eCryptfs: Handle failed metadata read in lookup
When failing to read the lower file's crypto metadata during a lookup,
eCryptfs must continue on without throwing an error. For example, there
may be a plaintext file in the lower mount point that the user wants to
delete through the eCryptfs mount.
If an error is encountered while reading the metadata in lookup(), the
eCryptfs inode's size could be incorrect. We must be sure to reread the
plaintext inode size from the metadata when performing an open() or
setattr(). The metadata is already being read in those paths, so this
adds minimal performance overhead.
This patch introduces a flag which will track whether or not the
plaintext inode size has been read so that an incorrect i_size can be
fixed in the open() or setattr() paths.
https://bugs.launchpad.net/bugs/509180
Cc: <stable@kernel.org>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index 380bee1..e702827 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -269,6 +269,7 @@
#define ECRYPTFS_ENCFN_USE_MOUNT_FNEK 0x00000800
#define ECRYPTFS_ENCFN_USE_FEK 0x00001000
#define ECRYPTFS_UNLINK_SIGS 0x00002000
+#define ECRYPTFS_I_SIZE_INITIALIZED 0x00004000
u32 flags;
unsigned int file_version;
size_t iv_bytes;
@@ -628,6 +629,7 @@
int ecryptfs_interpose(struct dentry *hidden_dentry,
struct dentry *this_dentry, struct super_block *sb,
u32 flags);
+void ecryptfs_i_size_init(const char *page_virt, struct inode *inode);
int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry,
struct dentry *lower_dentry,
struct inode *ecryptfs_dir_inode);