From: Byron Stanoszek <gandalf@winds.org> mainline inclusion from mainline-v5.9-rc6 commit bb3e96d63eb75a2f4ff790b089f6b93614c729a1 category: bugfix bugzilla: NA CVE: NA --------------------------- Commit e809d5f0b5c9 ("tmpfs: per-superblock i_ino support") made changes to shmem_reserve_inode() in mm/shmem.c, however the original test for (sbinfo->max_inodes) got dropped. This causes mounting tmpfs with option nr_inodes=0 to fail: # mount -ttmpfs -onr_inodes=0 none /ext0 mount: /ext0: mount(2) system call failed: Cannot allocate memory. This patch restores the nr_inodes=0 functionality. Fixes: e809d5f0b5c9 ("tmpfs: per-superblock i_ino support") Signed-off-by: Byron Stanoszek <gandalf@winds.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Hugh Dickins <hughd@google.com> Acked-by: Chris Down <chris@chrisdown.name> Link: https://lkml.kernel.org/r/20200902035715.16414-1-gandalf@winds.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Luo Meng <luomeng12@huawei.com> Reviewed-by: zhangyi (F) <yi.zhang@huawei.com> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Signed-off-by: Cheng Jian <cj.chengjian@huawei.com> --- mm/shmem.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index ad5ca9ed943e..b4be0be77327 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -284,11 +284,13 @@ static int shmem_reserve_inode(struct super_block *sb, ino_t *inop) if (!(sb->s_flags & SB_KERNMOUNT)) { spin_lock(&sbinfo->stat_lock); - if (!sbinfo->free_inodes) { - spin_unlock(&sbinfo->stat_lock); - return -ENOSPC; + if (sbinfo->max_inodes) { + if (!sbinfo->free_inodes) { + spin_unlock(&sbinfo->stat_lock); + return -ENOSPC; + } + sbinfo->free_inodes--; } - sbinfo->free_inodes--; if (inop) { ino = sbinfo->next_ino++; if (unlikely(is_zero_ino(ino))) -- 2.25.1