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-rw-r--r--mm/memory.c62
1 files changed, 3 insertions, 59 deletions
diff --git a/mm/memory.c b/mm/memory.c
index b1443ac07c00..ebcd3decac89 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -297,7 +297,8 @@ void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma,
297 unsigned long addr = vma->vm_start; 297 unsigned long addr = vma->vm_start;
298 298
299 /* 299 /*
300 * Hide vma from rmap and vmtruncate before freeing pgtables 300 * Hide vma from rmap and truncate_pagecache before freeing
301 * pgtables
301 */ 302 */
302 anon_vma_unlink(vma); 303 anon_vma_unlink(vma);
303 unlink_file_vma(vma); 304 unlink_file_vma(vma);
@@ -2407,7 +2408,7 @@ restart:
2407 * @mapping: the address space containing mmaps to be unmapped. 2408 * @mapping: the address space containing mmaps to be unmapped.
2408 * @holebegin: byte in first page to unmap, relative to the start of 2409 * @holebegin: byte in first page to unmap, relative to the start of
2409 * the underlying file. This will be rounded down to a PAGE_SIZE 2410 * the underlying file. This will be rounded down to a PAGE_SIZE
2410 * boundary. Note that this is different from vmtruncate(), which 2411 * boundary. Note that this is different from truncate_pagecache(), which
2411 * must keep the partial page. In contrast, we must get rid of 2412 * must keep the partial page. In contrast, we must get rid of
2412 * partial pages. 2413 * partial pages.
2413 * @holelen: size of prospective hole in bytes. This will be rounded 2414 * @holelen: size of prospective hole in bytes. This will be rounded
@@ -2458,63 +2459,6 @@ void unmap_mapping_range(struct address_space *mapping,
2458} 2459}
2459EXPORT_SYMBOL(unmap_mapping_range); 2460EXPORT_SYMBOL(unmap_mapping_range);
2460 2461
2461/**
2462 * vmtruncate - unmap mappings "freed" by truncate() syscall
2463 * @inode: inode of the file used
2464 * @offset: file offset to start truncating
2465 *
2466 * NOTE! We have to be ready to update the memory sharing
2467 * between the file and the memory map for a potential last
2468 * incomplete page. Ugly, but necessary.
2469 */
2470int vmtruncate(struct inode * inode, loff_t offset)
2471{
2472 if (inode->i_size < offset) {
2473 unsigned long limit;
2474
2475 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
2476 if (limit != RLIM_INFINITY && offset > limit)
2477 goto out_sig;
2478 if (offset > inode->i_sb->s_maxbytes)
2479 goto out_big;
2480 i_size_write(inode, offset);
2481 } else {
2482 struct address_space *mapping = inode->i_mapping;
2483
2484 /*
2485 * truncation of in-use swapfiles is disallowed - it would
2486 * cause subsequent swapout to scribble on the now-freed
2487 * blocks.
2488 */
2489 if (IS_SWAPFILE(inode))
2490 return -ETXTBSY;
2491 i_size_write(inode, offset);
2492
2493 /*
2494 * unmap_mapping_range is called twice, first simply for
2495 * efficiency so that truncate_inode_pages does fewer
2496 * single-page unmaps. However after this first call, and
2497 * before truncate_inode_pages finishes, it is possible for
2498 * private pages to be COWed, which remain after
2499 * truncate_inode_pages finishes, hence the second
2500 * unmap_mapping_range call must be made for correctness.
2501 */
2502 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
2503 truncate_inode_pages(mapping, offset);
2504 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
2505 }
2506
2507 if (inode->i_op->truncate)
2508 inode->i_op->truncate(inode);
2509 return 0;
2510
2511out_sig:
2512 send_sig(SIGXFSZ, current, 0);
2513out_big:
2514 return -EFBIG;
2515}
2516EXPORT_SYMBOL(vmtruncate);
2517
2518int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end) 2462int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end)
2519{ 2463{
2520 struct address_space *mapping = inode->i_mapping; 2464 struct address_space *mapping = inode->i_mapping;