[PATCH] eCryptfs: Consolidate lower dentry_open's

Opens on lower dentry objects happen in several places in eCryptfs, and they
all involve the same steps (dget, mntget, dentry_open).  This patch
consolidates the lower open events into a single function call.

Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

4 files changed, 63 insertions, 42 deletions

diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index 2a1b6aa1a4a1..f49f105394b7 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -1191,28 +1191,28 @@ int ecryptfs_cipher_code_to_string(char *str, u16 cipher_code)
 int ecryptfs_read_header_region(char *data, struct dentry *dentry,
                                 struct vfsmount *mnt)
 {
-        struct file *file;
+        struct file *lower_file;
         mm_segment_t oldfs;
         int rc;
 
-        mnt = mntget(mnt);
-        file = dentry_open(dentry, mnt, O_RDONLY);
-        if (IS_ERR(file)) {
-                ecryptfs_printk(KERN_DEBUG, "Error opening file to "
-                                "read header region\n");
-                mntput(mnt);
-                rc = PTR_ERR(file);
+        if ((rc = ecryptfs_open_lower_file(&lower_file, dentry, mnt,
+                                           O_RDONLY))) {
+                printk(KERN_ERR
+                       "Error opening lower_file to read header region\n");
                 goto out;
         }
-        file->f_pos = 0;
+        lower_file->f_pos = 0;
         oldfs = get_fs();
         set_fs(get_ds());
         /* For releases 0.1 and 0.2, all of the header information
          * fits in the first data extent-sized region. */
-        rc = file->f_op->read(file, (char __user *)data,
-                              ECRYPTFS_DEFAULT_EXTENT_SIZE, &file->f_pos);
+        rc = lower_file->f_op->read(lower_file, (char __user *)data,
+                              ECRYPTFS_DEFAULT_EXTENT_SIZE, &lower_file->f_pos);
         set_fs(oldfs);
-        fput(file);
+        if ((rc = ecryptfs_close_lower_file(lower_file))) {
+                printk(KERN_ERR "Error closing lower_file\n");
+                goto out;
+        }
         rc = 0;
 out:
         return rc;
diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index 199fcda50e1b..f992533d1692 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -482,5 +482,9 @@ ecryptfs_process_cipher(struct crypto_blkcipher **key_tfm, char *cipher_name,
 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode);
 int ecryptfs_inode_set(struct inode *inode, void *lower_inode);
 void ecryptfs_init_inode(struct inode *inode, struct inode *lower_inode);
+int ecryptfs_open_lower_file(struct file **lower_file,
+                             struct dentry *lower_dentry,
+                             struct vfsmount *lower_mnt, int flags);
+int ecryptfs_close_lower_file(struct file *lower_file);
 
 #endif /* #ifndef ECRYPTFS_KERNEL_H */
diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index c8550c9f9cd2..a92ef05eff8f 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -198,6 +198,33 @@ retry:
 
 struct kmem_cache *ecryptfs_file_info_cache;
 
+int ecryptfs_open_lower_file(struct file **lower_file,
+                             struct dentry *lower_dentry,
+                             struct vfsmount *lower_mnt, int flags)
+{
+        int rc = 0;
+
+        dget(lower_dentry);
+        mntget(lower_mnt);
+        *lower_file = dentry_open(lower_dentry, lower_mnt, flags);
+        if (IS_ERR(*lower_file)) {
+                printk(KERN_ERR "Error opening lower file for lower_dentry "
+                       "[0x%p], lower_mnt [0x%p], and flags [0x%x]\n",
+                       lower_dentry, lower_mnt, flags);
+                rc = PTR_ERR(*lower_file);
+                *lower_file = NULL;
+                goto out;
+        }
+out:
+        return rc;
+}
+
+int ecryptfs_close_lower_file(struct file *lower_file)
+{
+        fput(lower_file);
+        return 0;
+}
+
 /**
  * ecryptfs_open
  * @inode: inode speciying file to open
@@ -244,19 +271,15 @@ static int ecryptfs_open(struct inode *inode, struct file *file)
                 ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED);
         }
         mutex_unlock(&crypt_stat->cs_mutex);
-        /* This mntget & dget is undone via fput when the file is released */
-        dget(lower_dentry);
         lower_flags = file->f_flags;
         if ((lower_flags & O_ACCMODE) == O_WRONLY)
                 lower_flags = (lower_flags & O_ACCMODE) | O_RDWR;
         if (file->f_flags & O_APPEND)
                 lower_flags &= ~O_APPEND;
         lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
-        mntget(lower_mnt);
         /* Corresponding fput() in ecryptfs_release() */
-        lower_file = dentry_open(lower_dentry, lower_mnt, lower_flags);
-        if (IS_ERR(lower_file)) {
-                rc = PTR_ERR(lower_file);
+        if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
+                                           lower_flags))) {
                 ecryptfs_printk(KERN_ERR, "Error opening lower file\n");
                 goto out_puts;
         }
@@ -341,11 +364,16 @@ static int ecryptfs_release(struct inode *inode, struct file *file)
         struct file *lower_file = ecryptfs_file_to_lower(file);
         struct ecryptfs_file_info *file_info = ecryptfs_file_to_private(file);
         struct inode *lower_inode = ecryptfs_inode_to_lower(inode);
+        int rc;
 
-        fput(lower_file);
+        if ((rc = ecryptfs_close_lower_file(lower_file))) {
+                printk(KERN_ERR "Error closing lower_file\n");
+                goto out;
+        }
         inode->i_blocks = lower_inode->i_blocks;
         kmem_cache_free(ecryptfs_file_info_cache, file_info);
-        return 0;
+out:
+        return rc;
 }
 
 static int
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index efdd2b7b62d7..2f2c6cf972f7 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -231,7 +231,6 @@ static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
         int lower_flags;
         struct ecryptfs_crypt_stat *crypt_stat;
         struct dentry *lower_dentry;
-        struct dentry *tlower_dentry = NULL;
         struct file *lower_file;
         struct inode *inode, *lower_inode;
         struct vfsmount *lower_mnt;
@@ -241,30 +240,19 @@ static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
                         lower_dentry->d_name.name);
         inode = ecryptfs_dentry->d_inode;
         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
-        tlower_dentry = dget(lower_dentry);
-        if (!tlower_dentry) {
-                rc = -ENOMEM;
-                ecryptfs_printk(KERN_ERR, "Error dget'ing lower_dentry\n");
-                goto out;
-        }
         lower_flags = ((O_CREAT | O_WRONLY | O_TRUNC) & O_ACCMODE) | O_RDWR;
 #if BITS_PER_LONG != 32
         lower_flags |= O_LARGEFILE;
 #endif
         lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
-        mntget(lower_mnt);
         /* Corresponding fput() at end of this function */
-        lower_file = dentry_open(tlower_dentry, lower_mnt, lower_flags);
-        if (IS_ERR(lower_file)) {
-                rc = PTR_ERR(lower_file);
+        if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
+                                           lower_flags))) {
                 ecryptfs_printk(KERN_ERR,
                                 "Error opening dentry; rc = [%i]\n", rc);
                 goto out;
         }
-        /* fput(lower_file) should handle the puts if we do this */
-        lower_file->f_dentry = tlower_dentry;
-        lower_file->f_vfsmnt = lower_mnt;
-        lower_inode = tlower_dentry->d_inode;
+        lower_inode = lower_dentry->d_inode;
         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
                 ECRYPTFS_CLEAR_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED);
@@ -285,7 +273,8 @@ static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
         }
         rc = grow_file(ecryptfs_dentry, lower_file, inode, lower_inode);
 out_fput:
-        fput(lower_file);
+        if ((rc = ecryptfs_close_lower_file(lower_file)))
+                printk(KERN_ERR "Error closing lower_file\n");
 out:
         return rc;
 }
@@ -832,12 +821,11 @@ int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
         }
         lower_dentry = ecryptfs_dentry_to_lower(dentry);
         /* This dget & mntget is released through fput at out_fput: */
-        dget(lower_dentry);
         lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
-        mntget(lower_mnt);
-        lower_file = dentry_open(lower_dentry, lower_mnt, O_RDWR);
-        if (unlikely(IS_ERR(lower_file))) {
-                rc = PTR_ERR(lower_file);
+        if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
+                                           O_RDWR))) {
+                ecryptfs_printk(KERN_ERR,
+                                "Error opening dentry; rc = [%i]\n", rc);
                 goto out_free;
         }
         ecryptfs_set_file_lower(&fake_ecryptfs_file, lower_file);
@@ -879,7 +867,8 @@ int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
                 = CURRENT_TIME;
         mark_inode_dirty_sync(inode);
 out_fput:
-        fput(lower_file);
+        if ((rc = ecryptfs_close_lower_file(lower_file)))
+                printk(KERN_ERR "Error closing lower_file\n");
 out_free:
         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
                 kmem_cache_free(ecryptfs_file_info_cache,