Subject: [PATCH] P: linux-5.14/ext4-projid-xattrs.patch

---
 fs/ext4/ext4.h  |  1 +
 fs/ext4/ioctl.c |  4 +--
 fs/ext4/xattr.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 87 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index afca42d..9ba2e8b 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -3164,6 +3164,7 @@ extern int ext4_ind_remove_space(handle_t *handle, struct inode *inode,
 				 ext4_lblk_t start, ext4_lblk_t end);
 
 /* ioctl.c */
+extern int ext4_ioctl_setproject(struct inode *, __u32);
 extern long ext4_ioctl(struct file *, unsigned int, unsigned long);
 extern long ext4_compat_ioctl(struct file *, unsigned int, unsigned long);
 int ext4_fileattr_set(struct user_namespace *mnt_userns,
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 6eed617..88cb1fb 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -461,7 +461,7 @@ flags_out:
 }
 
 #ifdef CONFIG_QUOTA
-static int ext4_ioctl_setproject(struct inode *inode, __u32 projid)
+int ext4_ioctl_setproject(struct inode *inode, __u32 projid)
 {
 	struct super_block *sb = inode->i_sb;
 	struct ext4_inode_info *ei = EXT4_I(inode);
@@ -546,7 +546,7 @@ out_stop:
 	return err;
 }
 #else
-static int ext4_ioctl_setproject(struct inode *inode, __u32 projid)
+int ext4_ioctl_setproject(struct inode *inode, __u32 projid)
 {
 	if (projid != EXT4_DEF_PROJID)
 		return -EOPNOTSUPP;
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index aabc92e..442bfbd 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -62,6 +62,8 @@
 #include "xattr.h"
 #include "acl.h"
 
+#define EXT4_XATTR_PROJID "projid"
+
 #ifdef EXT4_XATTR_DEBUG
 # define ea_idebug(inode, fmt, ...)					\
 	printk(KERN_DEBUG "inode %s:%lu: " fmt "\n",			\
@@ -648,11 +650,30 @@ ext4_xattr_get(struct inode *inode, int name_index, const char *name,
 		return -ERANGE;
 
 	down_read(&EXT4_I(inode)->xattr_sem);
+	if (name_index == EXT4_XATTR_INDEX_TRUSTED &&
+	    strncmp(name, EXT4_XATTR_PROJID, strlen(name)) == 0 &&
+	    ext4_has_feature_project(inode->i_sb)) {
+		/* 10 chars to hold u32 in decimal, plus ending \0 */
+		char value[11];
+		__u32 projid = (__u32)from_kprojid(&init_user_ns,
+						   EXT4_I(inode)->i_projid);
+		error = snprintf(value, sizeof(value), "%u", projid);
+		if (buffer) {
+			if (error > buffer_size) {
+				error = -ERANGE;
+				goto out;
+			}
+			memcpy(buffer, value, error);
+		}
+		goto out;
+	}
+
 	error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
 				     buffer_size);
 	if (error == -ENODATA)
 		error = ext4_xattr_block_get(inode, name_index, name, buffer,
 					     buffer_size);
+out:
 	up_read(&EXT4_I(inode)->xattr_sem);
 	return error;
 }
@@ -775,7 +796,33 @@ ext4_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
 	ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
 	if (ret < 0)
 		goto errout;
+	if (buffer) {
+		buffer += ret;
+		buffer_size -= ret;
+	}
 	ret += ret2;
+	if (ext4_has_feature_project(dentry->d_sb)) {
+		size_t prefix_len = strlen(XATTR_TRUSTED_PREFIX);
+		size_t name_len = strlen(EXT4_XATTR_PROJID);
+		size_t size = prefix_len + name_len + 1;
+
+		if (__kprojid_val(EXT4_I(dentry->d_inode)->i_projid) ==
+							EXT4_DEF_PROJID)
+			goto errout;
+		if (buffer) {
+			if (size > buffer_size) {
+				ret = -ERANGE;
+				goto errout;
+			}
+			strncpy(buffer, XATTR_TRUSTED_PREFIX, prefix_len);
+			buffer += prefix_len;
+			strncpy(buffer, EXT4_XATTR_PROJID, name_len);
+			buffer += name_len;
+			*buffer++ = 0;
+			buffer_size -= size;
+		}
+		ret += size;
+	}
 errout:
 	up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
 	return ret;
@@ -2456,6 +2503,43 @@ ext4_xattr_set(struct inode *inode, int name_index, const char *name,
 	int error, retries = 0;
 	int credits;
 
+	if (name_index == EXT4_XATTR_INDEX_TRUSTED &&
+	    strncmp(name, EXT4_XATTR_PROJID, strlen(name)) == 0 &&
+	    ext4_has_feature_project(inode->i_sb)) {
+		/* 10 chars to hold u32 in decimal, plus ending \0 */
+		char buffer[11];
+		__u32 projid;
+
+		/*
+		 * Project Quota ID state is only allowed to change from within
+		 * the init namespace.
+		 */
+		if (current_user_ns() != &init_user_ns)
+			return -EINVAL;
+
+		if (value && value_len) {
+			if (value_len >= sizeof(buffer))
+				return -EINVAL;
+			memcpy(buffer, value, value_len);
+			buffer[value_len] = '\0';
+			error = kstrtouint(buffer, 0, &projid);
+			if (error)
+				return error;
+		} else {
+			projid = EXT4_DEF_PROJID;
+		}
+
+		/*
+		 * Caller is allowed to change the project ID. If it is being
+		 * changed, make sure that the new value is valid.
+		 */
+		if (!projid_valid(make_kprojid(&init_user_ns, projid)))
+			return -EINVAL;
+
+		error = ext4_ioctl_setproject(inode, projid);
+		return error;
+	}
+
 	error = dquot_initialize(inode);
 	if (error)
 		return error;
-- 
2.27.0