diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/madvise.c | 35 | ||||
| -rw-r--r-- | mm/memory.c | 25 | ||||
| -rw-r--r-- | mm/shmem.c | 32 |
3 files changed, 83 insertions, 9 deletions
diff --git a/mm/madvise.c b/mm/madvise.c index 2b7cf0400a21..ae0ae3ea299a 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -140,6 +140,36 @@ static long madvise_dontneed(struct vm_area_struct * vma, return 0; } +/* + * Application wants to free up the pages and associated backing store. + * This is effectively punching a hole into the middle of a file. + * + * NOTE: Currently, only shmfs/tmpfs is supported for this operation. + * Other filesystems return -ENOSYS. + */ +static long madvise_remove(struct vm_area_struct *vma, + unsigned long start, unsigned long end) +{ + struct address_space *mapping; + loff_t offset, endoff; + + if (vma->vm_flags & (VM_LOCKED|VM_NONLINEAR|VM_HUGETLB)) + return -EINVAL; + + if (!vma->vm_file || !vma->vm_file->f_mapping + || !vma->vm_file->f_mapping->host) { + return -EINVAL; + } + + mapping = vma->vm_file->f_mapping; + + offset = (loff_t)(start - vma->vm_start) + + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); + endoff = (loff_t)(end - vma->vm_start - 1) + + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); + return vmtruncate_range(mapping->host, offset, endoff); +} + static long madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev, unsigned long start, unsigned long end, int behavior) @@ -152,6 +182,9 @@ madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev, case MADV_RANDOM: error = madvise_behavior(vma, prev, start, end, behavior); break; + case MADV_REMOVE: + error = madvise_remove(vma, start, end); + break; case MADV_WILLNEED: error = madvise_willneed(vma, prev, start, end); @@ -190,6 +223,8 @@ madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev, * some pages ahead. * MADV_DONTNEED - the application is finished with the given range, * so the kernel can free resources associated with it. + * MADV_REMOVE - the application wants to free up the given range of + * pages and associated backing store. * * return values: * zero - success diff --git a/mm/memory.c b/mm/memory.c index d8dde07a3656..e249088908c4 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1770,9 +1770,32 @@ out_big: out_busy: return -ETXTBSY; } - EXPORT_SYMBOL(vmtruncate); +int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end) +{ + struct address_space *mapping = inode->i_mapping; + + /* + * If the underlying filesystem is not going to provide + * a way to truncate a range of blocks (punch a hole) - + * we should return failure right now. + */ + if (!inode->i_op || !inode->i_op->truncate_range) + return -ENOSYS; + + down(&inode->i_sem); + down_write(&inode->i_alloc_sem); + unmap_mapping_range(mapping, offset, (end - offset), 1); + truncate_inode_pages_range(mapping, offset, end); + inode->i_op->truncate_range(inode, offset, end); + up_write(&inode->i_alloc_sem); + up(&inode->i_sem); + + return 0; +} +EXPORT_SYMBOL(vmtruncate_range); + /* * Primitive swap readahead code. We simply read an aligned block of * (1 << page_cluster) entries in the swap area. This method is chosen diff --git a/mm/shmem.c b/mm/shmem.c index d9fc277940da..65c148efa2ed 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -457,7 +457,7 @@ static void shmem_free_pages(struct list_head *next) } while (next); } -static void shmem_truncate(struct inode *inode) +static void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end) { struct shmem_inode_info *info = SHMEM_I(inode); unsigned long idx; @@ -475,18 +475,27 @@ static void shmem_truncate(struct inode *inode) long nr_swaps_freed = 0; int offset; int freed; + int punch_hole = 0; inode->i_ctime = inode->i_mtime = CURRENT_TIME; - idx = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; + idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; if (idx >= info->next_index) return; spin_lock(&info->lock); info->flags |= SHMEM_TRUNCATE; - limit = info->next_index; - info->next_index = idx; + if (likely(end == (loff_t) -1)) { + limit = info->next_index; + info->next_index = idx; + } else { + limit = (end + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; + if (limit > info->next_index) + limit = info->next_index; + punch_hole = 1; + } + topdir = info->i_indirect; - if (topdir && idx <= SHMEM_NR_DIRECT) { + if (topdir && idx <= SHMEM_NR_DIRECT && !punch_hole) { info->i_indirect = NULL; nr_pages_to_free++; list_add(&topdir->lru, &pages_to_free); @@ -573,11 +582,12 @@ static void shmem_truncate(struct inode *inode) set_page_private(subdir, page_private(subdir) - freed); if (offset) spin_unlock(&info->lock); - BUG_ON(page_private(subdir) > offset); + if (!punch_hole) + BUG_ON(page_private(subdir) > offset); } if (offset) offset = 0; - else if (subdir) { + else if (subdir && !page_private(subdir)) { dir[diroff] = NULL; nr_pages_to_free++; list_add(&subdir->lru, &pages_to_free); @@ -594,7 +604,7 @@ done2: * Also, though shmem_getpage checks i_size before adding to * cache, no recheck after: so fix the narrow window there too. */ - truncate_inode_pages(inode->i_mapping, inode->i_size); + truncate_inode_pages_range(inode->i_mapping, start, end); } spin_lock(&info->lock); @@ -614,6 +624,11 @@ done2: } } +static void shmem_truncate(struct inode *inode) +{ + shmem_truncate_range(inode, inode->i_size, (loff_t)-1); +} + static int shmem_notify_change(struct dentry *dentry, struct iattr *attr) { struct inode *inode = dentry->d_inode; @@ -2083,6 +2098,7 @@ static struct file_operations shmem_file_operations = { static struct inode_operations shmem_inode_operations = { .truncate = shmem_truncate, .setattr = shmem_notify_change, + .truncate_range = shmem_truncate_range, }; static struct inode_operations shmem_dir_inode_operations = { |