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Message-Id: <1298590286-26117-1-git-send-email-thieule@chromium.org>
Date: Thu, 24 Feb 2011 15:31:26 -0800
From: Thieu Le <thieule@...omium.org>
To: tyhicks@...ux.vnet.ibm.com, kirkland@...onical.com
Cc: ecryptfs-devel@...ts.launchpad.net, linux-kernel@...r.kernel.org,
Thieu Le <thieule@...omium.org>
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 <thieule@...omium.org>
---
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 | 1 -
6 files changed, 37 insertions(+), 29 deletions(-)
diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index dbc84ed..13517ac 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -297,7 +297,6 @@ 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 81e10e6..9f7ce63 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 758323a..63e412c 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 cc64fca..d36829f 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;
}
@@ -486,6 +498,7 @@ 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;
if (crypt_stat->flags & ECRYPTFS_NEW_FILE) {
ecryptfs_printk(KERN_DEBUG, "ECRYPTFS_NEW_FILE flag set in "
@@ -512,26 +525,26 @@ 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 db184ef..85d4309 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 3042fe1..15c969e 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:
--
1.7.3.1
--
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