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Subject[PATCH 05/11] ovl: return dentry from ovl_create_real()
Date
From: Amir Goldstein <amir73il@gmail.com>

Al Viro suggested to simplify callers of ovl_create_real() by
returning the created dentry (or ERR_PTR) from ovl_create_real().
This prep patch makes Al's patch change less callers.

Also used ovl_create_temp() in ovl_create_index() instead of calling
ovl_do_mkdir() directly, so now all callers of ovl_do_mkdir() are routed
through ovl_create_real(), which paves the way for Al's fix for non-hashed
result from vfs_mkdir().

Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
fs/overlayfs/copy_up.c | 15 ++++--------
fs/overlayfs/dir.c | 62 +++++++++++++++++++++++-------------------------
fs/overlayfs/overlayfs.h | 4 ++--
fs/overlayfs/super.c | 7 +++---
4 files changed, 40 insertions(+), 48 deletions(-)

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 5f4c78b1bbeb..d3e9c1eeb7a4 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -502,19 +502,12 @@ static int ovl_get_tmpfile(struct ovl_copy_up_ctx *c, struct dentry **tempp)

if (c->tmpfile) {
temp = ovl_do_tmpfile(c->workdir, c->stat.mode);
- if (IS_ERR(temp))
- goto temp_err;
} else {
- temp = ovl_lookup_temp(c->workdir);
- if (IS_ERR(temp))
- goto temp_err;
-
- err = ovl_create_real(d_inode(c->workdir), temp, &cattr);
- if (err) {
- dput(temp);
- goto out;
- }
+ temp = ovl_create_real(d_inode(c->workdir),
+ ovl_lookup_temp(c->workdir), &cattr);
}
+ if (IS_ERR(temp))
+ goto temp_err;
err = 0;
*tempp = temp;
out:
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 0fb3ef85f298..425ddb098c4a 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -114,13 +114,17 @@ int ovl_cleanup_and_whiteout(struct dentry *workdir, struct inode *dir,
goto out;
}

-int ovl_create_real(struct inode *dir, struct dentry *newdentry,
- struct ovl_cattr *attr)
+struct dentry *ovl_create_real(struct inode *dir, struct dentry *newdentry,
+ struct ovl_cattr *attr)
{
int err;

+ if (IS_ERR(newdentry))
+ return newdentry;
+
+ err = -ESTALE;
if (newdentry->d_inode)
- return -ESTALE;
+ goto out;

if (attr->hardlink) {
err = ovl_do_link(attr->hardlink, dir, newdentry);
@@ -157,7 +161,12 @@ int ovl_create_real(struct inode *dir, struct dentry *newdentry,
*/
err = -ENOENT;
}
- return err;
+out:
+ if (err) {
+ dput(newdentry);
+ return ERR_PTR(err);
+ }
+ return newdentry;
}

static int ovl_set_opaque_xerr(struct dentry *dentry, struct dentry *upper,
@@ -224,14 +233,14 @@ static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
attr->mode &= ~current_umask();

inode_lock_nested(udir, I_MUTEX_PARENT);
- newdentry = lookup_one_len(dentry->d_name.name, upperdir,
- dentry->d_name.len);
+ newdentry = ovl_create_real(udir,
+ lookup_one_len(dentry->d_name.name,
+ upperdir,
+ dentry->d_name.len),
+ attr);
err = PTR_ERR(newdentry);
if (IS_ERR(newdentry))
goto out_unlock;
- err = ovl_create_real(udir, newdentry, attr);
- if (err)
- goto out_dput;

if (ovl_type_merge(dentry->d_parent) && d_is_dir(newdentry)) {
/* Setting opaque here is just an optimization, allow to fail */
@@ -239,9 +248,7 @@ static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
}

ovl_instantiate(dentry, inode, newdentry, !!attr->hardlink);
- newdentry = NULL;
-out_dput:
- dput(newdentry);
+ err = 0;
out_unlock:
inode_unlock(udir);
return err;
@@ -280,15 +287,12 @@ static struct dentry *ovl_clear_empty(struct dentry *dentry,
if (upper->d_parent->d_inode != udir)
goto out_unlock;

- opaquedir = ovl_lookup_temp(workdir);
+ opaquedir = ovl_create_real(wdir, ovl_lookup_temp(workdir),
+ OVL_CATTR(stat.mode));
err = PTR_ERR(opaquedir);
if (IS_ERR(opaquedir))
goto out_unlock;

- err = ovl_create_real(wdir, opaquedir, OVL_CATTR(stat.mode));
- if (err)
- goto out_dput;
-
err = ovl_copy_xattr(upper, opaquedir);
if (err)
goto out_cleanup;
@@ -318,7 +322,6 @@ static struct dentry *ovl_clear_empty(struct dentry *dentry,

out_cleanup:
ovl_cleanup(wdir, opaquedir);
-out_dput:
dput(opaquedir);
out_unlock:
unlock_rename(workdir, upperdir);
@@ -379,20 +382,16 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
if (err)
goto out;

- newdentry = ovl_lookup_temp(workdir);
- err = PTR_ERR(newdentry);
- if (IS_ERR(newdentry))
- goto out_unlock;
-
upper = lookup_one_len(dentry->d_name.name, upperdir,
dentry->d_name.len);
err = PTR_ERR(upper);
if (IS_ERR(upper))
- goto out_dput;
+ goto out_unlock;

- err = ovl_create_real(wdir, newdentry, cattr);
- if (err)
- goto out_dput2;
+ newdentry = ovl_create_real(wdir, ovl_lookup_temp(workdir), cattr);
+ err = PTR_ERR(newdentry);
+ if (IS_ERR(newdentry))
+ goto out_dput;

/*
* mode could have been mutilated due to umask (e.g. sgid directory)
@@ -439,11 +438,9 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
goto out_cleanup;
}
ovl_instantiate(dentry, inode, newdentry, hardlink);
- newdentry = NULL;
-out_dput2:
- dput(upper);
+ err = 0;
out_dput:
- dput(newdentry);
+ dput(upper);
out_unlock:
unlock_rename(workdir, upperdir);
out:
@@ -455,7 +452,8 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,

out_cleanup:
ovl_cleanup(wdir, newdentry);
- goto out_dput2;
+ dput(newdentry);
+ goto out_dput;
}

static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index aa8286419133..6bbde513e068 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -358,8 +358,8 @@ struct ovl_cattr {

#define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) })

-int ovl_create_real(struct inode *dir, struct dentry *newdentry,
- struct ovl_cattr *attr);
+struct dentry *ovl_create_real(struct inode *dir, struct dentry *newdentry,
+ struct ovl_cattr *attr);
int ovl_cleanup(struct inode *dir, struct dentry *dentry);

/* copy_up.c */
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 286d36772e9c..704b37311467 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -611,9 +611,10 @@ static struct dentry *ovl_workdir_create(struct ovl_fs *ofs,
goto retry;
}

- err = ovl_create_real(dir, work, OVL_CATTR(attr.ia_mode));
- if (err)
- goto out_dput;
+ work = ovl_create_real(dir, work, OVL_CATTR(attr.ia_mode));
+ err = PTR_ERR(work);
+ if (IS_ERR(work))
+ goto out_err;

/*
* Try to remove POSIX ACL xattrs from workdir. We are good if:
--
2.14.3
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