A change was made about a year ago to get eCryptfs to better utilize its
page cache during writes. The idea was to do the page encryption
operations during page writeback, rather than doing them when initially
writing into the page cache, to reduce the number of page encryption
operations during sequential writes. This meant that the encrypted page
would only be written to the lower filesystem during page writeback,
which was a change from how eCryptfs had previously wrote to the lower
filesystem in ecryptfs_write_end().
The change caused a few eCryptfs-internal bugs that were shook out.
Unfortunately, more grave side effects have been identified that will
force changes outside of eCryptfs. Because the lower filesystem isn't
consulted until page writeback, eCryptfs has no way to pass lower write
errors (ENOSPC, mainly) back to userspace. Additionaly, it was reported
that quotas could be bypassed because of the way eCryptfs may sometimes
open the lower filesystem using a privileged kthread.
It would be nice to resolve the latest issues, but it is best if the
eCryptfs commits be reverted to the old behavior in the meantime.
This reverts:
32001d6f "eCryptfs: Flush file in vma close"
5be79de2 "eCryptfs: Flush dirty pages in setattr"
57db4e8d "ecryptfs: modify write path to encrypt page in writepage"
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Tested-by: Colin King <colin.king@canonical.com>
Cc: Colin King <colin.king@canonical.com>
Cc: Thieu Le <thieule@google.com>
(cherry picked from commit 821f7494a77627fb1ab539591c57b22cdca702d6)
- if (S_ISREG(inode->i_mode)) {
- rc = filemap_write_and_wait(inode->i_mapping);
- if (rc)
- goto out;
- fsstack_copy_attr_all(inode, lower_inode);
- }
memcpy(&lower_ia, ia, sizeof(lower_ia));
if (ia->ia_valid & ATTR_FILE)
lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
index 6a44148..93a998a 100644
--- a/fs/ecryptfs/mmap.c
+++ b/fs/ecryptfs/mmap.c
@@ -62,18 +62,6 @@ 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 "
@@ -498,7 +486,6 @@ 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;
--
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https://lists.ubuntu.com/mailman/listinfo/kernel-team
08-20-2012, 11:59 AM
Colin King
eCryptfs: Revert to a writethrough cache model
From: Colin Ian King <colin.king@canonical.com>
BugLink: http://bugs.launchpad.net/bugs/1034012
A change was made about a year ago to get eCryptfs to better utilize its
page cache during writes. The idea was to do the page encryption
operations during page writeback, rather than doing them when initially
writing into the page cache, to reduce the number of page encryption
operations during sequential writes. This meant that the encrypted page
would only be written to the lower filesystem during page writeback,
which was a change from how eCryptfs had previously wrote to the lower
filesystem in ecryptfs_write_end().
The change caused a few eCryptfs-internal bugs that were shook out.
Unfortunately, more grave side effects have been identified that will
force changes outside of eCryptfs. Because the lower filesystem isn't
consulted until page writeback, eCryptfs has no way to pass lower write
errors (ENOSPC, mainly) back to userspace. Additionaly, it was reported
that quotas could be bypassed because of the way eCryptfs may sometimes
open the lower filesystem using a privileged kthread.
It would be nice to resolve the latest issues, but it is best if the
eCryptfs commits be reverted to the old behavior in the meantime.
This reverts:
32001d6f "eCryptfs: Flush file in vma close"
5be79de2 "eCryptfs: Flush dirty pages in setattr"
57db4e8d "ecryptfs: modify write path to encrypt page in writepage"
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Tested-by: Colin King <colin.king@canonical.com>
Cc: Colin King <colin.king@canonical.com>
Cc: Thieu Le <thieule@google.com>A
(backported fromn commit 821f7494a77627fb1ab539591c57b22cdca702d6)
---
fs/ecryptfs/file.c | 32 ++------------------------------
fs/ecryptfs/inode.c | 6 ------
fs/ecryptfs/mmap.c | 39 +++++++++++++--------------------------
3 files changed, 15 insertions(+), 62 deletions(-)
- if (S_ISREG(inode->i_mode)) {
- rc = filemap_write_and_wait(inode->i_mapping);
- if (rc)
- goto out;
- fsstack_copy_attr_all(inode, lower_inode);
- }
memcpy(&lower_ia, ia, sizeof(lower_ia));
if (ia->ia_valid & ATTR_FILE)
lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
index 6a44148..93a998a 100644
--- a/fs/ecryptfs/mmap.c
+++ b/fs/ecryptfs/mmap.c
@@ -62,18 +62,6 @@ 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 "
@@ -498,7 +486,6 @@ 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;
--
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09-29-2012, 01:51 PM
Ben Hutchings
eCryptfs: Revert to a writethrough cache model
On Mon, 2012-08-20 at 12:59 +0100, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> BugLink: http://bugs.launchpad.net/bugs/1034012
[...]
> (backported fromn commit 821f7494a77627fb1ab539591c57b22cdca702d6)
[...]
Should this go into 3.2.y and other stable branches?
Ben.
--
Ben Hutchings
Usenet is essentially a HUGE group of people passing notes in class.
- Rachel Kadel, `A Quick Guide to Newsgroup Etiquette'
--
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09-29-2012, 05:09 PM
Colin Ian King
eCryptfs: Revert to a writethrough cache model
On 29/09/12 14:51, Ben Hutchings wrote:
On Mon, 2012-08-20 at 12:59 +0100, Colin King wrote:
Should this go into 3.2.y and other stable branches?
Well it definitely should be applied from 3.2.y up to 3.5-rc6, but it
won't cleanly apply to 3.2.y. I've had a quick look and there seems to
be some commits in precise that aren't in 3.2.y, namely:
eCryptfs: Revert to a writethrough cache model
