diff options
Diffstat (limited to 'fs/buffer.c')
| -rw-r--r-- | fs/buffer.c | 55 |
1 files changed, 52 insertions, 3 deletions
diff --git a/fs/buffer.c b/fs/buffer.c index d2a4d1bb2d5..4d7433534f5 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -83,6 +83,40 @@ void unlock_buffer(struct buffer_head *bh) EXPORT_SYMBOL(unlock_buffer); /* + * Returns if the page has dirty or writeback buffers. If all the buffers + * are unlocked and clean then the PageDirty information is stale. If + * any of the pages are locked, it is assumed they are locked for IO. + */ +void buffer_check_dirty_writeback(struct page *page, + bool *dirty, bool *writeback) +{ + struct buffer_head *head, *bh; + *dirty = false; + *writeback = false; + + BUG_ON(!PageLocked(page)); + + if (!page_has_buffers(page)) + return; + + if (PageWriteback(page)) + *writeback = true; + + head = page_buffers(page); + bh = head; + do { + if (buffer_locked(bh)) + *writeback = true; + + if (buffer_dirty(bh)) + *dirty = true; + + bh = bh->b_this_page; + } while (bh != head); +} +EXPORT_SYMBOL(buffer_check_dirty_writeback); + +/* * Block until a buffer comes unlocked. This doesn't stop it * from becoming locked again - you have to lock it yourself * if you want to preserve its state. @@ -1454,7 +1488,8 @@ static void discard_buffer(struct buffer_head * bh) * block_invalidatepage - invalidate part or all of a buffer-backed page * * @page: the page which is affected - * @offset: the index of the truncation point + * @offset: start of the range to invalidate + * @length: length of the range to invalidate * * block_invalidatepage() is called when all or part of the page has become * invalidated by a truncate operation. @@ -1465,15 +1500,22 @@ static void discard_buffer(struct buffer_head * bh) * point. Because the caller is about to free (and possibly reuse) those * blocks on-disk. */ -void block_invalidatepage(struct page *page, unsigned long offset) +void block_invalidatepage(struct page *page, unsigned int offset, + unsigned int length) { struct buffer_head *head, *bh, *next; unsigned int curr_off = 0; + unsigned int stop = length + offset; BUG_ON(!PageLocked(page)); if (!page_has_buffers(page)) goto out; + /* + * Check for overflow + */ + BUG_ON(stop > PAGE_CACHE_SIZE || stop < length); + head = page_buffers(page); bh = head; do { @@ -1481,6 +1523,12 @@ void block_invalidatepage(struct page *page, unsigned long offset) next = bh->b_this_page; /* + * Are we still fully in range ? + */ + if (next_off > stop) + goto out; + + /* * is this block fully invalidated? */ if (offset <= curr_off) @@ -1501,6 +1549,7 @@ out: } EXPORT_SYMBOL(block_invalidatepage); + /* * We attach and possibly dirty the buffers atomically wrt * __set_page_dirty_buffers() via private_lock. try_to_free_buffers @@ -2841,7 +2890,7 @@ int block_write_full_page_endio(struct page *page, get_block_t *get_block, * they may have been added in ext3_writepage(). Make them * freeable here, so the page does not leak. */ - do_invalidatepage(page, 0); + do_invalidatepage(page, 0, PAGE_CACHE_SIZE); unlock_page(page); return 0; /* don't care */ } |