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From: Vyacheslav Yurkov <uvv.mail@gmail.com>
To: Miklos Szeredi <miklos@szeredi.hu>, Amir Goldstein <amir73il@gmail.com>
Cc: linux-unionfs@vger.kernel.org,
	Vyacheslav Yurkov <Vyacheslav.Yurkov@bruker.com>
Subject: [PATCH v3 3/3] ovl: do not set overlay.opaque for new directories
Date: Thu, 27 May 2021 19:45:47 +0200	[thread overview]
Message-ID: <20210527174547.109269-3-uvv.mail@gmail.com> (raw)
In-Reply-To: <20210527174547.109269-1-uvv.mail@gmail.com>

From: Vyacheslav Yurkov <Vyacheslav.Yurkov@bruker.com>

Enable optimizations only if user opted-in for any of extended features.
If optimization is enabled, it breaks existing use case when a lower layer
directory appears after directory was created on a merged layer. If
overlay.opaque is applied, new files on lower layer are not visible.

Consider the following scenario:
- /lower and /upper are mounted to /merged
- directory /merged/new-dir is created with a file test1
- overlay is unmounted
- directory /lower/new-dir is created with a file test2
- overlay is mounted again

If opaque is applied by default, file test2 is not going to be visible
without explicitly clearing the overlay.opaque attribute

Signed-off-by: Vyacheslav Yurkov <Vyacheslav.Yurkov@bruker.com>
---
 fs/overlayfs/dir.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 93efe7048a77..03a22954fe61 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -320,6 +320,7 @@ static bool ovl_type_origin(struct dentry *dentry)
 static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
 			    struct ovl_cattr *attr)
 {
+	struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
 	struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
 	struct inode *udir = upperdir->d_inode;
 	struct dentry *newdentry;
@@ -338,7 +339,8 @@ static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
 	if (IS_ERR(newdentry))
 		goto out_unlock;
 
-	if (ovl_type_merge(dentry->d_parent) && d_is_dir(newdentry)) {
+	if (ovl_type_merge(dentry->d_parent) && d_is_dir(newdentry) &&
+	    !ovl_allow_offline_changes(ofs)) {
 		/* Setting opaque here is just an optimization, allow to fail */
 		ovl_set_opaque(dentry, newdentry);
 	}
-- 
2.25.1


  parent reply	other threads:[~2021-05-27 17:46 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-27 17:45 [PATCH v3 1/3] ovl: disable decoding null uuid with redirect dir Vyacheslav Yurkov
2021-05-27 17:45 ` [PATCH v3 2/3] ovl: add ovl_allow_offline_changes() helper Vyacheslav Yurkov
2021-05-27 17:45 ` Vyacheslav Yurkov [this message]
2021-05-28 11:38   ` [PATCH v3 3/3] ovl: do not set overlay.opaque for new directories Amir Goldstein
2021-06-01  6:53     ` Yurkov, Vyacheslav
2021-06-01  8:33       ` Amir Goldstein
2021-06-01 16:29         ` Yurkov, Vyacheslav
2021-06-01 18:29           ` Amir Goldstein
2021-06-04 12:32             ` Amir Goldstein
2021-06-04 14:50               ` Yurkov, Vyacheslav
2021-06-04 19:18                 ` Amir Goldstein
2021-07-19 14:29   ` Miklos Szeredi

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