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 <hughd@google.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/shmem.c b/mm/shmem.c
index 58da7c1..8fa27e4 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -421,7 +421,8 @@
* 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 @@
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;