From bda97eab0cc9c6385b9f26abdda6459f630f4513 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Wed, 3 Aug 2011 16:21:21 -0700 Subject: [PATCH] tmpfs: copy truncate_inode_pages_range Bring truncate.c's code for truncate_inode_pages_range() inline into shmem_truncate_range(), replacing its first call (there's a followup call below, but leave that one, it will disappear next). Don't play with it yet, apart from leaving out the cleancache flush, and (importantly) the nrpages == 0 skip, and moving shmem_setattr()'s partial page preparation into its partial page handling. Signed-off-by: Hugh Dickins Acked-by: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/shmem.c | 99 +++++++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 79 insertions(+), 20 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index 24e95ac16053..e101c211ed1f 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -50,6 +50,7 @@ static struct vfsmount *shm_mnt; #include #include #include +#include #include #include #include @@ -242,11 +243,88 @@ void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) struct address_space *mapping = inode->i_mapping; struct shmem_inode_info *info = SHMEM_I(inode); pgoff_t start = (lstart + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; + unsigned partial = lstart & (PAGE_CACHE_SIZE - 1); pgoff_t end = (lend >> PAGE_CACHE_SHIFT); + struct pagevec pvec; pgoff_t index; swp_entry_t swap; + int i; + + BUG_ON((lend & (PAGE_CACHE_SIZE - 1)) != (PAGE_CACHE_SIZE - 1)); + + pagevec_init(&pvec, 0); + index = start; + while (index <= end && pagevec_lookup(&pvec, mapping, index, + min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1)) { + mem_cgroup_uncharge_start(); + for (i = 0; i < pagevec_count(&pvec); i++) { + struct page *page = pvec.pages[i]; + + /* We rely upon deletion not changing page->index */ + index = page->index; + if (index > end) + break; + + if (!trylock_page(page)) + continue; + WARN_ON(page->index != index); + if (PageWriteback(page)) { + unlock_page(page); + continue; + } + truncate_inode_page(mapping, page); + unlock_page(page); + } + pagevec_release(&pvec); + mem_cgroup_uncharge_end(); + cond_resched(); + index++; + } + + if (partial) { + struct page *page = NULL; + shmem_getpage(inode, start - 1, &page, SGP_READ, NULL); + if (page) { + zero_user_segment(page, partial, PAGE_CACHE_SIZE); + set_page_dirty(page); + unlock_page(page); + page_cache_release(page); + } + } + + index = start; + for ( ; ; ) { + cond_resched(); + if (!pagevec_lookup(&pvec, mapping, index, + min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1)) { + if (index == start) + break; + index = start; + continue; + } + if (index == start && pvec.pages[0]->index > end) { + pagevec_release(&pvec); + break; + } + mem_cgroup_uncharge_start(); + for (i = 0; i < pagevec_count(&pvec); i++) { + struct page *page = pvec.pages[i]; - truncate_inode_pages_range(mapping, lstart, lend); + /* We rely upon deletion not changing page->index */ + index = page->index; + if (index > end) + break; + + lock_page(page); + WARN_ON(page->index != index); + wait_on_page_writeback(page); + truncate_inode_page(mapping, page); + unlock_page(page); + } + pagevec_release(&pvec); + mem_cgroup_uncharge_end(); + index++; + } if (end > SHMEM_NR_DIRECT) end = SHMEM_NR_DIRECT; @@ -289,24 +367,7 @@ static int shmem_setattr(struct dentry *dentry, struct iattr *attr) if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) { loff_t oldsize = inode->i_size; loff_t newsize = attr->ia_size; - struct page *page = NULL; - if (newsize < oldsize) { - /* - * If truncating down to a partial page, then - * if that page is already allocated, hold it - * in memory until the truncation is over, so - * truncate_partial_page cannot miss it were - * it assigned to swap. - */ - if (newsize & (PAGE_CACHE_SIZE-1)) { - (void) shmem_getpage(inode, - newsize >> PAGE_CACHE_SHIFT, - &page, SGP_READ, NULL); - if (page) - unlock_page(page); - } - } if (newsize != oldsize) { i_size_write(inode, newsize); inode->i_ctime = inode->i_mtime = CURRENT_TIME; @@ -318,8 +379,6 @@ static int shmem_setattr(struct dentry *dentry, struct iattr *attr) /* unmap again to remove racily COWed private pages */ unmap_mapping_range(inode->i_mapping, holebegin, 0, 1); } - if (page) - page_cache_release(page); } setattr_copy(inode, attr); -- 2.20.1