From: Kevin Locke kevin@kevinlocke.name
mainline inclusion from mainline-v5.11-rc1 commit 0a8d0b64dd6acfbc9e9b79022654bbe1ade4a29a category: bugfix bugzilla: NA CVE: NA
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When the lower file of a metacopy is inaccessible, -EIO is returned. For users not familiar with overlayfs internals, such as myself, the meaning of this error may not be apparent or easy to determine, since the (metacopy) file is present and open/stat succeed when accessed outside of the overlay.
Add a rate-limited warning for orphan metacopy to give users a hint when investigating such errors.
Link: https://lore.kernel.org/linux-unionfs/CAOQ4uxi23Zsmfb4rCed1n=On0NNA5KZD74jjj... Signed-off-by: Kevin Locke kevin@kevinlocke.name Signed-off-by: Miklos Szeredi mszeredi@redhat.com Signed-off-by: Zheng Liang zhengliang6@huawei.com Reviewed-by: Zhang Yi yi.zhang@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- fs/overlayfs/namei.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c index ba970c16899f9..d261c867404ee 100644 --- a/fs/overlayfs/namei.c +++ b/fs/overlayfs/namei.c @@ -1006,6 +1006,8 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, * Just make sure a corresponding data dentry has been found. */ if (d.metacopy || (uppermetacopy && !ctr)) { + pr_warn_ratelimited("metacopy with no lower data found - abort lookup (%pd2)\n", + dentry); err = -EIO; goto out_put; } else if (!d.is_dir && upperdentry && !ctr && origin_path) {