>From 09084a94d2b176e33ee52a0bb41409988e6ff744 Mon Sep 17 00:00:00 2001 From: Vegard Nossum Date: Wed, 6 Jul 2016 15:01:36 +0200 Subject: [PATCH] ext4: fix reference counting bug on block allocation error If we hit this error when mounted with errors=continue or errors=remount-ro: EXT4-fs error (device loop0): ext4_mb_mark_diskspace_used:2940: comm ext4.exe: Allocating blocks 5090-6081 which overlap fs metadata then ext4_mb_new_blocks() will call ext4_mb_release_context() and try to continue. However, ext4_mb_release_context() is the wrong thing to call here since we are still actually using the allocation context. Instead, just error out. We could retry the allocation, but there is a possibility of getting stuck in an infinite loop instead, so this seems safer. Fixes: 8556e8f3b6 ("ext4: Don't allow new groups to be added during block allocation") Cc: Aneesh Kumar K.V Signed-off-by: Vegard Nossum --- fs/ext4/mballoc.c | 13 +------------ 1 file changed, 1 insertion(+), 12 deletions(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index c1ab3ec..e65400a 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -4513,18 +4513,7 @@ repeat: } if (likely(ac->ac_status == AC_STATUS_FOUND)) { *errp = ext4_mb_mark_diskspace_used(ac, handle, reserv_clstrs); - if (*errp == -EAGAIN) { - /* - * drop the reference that we took - * in ext4_mb_use_best_found - */ - ext4_mb_release_context(ac); - ac->ac_b_ex.fe_group = 0; - ac->ac_b_ex.fe_start = 0; - ac->ac_b_ex.fe_len = 0; - ac->ac_status = AC_STATUS_CONTINUE; - goto repeat; - } else if (*errp) { + if (*errp) { ext4_discard_allocated_blocks(ac); goto errout; } else { -- 1.9.1