eCryptfs: make open, truncate, and setattr use persistent file
Michael Halcrow [Tue, 16 Oct 2007 08:28:10 +0000 (01:28 -0700)]
Rather than open a new lower file for every eCryptfs file that is opened,
truncated, or setattr'd, instead use the existing lower persistent file for
the eCryptfs inode.  Change truncate to use read_write.c functions.  Change
ecryptfs_getxattr() to use the common ecryptfs_getxattr_lower() function.

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/crypto.c
fs/ecryptfs/file.c
fs/ecryptfs/inode.c

index 55110ff..26070d6 100644 (file)
@@ -1673,7 +1673,7 @@ out:
 /**
  * ecryptfs_read_xattr_region
  * @page_virt: The vitual address into which to read the xattr data
- * @ecryptfs_dentry: The eCryptfs dentry
+ * @ecryptfs_inode: The eCryptfs inode
  *
  * Attempts to read the crypto metadata from the extended attribute
  * region of the lower file.
index df70bfa..95be9a9 100644 (file)
@@ -187,11 +187,7 @@ static int ecryptfs_open(struct inode *inode, struct file *file)
        /* Private value of ecryptfs_dentry allocated in
         * ecryptfs_lookup() */
        struct dentry *lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
-       struct inode *lower_inode = NULL;
-       struct file *lower_file = NULL;
-       struct vfsmount *lower_mnt;
        struct ecryptfs_file_info *file_info;
-       int lower_flags;
 
        mount_crypt_stat = &ecryptfs_superblock_to_private(
                ecryptfs_dentry->d_sb)->mount_crypt_stat;
@@ -219,26 +215,12 @@ static int ecryptfs_open(struct inode *inode, struct file *file)
        if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
                ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
                /* Policy code enabled in future release */
-               crypt_stat->flags |= ECRYPTFS_POLICY_APPLIED;
-               crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
+               crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED
+                                     | ECRYPTFS_ENCRYPTED);
        }
        mutex_unlock(&crypt_stat->cs_mutex);
-       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);
-       /* Corresponding fput() in ecryptfs_release() */
-       rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
-                                     lower_flags);
-       if (rc) {
-               ecryptfs_printk(KERN_ERR, "Error opening lower file\n");
-               goto out_puts;
-       }
-       ecryptfs_set_file_lower(file, lower_file);
-       /* Isn't this check the same as the one in lookup? */
-       lower_inode = lower_dentry->d_inode;
+       ecryptfs_set_file_lower(
+               file, ecryptfs_inode_to_private(inode)->lower_file);
        if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
                ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
                crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
@@ -260,7 +242,7 @@ static int ecryptfs_open(struct inode *inode, struct file *file)
                                       "and plaintext passthrough mode is not "
                                       "enabled; returning -EIO\n");
                                mutex_unlock(&crypt_stat->cs_mutex);
-                               goto out_puts;
+                               goto out_free;
                        }
                        rc = 0;
                        crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
@@ -272,11 +254,8 @@ static int ecryptfs_open(struct inode *inode, struct file *file)
        ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = [0x%.16x] "
                        "size: [0x%.16x]\n", inode, inode->i_ino,
                        i_size_read(inode));
-       ecryptfs_set_file_lower(file, lower_file);
        goto out;
-out_puts:
-       mntput(lower_mnt);
-       dput(lower_dentry);
+out_free:
        kmem_cache_free(ecryptfs_file_info_cache,
                        ecryptfs_file_to_private(file));
 out:
@@ -296,20 +275,9 @@ static int ecryptfs_flush(struct file *file, fl_owner_t td)
 
 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;
-
-       rc = ecryptfs_close_lower_file(lower_file);
-       if (rc) {
-               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);
-out:
-       return rc;
+       kmem_cache_free(ecryptfs_file_info_cache,
+                       ecryptfs_file_to_private(file));
+       return 0;
 }
 
 static int
index a29dc31..5701f81 100644 (file)
@@ -739,8 +739,7 @@ int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
        int rc = 0;
        struct inode *inode = dentry->d_inode;
        struct dentry *lower_dentry;
-       struct vfsmount *lower_mnt;
-       struct file fake_ecryptfs_file, *lower_file = NULL;
+       struct file fake_ecryptfs_file;
        struct ecryptfs_crypt_stat *crypt_stat;
        loff_t i_size = i_size_read(inode);
        loff_t lower_size_before_truncate;
@@ -763,51 +762,43 @@ int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
                goto out;
        }
        lower_dentry = ecryptfs_dentry_to_lower(dentry);
-       /* This dget & mntget is released through fput at out_fput: */
-       lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
-       rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
-                                     O_RDWR);
-       if (rc) {
-               ecryptfs_printk(KERN_ERR,
-                               "Error opening dentry; rc = [%i]\n", rc);
-               goto out_free;
-       }
-       ecryptfs_set_file_lower(&fake_ecryptfs_file, lower_file);
+       ecryptfs_set_file_lower(
+               &fake_ecryptfs_file,
+               ecryptfs_inode_to_private(dentry->d_inode)->lower_file);
        /* Switch on growing or shrinking file */
        if (new_length > i_size) {
-               rc = ecryptfs_fill_zeros(&fake_ecryptfs_file, new_length);
-               if (rc) {
-                       ecryptfs_printk(KERN_ERR,
-                                       "Problem with fill_zeros\n");
-                       goto out_fput;
-               }
-               i_size_write(inode, new_length);
-               rc = ecryptfs_write_inode_size_to_metadata(inode);
-               if (rc) {
-                       printk(KERN_ERR "Problem with "
-                              "ecryptfs_write_inode_size_to_metadata; "
-                              "rc = [%d]\n", rc);
-                       goto out_fput;
-               }
+               char zero[] = { 0x00 };
+
+               /* Write a single 0 at the last position of the file;
+                * this triggers code that will fill in 0's throughout
+                * the intermediate portion of the previous end of the
+                * file and the new and of the file */
+               rc = ecryptfs_write(&fake_ecryptfs_file, zero,
+                                   (new_length - 1), 1);
        } else { /* new_length < i_size_read(inode) */
-               pgoff_t index = 0;
-               int end_pos_in_page = -1;
-
-               if (new_length != 0) {
-                       index = ((new_length - 1) >> PAGE_CACHE_SHIFT);
-                       end_pos_in_page = ((new_length - 1) & ~PAGE_CACHE_MASK);
-               }
-               if (end_pos_in_page != (PAGE_CACHE_SIZE - 1)) {
-                       rc = ecryptfs_write_zeros(&fake_ecryptfs_file,
-                                                 index,
-                                                 (end_pos_in_page + 1),
-                                                 ((PAGE_CACHE_SIZE - 1)
-                                                  - end_pos_in_page));
+               /* We're chopping off all the pages down do the page
+                * in which new_length is located. Fill in the end of
+                * that page from (new_length & ~PAGE_CACHE_MASK) to
+                * PAGE_CACHE_SIZE with zeros. */
+               size_t num_zeros = (PAGE_CACHE_SIZE
+                                   - (new_length & ~PAGE_CACHE_MASK));
+
+               if (num_zeros) {
+                       char *zeros_virt;
+
+                       zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
+                       if (!zeros_virt) {
+                               rc = -ENOMEM;
+                               goto out_free;
+                       }
+                       rc = ecryptfs_write(&fake_ecryptfs_file, zeros_virt,
+                                           new_length, num_zeros);
+                       kfree(zeros_virt);
                        if (rc) {
                                printk(KERN_ERR "Error attempting to zero out "
                                       "the remainder of the end page on "
                                       "reducing truncate; rc = [%d]\n", rc);
-                               goto out_fput;
+                               goto out_free;
                        }
                }
                vmtruncate(inode, new_length);
@@ -816,7 +807,7 @@ int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
                        printk(KERN_ERR "Problem with "
                               "ecryptfs_write_inode_size_to_metadata; "
                               "rc = [%d]\n", rc);
-                       goto out_fput;
+                       goto out_free;
                }
                /* We are reducing the size of the ecryptfs file, and need to
                 * know if we need to reduce the size of the lower file. */
@@ -828,14 +819,6 @@ int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
                        vmtruncate(lower_dentry->d_inode,
                                   lower_size_after_truncate);
        }
-       /* Update the access times */
-       lower_dentry->d_inode->i_mtime = lower_dentry->d_inode->i_ctime
-               = CURRENT_TIME;
-       mark_inode_dirty_sync(inode);
-out_fput:
-       rc = ecryptfs_close_lower_file(lower_file);
-       if (rc)
-               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,
@@ -895,21 +878,8 @@ static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
        else if (S_ISREG(dentry->d_inode->i_mode)
                 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
                     || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
-               struct vfsmount *lower_mnt;
-               struct file *lower_file = NULL;
                struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
-               int lower_flags;
 
-               lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
-               lower_flags = O_RDONLY;
-               rc = ecryptfs_open_lower_file(&lower_file, lower_dentry,
-                                             lower_mnt, lower_flags);
-               if (rc) {
-                       printk(KERN_ERR
-                              "Error opening lower file; rc = [%d]\n", rc);
-                       mutex_unlock(&crypt_stat->cs_mutex);
-                       goto out;
-               }
                mount_crypt_stat = &ecryptfs_superblock_to_private(
                        dentry->d_sb)->mount_crypt_stat;
                rc = ecryptfs_read_metadata(dentry);
@@ -923,16 +893,13 @@ static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
                                       "enabled; returning -EIO\n");
 
                                mutex_unlock(&crypt_stat->cs_mutex);
-                               fput(lower_file);
                                goto out;
                        }
                        rc = 0;
                        crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
                        mutex_unlock(&crypt_stat->cs_mutex);
-                       fput(lower_file);
                        goto out;
                }
-               fput(lower_file);
        }
        mutex_unlock(&crypt_stat->cs_mutex);
        if (ia->ia_valid & ATTR_SIZE) {
@@ -995,20 +962,8 @@ ssize_t
 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
                  size_t size)
 {
-       int rc = 0;
-       struct dentry *lower_dentry;
-
-       lower_dentry = ecryptfs_dentry_to_lower(dentry);
-       if (!lower_dentry->d_inode->i_op->getxattr) {
-               rc = -ENOSYS;
-               goto out;
-       }
-       mutex_lock(&lower_dentry->d_inode->i_mutex);
-       rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
-                                                  size);
-       mutex_unlock(&lower_dentry->d_inode->i_mutex);
-out:
-       return rc;
+       return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
+                                      value, size);
 }
 
 static ssize_t