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From: Marat Khalili <mkh@rqc.ru>
To: kreijack@inwind.it, Goffredo Baroncelli <kreijack@inwind.it>,
	"Austin S. Hemmelgarn" <ahferroin7@gmail.com>,
	linux-btrfs@vger.kernel.org
Cc: pwm <pwm@iapetus.neab.net>, Hugo Mills <hugo@carfax.org.uk>
Subject: Re: Massive loss of disk space
Date: Thu, 03 Aug 2017 20:15:53 +0300	[thread overview]
Message-ID: <AAADF381-631F-4630-B855-46A1658498B2@rqc.ru> (raw)
In-Reply-To: <ed61fc9b-6d12-f9d1-6e5a-b11b357d377c@inwind.it>

On August 3, 2017 7:01:06 PM GMT+03:00, Goffredo Baroncelli 
>The file is physically extended
>
>ghigo@venice:/tmp$ fallocate -l 1000 foo.txt

For clarity let's replace the fallocate above with:
$ head -c 1000 </dev/urandom >foo.txt

>ghigo@venice:/tmp$ ls -l foo.txt
>-rw-r--r-- 1 ghigo ghigo 1000 Aug  3 18:00 foo.txt
>ghigo@venice:/tmp$ fallocate -o 500 -l 1000 foo.txt
>ghigo@venice:/tmp$ ls -l foo.txt
>-rw-r--r-- 1 ghigo ghigo 1500 Aug  3 18:00 foo.txt
>ghigo@venice:/tmp$

According to explanation by Austin the foo.txt at this point somehow occupies 2000 bytes of space because I can reflink it and then write another 1000 bytes of data into it without losing 1000 bytes I already have or getting out of drive space. (Or is it only true while there are open file handles?)
-- 

With Best Regards,
Marat Khalili

  reply	other threads:[~2017-08-03 17:16 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-01 11:43 Massive loss of disk space pwm
2017-08-01 12:20 ` Hugo Mills
2017-08-01 14:39   ` pwm
2017-08-01 14:47     ` Austin S. Hemmelgarn
2017-08-01 15:00       ` Austin S. Hemmelgarn
2017-08-01 15:24         ` pwm
2017-08-01 15:45           ` Austin S. Hemmelgarn
2017-08-01 16:50             ` pwm
2017-08-01 17:04               ` Austin S. Hemmelgarn
2017-08-02 17:52         ` Goffredo Baroncelli
2017-08-02 19:10           ` Austin S. Hemmelgarn
2017-08-02 21:05             ` Goffredo Baroncelli
2017-08-03 11:39               ` Austin S. Hemmelgarn
2017-08-03 16:37                 ` Goffredo Baroncelli
2017-08-03 17:23                   ` Austin S. Hemmelgarn
2017-08-04 14:45                     ` Goffredo Baroncelli
2017-08-04 15:05                       ` Austin S. Hemmelgarn
2017-08-03  3:48           ` Duncan
2017-08-03 11:44           ` Marat Khalili
2017-08-03 11:52             ` Austin S. Hemmelgarn
2017-08-03 16:01             ` Goffredo Baroncelli
2017-08-03 17:15               ` Marat Khalili [this message]
2017-08-03 17:25                 ` Austin S. Hemmelgarn
2017-08-03 22:51               ` pwm
2017-08-02  4:14       ` Duncan
2017-08-02 11:18         ` Austin S. Hemmelgarn

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