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authorTyler Hicks <tyhicks@linux.vnet.ibm.com>2011-04-15 00:35:11 +0400
committerTyler Hicks <tyhicks@linux.vnet.ibm.com>2011-04-26 03:32:37 +0400
commit332ab16f830f59e7621ae8eb2c353dc135a316f6 (patch)
treec5b249f34dcacf2aa5ee24de8d332d8171398203 /fs/ecryptfs/super.c
parentdd55c89852481a0708c3fd4b48f3081f4280d9d3 (diff)
downloadlinux-332ab16f830f59e7621ae8eb2c353dc135a316f6.tar.xz
eCryptfs: Add reference counting to lower files
For any given lower inode, eCryptfs keeps only one lower file open and multiplexes all eCryptfs file operations through that lower file. The lower file was considered "persistent" and stayed open from the first lookup through the lifetime of the inode. This patch keeps the notion of a single, per-inode lower file, but adds reference counting around the lower file so that it is closed when not currently in use. If the reference count is at 0 when an operation (such as open, create, etc.) needs to use the lower file, a new lower file is opened. Since the file is no longer persistent, all references to the term persistent file are changed to lower file. Locking is added around the sections of code that opens the lower file and assign the pointer in the inode info, as well as the code the fputs the lower file when all eCryptfs users are done with it. This patch is needed to fix issues, when mounted on top of the NFSv3 client, where the lower file is left silly renamed until the eCryptfs inode is destroyed. Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Diffstat (limited to 'fs/ecryptfs/super.c')
-rw-r--r--fs/ecryptfs/super.c16
1 files changed, 4 insertions, 12 deletions
diff --git a/fs/ecryptfs/super.c b/fs/ecryptfs/super.c
index bacc882e1ae4..245b517bf1b6 100644
--- a/fs/ecryptfs/super.c
+++ b/fs/ecryptfs/super.c
@@ -55,6 +55,8 @@ static struct inode *ecryptfs_alloc_inode(struct super_block *sb)
if (unlikely(!inode_info))
goto out;
ecryptfs_init_crypt_stat(&inode_info->crypt_stat);
+ mutex_init(&inode_info->lower_file_mutex);
+ atomic_set(&inode_info->lower_file_count, 0);
inode_info->lower_file = NULL;
inode = &inode_info->vfs_inode;
out:
@@ -77,8 +79,7 @@ static void ecryptfs_i_callback(struct rcu_head *head)
*
* This is used during the final destruction of the inode. All
* allocation of memory related to the inode, including allocated
- * memory in the crypt_stat struct, will be released here. This
- * function also fput()'s the persistent file for the lower inode.
+ * memory in the crypt_stat struct, will be released here.
* There should be no chance that this deallocation will be missed.
*/
static void ecryptfs_destroy_inode(struct inode *inode)
@@ -86,16 +87,7 @@ static void ecryptfs_destroy_inode(struct inode *inode)
struct ecryptfs_inode_info *inode_info;
inode_info = ecryptfs_inode_to_private(inode);
- if (inode_info->lower_file) {
- struct dentry *lower_dentry =
- inode_info->lower_file->f_dentry;
-
- BUG_ON(!lower_dentry);
- if (lower_dentry->d_inode) {
- fput(inode_info->lower_file);
- inode_info->lower_file = NULL;
- }
- }
+ BUG_ON(inode_info->lower_file);
ecryptfs_destroy_crypt_stat(&inode_info->crypt_stat);
call_rcu(&inode->i_rcu, ecryptfs_i_callback);
}