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authorChristian Brauner <brauner@kernel.org>2023-02-01 16:15:01 +0300
committerChristian Brauner (Microsoft) <brauner@kernel.org>2023-03-06 11:59:20 +0300
commite499214ce3ef50c50522719e753a1ffc928c2ec1 (patch)
tree63f403e964ca4b9e80eacad844177b416306d9a0 /fs/xattr.c
parenta1fbb607340d49f208e90cc0d7bdfff2141cce8d (diff)
downloadlinux-e499214ce3ef50c50522719e753a1ffc928c2ec1.tar.xz
acl: don't depend on IOP_XATTR
All codepaths that don't want to implement POSIX ACLs should simply not implement the associated inode operations instead of relying on IOP_XATTR. That's the case for all filesystems today. For vfs_listxattr() all filesystems that explicitly turn of xattrs for a given inode all set inode->i_op to a dedicated set of inode operations that doesn't implement ->listxattr(). We can remove the dependency of vfs_listxattr() on IOP_XATTR. Removing this dependency will allow us to decouple POSIX ACLs from IOP_XATTR and they can still be listed even if no other xattr handlers are implemented. Otherwise we would have to implement elaborate schemes to raise IOP_XATTR even if sb->s_xattr is set to NULL. Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Diffstat (limited to 'fs/xattr.c')
-rw-r--r--fs/xattr.c25
1 files changed, 24 insertions, 1 deletions
diff --git a/fs/xattr.c b/fs/xattr.c
index 95bb6b30ab13..fcf67d80d7f9 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -458,6 +458,28 @@ nolsm:
}
EXPORT_SYMBOL_GPL(vfs_getxattr);
+/**
+ * vfs_listxattr - retrieve \0 separated list of xattr names
+ * @dentry: the dentry from whose inode the xattr names are retrieved
+ * @list: buffer to store xattr names into
+ * @size: size of the buffer
+ *
+ * This function returns the names of all xattrs associated with the
+ * inode of @dentry.
+ *
+ * Note, for legacy reasons the vfs_listxattr() function lists POSIX
+ * ACLs as well. Since POSIX ACLs are decoupled from IOP_XATTR the
+ * vfs_listxattr() function doesn't check for this flag since a
+ * filesystem could implement POSIX ACLs without implementing any other
+ * xattrs.
+ *
+ * However, since all codepaths that remove IOP_XATTR also assign of
+ * inode operations that either don't implement or implement a stub
+ * ->listxattr() operation.
+ *
+ * Return: On success, the size of the buffer that was used. On error a
+ * negative error code.
+ */
ssize_t
vfs_listxattr(struct dentry *dentry, char *list, size_t size)
{
@@ -467,7 +489,8 @@ vfs_listxattr(struct dentry *dentry, char *list, size_t size)
error = security_inode_listxattr(dentry);
if (error)
return error;
- if (inode->i_op->listxattr && (inode->i_opflags & IOP_XATTR)) {
+
+ if (inode->i_op->listxattr) {
error = inode->i_op->listxattr(dentry, list, size);
} else {
error = security_inode_listsecurity(inode, list, size);