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authorTyler Hicks <tyhicks@canonical.com>2012-01-18 18:30:04 -0600
committerTyler Hicks <tyhicks@canonical.com>2012-01-25 14:43:40 -0600
commit5e6f0d769017cc49207ef56996e42363ec26c1f0 (patch)
tree1cfcfdaeda81e1d17725bdd1e1a964cc5a0b40b5
parent684a3ff7e69acc7c678d1a1394fe9e757993fd34 (diff)
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eCryptfs: Make truncate path killable
ecryptfs_write() handles the truncation of eCryptfs inodes. It grabs a page, zeroes out the appropriate portions, and then encrypts the page before writing it to the lower filesystem. It was unkillable and due to the lack of sparse file support could result in tying up a large portion of system resources, while encrypting pages of zeros, with no way for the truncate operation to be stopped from userspace. This patch adds the ability for ecryptfs_write() to detect a pending fatal signal and return as gracefully as possible. The intent is to leave the lower file in a useable state, while still allowing a user to break out of the encryption loop. If a pending fatal signal is detected, the eCryptfs inode size is updated to reflect the modified inode size and then -EINTR is returned. Signed-off-by: Tyler Hicks <tyhicks@canonical.com> Cc: <stable@vger.kernel.org>
-rw-r--r--fs/ecryptfs/read_write.c19
1 files changed, 14 insertions, 5 deletions
diff --git a/fs/ecryptfs/read_write.c b/fs/ecryptfs/read_write.c
index ec3d9368dc5..608c1c3fde1 100644
--- a/fs/ecryptfs/read_write.c
+++ b/fs/ecryptfs/read_write.c
@@ -132,6 +132,11 @@ int ecryptfs_write(struct inode *ecryptfs_inode, char *data, loff_t offset,
size_t num_bytes = (PAGE_CACHE_SIZE - start_offset_in_page);
loff_t total_remaining_bytes = ((offset + size) - pos);
+ if (fatal_signal_pending(current)) {
+ rc = -EINTR;
+ break;
+ }
+
if (num_bytes > total_remaining_bytes)
num_bytes = total_remaining_bytes;
if (pos < offset) {
@@ -193,15 +198,19 @@ int ecryptfs_write(struct inode *ecryptfs_inode, char *data, loff_t offset,
}
pos += num_bytes;
}
- if ((offset + size) > ecryptfs_file_size) {
- i_size_write(ecryptfs_inode, (offset + size));
+ if (pos > ecryptfs_file_size) {
+ i_size_write(ecryptfs_inode, pos);
if (crypt_stat->flags & ECRYPTFS_ENCRYPTED) {
- rc = ecryptfs_write_inode_size_to_metadata(
+ int rc2;
+
+ rc2 = ecryptfs_write_inode_size_to_metadata(
ecryptfs_inode);
- if (rc) {
+ if (rc2) {
printk(KERN_ERR "Problem with "
"ecryptfs_write_inode_size_to_metadata; "
- "rc = [%d]\n", rc);
+ "rc = [%d]\n", rc2);
+ if (!rc)
+ rc = rc2;
goto out;
}
}