From 57db4e8d73ef2b5e94a3f412108dff2576670a8a Mon Sep 17 00:00:00 2001 From: Thieu Le Date: Tue, 8 Mar 2011 16:26:03 -0800 Subject: ecryptfs: modify write path to encrypt page in writepage Change the write path to encrypt the data only when the page is written to disk in ecryptfs_writepage. Previously, ecryptfs encrypts the page in ecryptfs_write_end which means that if there are multiple write requests to the same page, ecryptfs ends up re-encrypting that page over and over again. This patch minimizes the number of encryptions needed. Signed-off-by: Thieu Le [tyhicks: Changed NULL .drop_inode sop pointer to generic_drop_inode] Signed-off-by: Tyler Hicks --- fs/ecryptfs/mmap.c | 41 +++++++++++++++++++++++++++-------------- 1 file changed, 27 insertions(+), 14 deletions(-) (limited to 'fs/ecryptfs/mmap.c') diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c index 519af27db059..5e150131eb9d 100644 --- a/fs/ecryptfs/mmap.c +++ b/fs/ecryptfs/mmap.c @@ -62,6 +62,18 @@ static int ecryptfs_writepage(struct page *page, struct writeback_control *wbc) { int rc; + /* + * Refuse to write the page out if we are called from reclaim context + * since our writepage() path may potentially allocate memory when + * calling into the lower fs vfs_write() which may in turn invoke + * us again. + */ + if (current->flags & PF_MEMALLOC) { + redirty_page_for_writepage(wbc, page); + rc = 0; + goto out; + } + rc = ecryptfs_encrypt_page(page); if (rc) { ecryptfs_printk(KERN_WARNING, "Error encrypting " @@ -70,8 +82,8 @@ static int ecryptfs_writepage(struct page *page, struct writeback_control *wbc) goto out; } SetPageUptodate(page); - unlock_page(page); out: + unlock_page(page); return rc; } @@ -481,6 +493,7 @@ static int ecryptfs_write_end(struct file *file, struct ecryptfs_crypt_stat *crypt_stat = &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; int rc; + int need_unlock_page = 1; ecryptfs_printk(KERN_DEBUG, "Calling fill_zeros_to_end_of_page" "(page w/ index = [0x%.16lx], to = [%d])\n", index, to); @@ -501,26 +514,26 @@ static int ecryptfs_write_end(struct file *file, "zeros in page with index = [0x%.16lx]\n", index); goto out; } - rc = ecryptfs_encrypt_page(page); - if (rc) { - ecryptfs_printk(KERN_WARNING, "Error encrypting page (upper " - "index [0x%.16lx])\n", index); - goto out; - } + set_page_dirty(page); + unlock_page(page); + need_unlock_page = 0; if (pos + copied > i_size_read(ecryptfs_inode)) { i_size_write(ecryptfs_inode, pos + copied); ecryptfs_printk(KERN_DEBUG, "Expanded file size to " "[0x%.16llx]\n", (unsigned long long)i_size_read(ecryptfs_inode)); + balance_dirty_pages_ratelimited(mapping); + rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode); + if (rc) { + printk(KERN_ERR "Error writing inode size to metadata; " + "rc = [%d]\n", rc); + goto out; + } } - rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode); - if (rc) - printk(KERN_ERR "Error writing inode size to metadata; " - "rc = [%d]\n", rc); - else - rc = copied; + rc = copied; out: - unlock_page(page); + if (need_unlock_page) + unlock_page(page); page_cache_release(page); return rc; } -- cgit v1.2.3