From fc5da22ae35d4720be59af8787a8a6d5e4da9517 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Thu, 14 Apr 2011 15:22:07 -0700 Subject: [PATCH] tmpfs: fix off-by-one in max_blocks checks If you fill up a tmpfs, df was showing tmpfs 460800 - - - /tmp because of an off-by-one in the max_blocks checks. Fix it so df shows tmpfs 460800 460800 0 100% /tmp Signed-off-by: Hugh Dickins Cc: Tim Chen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/shmem.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index 58da7c150ba6..8fa27e4e582a 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -421,7 +421,8 @@ static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long * a waste to allocate index if we cannot allocate data. */ if (sbinfo->max_blocks) { - if (percpu_counter_compare(&sbinfo->used_blocks, (sbinfo->max_blocks - 1)) > 0) + if (percpu_counter_compare(&sbinfo->used_blocks, + sbinfo->max_blocks - 1) >= 0) return ERR_PTR(-ENOSPC); percpu_counter_inc(&sbinfo->used_blocks); spin_lock(&inode->i_lock); @@ -1397,7 +1398,8 @@ repeat: shmem_swp_unmap(entry); sbinfo = SHMEM_SB(inode->i_sb); if (sbinfo->max_blocks) { - if ((percpu_counter_compare(&sbinfo->used_blocks, sbinfo->max_blocks) > 0) || + if (percpu_counter_compare(&sbinfo->used_blocks, + sbinfo->max_blocks) >= 0 || shmem_acct_block(info->flags)) { spin_unlock(&info->lock); error = -ENOSPC; -- 2.30.2