NTFS: Fix cluster (de)allocators to work when the runlist is NULL and more
importantly to take a locked runlist rather than them locking it
which leads to lock reversal.
Signed-off-by: Anton Altaparmakov <aia21@cantab.net>
diff --git a/fs/ntfs/lcnalloc.c b/fs/ntfs/lcnalloc.c
index a4bc076..7b59342 100644
--- a/fs/ntfs/lcnalloc.c
+++ b/fs/ntfs/lcnalloc.c
@@ -54,6 +54,8 @@
int ret = 0;
ntfs_debug("Entering.");
+ if (!rl)
+ return 0;
for (; rl->length; rl++) {
int err;
@@ -163,17 +165,9 @@
BUG_ON(zone < FIRST_ZONE);
BUG_ON(zone > LAST_ZONE);
- /* Return empty runlist if @count == 0 */
- // FIXME: Do we want to just return NULL instead? (AIA)
- if (!count) {
- rl = ntfs_malloc_nofs(PAGE_SIZE);
- if (!rl)
- return ERR_PTR(-ENOMEM);
- rl[0].vcn = start_vcn;
- rl[0].lcn = LCN_RL_NOT_MAPPED;
- rl[0].length = 0;
- return rl;
- }
+ /* Return NULL if @count is zero. */
+ if (!count)
+ return NULL;
/* Take the lcnbmp lock for writing. */
down_write(&vol->lcnbmp_lock);
/*
@@ -788,7 +782,8 @@
* @vi: vfs inode whose runlist describes the clusters to free
* @start_vcn: vcn in the runlist of @vi at which to start freeing clusters
* @count: number of clusters to free or -1 for all clusters
- * @is_rollback: if TRUE this is a rollback operation
+ * @write_locked: true if the runlist is locked for writing
+ * @is_rollback: true if this is a rollback operation
*
* Free @count clusters starting at the cluster @start_vcn in the runlist
* described by the vfs inode @vi.
@@ -806,17 +801,17 @@
* Return the number of deallocated clusters (not counting sparse ones) on
* success and -errno on error.
*
- * Locking: - The runlist described by @vi must be unlocked on entry and is
- * unlocked on return.
- * - This function takes the runlist lock of @vi for reading and
- * sometimes for writing and sometimes modifies the runlist.
+ * Locking: - The runlist described by @vi must be locked on entry and is
+ * locked on return. Note if the runlist is locked for reading the
+ * lock may be dropped and reacquired. Note the runlist may be
+ * modified when needed runlist fragments need to be mapped.
* - The volume lcn bitmap must be unlocked on entry and is unlocked
* on return.
* - This function takes the volume lcn bitmap lock for writing and
* modifies the bitmap contents.
*/
s64 __ntfs_cluster_free(struct inode *vi, const VCN start_vcn, s64 count,
- const BOOL is_rollback)
+ const BOOL write_locked, const BOOL is_rollback)
{
s64 delta, to_free, total_freed, real_freed;
ntfs_inode *ni;
@@ -848,8 +843,7 @@
total_freed = real_freed = 0;
- down_read(&ni->runlist.lock);
- rl = ntfs_attr_find_vcn_nolock(ni, start_vcn, FALSE);
+ rl = ntfs_attr_find_vcn_nolock(ni, start_vcn, write_locked);
if (IS_ERR(rl)) {
if (!is_rollback)
ntfs_error(vol->sb, "Failed to find first runlist "
@@ -903,7 +897,7 @@
/* Attempt to map runlist. */
vcn = rl->vcn;
- rl = ntfs_attr_find_vcn_nolock(ni, vcn, FALSE);
+ rl = ntfs_attr_find_vcn_nolock(ni, vcn, write_locked);
if (IS_ERR(rl)) {
err = PTR_ERR(rl);
if (!is_rollback)
@@ -950,7 +944,6 @@
/* Update the total done clusters. */
total_freed += to_free;
}
- up_read(&ni->runlist.lock);
if (likely(!is_rollback))
up_write(&vol->lcnbmp_lock);
@@ -960,7 +953,6 @@
ntfs_debug("Done.");
return real_freed;
err_out:
- up_read(&ni->runlist.lock);
if (is_rollback)
return err;
/* If no real clusters were freed, no need to rollback. */
@@ -973,7 +965,8 @@
* If rollback fails, set the volume errors flag, emit an error
* message, and return the error code.
*/
- delta = __ntfs_cluster_free(vi, start_vcn, total_freed, TRUE);
+ delta = __ntfs_cluster_free(vi, start_vcn, total_freed, write_locked,
+ TRUE);
if (delta < 0) {
ntfs_error(vol->sb, "Failed to rollback (error %i). Leaving "
"inconsistent metadata! Unmount and run "