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-rw-r--r--fs/hugetlbfs/inode.c28
1 files changed, 20 insertions, 8 deletions
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index ce9d354ea5c2..991c60c7ffe0 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -393,10 +393,9 @@ hugetlb_vmdelete_list(struct rb_root_cached *root, pgoff_t start, pgoff_t end)
* In this case, we first scan the range and release found pages.
* After releasing pages, hugetlb_unreserve_pages cleans up region/reserv
* maps and global counts. Page faults can not race with truncation
- * in this routine. hugetlb_no_page() prevents page faults in the
- * truncated range. It checks i_size before allocation, and again after
- * with the page table lock for the page held. The same lock must be
- * acquired to unmap a page.
+ * in this routine. hugetlb_no_page() holds i_mmap_rwsem and prevents
+ * page faults in the truncated range by checking i_size. i_size is
+ * modified while holding i_mmap_rwsem.
* hole punch is indicated if end is not LLONG_MAX
* In the hole punch case we scan the range and release found pages.
* Only when releasing a page is the associated region/reserv map
@@ -436,7 +435,15 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
index = page->index;
hash = hugetlb_fault_mutex_hash(mapping, index);
- mutex_lock(&hugetlb_fault_mutex_table[hash]);
+ if (!truncate_op) {
+ /*
+ * Only need to hold the fault mutex in the
+ * hole punch case. This prevents races with
+ * page faults. Races are not possible in the
+ * case of truncation.
+ */
+ mutex_lock(&hugetlb_fault_mutex_table[hash]);
+ }
/*
* If page is mapped, it was faulted in after being
@@ -479,7 +486,8 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
}
unlock_page(page);
- mutex_unlock(&hugetlb_fault_mutex_table[hash]);
+ if (!truncate_op)
+ mutex_unlock(&hugetlb_fault_mutex_table[hash]);
}
huge_pagevec_release(&pvec);
cond_resched();
@@ -517,8 +525,8 @@ static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
BUG_ON(offset & ~huge_page_mask(h));
pgoff = offset >> PAGE_SHIFT;
- i_size_write(inode, offset);
i_mmap_lock_write(mapping);
+ i_size_write(inode, offset);
if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
hugetlb_vmdelete_list(&mapping->i_mmap, pgoff, 0);
i_mmap_unlock_write(mapping);
@@ -640,7 +648,11 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
/* addr is the offset within the file (zero based) */
addr = index * hpage_size;
- /* mutex taken here, fault path and hole punch */
+ /*
+ * fault mutex taken here, protects against fault path
+ * and hole punch. inode_lock previously taken protects
+ * against truncation.
+ */
hash = hugetlb_fault_mutex_hash(mapping, index);
mutex_lock(&hugetlb_fault_mutex_table[hash]);