From 57db4e8d73ef2b5e94a3f412108dff2576670a8a Mon Sep 17 00:00:00 2001 From: Thieu Le Date: Tue, 8 Mar 2011 16:26:03 -0800 Subject: [PATCH] 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/ecryptfs_kernel.h | 1 - fs/ecryptfs/file.c | 9 +++++++- fs/ecryptfs/main.c | 2 -- fs/ecryptfs/mmap.c | 41 +++++++++++++++++++++++------------ fs/ecryptfs/read_write.c | 12 ++-------- fs/ecryptfs/super.c | 3 +-- 6 files changed, 38 insertions(+), 30 deletions(-) diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h index 427478e2976..3ef5b003023 100644 --- a/fs/ecryptfs/ecryptfs_kernel.h +++ b/fs/ecryptfs/ecryptfs_kernel.h @@ -296,7 +296,6 @@ struct ecryptfs_inode_info { struct inode vfs_inode; struct inode *wii_inode; struct file *lower_file; - struct mutex lower_file_mutex; struct ecryptfs_crypt_stat crypt_stat; }; diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c index 7d1050e254f..cedc913d11b 100644 --- a/fs/ecryptfs/file.c +++ b/fs/ecryptfs/file.c @@ -273,7 +273,14 @@ static int ecryptfs_release(struct inode *inode, struct file *file) static int ecryptfs_fsync(struct file *file, int datasync) { - return vfs_fsync(ecryptfs_file_to_lower(file), datasync); + int rc = 0; + + rc = generic_file_fsync(file, datasync); + if (rc) + goto out; + rc = vfs_fsync(ecryptfs_file_to_lower(file), datasync); +out: + return rc; } static int ecryptfs_fasync(int fd, struct file *file, int flag) diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c index 758323a0f09..63e412cf0fa 100644 --- a/fs/ecryptfs/main.c +++ b/fs/ecryptfs/main.c @@ -122,7 +122,6 @@ int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry) ecryptfs_inode_to_private(ecryptfs_dentry->d_inode); int rc = 0; - mutex_lock(&inode_info->lower_file_mutex); if (!inode_info->lower_file) { struct dentry *lower_dentry; struct vfsmount *lower_mnt = @@ -138,7 +137,6 @@ int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry) inode_info->lower_file = NULL; } } - mutex_unlock(&inode_info->lower_file_mutex); return rc; } diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c index 519af27db05..5e150131eb9 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; } diff --git a/fs/ecryptfs/read_write.c b/fs/ecryptfs/read_write.c index db184ef15d3..85d43096311 100644 --- a/fs/ecryptfs/read_write.c +++ b/fs/ecryptfs/read_write.c @@ -44,15 +44,11 @@ int ecryptfs_write_lower(struct inode *ecryptfs_inode, char *data, ssize_t rc; inode_info = ecryptfs_inode_to_private(ecryptfs_inode); - mutex_lock(&inode_info->lower_file_mutex); BUG_ON(!inode_info->lower_file); - inode_info->lower_file->f_pos = offset; fs_save = get_fs(); set_fs(get_ds()); - rc = vfs_write(inode_info->lower_file, data, size, - &inode_info->lower_file->f_pos); + rc = vfs_write(inode_info->lower_file, data, size, &offset); set_fs(fs_save); - mutex_unlock(&inode_info->lower_file_mutex); mark_inode_dirty_sync(ecryptfs_inode); return rc; } @@ -234,15 +230,11 @@ int ecryptfs_read_lower(char *data, loff_t offset, size_t size, mm_segment_t fs_save; ssize_t rc; - mutex_lock(&inode_info->lower_file_mutex); BUG_ON(!inode_info->lower_file); - inode_info->lower_file->f_pos = offset; fs_save = get_fs(); set_fs(get_ds()); - rc = vfs_read(inode_info->lower_file, data, size, - &inode_info->lower_file->f_pos); + rc = vfs_read(inode_info->lower_file, data, size, &offset); set_fs(fs_save); - mutex_unlock(&inode_info->lower_file_mutex); return rc; } diff --git a/fs/ecryptfs/super.c b/fs/ecryptfs/super.c index 3042fe123a3..bacc882e1ae 100644 --- a/fs/ecryptfs/super.c +++ b/fs/ecryptfs/super.c @@ -55,7 +55,6 @@ static struct inode *ecryptfs_alloc_inode(struct super_block *sb) if (unlikely(!inode_info)) goto out; ecryptfs_init_crypt_stat(&inode_info->crypt_stat); - mutex_init(&inode_info->lower_file_mutex); inode_info->lower_file = NULL; inode = &inode_info->vfs_inode; out: @@ -198,7 +197,7 @@ static int ecryptfs_show_options(struct seq_file *m, struct vfsmount *mnt) const struct super_operations ecryptfs_sops = { .alloc_inode = ecryptfs_alloc_inode, .destroy_inode = ecryptfs_destroy_inode, - .drop_inode = generic_delete_inode, + .drop_inode = generic_drop_inode, .statfs = ecryptfs_statfs, .remount_fs = NULL, .evict_inode = ecryptfs_evict_inode, -- 2.20.1