NTFS: Fixup handling of sparse, compressed, and encrypted attributes in
fs/ntfs/aops.c::ntfs_writepage().
Signed-off-by: Anton Altaparmakov <aia21@cantab.net>
diff --git a/fs/ntfs/ChangeLog b/fs/ntfs/ChangeLog
index b176664..4b8666d 100644
--- a/fs/ntfs/ChangeLog
+++ b/fs/ntfs/ChangeLog
@@ -79,6 +79,8 @@
fs/ntfs/inode.c::ntfs_read_locked_{,attr_,index_}inode().
- Make ntfs_write_block() not instantiate sparse blocks if they contain
only zeroes.
+ - Fixup handling of sparse, compressed, and encrypted attributes in
+ fs/ntfs/aops.c::ntfs_writepage().
2.1.23 - Implement extension of resident files and make writing safe as well as
many bug fixes, cleanups, and enhancements...
diff --git a/fs/ntfs/aops.c b/fs/ntfs/aops.c
index f3ad36d..6f2954a 100644
--- a/fs/ntfs/aops.c
+++ b/fs/ntfs/aops.c
@@ -1301,38 +1301,42 @@
ntfs_debug("Write outside i_size - truncated?");
return 0;
}
+ /*
+ * Only $DATA attributes can be encrypted and only unnamed $DATA
+ * attributes can be compressed. Index root can have the flags set but
+ * this means to create compressed/encrypted files, not that the
+ * attribute is compressed/encrypted.
+ */
+ if (ni->type != AT_INDEX_ROOT) {
+ /* If file is encrypted, deny access, just like NT4. */
+ if (NInoEncrypted(ni)) {
+ unlock_page(page);
+ BUG_ON(ni->type != AT_DATA);
+ ntfs_debug("Denying write access to encrypted "
+ "file.");
+ return -EACCES;
+ }
+ /* Compressed data streams are handled in compress.c. */
+ if (NInoNonResident(ni) && NInoCompressed(ni)) {
+ BUG_ON(ni->type != AT_DATA);
+ BUG_ON(ni->name_len);
+ // TODO: Implement and replace this with
+ // return ntfs_write_compressed_block(page);
+ unlock_page(page);
+ ntfs_error(vi->i_sb, "Writing to compressed files is "
+ "not supported yet. Sorry.");
+ return -EOPNOTSUPP;
+ }
+ // TODO: Implement and remove this check.
+ if (NInoNonResident(ni) && NInoSparse(ni)) {
+ unlock_page(page);
+ ntfs_error(vi->i_sb, "Writing to sparse files is not "
+ "supported yet. Sorry.");
+ return -EOPNOTSUPP;
+ }
+ }
/* NInoNonResident() == NInoIndexAllocPresent() */
if (NInoNonResident(ni)) {
- /*
- * Only unnamed $DATA attributes can be compressed, encrypted,
- * and/or sparse.
- */
- if (ni->type == AT_DATA && !ni->name_len) {
- /* If file is encrypted, deny access, just like NT4. */
- if (NInoEncrypted(ni)) {
- unlock_page(page);
- ntfs_debug("Denying write access to encrypted "
- "file.");
- return -EACCES;
- }
- /* Compressed data streams are handled in compress.c. */
- if (NInoCompressed(ni)) {
- // TODO: Implement and replace this check with
- // return ntfs_write_compressed_block(page);
- unlock_page(page);
- ntfs_error(vi->i_sb, "Writing to compressed "
- "files is not supported yet. "
- "Sorry.");
- return -EOPNOTSUPP;
- }
- // TODO: Implement and remove this check.
- if (NInoSparse(ni)) {
- unlock_page(page);
- ntfs_error(vi->i_sb, "Writing to sparse files "
- "is not supported yet. Sorry.");
- return -EOPNOTSUPP;
- }
- }
/* We have to zero every time due to mmap-at-end-of-file. */
if (page->index >= (i_size >> PAGE_CACHE_SHIFT)) {
/* The page straddles i_size. */
@@ -1345,14 +1349,16 @@
/* Handle mst protected attributes. */
if (NInoMstProtected(ni))
return ntfs_write_mst_block(page, wbc);
- /* Normal data stream. */
+ /* Normal, non-resident data stream. */
return ntfs_write_block(page, wbc);
}
/*
- * Attribute is resident, implying it is not compressed, encrypted,
- * sparse, or mst protected. This also means the attribute is smaller
- * than an mft record and hence smaller than a page, so can simply
- * return error on any pages with index above 0.
+ * Attribute is resident, implying it is not compressed, encrypted, or
+ * mst protected. This also means the attribute is smaller than an mft
+ * record and hence smaller than a page, so can simply return error on
+ * any pages with index above 0. Note the attribute can actually be
+ * marked compressed but if it is resident the actual data is not
+ * compressed so we are ok to ignore the compressed flag here.
*/
BUG_ON(page_has_buffers(page));
BUG_ON(!PageUptodate(page));
@@ -1401,30 +1407,14 @@
BUG_ON(PageWriteback(page));
set_page_writeback(page);
unlock_page(page);
-
/*
- * Here, we don't need to zero the out of bounds area everytime because
- * the below memcpy() already takes care of the mmap-at-end-of-file
- * requirements. If the file is converted to a non-resident one, then
- * the code path use is switched to the non-resident one where the
- * zeroing happens on each ntfs_writepage() invocation.
- *
- * The above also applies nicely when i_size is decreased.
- *
- * When i_size is increased, the memory between the old and new i_size
- * _must_ be zeroed (or overwritten with new data). Otherwise we will
- * expose data to userspace/disk which should never have been exposed.
- *
- * FIXME: Ensure that i_size increases do the zeroing/overwriting and
- * if we cannot guarantee that, then enable the zeroing below. If the
- * zeroing below is enabled, we MUST move the unlock_page() from above
- * to after the kunmap_atomic(), i.e. just before the
- * end_page_writeback().
- * UPDATE: ntfs_prepare/commit_write() do the zeroing on i_size
- * increases for resident attributes so those are ok.
- * TODO: ntfs_truncate(), others?
+ * Here, we do not need to zero the out of bounds area everytime
+ * because the below memcpy() already takes care of the
+ * mmap-at-end-of-file requirements. If the file is converted to a
+ * non-resident one, then the code path use is switched to the
+ * non-resident one where the zeroing happens on each ntfs_writepage()
+ * invocation.
*/
-
attr_len = le32_to_cpu(ctx->attr->data.resident.value_length);
i_size = i_size_read(vi);
if (unlikely(attr_len > i_size)) {