[PATCH] tmpfs: fix off-by-one in max_blocks checks
From: Hugh Dickins <hughd@google.com>
Date: 2011-03-20 05:33:09
Also in:
lkml
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 <hughd@google.com> --- mm/shmem.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- 2.6.38/mm/shmem.c 2011-03-14 18:20:32.000000000 -0700
+++ linux/mm/shmem.c 2011-03-19 22:02:17.000000000 -0700@@ -422,7 +422,8 @@ static swp_entry_t *shmem_swp_alloc(stru * 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);
@@ -1399,7 +1400,8 @@ 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; --
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