Currently we update inode and shmem_inode_info before verifying that
used_blocks will not exceed max_blocks. In case it will, we undo the
update. Let's switch the order and move the verification of the blocks
count before the inode and shmem_inode_info update.
Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
---
mm/shmem.c | 25 ++++++++++++-------------
1 file changed, 12 insertions(+), 13 deletions(-)
diff --git a/mm/shmem.c b/mm/shmem.c
index e67d6ba..40a43ae 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -265,6 +265,14 @@ bool shmem_charge(struct inode *inode, long pages)
if (shmem_acct_block(info->flags, pages))
return false;
+
+ if (sbinfo->max_blocks) {
+ if (percpu_counter_compare(&sbinfo->used_blocks,
+ sbinfo->max_blocks - pages) > 0)
+ goto unacct;
+ percpu_counter_add(&sbinfo->used_blocks, pages);
+ }
+
spin_lock_irqsave(&info->lock, flags);
info->alloced += pages;
inode->i_blocks += pages * BLOCKS_PER_PAGE;
@@ -272,20 +280,11 @@ bool shmem_charge(struct inode *inode, long pages)
spin_unlock_irqrestore(&info->lock, flags);
inode->i_mapping->nrpages += pages;
- if (!sbinfo->max_blocks)
- return true;
- if (percpu_counter_compare(&sbinfo->used_blocks,
- sbinfo->max_blocks - pages) > 0) {
- inode->i_mapping->nrpages -= pages;
- spin_lock_irqsave(&info->lock, flags);
- info->alloced -= pages;
- shmem_recalc_inode(inode);
- spin_unlock_irqrestore(&info->lock, flags);
- shmem_unacct_blocks(info->flags, pages);
- return false;
- }
- percpu_counter_add(&sbinfo->used_blocks, pages);
return true;
+
+unacct:
+ shmem_unacct_blocks(info->flags, pages);
+ return false;
}
void shmem_uncharge(struct inode *inode, long pages)
--
2.7.4
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