fs: split off do_getxattr from getxattr

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>
Link: https://lore.kernel.org/r/20220323154420.3301504-3-shr@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/internal.h b/fs/internal.h
index 5fb219f..9a6c233 100644 (file)
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -212,6 +212,11 @@ struct xattr_ctx {
        unsigned int flags;
 };
 
+
+ssize_t do_getxattr(struct user_namespace *mnt_userns,
+                   struct dentry *d,
+                   struct xattr_ctx *ctx);
+
 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 7117cb2..e8dd03e 100644 (file)
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -676,44 +676,61 @@ 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,
+       struct xattr_ctx *ctx)
 {
        ssize_t error;
-       void *kvalue = NULL;
-       char kname[XATTR_NAME_MAX + 1];
+       char *kname = ctx->kname->name;
 
-       error = strncpy_from_user(kname, name, sizeof(kname));
-       if (error == 0 || error == sizeof(kname))
-               error = -ERANGE;
-       if (error < 0)
-               return error;
-
-       if (size) {
-               if (size > XATTR_SIZE_MAX)
-                       size = XATTR_SIZE_MAX;
-               kvalue = kvzalloc(size, GFP_KERNEL);
-               if (!kvalue)
+       if (ctx->size) {
+               if (ctx->size > XATTR_SIZE_MAX)
+                       ctx->size = XATTR_SIZE_MAX;
+               ctx->kvalue = kvzalloc(ctx->size, GFP_KERNEL);
+               if (!ctx->kvalue)
                        return -ENOMEM;
        }
 
-       error = vfs_getxattr(mnt_userns, d, kname, kvalue, size);
+       error = vfs_getxattr(mnt_userns, d, kname, ctx->kvalue, ctx->size);
        if (error > 0) {
                if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
                    (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
                        posix_acl_fix_xattr_to_user(mnt_userns, d_inode(d),
-                                                   kvalue, error);
-               if (size && copy_to_user(value, kvalue, error))
+                                                       ctx->kvalue, error);
+               if (ctx->size && copy_to_user(ctx->value, ctx->kvalue, error))
                        error = -EFAULT;
-       } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) {
+       } else if (error == -ERANGE && ctx->size >= XATTR_SIZE_MAX) {
                /* The file system tried to returned a value bigger
                   than XATTR_SIZE_MAX bytes. Not possible. */
                error = -E2BIG;
        }
 
-       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;
+       struct xattr_ctx ctx = {
+               .value    = value,
+               .kvalue   = NULL,
+               .size     = size,
+               .kname    = &kname,
+               .flags    = 0,
+       };
+
+       error = strncpy_from_user(kname.name, name, sizeof(kname.name));
+       if (error == 0 || error == sizeof(kname.name))
+               error = -ERANGE;
+       if (error < 0)
+               return error;
 
+       error =  do_getxattr(mnt_userns, d, &ctx);
+
+       kvfree(ctx.kvalue);
        return error;
 }