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eCryptfs: Read/write entire page during page IO

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When reading and writing encrypted pages, perform IO using the entire
page all at once rather than 4096 bytes at a time.

This only affects architectures where PAGE_CACHE_SIZE is larger than
4096 bytes.

Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
This commit is contained in:
Tyler Hicks 2013-04-15 16:16:24 -07:00
parent 12003e5b18
commit 0f89617623
1 changed files with 31 additions and 35 deletions
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66
fs/ecryptfs/crypto.c
View file

@ -490,6 +490,7 @@ int ecryptfs_encrypt_page(struct page *page)
char *enc_extent_virt; char *enc_extent_virt;
struct page *enc_extent_page = NULL; struct page *enc_extent_page = NULL;
loff_t extent_offset; loff_t extent_offset;
loff_t lower_offset;
int rc = 0; int rc = 0;
ecryptfs_inode = page->mapping->host; ecryptfs_inode = page->mapping->host;
@ -503,12 +504,10 @@ int ecryptfs_encrypt_page(struct page *page)
"encrypted extent\n"); "encrypted extent\n");
goto out; goto out;
} }
enc_extent_virt = kmap(enc_extent_page);
for (extent_offset = 0; for (extent_offset = 0;
extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size); extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
extent_offset++) { extent_offset++) {
loff_t offset;
rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page, rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page,
extent_offset); extent_offset);
if (rc) { if (rc) {
@ -516,25 +515,24 @@ int ecryptfs_encrypt_page(struct page *page)
"rc = [%d]\n", __func__, rc); "rc = [%d]\n", __func__, rc);
goto out; goto out;
} }
ecryptfs_lower_offset_for_extent( }
&offset, ((((loff_t)page->index)
* (PAGE_CACHE_SIZE ecryptfs_lower_offset_for_extent(&lower_offset,
/ crypt_stat->extent_size)) page->index * (PAGE_CACHE_SIZE / crypt_stat->extent_size),
+ extent_offset), crypt_stat); crypt_stat);
rc = ecryptfs_write_lower(ecryptfs_inode, (enc_extent_virt + enc_extent_virt = kmap(enc_extent_page);
extent_offset * crypt_stat->extent_size), rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt, lower_offset,
offset, crypt_stat->extent_size); PAGE_CACHE_SIZE);
if (rc < 0) { kunmap(enc_extent_page);
ecryptfs_printk(KERN_ERR, "Error attempting " if (rc < 0) {
"to write lower page; rc = [%d]" ecryptfs_printk(KERN_ERR,
"\n", rc); "Error attempting to write lower page; rc = [%d]\n",
goto out; rc);
} goto out;
} }
rc = 0; rc = 0;
out: out:
if (enc_extent_page) { if (enc_extent_page) {
kunmap(enc_extent_page);
__free_page(enc_extent_page); __free_page(enc_extent_page);
} }
return rc; return rc;
@ -599,6 +597,7 @@ int ecryptfs_decrypt_page(struct page *page)
char *enc_extent_virt; char *enc_extent_virt;
struct page *enc_extent_page = NULL; struct page *enc_extent_page = NULL;
unsigned long extent_offset; unsigned long extent_offset;
loff_t lower_offset;
int rc = 0; int rc = 0;
ecryptfs_inode = page->mapping->host; ecryptfs_inode = page->mapping->host;
@ -612,26 +611,24 @@ int ecryptfs_decrypt_page(struct page *page)
"encrypted extent\n"); "encrypted extent\n");
goto out; goto out;
} }
ecryptfs_lower_offset_for_extent(&lower_offset,
page->index * (PAGE_CACHE_SIZE / crypt_stat->extent_size),
crypt_stat);
enc_extent_virt = kmap(enc_extent_page); enc_extent_virt = kmap(enc_extent_page);
rc = ecryptfs_read_lower(enc_extent_virt, lower_offset, PAGE_CACHE_SIZE,
ecryptfs_inode);
kunmap(enc_extent_page);
if (rc < 0) {
ecryptfs_printk(KERN_ERR,
"Error attempting to read lower page; rc = [%d]\n",
rc);
goto out;
}
for (extent_offset = 0; for (extent_offset = 0;
extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size); extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
extent_offset++) { extent_offset++) {
loff_t offset;
ecryptfs_lower_offset_for_extent(
&offset, ((page->index * (PAGE_CACHE_SIZE
/ crypt_stat->extent_size))
+ extent_offset), crypt_stat);
rc = ecryptfs_read_lower((enc_extent_virt +
extent_offset * crypt_stat->extent_size),
offset, crypt_stat->extent_size,
ecryptfs_inode);
if (rc < 0) {
ecryptfs_printk(KERN_ERR, "Error attempting "
"to read lower page; rc = [%d]"
"\n", rc);
goto out;
}
rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page, rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page,
extent_offset); extent_offset);
if (rc) { if (rc) {
@ -642,7 +639,6 @@ int ecryptfs_decrypt_page(struct page *page)
} }
out: out:
if (enc_extent_page) { if (enc_extent_page) {
kunmap(enc_extent_page);
__free_page(enc_extent_page); __free_page(enc_extent_page);
} }
return rc; return rc;