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[PATCH] eCryptfs: resolve lower page unlocking problem

Browse source 
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: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Michael Halcrow 2007-02-28 20:12:16 -08:00 committed by Linus Torvalds
parent 05fb6bf0b2
commit ae73fc093a
1 changed files with 23 additions and 5 deletions
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28
fs/ecryptfs/mmap.c
View file

@ -422,9 +422,11 @@ 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)
{
unlock_page(lower_page);
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;
}