[PATCH v9 0/5] io_uring: add xattr support

[PATCH v9 0/5] io_uring: add xattr support

[Stefan Roesch]

This adds the xattr support to io_uring. The intent is to have a more
complete support for file operations in io_uring.

This change adds support for the following functions to io_uring:
- fgetxattr
- fsetxattr
- getxattr
- setxattr

Patch 1: fs: split off do_user_path_at_empty from user_path_at_empty()
  This splits off a new function do_user_path_at_empty from
  user_path_at_empty that is based on filename and not on a
  user-specified string.

Patch 2: fs: split off setxattr_copy and do_setxattr function from setxattr
  Split off the setup part of the setxattr function in the setxattr_copy
  function. Split off the processing part in do_setxattr.

Patch 3: fs: split off do_getxattr from getxattr
  Split of the do_getxattr part from getxattr. This will
  allow it to be invoked it from io_uring.

Patch 4: io_uring: add fsetxattr and setxattr support
  This adds new functions to support the fsetxattr and setxattr
  functions.

Patch 5: io_uring: add fgetxattr and getxattr support
  This adds new functions to support the fgetxattr and getxattr
  functions.


There are two additional patches:
  liburing: Add support for xattr api's.
            This also includes the tests for the new code.
  xfstests: Add support for io_uring xattr support.


V9: - keep kvalue in struct xattr_ctx
V8: - introduce xattr_name struct as advised by Linus
    - remove kname_sz field in xattr_ctx
V7: - split off setxattr in two functions as recommeneded by
      Christian.
V6: - reverted addition of kname array to xattr_ctx structure
      Adding the kname array increases the io_kiocb beyond 64 bytes
      (increases it to 224 bytes). We try hard to limit it to 64 bytes.
      Keeping the original interface also is a bit more efficient.
    - addressed Pavel's reordering comment
    - addressed Pavel's putname comment
    - addressed Pavel's kvfree comment
    - rebased on for-5.17/io_uring-getdents64
V5: - add kname array to xattr_ctx structure
V4: - rebased patch series
V3: - remove req->file checks in prep functions
    - change size parameter in do_xattr
V2: - split off function do_user_path_empty instead of changing
      the function signature of user_path_at
    - Fix datatype size problem in do_getxattr


Stefan Roesch (5):
  fs: split off do_user_path_at_empty from user_path_at_empty()
  fs: split off setxattr_copy and do_setxattr function from setxattr
  fs: split off do_getxattr from getxattr
  io_uring: add fsetxattr and setxattr support
  io_uring: add fgetxattr and getxattr support

 fs/internal.h                 |  28 +++
 fs/io_uring.c                 | 314 ++++++++++++++++++++++++++++++++++
 fs/namei.c                    |  10 +-
 fs/xattr.c                    | 114 ++++++++----
 include/linux/namei.h         |   2 +
 include/uapi/linux/io_uring.h |   8 +-
 6 files changed, 438 insertions(+), 38 deletions(-)


base-commit: b4518682080d3a1cdd6ea45a54ff6772b8b2797a
-- 
2.30.2

[PATCH v9 1/5] fs: split off do_user_path_at_empty from user_path_at_empty()

[Stefan Roesch]

This splits off a do_user_path_at_empty function from the
user_path_at_empty_function. This is required so it can be
called from io_uring.

Signed-off-by: Stefan Roesch <shr@fb.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
---
 fs/namei.c            | 10 ++++++++--
 include/linux/namei.h |  2 ++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 1f9d2187c765..d988e241b32c 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2794,12 +2794,18 @@ int path_pts(struct path *path)
 }
 #endif
 
+int do_user_path_at_empty(int dfd, struct filename *filename, unsigned int flags,
+		       struct path *path)
+{
+	return filename_lookup(dfd, filename, flags, path, NULL);
+}
+
 int user_path_at_empty(int dfd, const char __user *name, unsigned flags,
-		 struct path *path, int *empty)
+		struct path *path, int *empty)
 {
 	struct filename *filename = getname_flags(name, flags, empty);
-	int ret = filename_lookup(dfd, filename, flags, path, NULL);
 
+	int ret = do_user_path_at_empty(dfd, filename, flags, path);
 	putname(filename);
 	return ret;
 }
diff --git a/include/linux/namei.h b/include/linux/namei.h
index e89329bb3134..8f3ef38c057b 100644
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -49,6 +49,8 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT};
 
 extern int path_pts(struct path *path);
 
+extern int do_user_path_at_empty(int dfd, struct filename *filename,
+				unsigned int flags, struct path *path);
 extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty);
 
 static inline int user_path_at(int dfd, const char __user *name, unsigned flags,
-- 
2.30.2

[PATCH v9 2/5] fs: split off setxattr_copy and do_setxattr function from setxattr

[Stefan Roesch]

This splits of the setup part of the function
setxattr in its own dedicated function called
setxattr_copy. In addition it also exposes a
new function called do_setxattr for making the
setxattr call.

This makes it possible to call these two functions
from io_uring in the processing of an xattr request.

Signed-off-by: Stefan Roesch <shr@fb.com>
---
 fs/internal.h | 21 +++++++++++++
 fs/xattr.c    | 82 ++++++++++++++++++++++++++++++++++++---------------
 2 files changed, 80 insertions(+), 23 deletions(-)

diff --git a/fs/internal.h b/fs/internal.h
index 432ea3ce76ec..00c98b0cd634 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -202,3 +202,24 @@ struct linux_dirent64;
 
 int vfs_getdents(struct file *file, struct linux_dirent64 __user *dirent,
 		 unsigned int count, loff_t *pos);
+
+ /*
+  * fs/xattr.c:
+  */
+struct xattr_name {
+	char name[XATTR_NAME_MAX + 1];
+};
+
+struct xattr_ctx {
+	/* Value of attribute */
+	const void __user *value;
+	void *kvalue;
+	size_t size;
+	/* Attribute name */
+	struct xattr_name *kname;
+	unsigned int flags;
+};
+
+int setxattr_copy(const char __user *name, struct xattr_ctx *ctx);
+int do_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+		struct xattr_ctx *ctx);
diff --git a/fs/xattr.c b/fs/xattr.c
index 5c8c5175b385..923ba944d20e 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -25,6 +25,8 @@
 
 #include <linux/uaccess.h>
 
+#include "internal.h"
+
 static const char *
 strcmp_prefix(const char *a, const char *a_prefix)
 {
@@ -539,43 +541,77 @@ EXPORT_SYMBOL_GPL(vfs_removexattr);
 /*
  * Extended attribute SET operations
  */
-static long
-setxattr(struct user_namespace *mnt_userns, struct dentry *d,
-	 const char __user *name, const void __user *value, size_t size,
-	 int flags)
+
+int setxattr_copy(const char __user *name, struct xattr_ctx *ctx)
 {
 	int error;
-	void *kvalue = NULL;
-	char kname[XATTR_NAME_MAX + 1];
 
-	if (flags & ~(XATTR_CREATE|XATTR_REPLACE))
+	if (ctx->flags & ~(XATTR_CREATE|XATTR_REPLACE))
 		return -EINVAL;
 
-	error = strncpy_from_user(kname, name, sizeof(kname));
-	if (error == 0 || error == sizeof(kname))
-		error = -ERANGE;
+	error = strncpy_from_user(ctx->kname->name, name,
+				sizeof(ctx->kname->name));
+	if (error == 0 || error == sizeof(ctx->kname->name))
+		return  -ERANGE;
 	if (error < 0)
 		return error;
 
-	if (size) {
-		if (size > XATTR_SIZE_MAX)
+	if (ctx->size) {
+		if (ctx->size > XATTR_SIZE_MAX)
 			return -E2BIG;
-		kvalue = kvmalloc(size, GFP_KERNEL);
-		if (!kvalue)
+
+		ctx->kvalue = kvmalloc(ctx->size, GFP_KERNEL);
+		if (!ctx->kvalue)
 			return -ENOMEM;
-		if (copy_from_user(kvalue, value, size)) {
-			error = -EFAULT;
-			goto out;
+
+		if (copy_from_user(ctx->kvalue, ctx->value, ctx->size)) {
+			kvfree(ctx->kvalue);
+			return -EFAULT;
 		}
-		if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
-		    (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
-			posix_acl_fix_xattr_from_user(mnt_userns, kvalue, size);
 	}
 
-	error = vfs_setxattr(mnt_userns, d, kname, kvalue, size, flags);
-out:
-	kvfree(kvalue);
+	return 0;
+}
+
+static void setxattr_convert(struct user_namespace *mnt_userns,
+			struct xattr_ctx *ctx)
+{
+	if (ctx->size &&
+		((strcmp(ctx->kname->name, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
+		(strcmp(ctx->kname->name, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)))
+		posix_acl_fix_xattr_from_user(mnt_userns, ctx->kvalue, ctx->size);
+}
+
+int do_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+		struct xattr_ctx *ctx)
+{
+	setxattr_convert(mnt_userns, ctx);
+	return vfs_setxattr(mnt_userns, dentry, ctx->kname->name,
+			ctx->kvalue, ctx->size, ctx->flags);
+}
+
+static long
+setxattr(struct user_namespace *mnt_userns, struct dentry *d,
+	const char __user *name, const void __user *value, size_t size,
+	int flags)
+{
+	struct xattr_name kname;
+	struct xattr_ctx ctx = {
+		.value    = value,
+		.kvalue   = NULL,
+		.size     = size,
+		.kname    = &kname,
+		.flags    = flags,
+	};
+	int error;
+
+	error = setxattr_copy(name, &ctx);
+	if (error)
+		return error;
+
+	error = do_setxattr(mnt_userns, d, &ctx);
 
+	kvfree(ctx.kvalue);
 	return error;
 }
 
-- 
2.30.2

[PATCH v9 3/5] fs: split off do_getxattr from getxattr

[Stefan Roesch]

This splits off do_getxattr function from the getxattr
function. This will allow io_uring to call it from its
io worker.

Signed-off-by: Stefan Roesch <shr@fb.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
---
 fs/internal.h |  7 +++++++
 fs/xattr.c    | 32 ++++++++++++++++++++------------
 2 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/fs/internal.h b/fs/internal.h
index 00c98b0cd634..942b2005a2be 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -220,6 +220,13 @@ struct xattr_ctx {
 	unsigned int flags;
 };
 
+
+ssize_t do_getxattr(struct user_namespace *mnt_userns,
+		    struct dentry *d,
+		    const char *kname,
+		    void __user *value,
+		    size_t size);
+
 int setxattr_copy(const char __user *name, struct xattr_ctx *ctx);
 int do_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry,
 		struct xattr_ctx *ctx);
diff --git a/fs/xattr.c b/fs/xattr.c
index 923ba944d20e..3b6d683d07b9 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -677,19 +677,12 @@ SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
 /*
  * Extended attribute GET operations
  */
-static ssize_t
-getxattr(struct user_namespace *mnt_userns, struct dentry *d,
-	 const char __user *name, void __user *value, size_t size)
+ssize_t
+do_getxattr(struct user_namespace *mnt_userns, struct dentry *d,
+	const char *kname, void __user *value, size_t size)
 {
-	ssize_t error;
 	void *kvalue = NULL;
-	char kname[XATTR_NAME_MAX + 1];
-
-	error = strncpy_from_user(kname, name, sizeof(kname));
-	if (error == 0 || error == sizeof(kname))
-		error = -ERANGE;
-	if (error < 0)
-		return error;
+	ssize_t error;
 
 	if (size) {
 		if (size > XATTR_SIZE_MAX)
@@ -713,10 +706,25 @@ getxattr(struct user_namespace *mnt_userns, struct dentry *d,
 	}
 
 	kvfree(kvalue);
-
 	return error;
 }
 
+static ssize_t
+getxattr(struct user_namespace *mnt_userns, struct dentry *d,
+	 const char __user *name, void __user *value, size_t size)
+{
+	ssize_t error;
+	struct xattr_name kname;
+
+	error = strncpy_from_user(kname.name, name, sizeof(kname.name));
+	if (error == 0 || error == sizeof(kname.name))
+		error = -ERANGE;
+	if (error < 0)
+		return error;
+
+	return do_getxattr(mnt_userns, d, kname.name, value, size);
+}
+
 static ssize_t path_getxattr(const char __user *pathname,
 			     const char __user *name, void __user *value,
 			     size_t size, unsigned int lookup_flags)
-- 
2.30.2

[PATCH v9 4/5] io_uring: add fsetxattr and setxattr support

[Stefan Roesch]

This adds support to io_uring for the fsetxattr and setxattr API.

Signed-off-by: Stefan Roesch <shr@fb.com>
---
 fs/io_uring.c                 | 165 ++++++++++++++++++++++++++++++++++
 include/uapi/linux/io_uring.h |   6 +-
 2 files changed, 170 insertions(+), 1 deletion(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index c8258c784116..2a0138a2876a 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -82,6 +82,7 @@
 #include <linux/audit.h>
 #include <linux/security.h>
 #include <linux/atomic-ref.h>
+#include <linux/xattr.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/io_uring.h>
@@ -726,6 +727,12 @@ struct io_async_rw {
 	struct wait_page_queue		wpq;
 };
 
+struct io_xattr {
+	struct file			*file;
+	struct xattr_ctx		ctx;
+	struct filename			*filename;
+};
+
 enum {
 	REQ_F_FIXED_FILE_BIT	= IOSQE_FIXED_FILE_BIT,
 	REQ_F_IO_DRAIN_BIT	= IOSQE_IO_DRAIN_BIT,
@@ -866,6 +873,7 @@ struct io_kiocb {
 		struct io_symlink	symlink;
 		struct io_hardlink	hardlink;
 		struct io_getdents	getdents;
+		struct io_xattr		xattr;
 	};
 
 	u8				opcode;
@@ -1118,6 +1126,10 @@ static const struct io_op_def io_op_defs[] = {
 	[IORING_OP_GETDENTS] = {
 		.needs_file		= 1,
 	},
+	[IORING_OP_FSETXATTR] = {
+		.needs_file = 1
+	},
+	[IORING_OP_SETXATTR] = {},
 };
 
 /* requests with any of those set should undergo io_disarm_next() */
@@ -3887,6 +3899,140 @@ static int io_renameat(struct io_kiocb *req, unsigned int issue_flags)
 	return 0;
 }
 
+static int __io_setxattr_prep(struct io_kiocb *req,
+			const struct io_uring_sqe *sqe)
+{
+	struct io_xattr *ix = &req->xattr;
+	const char __user *name;
+	int ret;
+
+	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
+		return -EINVAL;
+	if (unlikely(sqe->ioprio))
+		return -EINVAL;
+	if (unlikely(req->flags & REQ_F_FIXED_FILE))
+		return -EBADF;
+
+	ix->filename = NULL;
+	name = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	ix->ctx.value = u64_to_user_ptr(READ_ONCE(sqe->addr2));
+	ix->ctx.kvalue = NULL;
+	ix->ctx.size = READ_ONCE(sqe->len);
+	ix->ctx.flags = READ_ONCE(sqe->xattr_flags);
+
+	ix->ctx.kname = kmalloc(sizeof(*ix->ctx.kname), GFP_KERNEL);
+	if (!ix->ctx.kname)
+		return -ENOMEM;
+
+	ret = setxattr_copy(name, &ix->ctx);
+	if (ret) {
+		kfree(ix->ctx.kname);
+		return ret;
+	}
+
+	req->flags |= REQ_F_NEED_CLEANUP;
+	return 0;
+}
+
+static int io_setxattr_prep(struct io_kiocb *req,
+			const struct io_uring_sqe *sqe)
+{
+	struct io_xattr *ix = &req->xattr;
+	const char __user *path;
+	int ret;
+
+	ret = __io_setxattr_prep(req, sqe);
+	if (ret)
+		return ret;
+
+	path = u64_to_user_ptr(READ_ONCE(sqe->addr3));
+
+	ix->filename = getname_flags(path, LOOKUP_FOLLOW, NULL);
+	if (IS_ERR(ix->filename)) {
+		ret = PTR_ERR(ix->filename);
+		ix->filename = NULL;
+	}
+
+	return ret;
+}
+
+static int io_fsetxattr_prep(struct io_kiocb *req,
+			const struct io_uring_sqe *sqe)
+{
+	return __io_setxattr_prep(req, sqe);
+}
+
+static int __io_setxattr(struct io_kiocb *req, unsigned int issue_flags,
+			struct path *path)
+{
+	struct io_xattr *ix = &req->xattr;
+	int ret;
+
+	ret = mnt_want_write(path->mnt);
+	if (!ret) {
+		ret = do_setxattr(mnt_user_ns(path->mnt), path->dentry, &ix->ctx);
+		mnt_drop_write(path->mnt);
+	}
+
+	return ret;
+}
+
+static int io_fsetxattr(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_xattr *ix = &req->xattr;
+	int ret;
+
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		return -EAGAIN;
+
+	ret = __io_setxattr(req, issue_flags, &req->file->f_path);
+
+	req->flags &= ~REQ_F_NEED_CLEANUP;
+	kfree(ix->ctx.kname);
+
+	if (ix->ctx.kvalue)
+		kvfree(ix->ctx.kvalue);
+	if (ret < 0)
+		req_set_fail(req);
+
+	io_req_complete(req, ret);
+	return 0;
+}
+
+static int io_setxattr(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_xattr *ix = &req->xattr;
+	unsigned int lookup_flags = LOOKUP_FOLLOW;
+	struct path path;
+	int ret;
+
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		return -EAGAIN;
+
+retry:
+	ret = do_user_path_at_empty(AT_FDCWD, ix->filename, lookup_flags, &path);
+	if (!ret) {
+		ret = __io_setxattr(req, issue_flags, &path);
+		path_put(&path);
+		if (retry_estale(ret, lookup_flags)) {
+			lookup_flags |= LOOKUP_REVAL;
+			goto retry;
+		}
+	}
+	putname(ix->filename);
+
+	req->flags &= ~REQ_F_NEED_CLEANUP;
+	kfree(ix->ctx.kname);
+
+	if (ix->ctx.kvalue)
+		kvfree(ix->ctx.kvalue);
+	if (ret < 0)
+		req_set_fail(req);
+
+	io_req_complete(req, ret);
+	return 0;
+}
+
 static int io_unlinkat_prep(struct io_kiocb *req,
 			    const struct io_uring_sqe *sqe)
 {
@@ -6623,6 +6769,10 @@ static int io_req_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 		return io_linkat_prep(req, sqe);
 	case IORING_OP_GETDENTS:
 		return io_getdents_prep(req, sqe);
+	case IORING_OP_FSETXATTR:
+		return io_fsetxattr_prep(req, sqe);
+	case IORING_OP_SETXATTR:
+		return io_setxattr_prep(req, sqe);
 	}
 
 	printk_once(KERN_WARNING "io_uring: unhandled opcode %d\n",
@@ -6764,6 +6914,14 @@ static void io_clean_op(struct io_kiocb *req)
 			putname(req->hardlink.oldpath);
 			putname(req->hardlink.newpath);
 			break;
+		case IORING_OP_SETXATTR:
+			if (req->xattr.filename)
+				putname(req->xattr.filename);
+			fallthrough;
+		case IORING_OP_FSETXATTR:
+			kfree(req->xattr.ctx.kname);
+			kvfree(req->xattr.ctx.kvalue);
+			break;
 		}
 	}
 	if ((req->flags & REQ_F_POLLED) && req->apoll) {
@@ -6909,6 +7067,12 @@ static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags)
 	case IORING_OP_GETDENTS:
 		ret = io_getdents(req, issue_flags);
 		break;
+	case IORING_OP_FSETXATTR:
+		ret = io_fsetxattr(req, issue_flags);
+		break;
+	case IORING_OP_SETXATTR:
+		ret = io_setxattr(req, issue_flags);
+		break;
 	default:
 		ret = -EINVAL;
 		break;
@@ -11277,6 +11441,7 @@ static int __init io_uring_init(void)
 	BUILD_BUG_SQE_ELEM(42, __u16,  personality);
 	BUILD_BUG_SQE_ELEM(44, __s32,  splice_fd_in);
 	BUILD_BUG_SQE_ELEM(44, __u32,  file_index);
+	BUILD_BUG_SQE_ELEM(48, __u64,  addr3);
 
 	BUILD_BUG_ON(sizeof(struct io_uring_files_update) !=
 		     sizeof(struct io_uring_rsrc_update));
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 57dc88db5793..c62a8bec8cd4 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -45,6 +45,7 @@ struct io_uring_sqe {
 		__u32		rename_flags;
 		__u32		unlink_flags;
 		__u32		hardlink_flags;
+		__u32		xattr_flags;
 	};
 	__u64	user_data;	/* data to be passed back at completion time */
 	/* pack this to avoid bogus arm OABI complaints */
@@ -60,7 +61,8 @@ struct io_uring_sqe {
 		__s32	splice_fd_in;
 		__u32	file_index;
 	};
-	__u64	__pad2[2];
+	__u64	addr3;
+	__u64	__pad2[1];
 };
 
 enum {
@@ -144,6 +146,8 @@ enum {
 	IORING_OP_SYMLINKAT,
 	IORING_OP_LINKAT,
 	IORING_OP_GETDENTS,
+	IORING_OP_FSETXATTR,
+	IORING_OP_SETXATTR,
 
 	/* this goes last, obviously */
 	IORING_OP_LAST,
-- 
2.30.2

[PATCH v9 5/5] io_uring: add fgetxattr and getxattr support

[Stefan Roesch]

This adds support to io_uring for the fgetxattr and getxattr API.

Signed-off-by: Stefan Roesch <shr@fb.com>
---
 fs/io_uring.c                 | 149 ++++++++++++++++++++++++++++++++++
 include/uapi/linux/io_uring.h |   2 +
 2 files changed, 151 insertions(+)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 2a0138a2876a..5b8370a62547 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1130,6 +1130,10 @@ static const struct io_op_def io_op_defs[] = {
 		.needs_file = 1
 	},
 	[IORING_OP_SETXATTR] = {},
+	[IORING_OP_FGETXATTR] = {
+		.needs_file = 1
+	},
+	[IORING_OP_GETXATTR] = {},
 };
 
 /* requests with any of those set should undergo io_disarm_next() */
@@ -3899,6 +3903,134 @@ static int io_renameat(struct io_kiocb *req, unsigned int issue_flags)
 	return 0;
 }
 
+static int __io_getxattr_prep(struct io_kiocb *req,
+			      const struct io_uring_sqe *sqe)
+{
+	struct io_xattr *ix = &req->xattr;
+	const char __user *name;
+	int ret;
+
+	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
+		return -EINVAL;
+	if (unlikely(sqe->ioprio))
+		return -EINVAL;
+	if (unlikely(req->flags & REQ_F_FIXED_FILE))
+		return -EBADF;
+
+	ix->filename = NULL;
+	ix->ctx.kvalue = NULL;
+	name = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	ix->ctx.value = u64_to_user_ptr(READ_ONCE(sqe->addr2));
+	ix->ctx.size = READ_ONCE(sqe->len);
+	ix->ctx.flags = READ_ONCE(sqe->xattr_flags);
+
+	if (ix->ctx.flags)
+		return -EINVAL;
+
+	ix->ctx.kname = kmalloc(sizeof(*ix->ctx.kname), GFP_KERNEL);
+	if (!ix->ctx.kname)
+		return -ENOMEM;
+
+	ret = strncpy_from_user(ix->ctx.kname->name, name,
+				sizeof(ix->ctx.kname->name));
+	if (!ret || ret == sizeof(ix->ctx.kname->name))
+		ret = -ERANGE;
+	if (ret < 0) {
+		kfree(ix->ctx.kname);
+		return ret;
+	}
+
+	req->flags |= REQ_F_NEED_CLEANUP;
+	return 0;
+}
+
+static int io_fgetxattr_prep(struct io_kiocb *req,
+			     const struct io_uring_sqe *sqe)
+{
+	return __io_getxattr_prep(req, sqe);
+}
+
+static int io_getxattr_prep(struct io_kiocb *req,
+			    const struct io_uring_sqe *sqe)
+{
+	struct io_xattr *ix = &req->xattr;
+	const char __user *path;
+	int ret;
+
+	ret = __io_getxattr_prep(req, sqe);
+	if (ret)
+		return ret;
+
+	path = u64_to_user_ptr(READ_ONCE(sqe->addr3));
+
+	ix->filename = getname_flags(path, LOOKUP_FOLLOW, NULL);
+	if (IS_ERR(ix->filename)) {
+		ret = PTR_ERR(ix->filename);
+		ix->filename = NULL;
+	}
+
+	return ret;
+}
+
+static int io_fgetxattr(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_xattr *ix = &req->xattr;
+	int ret;
+
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		return -EAGAIN;
+
+	ret = do_getxattr(mnt_user_ns(req->file->f_path.mnt),
+			req->file->f_path.dentry,
+			ix->ctx.kname->name,
+			(void __user *)ix->ctx.value,
+			ix->ctx.size);
+
+	req->flags &= ~REQ_F_NEED_CLEANUP;
+	kfree(ix->ctx.kname);
+	if (ret < 0)
+		req_set_fail(req);
+
+	io_req_complete(req, ret);
+	return 0;
+}
+
+static int io_getxattr(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_xattr *ix = &req->xattr;
+	unsigned int lookup_flags = LOOKUP_FOLLOW;
+	struct path path;
+	int ret;
+
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		return -EAGAIN;
+
+retry:
+	ret = do_user_path_at_empty(AT_FDCWD, ix->filename, lookup_flags, &path);
+	if (!ret) {
+		ret = do_getxattr(mnt_user_ns(path.mnt),
+				path.dentry,
+				ix->ctx.kname->name,
+				(void __user *)ix->ctx.value,
+				ix->ctx.size);
+
+		path_put(&path);
+		if (retry_estale(ret, lookup_flags)) {
+			lookup_flags |= LOOKUP_REVAL;
+			goto retry;
+		}
+	}
+	putname(ix->filename);
+
+	req->flags &= ~REQ_F_NEED_CLEANUP;
+	kfree(ix->ctx.kname);
+	if (ret < 0)
+		req_set_fail(req);
+
+	io_req_complete(req, ret);
+	return 0;
+}
+
 static int __io_setxattr_prep(struct io_kiocb *req,
 			const struct io_uring_sqe *sqe)
 {
@@ -6773,6 +6905,10 @@ static int io_req_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 		return io_fsetxattr_prep(req, sqe);
 	case IORING_OP_SETXATTR:
 		return io_setxattr_prep(req, sqe);
+	case IORING_OP_FGETXATTR:
+		return io_fgetxattr_prep(req, sqe);
+	case IORING_OP_GETXATTR:
+		return io_getxattr_prep(req, sqe);
 	}
 
 	printk_once(KERN_WARNING "io_uring: unhandled opcode %d\n",
@@ -6922,6 +7058,13 @@ static void io_clean_op(struct io_kiocb *req)
 			kfree(req->xattr.ctx.kname);
 			kvfree(req->xattr.ctx.kvalue);
 			break;
+		case IORING_OP_GETXATTR:
+			if (req->xattr.filename)
+				putname(req->xattr.filename);
+			fallthrough;
+		case IORING_OP_FGETXATTR:
+			kfree(req->xattr.ctx.kname);
+			break;
 		}
 	}
 	if ((req->flags & REQ_F_POLLED) && req->apoll) {
@@ -7073,6 +7216,12 @@ static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags)
 	case IORING_OP_SETXATTR:
 		ret = io_setxattr(req, issue_flags);
 		break;
+	case IORING_OP_FGETXATTR:
+		ret = io_fgetxattr(req, issue_flags);
+		break;
+	case IORING_OP_GETXATTR:
+		ret = io_getxattr(req, issue_flags);
+		break;
 	default:
 		ret = -EINVAL;
 		break;
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index c62a8bec8cd4..efc7ac9b3a6b 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -148,6 +148,8 @@ enum {
 	IORING_OP_GETDENTS,
 	IORING_OP_FSETXATTR,
 	IORING_OP_SETXATTR,
+	IORING_OP_FGETXATTR,
+	IORING_OP_GETXATTR,
 
 	/* this goes last, obviously */
 	IORING_OP_LAST,
-- 
2.30.2

Re: [PATCH v9 1/5] fs: split off do_user_path_at_empty from user_path_at_empty()

[Christian Brauner]

On Tue, Dec 28, 2021 at 10:41:41AM -0800, Stefan Roesch wrote:
> This splits off a do_user_path_at_empty function from the
> user_path_at_empty_function. This is required so it can be
> called from io_uring.
> 
> Signed-off-by: Stefan Roesch <shr@fb.com>
> Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
> ---
>  fs/namei.c            | 10 ++++++++--
>  include/linux/namei.h |  2 ++
>  2 files changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/namei.c b/fs/namei.c
> index 1f9d2187c765..d988e241b32c 100644
> --- a/fs/namei.c
> +++ b/fs/namei.c
> @@ -2794,12 +2794,18 @@ int path_pts(struct path *path)
>  }
>  #endif
>  
> +int do_user_path_at_empty(int dfd, struct filename *filename, unsigned int flags,
> +		       struct path *path)
> +{
> +	return filename_lookup(dfd, filename, flags, path, NULL);
> +}
> +
>  int user_path_at_empty(int dfd, const char __user *name, unsigned flags,
> -		 struct path *path, int *empty)
> +		struct path *path, int *empty)
>  {
>  	struct filename *filename = getname_flags(name, flags, empty);
> -	int ret = filename_lookup(dfd, filename, flags, path, NULL);
>  
> +	int ret = do_user_path_at_empty(dfd, filename, flags, path);
>  	putname(filename);
>  	return ret;
>  }
> diff --git a/include/linux/namei.h b/include/linux/namei.h
> index e89329bb3134..8f3ef38c057b 100644
> --- a/include/linux/namei.h
> +++ b/include/linux/namei.h
> @@ -49,6 +49,8 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT};
>  
>  extern int path_pts(struct path *path);
>  
> +extern int do_user_path_at_empty(int dfd, struct filename *filename,
> +				unsigned int flags, struct path *path);

Sorry, just seeing this now but this wants to live in internal.h not in
namei.h similar to all the other io_uring specific exports we added over
the last releases. There's no need to make this a kernel-wide thing if
we can avoid it, imho. With that changed:
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>

Re: [PATCH v9 2/5] fs: split off setxattr_copy and do_setxattr function from setxattr

[Christian Brauner]

On Tue, Dec 28, 2021 at 10:41:42AM -0800, Stefan Roesch wrote:
> This splits of the setup part of the function
> setxattr in its own dedicated function called
> setxattr_copy. In addition it also exposes a
> new function called do_setxattr for making the
> setxattr call.
> 
> This makes it possible to call these two functions
> from io_uring in the processing of an xattr request.
> 
> Signed-off-by: Stefan Roesch <shr@fb.com>
> ---

(One completely optional thing below.)

Looks good,
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>

>  fs/internal.h | 21 +++++++++++++
>  fs/xattr.c    | 82 ++++++++++++++++++++++++++++++++++++---------------
>  2 files changed, 80 insertions(+), 23 deletions(-)
> 
> diff --git a/fs/internal.h b/fs/internal.h
> index 432ea3ce76ec..00c98b0cd634 100644
> --- a/fs/internal.h
> +++ b/fs/internal.h
> @@ -202,3 +202,24 @@ struct linux_dirent64;
>  
>  int vfs_getdents(struct file *file, struct linux_dirent64 __user *dirent,
>  		 unsigned int count, loff_t *pos);
> +
> + /*
> +  * fs/xattr.c:
> +  */
> +struct xattr_name {
> +	char name[XATTR_NAME_MAX + 1];
> +};

Fwiw, one additional idea is to implement this similar to struct
filename and have it keep the __user name together with the kernel name:

struct xattr_name {
	const __user char	*uname;	/* original userland pointer */
	char name[XATTR_NAME_MAX + 1];
};

and then sm like:

From 3d85d31eb65f007e48e838fce776f16811732fc0 Mon Sep 17 00:00:00 2001
From: Christian Brauner <christian.brauner@ubuntu.com>
Date: Wed, 29 Dec 2021 15:43:46 +0100
Subject: [PATCH] UNTESTED

---
 fs/internal.h |  3 ++-
 fs/io_uring.c | 18 ++++++++----------
 fs/xattr.c    | 20 +++++++++++---------
 3 files changed, 21 insertions(+), 20 deletions(-)

diff --git a/fs/internal.h b/fs/internal.h
index 942b2005a2be..bb97042ebd04 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -207,7 +207,8 @@ int vfs_getdents(struct file *file, struct linux_dirent64 __user *dirent,
   * fs/xattr.c:
   */
 struct xattr_name {
-	char name[XATTR_NAME_MAX + 1];
+	const char __user *uname;
+	char kname[XATTR_NAME_MAX + 1];
 };
 
 struct xattr_ctx {
diff --git a/fs/io_uring.c b/fs/io_uring.c
index c88916b8cccc..55ad854d3c64 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3916,7 +3916,6 @@ static int __io_getxattr_prep(struct io_kiocb *req,
 			      const struct io_uring_sqe *sqe)
 {
 	struct io_xattr *ix = &req->xattr;
-	const char __user *name;
 	int ret;
 
 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
@@ -3928,7 +3927,7 @@ static int __io_getxattr_prep(struct io_kiocb *req,
 
 	ix->filename = NULL;
 	ix->ctx.kvalue = NULL;
-	name = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	ix->ctx.name = u64_to_user_ptr(READ_ONCE(sqe->addr));
 	ix->ctx.value = u64_to_user_ptr(READ_ONCE(sqe->addr2));
 	ix->ctx.size = READ_ONCE(sqe->len);
 	ix->ctx.flags = READ_ONCE(sqe->xattr_flags);
@@ -3940,9 +3939,9 @@ static int __io_getxattr_prep(struct io_kiocb *req,
 	if (!ix->ctx.kname)
 		return -ENOMEM;
 
-	ret = strncpy_from_user(ix->ctx.kname->name, name,
-				sizeof(ix->ctx.kname->name));
-	if (!ret || ret == sizeof(ix->ctx.kname->name))
+	ret = strncpy_from_user(ix->ctx.kname->kname, ix->ctx.name,
+				sizeof(ix->ctx.kname->kname));
+	if (!ret || ret == sizeof(ix->ctx.kname->kname))
 		ret = -ERANGE;
 	if (ret < 0) {
 		kfree(ix->ctx.kname);
@@ -3991,7 +3990,7 @@ static int io_fgetxattr(struct io_kiocb *req, unsigned int issue_flags)
 
 	ret = do_getxattr(mnt_user_ns(req->file->f_path.mnt),
 			req->file->f_path.dentry,
-			ix->ctx.kname->name,
+			ix->ctx.kname->kname,
 			(void __user *)ix->ctx.value,
 			ix->ctx.size);
 
@@ -4019,7 +4018,7 @@ static int io_getxattr(struct io_kiocb *req, unsigned int issue_flags)
 	if (!ret) {
 		ret = do_getxattr(mnt_user_ns(path.mnt),
 				path.dentry,
-				ix->ctx.kname->name,
+				ix->ctx.kname->kname,
 				(void __user *)ix->ctx.value,
 				ix->ctx.size);
 
@@ -4044,7 +4043,6 @@ static int __io_setxattr_prep(struct io_kiocb *req,
 			const struct io_uring_sqe *sqe)
 {
 	struct io_xattr *ix = &req->xattr;
-	const char __user *name;
 	int ret;
 
 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
@@ -4055,7 +4053,7 @@ static int __io_setxattr_prep(struct io_kiocb *req,
 		return -EBADF;
 
 	ix->filename = NULL;
-	name = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	ix->ctx.name = u64_to_user_ptr(READ_ONCE(sqe->addr));
 	ix->ctx.value = u64_to_user_ptr(READ_ONCE(sqe->addr2));
 	ix->ctx.kvalue = NULL;
 	ix->ctx.size = READ_ONCE(sqe->len);
@@ -4065,7 +4063,7 @@ static int __io_setxattr_prep(struct io_kiocb *req,
 	if (!ix->ctx.kname)
 		return -ENOMEM;
 
-	ret = setxattr_copy(name, &ix->ctx);
+	ret = setxattr_copy(&ix->ctx);
 	if (ret) {
 		kfree(ix->ctx.kname);
 		return ret;
diff --git a/fs/xattr.c b/fs/xattr.c
index 3b6d683d07b9..27c64bb0ca65 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -542,16 +542,16 @@ EXPORT_SYMBOL_GPL(vfs_removexattr);
  * Extended attribute SET operations
  */
 
-int setxattr_copy(const char __user *name, struct xattr_ctx *ctx)
+int setxattr_copy(struct xattr_ctx *ctx)
 {
 	int error;
 
 	if (ctx->flags & ~(XATTR_CREATE|XATTR_REPLACE))
 		return -EINVAL;
 
-	error = strncpy_from_user(ctx->kname->name, name,
-				sizeof(ctx->kname->name));
-	if (error == 0 || error == sizeof(ctx->kname->name))
+	error = strncpy_from_user(ctx->kname->kname, ctx->kname->name,
+				sizeof(ctx->kname->kname));
+	if (error == 0 || error == sizeof(ctx->kname->kname))
 		return  -ERANGE;
 	if (error < 0)
 		return error;
@@ -577,8 +577,8 @@ static void setxattr_convert(struct user_namespace *mnt_userns,
 			struct xattr_ctx *ctx)
 {
 	if (ctx->size &&
-		((strcmp(ctx->kname->name, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
-		(strcmp(ctx->kname->name, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)))
+		((strcmp(ctx->kname->kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
+		(strcmp(ctx->kname->kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)))
 		posix_acl_fix_xattr_from_user(mnt_userns, ctx->kvalue, ctx->size);
 }
 
@@ -586,7 +586,7 @@ int do_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry,
 		struct xattr_ctx *ctx)
 {
 	setxattr_convert(mnt_userns, ctx);
-	return vfs_setxattr(mnt_userns, dentry, ctx->kname->name,
+	return vfs_setxattr(mnt_userns, dentry, ctx->kname->kname,
 			ctx->kvalue, ctx->size, ctx->flags);
 }
 
@@ -595,7 +595,9 @@ setxattr(struct user_namespace *mnt_userns, struct dentry *d,
 	const char __user *name, const void __user *value, size_t size,
 	int flags)
 {
-	struct xattr_name kname;
+	struct xattr_name kname = {
+		.uname = name;
+	};
 	struct xattr_ctx ctx = {
 		.value    = value,
 		.kvalue   = NULL,
@@ -605,7 +607,7 @@ setxattr(struct user_namespace *mnt_userns, struct dentry *d,
 	};
 	int error;
 
-	error = setxattr_copy(name, &ctx);
+	error = setxattr_copy(&ctx);
 	if (error)
 		return error;
 
-- 
2.30.2

Re: [PATCH v9 4/5] io_uring: add fsetxattr and setxattr support

[Christian Brauner]

On Tue, Dec 28, 2021 at 10:41:44AM -0800, Stefan Roesch wrote:
> This adds support to io_uring for the fsetxattr and setxattr API.
> 
> Signed-off-by: Stefan Roesch <shr@fb.com>
> ---
>  fs/io_uring.c                 | 165 ++++++++++++++++++++++++++++++++++
>  include/uapi/linux/io_uring.h |   6 +-
>  2 files changed, 170 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index c8258c784116..2a0138a2876a 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -82,6 +82,7 @@
>  #include <linux/audit.h>
>  #include <linux/security.h>
>  #include <linux/atomic-ref.h>
> +#include <linux/xattr.h>
>  
>  #define CREATE_TRACE_POINTS
>  #include <trace/events/io_uring.h>
> @@ -726,6 +727,12 @@ struct io_async_rw {
>  	struct wait_page_queue		wpq;
>  };
>  
> +struct io_xattr {
> +	struct file			*file;
> +	struct xattr_ctx		ctx;
> +	struct filename			*filename;
> +};
> +
>  enum {
>  	REQ_F_FIXED_FILE_BIT	= IOSQE_FIXED_FILE_BIT,
>  	REQ_F_IO_DRAIN_BIT	= IOSQE_IO_DRAIN_BIT,
> @@ -866,6 +873,7 @@ struct io_kiocb {
>  		struct io_symlink	symlink;
>  		struct io_hardlink	hardlink;
>  		struct io_getdents	getdents;
> +		struct io_xattr		xattr;
>  	};
>  
>  	u8				opcode;
> @@ -1118,6 +1126,10 @@ static const struct io_op_def io_op_defs[] = {
>  	[IORING_OP_GETDENTS] = {
>  		.needs_file		= 1,
>  	},
> +	[IORING_OP_FSETXATTR] = {
> +		.needs_file = 1
> +	},
> +	[IORING_OP_SETXATTR] = {},
>  };
>  
>  /* requests with any of those set should undergo io_disarm_next() */
> @@ -3887,6 +3899,140 @@ static int io_renameat(struct io_kiocb *req, unsigned int issue_flags)
>  	return 0;
>  }
>  
> +static int __io_setxattr_prep(struct io_kiocb *req,
> +			const struct io_uring_sqe *sqe)
> +{
> +	struct io_xattr *ix = &req->xattr;
> +	const char __user *name;
> +	int ret;
> +
> +	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
> +		return -EINVAL;
> +	if (unlikely(sqe->ioprio))
> +		return -EINVAL;
> +	if (unlikely(req->flags & REQ_F_FIXED_FILE))
> +		return -EBADF;
> +
> +	ix->filename = NULL;
> +	name = u64_to_user_ptr(READ_ONCE(sqe->addr));
> +	ix->ctx.value = u64_to_user_ptr(READ_ONCE(sqe->addr2));
> +	ix->ctx.kvalue = NULL;
> +	ix->ctx.size = READ_ONCE(sqe->len);
> +	ix->ctx.flags = READ_ONCE(sqe->xattr_flags);
> +
> +	ix->ctx.kname = kmalloc(sizeof(*ix->ctx.kname), GFP_KERNEL);
> +	if (!ix->ctx.kname)
> +		return -ENOMEM;
> +
> +	ret = setxattr_copy(name, &ix->ctx);
> +	if (ret) {
> +		kfree(ix->ctx.kname);
> +		return ret;
> +	}
> +
> +	req->flags |= REQ_F_NEED_CLEANUP;
> +	return 0;
> +}
> +
> +static int io_setxattr_prep(struct io_kiocb *req,
> +			const struct io_uring_sqe *sqe)
> +{
> +	struct io_xattr *ix = &req->xattr;
> +	const char __user *path;
> +	int ret;
> +
> +	ret = __io_setxattr_prep(req, sqe);
> +	if (ret)
> +		return ret;
> +
> +	path = u64_to_user_ptr(READ_ONCE(sqe->addr3));
> +
> +	ix->filename = getname_flags(path, LOOKUP_FOLLOW, NULL);
> +	if (IS_ERR(ix->filename)) {
> +		ret = PTR_ERR(ix->filename);
> +		ix->filename = NULL;
> +	}
> +
> +	return ret;
> +}
> +
> +static int io_fsetxattr_prep(struct io_kiocb *req,
> +			const struct io_uring_sqe *sqe)
> +{
> +	return __io_setxattr_prep(req, sqe);
> +}
> +
> +static int __io_setxattr(struct io_kiocb *req, unsigned int issue_flags,
> +			struct path *path)
> +{
> +	struct io_xattr *ix = &req->xattr;
> +	int ret;
> +
> +	ret = mnt_want_write(path->mnt);
> +	if (!ret) {
> +		ret = do_setxattr(mnt_user_ns(path->mnt), path->dentry, &ix->ctx);
> +		mnt_drop_write(path->mnt);
> +	}
> +
> +	return ret;
> +}
> +
> +static int io_fsetxattr(struct io_kiocb *req, unsigned int issue_flags)
> +{
> +	struct io_xattr *ix = &req->xattr;
> +	int ret;
> +
> +	if (issue_flags & IO_URING_F_NONBLOCK)
> +		return -EAGAIN;
> +
> +	ret = __io_setxattr(req, issue_flags, &req->file->f_path);
> +
> +	req->flags &= ~REQ_F_NEED_CLEANUP;
> +	kfree(ix->ctx.kname);
> +
> +	if (ix->ctx.kvalue)
> +		kvfree(ix->ctx.kvalue);
> +	if (ret < 0)
> +		req_set_fail(req);
> +
> +	io_req_complete(req, ret);
> +	return 0;
> +}
> +
> +static int io_setxattr(struct io_kiocb *req, unsigned int issue_flags)
> +{
> +	struct io_xattr *ix = &req->xattr;
> +	unsigned int lookup_flags = LOOKUP_FOLLOW;
> +	struct path path;
> +	int ret;
> +
> +	if (issue_flags & IO_URING_F_NONBLOCK)
> +		return -EAGAIN;
> +
> +retry:
> +	ret = do_user_path_at_empty(AT_FDCWD, ix->filename, lookup_flags, &path);
> +	if (!ret) {
> +		ret = __io_setxattr(req, issue_flags, &path);
> +		path_put(&path);
> +		if (retry_estale(ret, lookup_flags)) {
> +			lookup_flags |= LOOKUP_REVAL;
> +			goto retry;
> +		}
> +	}
> +	putname(ix->filename);
> +
> +	req->flags &= ~REQ_F_NEED_CLEANUP;
> +	kfree(ix->ctx.kname);
> +
> +	if (ix->ctx.kvalue)
> +		kvfree(ix->ctx.kvalue);
> +	if (ret < 0)
> +		req_set_fail(req);
> +
> +	io_req_complete(req, ret);
> +	return 0;
> +}

(One suggestin below.)

Looks good,
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>

You could minimize the redudancy by implementing a simple helper
callable from both io_fsetxattr() and io_setxattr() if you think it's
worth with. So sm like:

From 2f837aa2a19b5cd8e73fffb9b87b6e6b22c5cae7 Mon Sep 17 00:00:00 2001
From: Christian Brauner <christian.brauner@ubuntu.com>
Date: Wed, 29 Dec 2021 15:22:34 +0100
Subject: [PATCH] UNTESTED

---
 fs/io_uring.c | 36 +++++++++++++++++-------------------
 1 file changed, 17 insertions(+), 19 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 7204b8d593e4..c88916b8cccc 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4118,6 +4118,21 @@ static int __io_setxattr(struct io_kiocb *req, unsigned int issue_flags,
 	return ret;
 }
 
+static void __io_setxattr_finish(struct io_kiocb *req, int ret)
+{
+	struct xattr_ctx *ctx = &req->xattr.ctx;
+
+	req->flags &= ~REQ_F_NEED_CLEANUP;
+
+	kfree(ctx->kname);
+	if (ctx->kvalue)
+		kvfree(ctx->kvalue);
+
+	if (ret < 0)
+		req_set_fail(req);
+
+	io_req_complete(req, ret);
+}
+
 static int io_fsetxattr(struct io_kiocb *req, unsigned int issue_flags)
 {
 	struct io_xattr *ix = &req->xattr;
@@ -4127,16 +4142,7 @@ static int io_fsetxattr(struct io_kiocb *req, unsigned int issue_flags)
 		return -EAGAIN;
 
 	ret = __io_setxattr(req, issue_flags, &req->file->f_path);
-
-	req->flags &= ~REQ_F_NEED_CLEANUP;
-	kfree(ix->ctx.kname);
-
-	if (ix->ctx.kvalue)
-		kvfree(ix->ctx.kvalue);
-	if (ret < 0)
-		req_set_fail(req);
-
-	io_req_complete(req, ret);
+	__io_setxattr_finish(req, ret);
 	return 0;
 }
 
@@ -4162,15 +4168,7 @@ static int io_setxattr(struct io_kiocb *req, unsigned int issue_flags)
 	}
 	putname(ix->filename);
 
-	req->flags &= ~REQ_F_NEED_CLEANUP;
-	kfree(ix->ctx.kname);
-
-	if (ix->ctx.kvalue)
-		kvfree(ix->ctx.kvalue);
-	if (ret < 0)
-		req_set_fail(req);
-
-	io_req_complete(req, ret);
+	__io_setxattr_finish(req, ret);
 	return 0;
 }
 
-- 
2.30.2

Re: [PATCH v9 1/5] fs: split off do_user_path_at_empty from user_path_at_empty()

[Stefan Roesch]

On 12/29/21 6:31 AM, Christian Brauner wrote:
> On Tue, Dec 28, 2021 at 10:41:41AM -0800, Stefan Roesch wrote:
>> This splits off a do_user_path_at_empty function from the
>> user_path_at_empty_function. This is required so it can be
>> called from io_uring.
>>
>> Signed-off-by: Stefan Roesch <shr@fb.com>
>> Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
>> ---
>>  fs/namei.c            | 10 ++++++++--
>>  include/linux/namei.h |  2 ++
>>  2 files changed, 10 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/namei.c b/fs/namei.c
>> index 1f9d2187c765..d988e241b32c 100644
>> --- a/fs/namei.c
>> +++ b/fs/namei.c
>> @@ -2794,12 +2794,18 @@ int path_pts(struct path *path)
>>  }
>>  #endif
>>  
>> +int do_user_path_at_empty(int dfd, struct filename *filename, unsigned int flags,
>> +		       struct path *path)
>> +{
>> +	return filename_lookup(dfd, filename, flags, path, NULL);
>> +}
>> +
>>  int user_path_at_empty(int dfd, const char __user *name, unsigned flags,
>> -		 struct path *path, int *empty)
>> +		struct path *path, int *empty)
>>  {
>>  	struct filename *filename = getname_flags(name, flags, empty);
>> -	int ret = filename_lookup(dfd, filename, flags, path, NULL);
>>  
>> +	int ret = do_user_path_at_empty(dfd, filename, flags, path);
>>  	putname(filename);
>>  	return ret;
>>  }
>> diff --git a/include/linux/namei.h b/include/linux/namei.h
>> index e89329bb3134..8f3ef38c057b 100644
>> --- a/include/linux/namei.h
>> +++ b/include/linux/namei.h
>> @@ -49,6 +49,8 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT};
>>  
>>  extern int path_pts(struct path *path);
>>  
>> +extern int do_user_path_at_empty(int dfd, struct filename *filename,
>> +				unsigned int flags, struct path *path);
> 
> Sorry, just seeing this now but this wants to live in internal.h not in
> namei.h similar to all the other io_uring specific exports we added over
> the last releases. There's no need to make this a kernel-wide thing if
> we can avoid it, imho. With that changed:
> Acked-by: Christian Brauner <christian.brauner@ubuntu.com>

I moved the declaration to fs/internal.h.

> 

Re: [PATCH v9 4/5] io_uring: add fsetxattr and setxattr support

[Stefan Roesch]

On 12/29/21 6:51 AM, Christian Brauner wrote:
> On Tue, Dec 28, 2021 at 10:41:44AM -0800, Stefan Roesch wrote:
>> This adds support to io_uring for the fsetxattr and setxattr API.
>>
>> Signed-off-by: Stefan Roesch <shr@fb.com>
>> ---
>>  fs/io_uring.c                 | 165 ++++++++++++++++++++++++++++++++++
>>  include/uapi/linux/io_uring.h |   6 +-
>>  2 files changed, 170 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/io_uring.c b/fs/io_uring.c
>> index c8258c784116..2a0138a2876a 100644
>> --- a/fs/io_uring.c
>> +++ b/fs/io_uring.c
>> @@ -82,6 +82,7 @@
>>  #include <linux/audit.h>
>>  #include <linux/security.h>
>>  #include <linux/atomic-ref.h>
>> +#include <linux/xattr.h>
>>  
>>  #define CREATE_TRACE_POINTS
>>  #include <trace/events/io_uring.h>
>> @@ -726,6 +727,12 @@ struct io_async_rw {
>>  	struct wait_page_queue		wpq;
>>  };
>>  
>> +struct io_xattr {
>> +	struct file			*file;
>> +	struct xattr_ctx		ctx;
>> +	struct filename			*filename;
>> +};
>> +
>>  enum {
>>  	REQ_F_FIXED_FILE_BIT	= IOSQE_FIXED_FILE_BIT,
>>  	REQ_F_IO_DRAIN_BIT	= IOSQE_IO_DRAIN_BIT,
>> @@ -866,6 +873,7 @@ struct io_kiocb {
>>  		struct io_symlink	symlink;
>>  		struct io_hardlink	hardlink;
>>  		struct io_getdents	getdents;
>> +		struct io_xattr		xattr;
>>  	};
>>  
>>  	u8				opcode;
>> @@ -1118,6 +1126,10 @@ static const struct io_op_def io_op_defs[] = {
>>  	[IORING_OP_GETDENTS] = {
>>  		.needs_file		= 1,
>>  	},
>> +	[IORING_OP_FSETXATTR] = {
>> +		.needs_file = 1
>> +	},
>> +	[IORING_OP_SETXATTR] = {},
>>  };
>>  
>>  /* requests with any of those set should undergo io_disarm_next() */
>> @@ -3887,6 +3899,140 @@ static int io_renameat(struct io_kiocb *req, unsigned int issue_flags)
>>  	return 0;
>>  }
>>  
>> +static int __io_setxattr_prep(struct io_kiocb *req,
>> +			const struct io_uring_sqe *sqe)
>> +{
>> +	struct io_xattr *ix = &req->xattr;
>> +	const char __user *name;
>> +	int ret;
>> +
>> +	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
>> +		return -EINVAL;
>> +	if (unlikely(sqe->ioprio))
>> +		return -EINVAL;
>> +	if (unlikely(req->flags & REQ_F_FIXED_FILE))
>> +		return -EBADF;
>> +
>> +	ix->filename = NULL;
>> +	name = u64_to_user_ptr(READ_ONCE(sqe->addr));
>> +	ix->ctx.value = u64_to_user_ptr(READ_ONCE(sqe->addr2));
>> +	ix->ctx.kvalue = NULL;
>> +	ix->ctx.size = READ_ONCE(sqe->len);
>> +	ix->ctx.flags = READ_ONCE(sqe->xattr_flags);
>> +
>> +	ix->ctx.kname = kmalloc(sizeof(*ix->ctx.kname), GFP_KERNEL);
>> +	if (!ix->ctx.kname)
>> +		return -ENOMEM;
>> +
>> +	ret = setxattr_copy(name, &ix->ctx);
>> +	if (ret) {
>> +		kfree(ix->ctx.kname);
>> +		return ret;
>> +	}
>> +
>> +	req->flags |= REQ_F_NEED_CLEANUP;
>> +	return 0;
>> +}
>> +
>> +static int io_setxattr_prep(struct io_kiocb *req,
>> +			const struct io_uring_sqe *sqe)
>> +{
>> +	struct io_xattr *ix = &req->xattr;
>> +	const char __user *path;
>> +	int ret;
>> +
>> +	ret = __io_setxattr_prep(req, sqe);
>> +	if (ret)
>> +		return ret;
>> +
>> +	path = u64_to_user_ptr(READ_ONCE(sqe->addr3));
>> +
>> +	ix->filename = getname_flags(path, LOOKUP_FOLLOW, NULL);
>> +	if (IS_ERR(ix->filename)) {
>> +		ret = PTR_ERR(ix->filename);
>> +		ix->filename = NULL;
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +static int io_fsetxattr_prep(struct io_kiocb *req,
>> +			const struct io_uring_sqe *sqe)
>> +{
>> +	return __io_setxattr_prep(req, sqe);
>> +}
>> +
>> +static int __io_setxattr(struct io_kiocb *req, unsigned int issue_flags,
>> +			struct path *path)
>> +{
>> +	struct io_xattr *ix = &req->xattr;
>> +	int ret;
>> +
>> +	ret = mnt_want_write(path->mnt);
>> +	if (!ret) {
>> +		ret = do_setxattr(mnt_user_ns(path->mnt), path->dentry, &ix->ctx);
>> +		mnt_drop_write(path->mnt);
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +static int io_fsetxattr(struct io_kiocb *req, unsigned int issue_flags)
>> +{
>> +	struct io_xattr *ix = &req->xattr;
>> +	int ret;
>> +
>> +	if (issue_flags & IO_URING_F_NONBLOCK)
>> +		return -EAGAIN;
>> +
>> +	ret = __io_setxattr(req, issue_flags, &req->file->f_path);
>> +
>> +	req->flags &= ~REQ_F_NEED_CLEANUP;
>> +	kfree(ix->ctx.kname);
>> +
>> +	if (ix->ctx.kvalue)
>> +		kvfree(ix->ctx.kvalue);
>> +	if (ret < 0)
>> +		req_set_fail(req);
>> +
>> +	io_req_complete(req, ret);
>> +	return 0;
>> +}
>> +
>> +static int io_setxattr(struct io_kiocb *req, unsigned int issue_flags)
>> +{
>> +	struct io_xattr *ix = &req->xattr;
>> +	unsigned int lookup_flags = LOOKUP_FOLLOW;
>> +	struct path path;
>> +	int ret;
>> +
>> +	if (issue_flags & IO_URING_F_NONBLOCK)
>> +		return -EAGAIN;
>> +
>> +retry:
>> +	ret = do_user_path_at_empty(AT_FDCWD, ix->filename, lookup_flags, &path);
>> +	if (!ret) {
>> +		ret = __io_setxattr(req, issue_flags, &path);
>> +		path_put(&path);
>> +		if (retry_estale(ret, lookup_flags)) {
>> +			lookup_flags |= LOOKUP_REVAL;
>> +			goto retry;
>> +		}
>> +	}
>> +	putname(ix->filename);
>> +
>> +	req->flags &= ~REQ_F_NEED_CLEANUP;
>> +	kfree(ix->ctx.kname);
>> +
>> +	if (ix->ctx.kvalue)
>> +		kvfree(ix->ctx.kvalue);
>> +	if (ret < 0)
>> +		req_set_fail(req);
>> +
>> +	io_req_complete(req, ret);
>> +	return 0;
>> +}
> 
> (One suggestin below.)
> 
> Looks good,
> Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
> 
> You could minimize the redudancy by implementing a simple helper
> callable from both io_fsetxattr() and io_setxattr() if you think it's
> worth with. So sm like:
> 
> From 2f837aa2a19b5cd8e73fffb9b87b6e6b22c5cae7 Mon Sep 17 00:00:00 2001
> From: Christian Brauner <christian.brauner@ubuntu.com>
> Date: Wed, 29 Dec 2021 15:22:34 +0100
> Subject: [PATCH] UNTESTED
> 

I added the helper function. I made a similar change for the get case.


> ---
>  fs/io_uring.c | 36 +++++++++++++++++-------------------
>  1 file changed, 17 insertions(+), 19 deletions(-)
> 
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index 7204b8d593e4..c88916b8cccc 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -4118,6 +4118,21 @@ static int __io_setxattr(struct io_kiocb *req, unsigned int issue_flags,
>  	return ret;
>  }
>  
> +static void __io_setxattr_finish(struct io_kiocb *req, int ret)
> +{
> +	struct xattr_ctx *ctx = &req->xattr.ctx;
> +
> +	req->flags &= ~REQ_F_NEED_CLEANUP;
> +
> +	kfree(ctx->kname);
> +	if (ctx->kvalue)
> +		kvfree(ctx->kvalue);
> +
> +	if (ret < 0)
> +		req_set_fail(req);
> +
> +	io_req_complete(req, ret);
> +}
> +
>  static int io_fsetxattr(struct io_kiocb *req, unsigned int issue_flags)
>  {
>  	struct io_xattr *ix = &req->xattr;
> @@ -4127,16 +4142,7 @@ static int io_fsetxattr(struct io_kiocb *req, unsigned int issue_flags)
>  		return -EAGAIN;
>  
>  	ret = __io_setxattr(req, issue_flags, &req->file->f_path);
> -
> -	req->flags &= ~REQ_F_NEED_CLEANUP;
> -	kfree(ix->ctx.kname);
> -
> -	if (ix->ctx.kvalue)
> -		kvfree(ix->ctx.kvalue);
> -	if (ret < 0)
> -		req_set_fail(req);
> -
> -	io_req_complete(req, ret);
> +	__io_setxattr_finish(req, ret);
>  	return 0;
>  }
>  
> @@ -4162,15 +4168,7 @@ static int io_setxattr(struct io_kiocb *req, unsigned int issue_flags)
>  	}
>  	putname(ix->filename);
>  
> -	req->flags &= ~REQ_F_NEED_CLEANUP;
> -	kfree(ix->ctx.kname);
> -
> -	if (ix->ctx.kvalue)
> -		kvfree(ix->ctx.kvalue);
> -	if (ret < 0)
> -		req_set_fail(req);
> -
> -	io_req_complete(req, ret);
> +	__io_setxattr_finish(req, ret);
>  	return 0;
>  }
>  
>