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@chromium.org>
[tyhicks: Changed NULL .drop_inode sop pointer to generic_drop_inode]
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
index 519af27..5e15013 100644
--- a/fs/ecryptfs/mmap.c
+++ b/fs/ecryptfs/mmap.c
@@ -62,6 +62,18 @@
{
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 @@
goto out;
}
SetPageUptodate(page);
- unlock_page(page);
out:
+ unlock_page(page);
return rc;
}
@@ -481,6 +493,7 @@
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 @@
"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;
}