Hi Andrew,
As part of moving all the filesystems to make use of new aops to
eventually remove prepare/commit_write, here is the patch to convert
ecryptfs to make use of new aops.
Originally written by Nick, I did few minor fixes and clean ups.
Shaggy identified a error return mishandling in my previous version.
Michael Halcrow tested and confirmed that it works.
Thanks,
Badari
Convert ecryptfs to use write_begin/write_end
Signed-off-by: Nick Piggin <npiggin@xxxxxxx>
Signed-off-by: Badari Pulavarty <pbadari@xxxxxxxxxx>
Acked-by: Michael Halcrow <mhalcrow@xxxxxxxxxx>
fs/ecryptfs/mmap.c | 71 +++++++++++++++++++++++++++++++----------------------
1 file changed, 42 insertions(+), 29 deletions(-)
Index: linux-2.6.27-rc8/fs/ecryptfs/mmap.c
===================================================================
--- linux-2.6.27-rc8.orig/fs/ecryptfs/mmap.c 2008-09-29 15:24:02.000000000 -0700
+++ linux-2.6.27-rc8/fs/ecryptfs/mmap.c 2008-10-02 19:23:48.000000000 -0700
@@ -265,9 +265,9 @@ out:
}
/**
- * ecryptfs_prepare_write
+ * ecryptfs_write_begin
* @file: The eCryptfs file
- * @page: The eCryptfs page
+ * @mapping: The eCryptfs object
* @from: The start byte from which we will write
* @to: The end byte to which we will write
*
@@ -275,12 +275,21 @@ out:
*
* Returns zero on success; non-zero otherwise
*/
-static int ecryptfs_prepare_write(struct file *file, struct page *page,
- unsigned from, unsigned to)
+static int ecryptfs_write_begin(struct file *file,
+ struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned flags,
+ struct page **pagep, void **fsdata)
{
+ pgoff_t index = pos >> PAGE_CACHE_SHIFT;
+ struct page *page;
loff_t prev_page_end_size;
int rc = 0;
+ page = __grab_cache_page(mapping, index);
+ if (!page)
+ return -ENOMEM;
+ *pagep = page;
+
if (!PageUptodate(page)) {
struct ecryptfs_crypt_stat *crypt_stat =
&ecryptfs_inode_to_private(
@@ -289,8 +298,7 @@ static int ecryptfs_prepare_write(struct
if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)
|| (crypt_stat->flags & ECRYPTFS_NEW_FILE)) {
rc = ecryptfs_read_lower_page_segment(
- page, page->index, 0, PAGE_CACHE_SIZE,
- page->mapping->host);
+ page, index, 0, PAGE_CACHE_SIZE, mapping->host);
if (rc) {
printk(KERN_ERR "%s: Error attemping to read "
"lower page segment; rc = [%d]\n",
@@ -316,8 +324,8 @@ static int ecryptfs_prepare_write(struct
SetPageUptodate(page);
} else {
rc = ecryptfs_read_lower_page_segment(
- page, page->index, 0, PAGE_CACHE_SIZE,
- page->mapping->host);
+ page, index, 0, PAGE_CACHE_SIZE,
+ mapping->host);
if (rc) {
printk(KERN_ERR "%s: Error reading "
"page; rc = [%d]\n",
@@ -339,10 +347,10 @@ static int ecryptfs_prepare_write(struct
SetPageUptodate(page);
}
}
- prev_page_end_size = ((loff_t)page->index << PAGE_CACHE_SHIFT);
+ prev_page_end_size = ((loff_t)index << PAGE_CACHE_SHIFT);
/* If creating a page or more of holes, zero them out via truncate.
* Note, this will increase i_size. */
- if (page->index != 0) {
+ if (index != 0) {
if (prev_page_end_size > i_size_read(page->mapping->host)) {
rc = ecryptfs_truncate(file->f_path.dentry,
prev_page_end_size);
@@ -357,8 +365,8 @@ static int ecryptfs_prepare_write(struct
}
/* Writing to a new page, and creating a small hole from start
* of page? Zero it out. */
- if ((i_size_read(page->mapping->host) == prev_page_end_size)
- && (from != 0))
+ if ((i_size_read(mapping->host) == prev_page_end_size)
+ && (pos != 0))
zero_user(page, 0, PAGE_CACHE_SIZE);
out:
return rc;
@@ -445,21 +453,25 @@ int ecryptfs_write_inode_size_to_metadat
}
/**
- * ecryptfs_commit_write
+ * ecryptfs_write_end
* @file: The eCryptfs file object
+ * @mapping: The eCryptfs object
+ * @pos, len: Ignored (we rotate the page IV on each write)
* @page: The eCryptfs page
- * @from: Ignored (we rotate the page IV on each write)
- * @to: Ignored
*
* This is where we encrypt the data and pass the encrypted data to
* the lower filesystem. In OpenPGP-compatible mode, we operate on
* entire underlying packets.
*/
-static int ecryptfs_commit_write(struct file *file, struct page *page,
- unsigned from, unsigned to)
+static int ecryptfs_write_end(struct file *file,
+ struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned copied,
+ struct page *page, void *fsdata)
{
- loff_t pos;
- struct inode *ecryptfs_inode = page->mapping->host;
+ pgoff_t index = pos >> PAGE_CACHE_SHIFT;
+ unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+ unsigned to = from + copied;
+ struct inode *ecryptfs_inode = mapping->host;
struct ecryptfs_crypt_stat *crypt_stat =
&ecryptfs_inode_to_private(file->f_path.dentry->d_inode)->crypt_stat;
int rc;
@@ -471,25 +483,22 @@ static int ecryptfs_commit_write(struct
} else
ecryptfs_printk(KERN_DEBUG, "Not a new file\n");
ecryptfs_printk(KERN_DEBUG, "Calling fill_zeros_to_end_of_page"
- "(page w/ index = [0x%.16x], to = [%d])\n", page->index,
- to);
+ "(page w/ index = [0x%.16x], to = [%d])\n", index, to);
/* Fills in zeros if 'to' goes beyond inode size */
rc = fill_zeros_to_end_of_page(page, to);
if (rc) {
ecryptfs_printk(KERN_WARNING, "Error attempting to fill "
- "zeros in page with index = [0x%.16x]\n",
- page->index);
+ "zeros in page with index = [0x%.16x]\n", index);
goto out;
}
rc = ecryptfs_encrypt_page(page);
if (rc) {
ecryptfs_printk(KERN_WARNING, "Error encrypting page (upper "
- "index [0x%.16x])\n", page->index);
+ "index [0x%.16x])\n", index);
goto out;
}
- pos = (((loff_t)page->index) << PAGE_CACHE_SHIFT) + to;
- if (pos > i_size_read(ecryptfs_inode)) {
- i_size_write(ecryptfs_inode, pos);
+ if (pos + copied > i_size_read(ecryptfs_inode)) {
+ i_size_write(ecryptfs_inode, pos + copied);
ecryptfs_printk(KERN_DEBUG, "Expanded file size to "
"[0x%.16x]\n", i_size_read(ecryptfs_inode));
}
@@ -497,7 +506,11 @@ static int ecryptfs_commit_write(struct
if (rc)
printk(KERN_ERR "Error writing inode size to metadata; "
"rc = [%d]\n", rc);
+ else
+ rc = copied;
out:
+ unlock_page(page);
+ page_cache_release(page);
return rc;
}
@@ -518,7 +531,7 @@ static sector_t ecryptfs_bmap(struct add
struct address_space_operations ecryptfs_aops = {
.writepage = ecryptfs_writepage,
.readpage = ecryptfs_readpage,
- .prepare_write = ecryptfs_prepare_write,
- .commit_write = ecryptfs_commit_write,
+ .write_begin = ecryptfs_write_begin,
+ .write_end = ecryptfs_write_end,
.bmap = ecryptfs_bmap,
};
--
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