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From: Aastha Mehta <aasthakm@gmail.com>
To: linux-btrfs <linux-btrfs@vger.kernel.org>
Subject: Questions regarding logging upon fsync in btrfs
Date: Sun, 29 Sep 2013 01:35:15 +0200	[thread overview]
Message-ID: <CAEx9m45FDjNCBLEYM0x7fY36R7QJesS0F-fzWzNi=d_cBSOjOQ@mail.gmail.com> (raw)

Hi,

I have few questions regarding logging triggered by calling fsync in BTRFS:

1. If I understand correctly, fsync will call to log entire inode in
the log tree. Does this mean that the data extents are also logged
into the log tree? Are they copied into the log tree, or just
referenced? Are they copied into the subvolume's extent tree again
upon replay?

2. During replay, when the extents are added into the extent
allocation tree, do they acquire the physical extent number during
replay? Does they physical extent allocated to the data in the log
tree differ from that in the subvolume?

3. I see there is a mount option of notreelog available. After
disabling tree logging, does fsync still lead to flushing of buffers
to the disk directly?

4. Is it possible to selectively identify certain files in the log
tree and flush them to disk directly, without waiting for the replay
to do it?

Thanks

-- 
Aastha Mehta

             reply	other threads:[~2013-09-28 23:35 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-28 23:35 Aastha Mehta [this message]
2013-09-28 23:46 ` Questions regarding logging upon fsync in btrfs Aastha Mehta
2013-09-29  0:21   ` Hugo Mills
2013-09-29  0:42 ` Josef Bacik
2013-09-29  9:22   ` Aastha Mehta
2013-09-29 13:12     ` Josef Bacik
2013-09-30 19:32       ` Aastha Mehta
2013-09-30 20:11         ` Josef Bacik
2013-09-30 20:30           ` Aastha Mehta
2013-09-30 20:47             ` Josef Bacik
2013-09-30 21:07               ` Aastha Mehta
2013-09-30 21:17                 ` Josef Bacik
2013-10-01 17:34                 ` Josef Bacik
2013-10-01 19:40                   ` Aastha Mehta
2013-10-01 19:42                     ` Aastha Mehta
2013-10-01 20:13                       ` Aastha Mehta
2013-10-02 11:52                         ` Josef Bacik
2013-10-02 20:12                           ` Aastha Mehta
2013-10-02 23:28                             ` Josef Bacik

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