Messages in this thread | | | From | Linus Torvalds <> | Date | Wed, 28 Nov 2012 18:04:06 -0800 | Subject | Re: [PATCH] Introduce a method to catch mmap_region (was: Recent kernel "mount" slow) |
| |
[ Sorry, I was offline for a while driving kids around ]
On Wed, Nov 28, 2012 at 4:38 PM, Mikulas Patocka <mpatocka@redhat.com> wrote: > > It can happen. Take your patch (the one that moves bd_block_size_semaphore > into blkdev_readpage, blkdev_writepage and blkdev_write_begin).
Interesting. The code *has* the block size (it's in "bh->b_size"), but it actually then uses the inode blocksize instead, and verifies the two against each other. It could just have used the block size directly (and then used the inode i_blkbits only when no buffers existed), avoiding that dependency entirely..
It actually does the same thing (with the same verification) in __block_write_full_page() and (_without_ the verification) in __block_commit_write().
Ho humm. All of those places actually do hold the rwsem for reading, it's just that I don't want to hold it for writing over the sync..
Need to think on this,
Linus
| |