eCryptfs: Propagate vfs_read and vfs_write return codes

Errors returned from vfs_read() and vfs_write() calls to the lower
filesystem were being masked as -EINVAL.  This caused some confusion to
users who saw EINVAL instead of ENOSPC when the disk was full, for
instance.

Also, the actual bytes read or written were not accessible by callers to
ecryptfs_read_lower() and ecryptfs_write_lower(), which may be useful in
some cases.  This patch updates the error handling logic where those
functions are called in order to accept positive return codes indicating
success.

Cc: Eric Sandeen <esandeen@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: ecryptfs-devel@lists.launchpad.net
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>

1 files changed, 11 insertions, 8 deletions

diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index bae20ad1a504..fbb6e5eed697 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -509,13 +509,14 @@ int ecryptfs_encrypt_page(struct page *page)
                                   + extent_offset), crypt_stat);
                 rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt,
                                           offset, crypt_stat->extent_size);
-                if (rc) {
+                if (rc < 0) {
                         ecryptfs_printk(KERN_ERR, "Error attempting "
                                         "to write lower page; rc = [%d]"
                                         "\n", rc);
                         goto out;
                 }
         }
+        rc = 0;
 out:
         if (enc_extent_page) {
                 kunmap(enc_extent_page);
@@ -631,7 +632,7 @@ int ecryptfs_decrypt_page(struct page *page)
                 rc = ecryptfs_read_lower(enc_extent_virt, offset,
                                          crypt_stat->extent_size,
                                          ecryptfs_inode);
-                if (rc) {
+                if (rc < 0) {
                         ecryptfs_printk(KERN_ERR, "Error attempting "
                                         "to read lower page; rc = [%d]"
                                         "\n", rc);
@@ -1213,14 +1214,15 @@ int ecryptfs_read_and_validate_header_region(char *data,
                 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
         rc = ecryptfs_read_lower(data, 0, crypt_stat->extent_size,
                                  ecryptfs_inode);
-        if (rc) {
+        if (rc < 0) {
                 printk(KERN_ERR "%s: Error reading header region; rc = [%d]\n",
                        __func__, rc);
                 goto out;
         }
         if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES)) {
                 rc = -EINVAL;
-        }
+        } else
+                rc = 0;
 out:
         return rc;
 }
@@ -1315,10 +1317,11 @@ ecryptfs_write_metadata_to_contents(struct dentry *ecryptfs_dentry,
 
         rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, virt,
                                   0, virt_len);
-        if (rc)
+        if (rc < 0)
                 printk(KERN_ERR "%s: Error attempting to write header "
-                       "information to lower file; rc = [%d]\n", __func__,
-                       rc);
+                       "information to lower file; rc = [%d]\n", __func__, rc);
+        else
+                rc = 0;
         return rc;
 }
 
@@ -1598,7 +1601,7 @@ int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
         }
         rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
                                  ecryptfs_inode);
-        if (!rc)
+        if (rc >= 0)
                 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
                                                 ecryptfs_dentry,
                                                 ECRYPTFS_VALIDATE_HEADER_SIZE);