig_dvp->vnode;
+	struct afs_vnode *new_dvnode = new_dvp->vnode;
+	struct afs_vnode *old_vnode = op->more_files[0].vnode;
+	struct afs_vnode *new_vnode = op->more_files[1].vnode;
+	struct dentry *old_dentry = op->dentry;
+	struct dentry *new_dentry = op->dentry_2;
+
+	_enter("op=%08x", op->debug_id);
+
+	if (new_dvnode == orig_dvnode) {
+		down_write(&orig_dvnode->validate_lock);
+		if (test_bit(AFS_VNODE_DIR_VALID, &orig_dvnode->flags) &&
+		    orig_dvnode->status.data_version == orig_dvp->dv_before + orig_dvp->dv_delta) {
+			afs_edit_dir_update(orig_dvnode, &old_dentry->d_name,
+					    new_vnode, afs_edit_dir_for_rename_0);
+			afs_edit_dir_update(orig_dvnode, &new_dentry->d_name,
+					    old_vnode, afs_edit_dir_for_rename_1);
+		}
+
+		d_exchange(old_dentry, new_dentry);
+		up_write(&orig_dvnode->validate_lock);
+	} else {
+		down_write(&orig_dvnode->validate_lock);
+		if (test_bit(AFS_VNODE_DIR_VALID, &orig_dvnode->flags) &&
+		    orig_dvnode->status.data_version == orig_dvp->dv_before + orig_dvp->dv_delta)
+			afs_edit_dir_update(orig_dvnode, &old_dentry->d_name,
+					    new_vnode, afs_edit_dir_for_rename_0);
+
+		up_write(&orig_dvnode->validate_lock);
+		down_write(&new_dvnode->validate_lock);
+
+		if (test_bit(AFS_VNODE_DIR_VALID, &new_dvnode->flags) &&
+		    new_dvnode->status.data_version == new_dvp->dv_before + new_dvp->dv_delta)
+			afs_edit_dir_update(new_dvnode, &new_dentry->d_name,
+					    old_vnode, afs_edit_dir_for_rename_1);
+
+		if (S_ISDIR(old_vnode->netfs.inode.i_mode) &&
+		    test_bit(AFS_VNODE_DIR_VALID, &old_vnode->flags))
+			afs_edit_dir_update(old_vnode, &dotdot_name, new_dvnode,
+					    afs_edit_dir_for_rename_sub);
+
+		if (S_ISDIR(new_vnode->netfs.inode.i_mode) &&
+		    test_bit(AFS_VNODE_DIR_VALID, &new_vnode->flags))
+			afs_edit_dir_update(new_vnode, &dotdot_name, orig_dvnode,
+					    afs_edit_dir_for_rename_sub);
+
+		/* Now we can update d_fsdata on the dentries to reflect their
+		 * new parents' data_version.
+		 */
+		afs_update_dentry_version(op, new_dvp, old_dentry);
+		afs_update_dentry_version(op, orig_dvp, new_dentry);
+
+		d_exchange(old_dentry, new_dentry);
+		up_write(&new_dvnode->validate_lock);
+	}
+}
+
 static void afs_rename_put(struct afs_operation *op)
 {
 	_enter("op=%08x", op->debug_id);
@@ -1948,6 +2025,32 @@ static const struct afs_operation_ops afs_rename_operation = {
 	.put		= afs_rename_put,
 };
 
+#if 0 /* Autoswitched in yfs_fs_rename_replace(). */
+static const struct afs_operation_ops afs_rename_replace_operation = {
+	.issue_afs_rpc	= NULL,
+	.issue_yfs_rpc	= yfs_fs_rename_replace,
+	.success	= afs_rename_success,
+	.edit_dir	= afs_rename_edit_dir,
+	.put		= afs_rename_put,
+};
+#endif
+
+static const struct afs_operation_ops afs_rename_noreplace_operation = {
+	.issue_afs_rpc	= NULL,
+	.issue_yfs_rpc	= yfs_fs_rename_noreplace,
+	.success	= afs_rename_success,
+	.edit_dir	= afs_rename_edit_dir,
+	.put		= afs_rename_put,
+};
+
+static const struct afs_operation_ops afs_rename_exchange_operation = {
+	.issue_afs_rpc	= NULL,
+	.issue_yfs_rpc	= yfs_fs_rename_exchange,
+	.success	= afs_rename_success,
+	.edit_dir	= afs_rename_exchange_edit_dir,
+	.put		= afs_rename_put,
+};
+
 /*
  * rename a file in an AFS filesystem and/or move it between directories
  */
@@ -1956,10 +2059,10 @@ static int afs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 		      struct dentry *new_dentry, unsigned int flags)
 {
 	struct afs_operation *op;
-	struct afs_vnode *orig_dvnode, *new_dvnode, *vnode;
+	struct afs_vnode *orig_dvnode, *new_dvnode, *vnode, *new_vnode = NULL;
 	int ret;
 
-	if (flags)
+	if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
 		return -EINVAL;
 
 	/* Don't allow silly-rename files be moved around. */
@@ -1969,6 +2072,8 @@ static int afs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 	vnode = AFS_FS_I(d_inode(old_dentry));
 	orig_dvnode = AFS_FS_I(old_dir);
 	new_dvnode = AFS_FS_I(new_dir);
+	if (d_is_positive(new_dentry))
+		new_vnode = AFS_FS_I(d_inode(new_dentry));
 
 	_enter("{%llx:%llu},{%llx:%llu},{%llx:%llu},{%pd}",
 	       orig_dvnode->fid.vid, orig_dvnode->fid.vnode,
@@ -1989,6 +2094,11 @@ static int afs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 	if (ret < 0)
 		goto error;
 
+	ret = -ENOMEM;
+	op->more_files = kvcalloc(2, sizeof(struct afs_vnode_param), GFP_KERNEL);
+	if (!op->more_files)
+		goto error;
+
 	afs_op_set_vnode(op, 0, orig_dvnode);
 	afs_op_set_vnode(op, 1, new_dvnode); /* May be same as orig_dvnode */
 	op->file[0].dv_delta = 1;
@@ -1997,46 +2107,63 @@ static int afs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 	op->file[1].modification = true;
 	op->file[0].update_ctime = true;
 	op->file[1].update_ctime = true;
+	op->more_files[0].vnode		= vnode;
+	op->more_files[0].speculative	= true;
+	op->more_files[1].vnode		= new_vnode;
+	op->more_files[1].speculative	= true;
+	op->nr_files = 4;
 
 	op->dentry		= old_dentry;
 	op->dentry_2		= new_dentry;
+	op->rename.rename_flags	= flags;
 	op->rename.new_negative	= d_is_negative(new_dentry);
-	op->ops			= &afs_rename_operation;
 
-	/* For non-directories, check whether the target is busy and if so,
-	 * make a copy of the dentry and then do a silly-rename.  If the
-	 * silly-rename succeeds, the copied dentry is hashed and becomes the
-	 * new target.
-	 */
-	if (d_is_positive(new_dentry) && !d_is_dir(new_dentry)) {
-		/* To prevent any new references to the target during the
-		 * rename, we unhash the dentry in advance.
+	if (flags & RENAME_NOREPLACE) {
+		op->ops		= &afs_rename_noreplace_operation;
+	} else if (flags & RENAME_EXCHANGE) {
+		op->ops		= &afs_rename_exchange_operation;
+		d_drop(new_dentry);
+	} else {
+		/* If we might displace the target, we might need to do silly
+		 * rename.
 		 */
-		if (!d_unhashed(new_dentry)) {
-			d_drop(new_dentry);
-			op->rename.rehash = new_dentry;
-		}
+		op->ops	= &afs_rename_operation;
 
-		if (d_count(new_dentry) > 2) {
-			/* copy the target dentry's name */
-			op->rename.tmp = d_alloc(new_dentry->d_parent,
-						 &new_dentry->d_name);
-			if (!op->rename.tmp) {
-				afs_op_nomem(op);
-				goto error;
+		/* For non-directories, check whether the target is busy and if
+		 * so, make a copy of the dentry and then do a silly-rename.
+		 * If the silly-rename succeeds, the copied dentry is hashed
+		 * and becomes the new target.
+		 */
+		if (d_is_positive(new_dentry) && !d_is_dir(new_dentry)) {
+			/* To prevent any new references to the target during
+			 * the rename, we unhash the dentry in advance.
+			 */
+			if (!d_unhashed(new_dentry)) {
+				d_drop(new_dentry);
+				op->rename.rehash = new_dentry;
 			}
 
-			ret = afs_sillyrename(new_dvnode,
-					      AFS_FS_I(d_inode(new_dentry)),
-					      new_dentry, op->key);
-			if (ret) {
-				afs_op_set_error(op, ret);
-				goto error;
+			if (d_count(new_dentry) > 2) {
+				/* copy the target dentry's name */
+				op->rename.tmp = d_alloc(new_dentry->d_parent,
+							 &new_dentry->d_name);
+				if (!op->rename.tmp) {
+					afs_op_nomem(op);
+					goto error;
+				}
+
+				ret = afs_sillyrename(new_dvnode,
+						      AFS_FS_I(d_inode(new_dentry)),
+						      new_dentry, op->key);
+				if (ret) {
+					afs_op_set_error(op, ret);
+					goto error;
+				}
+
+				op->dentry_2 = op->rename.tmp;
+				op->rename.rehash = NULL;
+				op->rename.new_negative = true;
 			}
-
-			op->dentry_2 = op->rename.tmp;
-			op->rename.rehash = NULL;
-			op->rename.new_negative = true;
 		}
 	}
 
@@ -2052,6 +2179,8 @@ static int afs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 	d_drop(old_dentry);
 
 	ret = afs_do_sync_operation(op);
+	if (ret == -ENOTSUPP)
+		ret = -EINVAL;
 out:
 	afs_dir_unuse_cookie(orig_dvnode, ret);
 	if (new_dvnode != orig_dvnode)

fs/afs/dir_edit.c

@@ -522,11 +522,11 @@ void afs_edit_dir_remove(struct afs_vnode *vnode,
 }
 
 /*
- * Edit a subdirectory that has been moved between directories to update the
- * ".." entry.
+ * Edit an entry in a directory to update the vnode it refers to.  This is also
+ * used to update the ".." entry in a directory.
  */
-void afs_edit_dir_update_dotdot(struct afs_vnode *vnode, struct afs_vnode *new_dvnode,
-				enum afs_edit_dir_reason why)
+void afs_edit_dir_update(struct afs_vnode *vnode, const struct qstr *name,
+			 struct afs_vnode *new_dvnode, enum afs_edit_dir_reason why)
 {
 	union afs_xdr_dir_block *block;
 	union afs_xdr_dirent *de;
@@ -557,7 +557,7 @@ void afs_edit_dir_update_dotdot(struct afs_vnode *vnode, struct afs_vnode *new_d
 		if (!test_bit(AFS_VNODE_DIR_VALID, &vnode->flags))
 			goto already_invalidated;
 
-		slot = afs_dir_scan_block(block, &dotdot_name, b);
+		slot = afs_dir_scan_block(block, name, b);
 		if (slot >= 0)
 			goto found_dirent;
 
@@ -566,7 +566,7 @@ void afs_edit_dir_update_dotdot(struct afs_vnode *vnode, struct afs_vnode *new_d
 
 	/* Didn't find the dirent to clobber.  Download the directory again. */
 	trace_afs_edit_dir(vnode, why, afs_edit_dir_update_nodd,
-			   0, 0, 0, 0, "..");
+			   0, 0, 0, 0, name->name);
 	afs_invalidate_dir(vnode, afs_dir_invalid_edit_upd_no_dd);
 	goto out;
 
@@ -576,7 +576,7 @@ void afs_edit_dir_update_dotdot(struct afs_vnode *vnode, struct afs_vnode *new_d
 	de->u.unique = htonl(new_dvnode->fid.unique);
 
 	trace_afs_edit_dir(vnode, why, afs_edit_dir_update_dd, b, slot,
-			   ntohl(de->u.vnode), ntohl(de->u.unique), "..");
+			   ntohl(de->u.vnode), ntohl(de->u.unique), name->name);
 
 	kunmap_local(block);
 	netfs_single_mark_inode_dirty(&vnode->netfs.inode);
@@ -589,12 +589,12 @@ void afs_edit_dir_update_dotdot(struct afs_vnode *vnode, struct afs_vnode *new_d
 already_invalidated:
 	kunmap_local(block);
 	trace_afs_edit_dir(vnode, why, afs_edit_dir_update_inval,
-			   0, 0, 0, 0, "..");
+			   0, 0, 0, 0, name->name);
 	goto out;
 
 error:
 	trace_afs_edit_dir(vnode, why, afs_edit_dir_update_error,
-			   0, 0, 0, 0, "..");
+			   0, 0, 0, 0, name->name);
 	goto out;
 }