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Commit e7676a70 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: don't allow ext4_free_blocks() to fail due to ENOMEM 



The filesystem should not be marked inconsistent if ext4_free_blocks()
is not able to allocate memory.  Unfortunately some callers (most
notably ext4_truncate) don't have a way to reflect an error back up to
the VFS.  And even if we did, most userspace applications won't deal
with most system calls returning ENOMEM anyway.

Reported-by: default avatarNagachandra P <nagachandra@gmail.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
parent bdafe42a

fs/ext4/mballoc.c

+8 −3
Original line number Diff line number Diff line
@@ -4740,11 +4740,16 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode, 
		 * blocks being freed are metadata. these blocks shouldn't

		 * be used until this transaction is committed

		 */

	retry:

		new_entry = kmem_cache_alloc(ext4_free_data_cachep, GFP_NOFS);

		if (!new_entry) {

			ext4_mb_unload_buddy(&e4b);

			err = -ENOMEM;

			goto error_return;

			/*

			 * We use a retry loop because

			 * ext4_free_blocks() is not allowed to fail.

			 */

			cond_resched();

			congestion_wait(BLK_RW_ASYNC, HZ/50);

			goto retry;

		}

		new_entry->efd_start_cluster = bit;

		new_entry->efd_group = block_group;