vfs-6.14-rc5.fixes

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Merge tag 'vfs-6.14-rc5.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs fixes from Christian Brauner:

 - Use __readahead_folio() in fuse again to fix a UAF issue
   when using splice

 - Remove d_op->d_delete method from pidfs

 - Remove d_op->d_delete method from nsfs

 - Simplify iomap_dio_bio_iter()

 - Fix a UAF in ovl_dentry_update_reval

 - Fix a miscalulated file range for filemap_fdatawrite_range_kick()

 - Don't skip skip dirty page in folio_unmap_invalidate()

* tag 'vfs-6.14-rc5.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  iomap: Minor code simplification in iomap_dio_bio_iter()
  nsfs: remove d_op->d_delete
  pidfs: remove d_op->d_delete
  mm/truncate: don't skip dirty page in folio_unmap_invalidate()
  mm/filemap: fix miscalculated file range for filemap_fdatawrite_range_kick()
  fuse: don't truncate cached, mutated symlink
  ovl: fix UAF in ovl_dentry_update_reval by moving dput() in ovl_link_up
  fuse: revert back to __readahead_folio() for readahead

fs/fuse/dev.c

@@ -838,6 +838,12 @@ static int fuse_check_folio(struct folio *folio)
 	return 0;
 }
 
+/*
+ * Attempt to steal a page from the splice() pipe and move it into the
+ * pagecache. If successful, the pointer in @pagep will be updated. The
+ * folio that was originally in @pagep will lose a reference and the new
+ * folio returned in @pagep will carry a reference.
+ */
 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
 {
 	int err;

fs/fuse/dir.c

@@ -1636,7 +1636,7 @@ static const char *fuse_get_link(struct dentry *dentry, struct inode *inode,
 		goto out_err;
 
 	if (fc->cache_symlinks)
-		return page_get_link(dentry, inode, callback);
+		return page_get_link_raw(dentry, inode, callback);
 
 	err = -ECHILD;
 	if (!dentry)

fs/fuse/file.c

@@ -955,8 +955,10 @@ static void fuse_readpages_end(struct fuse_mount *fm, struct fuse_args *args,
 		fuse_invalidate_atime(inode);
 	}
 
-	for (i = 0; i < ap->num_folios; i++)
+	for (i = 0; i < ap->num_folios; i++) {
 		folio_end_read(ap->folios[i], !err);
+		folio_put(ap->folios[i]);
+	}
 	if (ia->ff)
 		fuse_file_put(ia->ff, false);
 
@@ -1048,7 +1050,14 @@ static void fuse_readahead(struct readahead_control *rac)
 		ap = &ia->ap;
 
 		while (ap->num_folios < cur_pages) {
-			folio = readahead_folio(rac);
+			/*
+			 * This returns a folio with a ref held on it.
+			 * The ref needs to be held until the request is
+			 * completed, since the splice case (see
+			 * fuse_try_move_page()) drops the ref after it's
+			 * replaced in the page cache.
+			 */
+			folio = __readahead_folio(rac);
 			ap->folios[ap->num_folios] = folio;
 			ap->descs[ap->num_folios].length = folio_size(folio);
 			ap->num_folios++;

fs/iomap/direct-io.c

@@ -427,12 +427,10 @@ static loff_t iomap_dio_bio_iter(const struct iomap_iter *iter,
 			bio_put(bio);
 			goto zero_tail;
 		}
-		if (dio->flags & IOMAP_DIO_WRITE) {
+		if (dio->flags & IOMAP_DIO_WRITE)
 			task_io_account_write(n);
-		} else {
-			if (dio->flags & IOMAP_DIO_DIRTY)
-				bio_set_pages_dirty(bio);
-		}
+		else if (dio->flags & IOMAP_DIO_DIRTY)
+			bio_set_pages_dirty(bio);
 
 		dio->size += n;
 		copied += n;

fs/namei.c

@@ -5356,10 +5356,9 @@ const char *vfs_get_link(struct dentry *dentry, struct delayed_call *done)
 EXPORT_SYMBOL(vfs_get_link);
 
 /* get the link contents into pagecache */
-const char *page_get_link(struct dentry *dentry, struct inode *inode,
-			  struct delayed_call *callback)
+static char *__page_get_link(struct dentry *dentry, struct inode *inode,
+			     struct delayed_call *callback)
 {
-	char *kaddr;
 	struct page *page;
 	struct address_space *mapping = inode->i_mapping;
 
@@ -5378,8 +5377,23 @@ const char *page_get_link(struct dentry *dentry, struct inode *inode,
 	}
 	set_delayed_call(callback, page_put_link, page);
 	BUG_ON(mapping_gfp_mask(mapping) & __GFP_HIGHMEM);
-	kaddr = page_address(page);
-	nd_terminate_link(kaddr, inode->i_size, PAGE_SIZE - 1);
+	return page_address(page);
+}
+
+const char *page_get_link_raw(struct dentry *dentry, struct inode *inode,
+			      struct delayed_call *callback)
+{
+	return __page_get_link(dentry, inode, callback);
+}
+EXPORT_SYMBOL_GPL(page_get_link_raw);
+
+const char *page_get_link(struct dentry *dentry, struct inode *inode,
+					struct delayed_call *callback)
+{
+	char *kaddr = __page_get_link(dentry, inode, callback);
+
+	if (!IS_ERR(kaddr))
+		nd_terminate_link(kaddr, inode->i_size, PAGE_SIZE - 1);
 	return kaddr;
 }
 

fs/nsfs.c

@@ -37,7 +37,6 @@ static char *ns_dname(struct dentry *dentry, char *buffer, int buflen)
 }
 
 const struct dentry_operations ns_dentry_operations = {
-	.d_delete	= always_delete_dentry,
 	.d_dname	= ns_dname,
 	.d_prune	= stashed_dentry_prune,
 };

fs/overlayfs/copy_up.c

@@ -618,7 +618,6 @@ static int ovl_link_up(struct ovl_copy_up_ctx *c)
 	err = PTR_ERR(upper);
 	if (!IS_ERR(upper)) {
 		err = ovl_do_link(ofs, ovl_dentry_upper(c->dentry), udir, upper);
-		dput(upper);
 
 		if (!err) {
 			/* Restore timestamps on parent (best effort) */
@@ -626,6 +625,7 @@ static int ovl_link_up(struct ovl_copy_up_ctx *c)
 			ovl_dentry_set_upper_alias(c->dentry);
 			ovl_dentry_update_reval(c->dentry, upper);
 		}
+		dput(upper);
 	}
 	inode_unlock(udir);
 	if (err)

fs/pidfs.c

@@ -521,7 +521,6 @@ static char *pidfs_dname(struct dentry *dentry, char *buffer, int buflen)
 }
 
 const struct dentry_operations pidfs_dentry_operations = {
-	.d_delete	= always_delete_dentry,
 	.d_dname	= pidfs_dname,
 	.d_prune	= stashed_dentry_prune,
 };

include/linux/fs.h

@@ -2975,8 +2975,8 @@ static inline ssize_t generic_write_sync(struct kiocb *iocb, ssize_t count)
 	} else if (iocb->ki_flags & IOCB_DONTCACHE) {
 		struct address_space *mapping = iocb->ki_filp->f_mapping;
 
-		filemap_fdatawrite_range_kick(mapping, iocb->ki_pos,
-					      iocb->ki_pos + count);
+		filemap_fdatawrite_range_kick(mapping, iocb->ki_pos - count,
+					      iocb->ki_pos - 1);
 	}
 
 	return count;
@@ -3452,6 +3452,8 @@ extern const struct file_operations generic_ro_fops;
 
 extern int readlink_copy(char __user *, int, const char *, int);
 extern int page_readlink(struct dentry *, char __user *, int);
+extern const char *page_get_link_raw(struct dentry *, struct inode *,
+				     struct delayed_call *);
 extern const char *page_get_link(struct dentry *, struct inode *,
 				 struct delayed_call *);
 extern void page_put_link(void *);

mm/filemap.c

@@ -445,7 +445,7 @@ EXPORT_SYMBOL(filemap_fdatawrite_range);
  * filemap_fdatawrite_range_kick - start writeback on a range
  * @mapping:	target address_space
  * @start:	index to start writeback on
- * @end:	last (non-inclusive) index for writeback
+ * @end:	last (inclusive) index for writeback
  *
  * This is a non-integrity writeback helper, to start writing back folios
  * for the indicated range.

mm/truncate.c

@@ -548,8 +548,6 @@ int folio_unmap_invalidate(struct address_space *mapping, struct folio *folio,
 
 	VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
 
-	if (folio_test_dirty(folio))
-		return 0;
 	if (folio_mapped(folio))
 		unmap_mapping_folio(folio);
 	BUG_ON(folio_mapped(folio));