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Fix non-empty dir removal in overlayfs (rhbz 1220915)

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Josh Boyer 2015-05-14 08:20:07 -04:00
parent 8d884182ac
commit 2844a7d7e1
2 changed files with 66 additions and 0 deletions
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9
kernel.spec
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@ -613,6 +613,9 @@ Patch26192: blk-loop-avoid-too-many-pending-per-work-IO.patch
#rhbz 1219343
Patch26200: 0001-HID-usbhid-Add-HID_QUIRK_NOGET-for-Aten-DVI-KVM-swit.patch
#rhbz 1220915
Patch26201: ovl-don-t-remove-non-empty-opaque-directory.patch
# END OF PATCH DEFINITIONS
%endif
@ -1346,6 +1349,9 @@ ApplyPatch blk-loop-avoid-too-many-pending-per-work-IO.patch
#rhbz 1219343
ApplyPatch 0001-HID-usbhid-Add-HID_QUIRK_NOGET-for-Aten-DVI-KVM-swit.patch
#rhbz 1220915
ApplyPatch ovl-don-t-remove-non-empty-opaque-directory.patch
# END OF PATCH APPLICATIONS
%endif
@ -2206,6 +2212,9 @@ fi
#
#
%changelog
* Thu May 14 2015 Josh Boyer <jwboyer@fedoraproject.org>
- Fix non-empty dir removal in overlayfs (rhbz 1220915)
* Wed May 13 2015 Laura Abbott <labbott@fedoraproject.org>
- Fix spew from KVM switch (rhbz 1219343)

57
ovl-don-t-remove-non-empty-opaque-directory.patch Normal file
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@ -0,0 +1,57 @@
From: Miklos Szeredi <mszeredi@suse.cz>
Date: Thu, 14 May 2015 10:04:44 +0200
Subject: [PATCH] ovl: don't remove non-empty opaque directory
When removing an opaque directory we can't just call rmdir() to check for
emptiness, because the directory will need to be replaced with a whiteout.
The replacement is done with RENAME_EXCHANGE, which doesn't check
emptiness.
Solution is just to check emptiness by reading the directory. In the
future we could add a new rename flag to check for emptiness even for
RENAME_EXCHANGE to optimize this case.
Reported-by: Vincent Batts <vbatts@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Tested-by: Jordi Pujol Palomer <jordipujolp@gmail.com>
Fixes: 263b4a0fee43 ("ovl: dont replace opaque dir")
Cc: <stable@vger.kernel.org> # v4.0+
---
fs/overlayfs/dir.c | 24 +++++++++++++++++++-----
1 file changed, 19 insertions(+), 5 deletions(-)
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index d139405d2bfa..2578a0c0677d 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -506,11 +506,25 @@ static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir)
struct dentry *opaquedir = NULL;
int err;
- if (is_dir && OVL_TYPE_MERGE_OR_LOWER(ovl_path_type(dentry))) {
- opaquedir = ovl_check_empty_and_clear(dentry);
- err = PTR_ERR(opaquedir);
- if (IS_ERR(opaquedir))
- goto out;
+ if (is_dir) {
+ if (OVL_TYPE_MERGE_OR_LOWER(ovl_path_type(dentry))) {
+ opaquedir = ovl_check_empty_and_clear(dentry);
+ err = PTR_ERR(opaquedir);
+ if (IS_ERR(opaquedir))
+ goto out;
+ } else {
+ LIST_HEAD(list);
+
+ /*
+ * When removing an empty opaque directory, then it
+ * makes no sense to replace it with an exact replica of
+ * itself. But emptiness still needs to be checked.
+ */
+ err = ovl_check_empty_dir(dentry, &list);
+ ovl_cache_free(&list);
+ if (err)
+ goto out;
+ }
}
err = ovl_lock_rename_workdir(workdir, upperdir);