diff options
Diffstat (limited to 'fs/hugetlbfs/inode.c')
| -rw-r--r-- | fs/hugetlbfs/inode.c | 30 |
1 files changed, 22 insertions, 8 deletions
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index aff8642f0c2e..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 @@ -450,7 +457,9 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart, if (unlikely(page_mapped(page))) { BUG_ON(truncate_op); + mutex_unlock(&hugetlb_fault_mutex_table[hash]); i_mmap_lock_write(mapping); + mutex_lock(&hugetlb_fault_mutex_table[hash]); hugetlb_vmdelete_list(&mapping->i_mmap, index * pages_per_huge_page(h), (index + 1) * pages_per_huge_page(h)); @@ -477,7 +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(); @@ -515,8 +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); @@ -638,7 +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]); |