Revision ad576e63e0c8b274a8558b8e05a6d0526e804dc0 authored by Nick Piggin on 05 May 2005, 23:15:46 UTC, committed by Linus Torvalds on 05 May 2005, 23:36:40 UTC
When running fsstress -v -d $DIR/tmp -n 1000 -p 1000 -l 2 on an ext2 filesystem with 1024 byte block size, on SMP i386 with 4096 byte page size over loopback to an image file on a tmpfs filesystem, I would very quickly hit BUG_ON(!buffer_async_write(bh)); in fs/buffer.c:end_buffer_async_write It seems that more than one request would be submitted for a given bh at a time. What would happen is the following: 2 threads doing __mpage_writepages on the same page. Thread 1 - lock the page first, and enter __block_write_full_page. Thread 1 - (eg.) mark_buffer_async_write on the first 2 buffers. Thread 1 - set page writeback, unlock page. Thread 2 - lock page, wait on page writeback Thread 1 - submit_bh on the first 2 buffers. => both requests complete, none of the page buffers are async_write, end_page_writeback is called. Thread 2 - wakes up. enters __block_write_full_page. Thread 2 - mark_buffer_async_write on (eg.) the last buffer Thread 1 - finds the last buffer has async_write set, submit_bh on that. Thread 2 - submit_bh on the last buffer. => oops. So change __block_write_full_page to explicitly keep track of the last bh we need to issue, so we don't touch anything after issuing the last request. Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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File | Mode | Size |
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Makefile | -rw-r--r-- | 2.0 KB |
gen_init_cpio.c | -rw-r--r-- | 10.3 KB |
initramfs_data.S | -rw-r--r-- | 1.0 KB |
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