From ae73fc093a8cae4d92e22ab8b635e3590e80785d Mon Sep 17 00:00:00 2001
From: Michael Halcrow <mhalcrow@us.ibm.com>
Date: Wed, 28 Feb 2007 20:12:16 -0800
Subject: [PATCH] [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: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
fs/ecryptfs/mmap.c | 28 +++++++++++++++++++++++-----
1 file changed, 23 insertions(+), 5 deletions(-)
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
index 3a6f65c3f14f..82bdbed658d7 100644
--- a/fs/ecryptfs/mmap.c
+++ b/fs/ecryptfs/mmap.c
@@ -422,9 +422,11 @@ out:
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;
}
--
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