[PATCH v3 03/19] ovl: use wrappers to all vfs_*xattr() calls

[Christian Brauner <brauner@kernel.org>]

From: Amir Goldstein <amir73il@gmail.com>

Use helpers ovl_*xattr() to access user/trusted.overlay.* xattrs
and use helpers ovl_do_*xattr() to access generic xattrs. This is a
preparatory patch for using idmapped base layers with overlay.

Note that a few of those places called vfs_*xattr() calls directly to
reduce the amount of debug output. But as Miklos pointed out since
overlayfs has been stable for quite some time the debug output isn't all
that relevant anymore and the additional debug in all locations was
actually quite helpful when developing this patch series.

Cc: <linux-unionfs@vger.kernel.org>
Tested-by: Giuseppe Scrivano <gscrivan@redhat.com>
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
---
/* v2 */
- Miklos Szeredi <mszeredi@redhat.com>:
  - Mention the increase in pr_debug() loggin in the commit message due
    to this change.

/* v3 */
unchanged
---
 fs/overlayfs/copy_up.c   | 22 ++++++++++++----------
 fs/overlayfs/dir.c       |  4 +++-
 fs/overlayfs/inode.c     | 13 +++++++------
 fs/overlayfs/namei.c     |  6 +++---
 fs/overlayfs/overlayfs.h | 37 +++++++++++++++++++++++++++----------
 fs/overlayfs/readdir.c   |  4 ++--
 fs/overlayfs/super.c     | 12 ++++++------
 fs/overlayfs/util.c      | 16 ++++++++--------
 8 files changed, 68 insertions(+), 46 deletions(-)

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index e040970408d4..104de97f85d6 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -47,6 +47,7 @@ static bool ovl_must_copy_xattr(const char *name)
 int ovl_copy_xattr(struct super_block *sb, struct dentry *old,
 		   struct dentry *new)
 {
+	struct ovl_fs *ofs = OVL_FS(sb);
 	ssize_t list_size, size, value_size = 0;
 	char *buf, *name, *value = NULL;
 	int error = 0;
@@ -117,7 +118,7 @@ int ovl_copy_xattr(struct super_block *sb, struct dentry *old,
 			goto retry;
 		}
 
-		error = vfs_setxattr(&init_user_ns, new, name, value, size, 0);
+		error = ovl_do_setxattr(ofs, new, name, value, size, 0);
 		if (error) {
 			if (error != -EOPNOTSUPP || ovl_must_copy_xattr(name))
 				break;
@@ -433,7 +434,7 @@ static int ovl_set_upper_fh(struct ovl_fs *ofs, struct dentry *upper,
 	if (IS_ERR(fh))
 		return PTR_ERR(fh);
 
-	err = ovl_do_setxattr(ofs, index, OVL_XATTR_UPPER, fh->buf, fh->fb.len);
+	err = ovl_setxattr(ofs, index, OVL_XATTR_UPPER, fh->buf, fh->fb.len);
 
 	kfree(fh);
 	return err;
@@ -865,12 +866,13 @@ static bool ovl_need_meta_copy_up(struct dentry *dentry, umode_t mode,
 	return true;
 }
 
-static ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value)
+static ssize_t ovl_getxattr_value(struct ovl_fs *ofs, struct dentry *dentry,
+				  char *name, char **value)
 {
 	ssize_t res;
 	char *buf;
 
-	res = vfs_getxattr(&init_user_ns, dentry, name, NULL, 0);
+	res = ovl_do_getxattr(ofs, dentry, name, NULL, 0);
 	if (res == -ENODATA || res == -EOPNOTSUPP)
 		res = 0;
 
@@ -879,7 +881,7 @@ static ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value)
 		if (!buf)
 			return -ENOMEM;
 
-		res = vfs_getxattr(&init_user_ns, dentry, name, buf, res);
+		res = ovl_do_getxattr(ofs, dentry, name, buf, res);
 		if (res < 0)
 			kfree(buf);
 		else
@@ -906,8 +908,8 @@ static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
 		return -EIO;
 
 	if (c->stat.size) {
-		err = cap_size = ovl_getxattr(upperpath.dentry, XATTR_NAME_CAPS,
-					      &capability);
+		err = cap_size = ovl_getxattr_value(ofs, upperpath.dentry,
+						    XATTR_NAME_CAPS, &capability);
 		if (cap_size < 0)
 			goto out;
 	}
@@ -921,14 +923,14 @@ static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
 	 * don't want that to happen for normal copy-up operation.
 	 */
 	if (capability) {
-		err = vfs_setxattr(&init_user_ns, upperpath.dentry,
-				   XATTR_NAME_CAPS, capability, cap_size, 0);
+		err = ovl_do_setxattr(ofs, upperpath.dentry, XATTR_NAME_CAPS,
+				      capability, cap_size, 0);
 		if (err)
 			goto out_free;
 	}
 
 
-	err = ovl_do_removexattr(ofs, upperpath.dentry, OVL_XATTR_METACOPY);
+	err = ovl_removexattr(ofs, upperpath.dentry, OVL_XATTR_METACOPY);
 	if (err)
 		goto out_free;
 
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index f18490813170..d21e3bbcf082 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -435,6 +435,7 @@ static struct dentry *ovl_clear_empty(struct dentry *dentry,
 static int ovl_set_upper_acl(struct dentry *upperdentry, const char *name,
 			     const struct posix_acl *acl)
 {
+	struct ovl_fs *ofs = OVL_FS(upperdentry->d_sb);
 	void *buffer;
 	size_t size;
 	int err;
@@ -451,7 +452,8 @@ static int ovl_set_upper_acl(struct dentry *upperdentry, const char *name,
 	if (err < 0)
 		goto out_free;
 
-	err = vfs_setxattr(&init_user_ns, upperdentry, name, buffer, size, XATTR_CREATE);
+	err = ovl_do_setxattr(ofs, upperdentry, name, buffer, size,
+			      XATTR_CREATE);
 out_free:
 	kfree(buffer);
 	return err;
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 1f36158c7dbe..c51a9dd36cc7 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -342,6 +342,7 @@ int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
 		  const void *value, size_t size, int flags)
 {
 	int err;
+	struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
 	struct dentry *upperdentry = ovl_i_dentry_upper(inode);
 	struct dentry *realdentry = upperdentry ?: ovl_dentry_lower(dentry);
 	const struct cred *old_cred;
@@ -368,11 +369,11 @@ int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
 
 	old_cred = ovl_override_creds(dentry->d_sb);
 	if (value)
-		err = vfs_setxattr(&init_user_ns, realdentry, name, value, size,
-				   flags);
+		err = ovl_do_setxattr(ofs, realdentry, name, value, size,
+				      flags);
 	else {
 		WARN_ON(flags != XATTR_REPLACE);
-		err = vfs_removexattr(&init_user_ns, realdentry, name);
+		err = ovl_do_removexattr(ofs, realdentry, name);
 	}
 	revert_creds(old_cred);
 
@@ -871,8 +872,8 @@ static int ovl_set_nlink_common(struct dentry *dentry,
 	if (WARN_ON(len >= sizeof(buf)))
 		return -EIO;
 
-	return ovl_do_setxattr(OVL_FS(inode->i_sb), ovl_dentry_upper(dentry),
-			       OVL_XATTR_NLINK, buf, len);
+	return ovl_setxattr(OVL_FS(inode->i_sb), ovl_dentry_upper(dentry),
+			    OVL_XATTR_NLINK, buf, len);
 }
 
 int ovl_set_nlink_upper(struct dentry *dentry)
@@ -897,7 +898,7 @@ unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry,
 	if (!lowerdentry || !upperdentry || d_inode(lowerdentry)->i_nlink == 1)
 		return fallback;
 
-	err = ovl_do_getxattr(ofs, upperdentry, OVL_XATTR_NLINK,
+	err = ovl_getxattr(ofs, upperdentry, OVL_XATTR_NLINK,
 			      &buf, sizeof(buf) - 1);
 	if (err < 0)
 		goto fail;
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index 1a9b515fc45d..042f6394a3d5 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -111,7 +111,7 @@ static struct ovl_fh *ovl_get_fh(struct ovl_fs *ofs, struct dentry *dentry,
 	int res, err;
 	struct ovl_fh *fh = NULL;
 
-	res = ovl_do_getxattr(ofs, dentry, ox, NULL, 0);
+	res = ovl_getxattr(ofs, dentry, ox, NULL, 0);
 	if (res < 0) {
 		if (res == -ENODATA || res == -EOPNOTSUPP)
 			return NULL;
@@ -125,7 +125,7 @@ static struct ovl_fh *ovl_get_fh(struct ovl_fs *ofs, struct dentry *dentry,
 	if (!fh)
 		return ERR_PTR(-ENOMEM);
 
-	res = ovl_do_getxattr(ofs, dentry, ox, fh->buf, res);
+	res = ovl_getxattr(ofs, dentry, ox, fh->buf, res);
 	if (res < 0)
 		goto fail;
 
@@ -464,7 +464,7 @@ int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
 
 	err = ovl_verify_fh(ofs, dentry, ox, fh);
 	if (set && err == -ENODATA)
-		err = ovl_do_setxattr(ofs, dentry, ox, fh->buf, fh->fb.len);
+		err = ovl_setxattr(ofs, dentry, ox, fh->buf, fh->fb.len);
 	if (err)
 		goto fail;
 
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 2cd5741c873b..6a53ca0d2c96 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -183,10 +183,9 @@ static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry,
 }
 
 static inline ssize_t ovl_do_getxattr(struct ovl_fs *ofs, struct dentry *dentry,
-				      enum ovl_xattr ox, void *value,
+				      const char *name, void *value,
 				      size_t size)
 {
-	const char *name = ovl_xattr(ofs, ox);
 	int err = vfs_getxattr(&init_user_ns, dentry, name, value, size);
 	int len = (value && err > 0) ? err : 0;
 
@@ -195,26 +194,44 @@ static inline ssize_t ovl_do_getxattr(struct ovl_fs *ofs, struct dentry *dentry,
 	return err;
 }
 
+static inline ssize_t ovl_getxattr(struct ovl_fs *ofs, struct dentry *dentry,
+				   enum ovl_xattr ox, void *value,
+				   size_t size)
+{
+	return ovl_do_getxattr(ofs, dentry, ovl_xattr(ofs, ox), value, size);
+}
+
 static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
-				  enum ovl_xattr ox, const void *value,
-				  size_t size)
+				  const char *name, const void *value,
+				  size_t size, int flags)
 {
-	const char *name = ovl_xattr(ofs, ox);
-	int err = vfs_setxattr(&init_user_ns, dentry, name, value, size, 0);
-	pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n",
-		 dentry, name, min((int)size, 48), value, size, err);
+	int err = vfs_setxattr(&init_user_ns, dentry, name, value, size, flags);
+	pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, %d) = %i\n",
+		 dentry, name, min((int)size, 48), value, size, flags, err);
 	return err;
 }
 
+static inline int ovl_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
+			       enum ovl_xattr ox, const void *value,
+			       size_t size)
+{
+	return ovl_do_setxattr(ofs, dentry, ovl_xattr(ofs, ox), value, size, 0);
+}
+
 static inline int ovl_do_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
-				     enum ovl_xattr ox)
+				     const char *name)
 {
-	const char *name = ovl_xattr(ofs, ox);
 	int err = vfs_removexattr(&init_user_ns, dentry, name);
 	pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
 	return err;
 }
 
+static inline int ovl_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
+				  enum ovl_xattr ox)
+{
+	return ovl_do_removexattr(ofs, dentry, ovl_xattr(ofs, ox));
+}
+
 static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry,
 				struct inode *newdir, struct dentry *newdentry,
 				unsigned int flags)
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index 150fdf3bc68d..c7b542331065 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -623,8 +623,8 @@ static struct ovl_dir_cache *ovl_cache_get_impure(struct path *path)
 		 * Removing the "impure" xattr is best effort.
 		 */
 		if (!ovl_want_write(dentry)) {
-			ovl_do_removexattr(ofs, ovl_dentry_upper(dentry),
-					   OVL_XATTR_IMPURE);
+			ovl_removexattr(ofs, ovl_dentry_upper(dentry),
+					OVL_XATTR_IMPURE);
 			ovl_drop_write(dentry);
 		}
 		ovl_clear_flag(OVL_IMPURE, d_inode(dentry));
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 7bb0a47cb615..f35116db6e94 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -809,13 +809,13 @@ static struct dentry *ovl_workdir_create(struct ovl_fs *ofs,
 		 * allowed as upper are limited to "normal" ones, where checking
 		 * for the above two errors is sufficient.
 		 */
-		err = vfs_removexattr(&init_user_ns, work,
-				      XATTR_NAME_POSIX_ACL_DEFAULT);
+		err = ovl_do_removexattr(ofs, work,
+					 XATTR_NAME_POSIX_ACL_DEFAULT);
 		if (err && err != -ENODATA && err != -EOPNOTSUPP)
 			goto out_dput;
 
-		err = vfs_removexattr(&init_user_ns, work,
-				      XATTR_NAME_POSIX_ACL_ACCESS);
+		err = ovl_do_removexattr(ofs, work,
+					 XATTR_NAME_POSIX_ACL_ACCESS);
 		if (err && err != -ENODATA && err != -EOPNOTSUPP)
 			goto out_dput;
 
@@ -1411,7 +1411,7 @@ static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs,
 	/*
 	 * Check if upper/work fs supports (trusted|user).overlay.* xattr
 	 */
-	err = ovl_do_setxattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE, "0", 1);
+	err = ovl_setxattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE, "0", 1);
 	if (err) {
 		ofs->noxattr = true;
 		if (ofs->config.index || ofs->config.metacopy) {
@@ -1429,7 +1429,7 @@ static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs,
 		}
 		err = 0;
 	} else {
-		ovl_do_removexattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE);
+		ovl_removexattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE);
 	}
 
 	/*
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index f48284a2a896..453551f56467 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -554,7 +554,7 @@ bool ovl_check_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry)
 {
 	int res;
 
-	res = ovl_do_getxattr(ofs, dentry, OVL_XATTR_ORIGIN, NULL, 0);
+	res = ovl_getxattr(ofs, dentry, OVL_XATTR_ORIGIN, NULL, 0);
 
 	/* Zero size value means "copied up but origin unknown" */
 	if (res >= 0)
@@ -572,7 +572,7 @@ bool ovl_check_dir_xattr(struct super_block *sb, struct dentry *dentry,
 	if (!d_is_dir(dentry))
 		return false;
 
-	res = ovl_do_getxattr(OVL_FS(sb), dentry, ox, &val, 1);
+	res = ovl_getxattr(OVL_FS(sb), dentry, ox, &val, 1);
 	if (res == 1 && val == 'y')
 		return true;
 
@@ -612,7 +612,7 @@ int ovl_check_setxattr(struct ovl_fs *ofs, struct dentry *upperdentry,
 	if (ofs->noxattr)
 		return xerr;
 
-	err = ovl_do_setxattr(ofs, upperdentry, ox, value, size);
+	err = ovl_setxattr(ofs, upperdentry, ox, value, size);
 
 	if (err == -EOPNOTSUPP) {
 		pr_warn("cannot set %s xattr on upper\n", ovl_xattr(ofs, ox));
@@ -652,7 +652,7 @@ void ovl_check_protattr(struct inode *inode, struct dentry *upper)
 	char buf[OVL_PROTATTR_MAX+1];
 	int res, n;
 
-	res = ovl_do_getxattr(ofs, upper, OVL_XATTR_PROTATTR, buf,
+	res = ovl_getxattr(ofs, upper, OVL_XATTR_PROTATTR, buf,
 			      OVL_PROTATTR_MAX);
 	if (res < 0)
 		return;
@@ -708,7 +708,7 @@ int ovl_set_protattr(struct inode *inode, struct dentry *upper,
 		err = ovl_check_setxattr(ofs, upper, OVL_XATTR_PROTATTR,
 					 buf, len, -EPERM);
 	} else if (inode->i_flags & OVL_PROT_I_FLAGS_MASK) {
-		err = ovl_do_removexattr(ofs, upper, OVL_XATTR_PROTATTR);
+		err = ovl_removexattr(ofs, upper, OVL_XATTR_PROTATTR);
 		if (err == -EOPNOTSUPP || err == -ENODATA)
 			err = 0;
 	}
@@ -951,7 +951,7 @@ int ovl_check_metacopy_xattr(struct ovl_fs *ofs, struct dentry *dentry)
 	if (!S_ISREG(d_inode(dentry)->i_mode))
 		return 0;
 
-	res = ovl_do_getxattr(ofs, dentry, OVL_XATTR_METACOPY, NULL, 0);
+	res = ovl_getxattr(ofs, dentry, OVL_XATTR_METACOPY, NULL, 0);
 	if (res < 0) {
 		if (res == -ENODATA || res == -EOPNOTSUPP)
 			return 0;
@@ -993,7 +993,7 @@ char *ovl_get_redirect_xattr(struct ovl_fs *ofs, struct dentry *dentry,
 	int res;
 	char *s, *next, *buf = NULL;
 
-	res = ovl_do_getxattr(ofs, dentry, OVL_XATTR_REDIRECT, NULL, 0);
+	res = ovl_getxattr(ofs, dentry, OVL_XATTR_REDIRECT, NULL, 0);
 	if (res == -ENODATA || res == -EOPNOTSUPP)
 		return NULL;
 	if (res < 0)
@@ -1005,7 +1005,7 @@ char *ovl_get_redirect_xattr(struct ovl_fs *ofs, struct dentry *dentry,
 	if (!buf)
 		return ERR_PTR(-ENOMEM);
 
-	res = ovl_do_getxattr(ofs, dentry, OVL_XATTR_REDIRECT, buf, res);
+	res = ovl_getxattr(ofs, dentry, OVL_XATTR_REDIRECT, buf, res);
 	if (res < 0)
 		goto fail;
 	if (res == 0)
-- 
2.32.0