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Commit ae73fc09 authored by Michael Halcrow's avatar Michael Halcrow Committed by Linus Torvalds
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[PATCH] eCryptfs: resolve lower page unlocking problem 



eCryptfs lower file handling code has several issues:
  - Retval from prepare_write()/commit_write() wasn't checked to equality
    to AOP_TRUNCATED_PAGE.
  - In some places page wasn't unmapped and unlocked after error.

Signed-off-by: default avatarMichael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 05fb6bf0

fs/ecryptfs/mmap.c

+23 −5
Original line number Diff line number Diff line
@@ -422,8 +422,10 @@ int ecryptfs_writepage_and_release_lower_page(struct page *lower_page, 
	return rc;

}



static void ecryptfs_release_lower_page(struct page *lower_page)

static

void ecryptfs_release_lower_page(struct page *lower_page, int page_locked)

{

	if (page_locked)

		unlock_page(lower_page);

	page_cache_release(lower_page);

}
@@ -454,6 +456,13 @@ static int ecryptfs_write_inode_size_to_header(struct file *lower_file, 
	}

	lower_a_ops = lower_inode->i_mapping->a_ops;

	rc = lower_a_ops->prepare_write(lower_file, header_page, 0, 8);

	if (rc) {

		if (rc == AOP_TRUNCATED_PAGE)

			ecryptfs_release_lower_page(header_page, 0);

		else

			ecryptfs_release_lower_page(header_page, 1);

		goto out;

	}

	file_size = (u64)i_size_read(inode);

	ecryptfs_printk(KERN_DEBUG, "Writing size: [0x%.16x]\n", file_size);

	file_size = cpu_to_be64(file_size);
@@ -465,7 +474,10 @@ static int ecryptfs_write_inode_size_to_header(struct file *lower_file, 
	if (rc < 0)

		ecryptfs_printk(KERN_ERR, "Error commiting header page "

				"write\n");

	ecryptfs_release_lower_page(header_page);

	if (rc == AOP_TRUNCATED_PAGE)

		ecryptfs_release_lower_page(header_page, 0);

	else

		ecryptfs_release_lower_page(header_page, 1);

	lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;

	mark_inode_dirty_sync(inode);

out:
@@ -572,7 +584,10 @@ int ecryptfs_get_lower_page(struct page **lower_page, struct inode *lower_inode, 
	}

out:

	if (rc && (*lower_page)) {

		ecryptfs_release_lower_page(*lower_page);

		if (rc == AOP_TRUNCATED_PAGE)

			ecryptfs_release_lower_page(*lower_page, 0);

		else

			ecryptfs_release_lower_page(*lower_page, 1);

		(*lower_page) = NULL;

	}

	return rc;
@@ -588,16 +603,19 @@ ecryptfs_commit_lower_page(struct page *lower_page, struct inode *lower_inode, 
			   struct file *lower_file, int byte_offset,

			   int region_size)

{

	int page_locked = 1;

	int rc = 0;



	rc = lower_inode->i_mapping->a_ops->commit_write(

		lower_file, lower_page, byte_offset, region_size);

	if (rc == AOP_TRUNCATED_PAGE)

		page_locked = 0;

	if (rc < 0) {

		ecryptfs_printk(KERN_ERR,

				"Error committing write; rc = [%d]\n", rc);

	} else

		rc = 0;

	ecryptfs_release_lower_page(lower_page);

	ecryptfs_release_lower_page(lower_page, page_locked);

	return rc;

}