NTFS: Fix several bugs in fs/ntfs/attrib.c.
- Fix a bug in ntfs_map_runlist_nolock() where we forgot to protect
access to the allocated size in the ntfs inode with the size lock.
- Fix ntfs_attr_vcn_to_lcn_nolock() and ntfs_attr_find_vcn_nolock() to
return LCN_ENOENT when there is no runlist and the allocated size is
zero.
- Fix load_attribute_list() to handle the case of a NULL runlist.
Signed-off-by: Anton Altaparmakov <aia21@cantab.net>
diff --git a/fs/ntfs/attrib.c b/fs/ntfs/attrib.c
index 79dda39..98b5b96 100644
--- a/fs/ntfs/attrib.c
+++ b/fs/ntfs/attrib.c
@@ -43,6 +43,9 @@
* which is not an error as such. This is -ENOENT. It means that @vcn is out
* of bounds of the runlist.
*
+ * Note the runlist can be NULL after this function returns if @vcn is zero and
+ * the attribute has zero allocated size, i.e. there simply is no runlist.
+ *
* Locking: - The runlist must be locked for writing.
* - This function modifies the runlist.
*/
@@ -54,6 +57,7 @@
ATTR_RECORD *a;
ntfs_attr_search_ctx *ctx;
runlist_element *rl;
+ unsigned long flags;
int err = 0;
ntfs_debug("Mapping runlist part containing vcn 0x%llx.",
@@ -85,8 +89,11 @@
* ntfs_mapping_pairs_decompress() fails.
*/
end_vcn = sle64_to_cpu(a->data.non_resident.highest_vcn) + 1;
- if (unlikely(!a->data.non_resident.lowest_vcn && end_vcn <= 1))
+ if (unlikely(!a->data.non_resident.lowest_vcn && end_vcn <= 1)) {
+ read_lock_irqsave(&ni->size_lock, flags);
end_vcn = ni->allocated_size >> ni->vol->cluster_size_bits;
+ read_unlock_irqrestore(&ni->size_lock, flags);
+ }
if (unlikely(vcn >= end_vcn)) {
err = -ENOENT;
goto err_out;
@@ -165,6 +172,7 @@
const BOOL write_locked)
{
LCN lcn;
+ unsigned long flags;
BOOL is_retry = FALSE;
ntfs_debug("Entering for i_ino 0x%lx, vcn 0x%llx, %s_locked.",
@@ -173,6 +181,14 @@
BUG_ON(!ni);
BUG_ON(!NInoNonResident(ni));
BUG_ON(vcn < 0);
+ if (!ni->runlist.rl) {
+ read_lock_irqsave(&ni->size_lock, flags);
+ if (!ni->allocated_size) {
+ read_unlock_irqrestore(&ni->size_lock, flags);
+ return LCN_ENOENT;
+ }
+ read_unlock_irqrestore(&ni->size_lock, flags);
+ }
retry_remap:
/* Convert vcn to lcn. If that fails map the runlist and retry once. */
lcn = ntfs_rl_vcn_to_lcn(ni->runlist.rl, vcn);
@@ -255,6 +271,7 @@
runlist_element *ntfs_attr_find_vcn_nolock(ntfs_inode *ni, const VCN vcn,
const BOOL write_locked)
{
+ unsigned long flags;
runlist_element *rl;
int err = 0;
BOOL is_retry = FALSE;
@@ -265,6 +282,14 @@
BUG_ON(!ni);
BUG_ON(!NInoNonResident(ni));
BUG_ON(vcn < 0);
+ if (!ni->runlist.rl) {
+ read_lock_irqsave(&ni->size_lock, flags);
+ if (!ni->allocated_size) {
+ read_unlock_irqrestore(&ni->size_lock, flags);
+ return ERR_PTR(-ENOENT);
+ }
+ read_unlock_irqrestore(&ni->size_lock, flags);
+ }
retry_remap:
rl = ni->runlist.rl;
if (likely(rl && vcn >= rl[0].vcn)) {
@@ -528,6 +553,11 @@
block_size_bits = sb->s_blocksize_bits;
down_read(&runlist->lock);
rl = runlist->rl;
+ if (!rl) {
+ ntfs_error(sb, "Cannot read attribute list since runlist is "
+ "missing.");
+ goto err_out;
+ }
/* Read all clusters specified by the runlist one run at a time. */
while (rl->length) {
lcn = ntfs_rl_vcn_to_lcn(rl, rl->vcn);