From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f67.google.com ([74.125.82.67]:33194 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751047AbdAPL6e (ORCPT ); Mon, 16 Jan 2017 06:58:34 -0500 From: Amir Goldstein To: Miklos Szeredi Cc: Al Viro , linux-unionfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH v2 6/6] ovl: concurrent copy up of regular files Date: Mon, 16 Jan 2017 13:58:13 +0200 Message-Id: <1484567893-22987-1-git-send-email-amir73il@gmail.com> In-Reply-To: <1484488652-611-7-git-send-email-amir73il@gmail.com> References: <1484488652-611-7-git-send-email-amir73il@gmail.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Now that copy up of regular file is done using O_TMPFILE, we don't need to hold rename_lock throughout copy up. Use the copy up waitqueue to synchronize concurrent copy up of the same file. Different regular files can be copied up concurrently. The upper dir inode_lock is taken instead of rename_lock, because it is needed for lookup and later for linking the temp file, but it is released while copying up data. Suggested-by: Al Viro Signed-off-by: Amir Goldstein --- fs/overlayfs/copy_up.c | 46 ++++++++++++++++++++++++++++++++++++---------- 1 file changed, 36 insertions(+), 10 deletions(-) diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c index d3b6c15..0d1cb96 100644 --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -291,7 +291,14 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir, BUG_ON(upperpath.dentry != NULL); upperpath.dentry = temp; + if (tmpfile) + inode_unlock(udir); + err = ovl_copy_up_data(lowerpath, &upperpath, stat->size); + + if (tmpfile) + inode_lock_nested(udir, I_MUTEX_PARENT); + if (err) goto out_cleanup; } @@ -371,15 +378,28 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry, return PTR_ERR(link); } - err = -EIO; - if (lock_rename(workdir, upperdir) != NULL) { - pr_err("overlayfs: failed to lock workdir+upperdir\n"); - goto out_unlock; - } - if (ovl_dentry_upper(dentry)) { - /* Raced with another copy-up? Nothing to do, then... */ - err = 0; - goto out_unlock; + if (tmpfile) { + err = ovl_copy_up_start(dentry); + /* err < 0: interrupted, err > 0: raced with another copy-up */ + if (unlikely(err)) { + pr_debug("ovl_copy_up_start(%pd2) = %i\n", dentry, err); + if (err > 0) + err = 0; + goto out_done; + } + /* Lock upper dir for lookup, link tmpfile, set_timestamps */ + inode_lock_nested(upperdir->d_inode, I_MUTEX_PARENT); + } else { + err = -EIO; + if (lock_rename(workdir, upperdir) != NULL) { + pr_err("overlayfs: failed to lock workdir+upperdir\n"); + goto out_unlock; + } + if (ovl_dentry_upper(dentry)) { + /* Raced with another copy-up? Nothing to do */ + err = 0; + goto out_unlock; + } } err = ovl_copy_up_locked(workdir, upperdir, dentry, lowerpath, @@ -389,7 +409,13 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry, ovl_set_timestamps(upperdir, &pstat); } out_unlock: - unlock_rename(workdir, upperdir); + if (tmpfile) + inode_unlock(upperdir->d_inode); + else + unlock_rename(workdir, upperdir); + if (tmpfile) + ovl_copy_up_end(dentry); +out_done: do_delayed_call(&done); return err; -- 2.7.4