There are several write operations on upper fs not covered by
mnt_want_write():
- test set/remove OPAQUE xattr
- test create O_TMPFILE
- set ORIGIN xattr in ovl_verify_origin()
- cleanup of index entries in ovl_indexdir_cleanup()
Some of these go way back, but this patch only applies over the
v4.14 re-factoring of ovl_fill_super().
Cc: <stable@xxxxxxxxxxxxxxx> #v4.14
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/overlayfs/super.c | 25 +++++++++++++++++--------
1 file changed, 17 insertions(+), 8 deletions(-)
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 76440feb79f6..5f6d2385c0b3 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -520,10 +520,6 @@ static struct dentry *ovl_workdir_create(struct ovl_fs *ofs,
bool retried = false;
bool locked = false;
- err = mnt_want_write(mnt);
- if (err)
- goto out_err;
-
inode_lock_nested(dir, I_MUTEX_PARENT);
locked = true;
@@ -588,7 +584,6 @@ static struct dentry *ovl_workdir_create(struct ovl_fs *ofs,
goto out_err;
}
out_unlock:
- mnt_drop_write(mnt);
if (locked)
inode_unlock(dir);
@@ -929,12 +924,17 @@ static int ovl_get_upper(struct ovl_fs *ofs, struct path *upperpath)
static int ovl_make_workdir(struct ovl_fs *ofs, struct path *workpath)
{
+ struct vfsmount *mnt = ofs->upper_mnt;
struct dentry *temp;
int err;
+ err = mnt_want_write(mnt);
+ if (err)
+ return err;
+
ofs->workdir = ovl_workdir_create(ofs, OVL_WORKDIR_NAME, false);
if (!ofs->workdir)
- return 0;
+ goto out;
/*
* Upper should support d_type, else whiteouts are visible. Given
@@ -944,7 +944,7 @@ static int ovl_make_workdir(struct ovl_fs *ofs, struct path *workpath)
*/
err = ovl_check_d_type_supported(workpath);
if (err < 0)
- return err;
+ goto out;
/*
* We allowed this configuration and don't want to break users over
@@ -968,6 +968,7 @@ static int ovl_make_workdir(struct ovl_fs *ofs, struct path *workpath)
if (err) {
ofs->noxattr = true;
pr_warn("overlayfs: upper fs does not support xattr.\n");
+ err = 0;
} else {
vfs_removexattr(ofs->workdir, OVL_XATTR_OPAQUE);
}
@@ -979,7 +980,9 @@ static int ovl_make_workdir(struct ovl_fs *ofs, struct path *workpath)
pr_warn("overlayfs: upper fs does not support file handles, falling back to index=off.\n");
}
- return 0;
+out:
+ mnt_drop_write(mnt);
+ return err;
}
static int ovl_get_workdir(struct ovl_fs *ofs, struct path *upperpath)
@@ -1026,8 +1029,13 @@ static int ovl_get_workdir(struct ovl_fs *ofs, struct path *upperpath)
static int ovl_get_indexdir(struct ovl_fs *ofs, struct ovl_entry *oe,
struct path *upperpath)
{
+ struct vfsmount *mnt = ofs->upper_mnt;
int err;
+ err = mnt_want_write(mnt);
+ if (err)
+ return err;
+
/* Verify lower root is upper root origin */
err = ovl_verify_origin(upperpath->dentry, oe->lowerstack[0].dentry,
false, true);
@@ -1055,6 +1063,7 @@ static int ovl_get_indexdir(struct ovl_fs *ofs, struct ovl_entry *oe,
pr_warn("overlayfs: try deleting index dir or mounting with '-o index=off' to disable inodes index.\n");
out:
+ mnt_drop_write(mnt);
return err;
}
--
2.7.4
--
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