Having just fiddled with the refcounts of blockdev buffers, I want some
way of assuring that the code is correct and is not leaking
buffer_heads.
There's no easy way to do this: if a blockdev page has pinned buffers
then truncate_complete_page just cuts it loose and we leak memory.
The patch adds a bit of debug code to catch these leaks. This code,
PF_RADIX_TREE and buffer_error() need to be removed later on.
fs/buffer.c | 2 ++
include/linux/sched.h | 2 +-
mm/filemap.c | 7 ++++++-
3 files changed, 9 insertions(+), 2 deletions(-)
--- 2.5.24/mm/filemap.c~buffer-leak-check Thu Jul 4 16:17:12 2002
+++ 2.5.24-akpm/mm/filemap.c Thu Jul 4 16:22:11 2002
@@ -177,8 +177,13 @@ static inline void truncate_partial_page
static void truncate_complete_page(struct page *page)
{
/* Leave it on the LRU if it gets converted into anonymous buffers */
- if (!PagePrivate(page) || do_invalidatepage(page, 0))
+ if (!PagePrivate(page) || do_invalidatepage(page, 0)) {
lru_cache_del(page);
+ } else {
+ if (current->flags & PF_INVALIDATE)
+ printk("%s: buffer heads were leaked\n",
+ current->comm);
+ }
ClearPageDirty(page);
ClearPageUptodate(page);
remove_inode_page(page);
--- 2.5.24/fs/buffer.c~buffer-leak-check Thu Jul 4 16:17:12 2002
+++ 2.5.24-akpm/fs/buffer.c Thu Jul 4 16:22:11 2002
@@ -467,7 +467,9 @@ void invalidate_bdev(struct block_device
* We really want to use invalidate_inode_pages2() for
* that, but not until that's cleaned up.
*/
+ current->flags |= PF_INVALIDATE;
invalidate_inode_pages(bdev->bd_inode);
+ current->flags &= ~PF_INVALIDATE;
}
void __invalidate_buffers(kdev_t dev, int destroy_dirty_buffers)
--- 2.5.24/include/linux/sched.h~buffer-leak-check Thu Jul 4 16:17:12 2002
+++ 2.5.24-akpm/include/linux/sched.h Thu Jul 4 16:22:11 2002
@@ -391,7 +391,7 @@ do { if (atomic_dec_and_test(&(tsk)->usa
#define PF_FREEZE 0x00010000 /* this task should be frozen for suspend */
#define PF_IOTHREAD 0x00020000 /* this thread is needed for doing I/O to swap */
#define PF_FROZEN 0x00040000 /* frozen for system suspend */
-
+#define PF_INVALIDATE 0x00080000 /* debug: unmounting an fs. killme. */
/*
* Ptrace flags
*/
-
-
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This archive was generated by hypermail 2b29 : Sun Jul 07 2002 - 22:00:14 EST