From 332ab16f830f59e7621ae8eb2c353dc135a316f6 Mon Sep 17 00:00:00 2001 From: Tyler Hicks Date: Thu, 14 Apr 2011 15:35:11 -0500 Subject: 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 --- fs/ecryptfs/file.c | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-) (limited to 'fs/ecryptfs/file.c') diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c index cedc913d11ba..146c4edff70c 100644 --- a/fs/ecryptfs/file.c +++ b/fs/ecryptfs/file.c @@ -191,10 +191,10 @@ static int ecryptfs_open(struct inode *inode, struct file *file) | ECRYPTFS_ENCRYPTED); } mutex_unlock(&crypt_stat->cs_mutex); - rc = ecryptfs_init_persistent_file(ecryptfs_dentry); + rc = ecryptfs_get_lower_file(ecryptfs_dentry); if (rc) { printk(KERN_ERR "%s: Error attempting to initialize " - "the persistent file for the dentry with name " + "the lower file for the dentry with name " "[%s]; rc = [%d]\n", __func__, ecryptfs_dentry->d_name.name, rc); goto out_free; @@ -202,9 +202,9 @@ static int ecryptfs_open(struct inode *inode, struct file *file) if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE) == O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) { rc = -EPERM; - printk(KERN_WARNING "%s: Lower persistent file is RO; eCryptfs " + printk(KERN_WARNING "%s: Lower file is RO; eCryptfs " "file must hence be opened RO\n", __func__); - goto out_free; + goto out_put; } ecryptfs_set_file_lower( file, ecryptfs_inode_to_private(inode)->lower_file); @@ -232,7 +232,7 @@ static int ecryptfs_open(struct inode *inode, struct file *file) "Plaintext passthrough mode is not " "enabled; returning -EIO\n"); mutex_unlock(&crypt_stat->cs_mutex); - goto out_free; + goto out_put; } rc = 0; crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); @@ -245,6 +245,8 @@ static int ecryptfs_open(struct inode *inode, struct file *file) "[0x%.16lx] size: [0x%.16llx]\n", inode, inode->i_ino, (unsigned long long)i_size_read(inode)); goto out; +out_put: + ecryptfs_put_lower_file(inode); out_free: kmem_cache_free(ecryptfs_file_info_cache, ecryptfs_file_to_private(file)); @@ -254,17 +256,13 @@ out: static int ecryptfs_flush(struct file *file, fl_owner_t td) { - int rc = 0; - struct file *lower_file = NULL; - - lower_file = ecryptfs_file_to_lower(file); - if (lower_file->f_op && lower_file->f_op->flush) - rc = lower_file->f_op->flush(lower_file, td); - return rc; + return file->f_mode & FMODE_WRITE + ? filemap_write_and_wait(file->f_mapping) : 0; } static int ecryptfs_release(struct inode *inode, struct file *file) { + ecryptfs_put_lower_file(inode); kmem_cache_free(ecryptfs_file_info_cache, ecryptfs_file_to_private(file)); return 0; -- cgit v1.2.3 From 3aeb86ea4cd15f728147a3bd5469a205ada8c767 Mon Sep 17 00:00:00 2001 From: Tyler Hicks Date: Tue, 15 Mar 2011 14:54:00 -0500 Subject: 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: Signed-off-by: Tyler Hicks --- fs/ecryptfs/file.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'fs/ecryptfs/file.c') diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c index 146c4edff70c..566e5472f78c 100644 --- a/fs/ecryptfs/file.c +++ b/fs/ecryptfs/file.c @@ -235,7 +235,8 @@ static int ecryptfs_open(struct inode *inode, struct file *file) goto out_put; } rc = 0; - crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); + crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED + | ECRYPTFS_ENCRYPTED); mutex_unlock(&crypt_stat->cs_mutex); goto out; } -- cgit v1.2.3 From 3b06b3ebf44170c90c893c6c80916db6e922b9f2 Mon Sep 17 00:00:00 2001 From: Tyler Hicks Date: Tue, 24 May 2011 03:49:02 -0500 Subject: eCryptfs: Fix new inode race condition Only unlock and d_add() new inodes after the plaintext inode size has been read from the lower filesystem. This fixes a race condition that was sometimes seen during a multi-job kernel build in an eCryptfs mount. https://bugzilla.kernel.org/show_bug.cgi?id=36002 Signed-off-by: Tyler Hicks Reported-by: David Tested-by: David --- fs/ecryptfs/file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/ecryptfs/file.c') diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c index 566e5472f78c..4ec9eb00a241 100644 --- a/fs/ecryptfs/file.c +++ b/fs/ecryptfs/file.c @@ -191,7 +191,7 @@ static int ecryptfs_open(struct inode *inode, struct file *file) | ECRYPTFS_ENCRYPTED); } mutex_unlock(&crypt_stat->cs_mutex); - rc = ecryptfs_get_lower_file(ecryptfs_dentry); + rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode); if (rc) { printk(KERN_ERR "%s: Error attempting to initialize " "the lower file for the dentry with name " -- cgit v1.2.3