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From: Ted Ts'o <tytso@mit.edu>
To: Arnd Bergmann <arnd.bergmann@linaro.org>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>,
	Alex Lemberg <Alex.Lemberg@sandisk.com>,
	HYOJIN JEONG <syr.jeong@samsung.com>,
	Saugata Das <saugata.das@linaro.org>,
	Artem Bityutskiy <dedekind1@gmail.com>,
	Saugata Das <saugata.das@stericsson.com>,
	linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-mmc@vger.kernel.org, patches@linaro.org, venkat@linaro.org,
	"Luca Porzio (lporzio)" <lporzio@micron.com>
Subject: Re: [PATCH 2/3] ext4: Context support
Date: Fri, 15 Jun 2012 17:30:46 -0400	[thread overview]
Message-ID: <20120615213046.GB7363@thunk.org> (raw)
In-Reply-To: <201206150919.23484.arnd.bergmann@linaro.org>

On Fri, Jun 15, 2012 at 09:19:23AM +0000, Arnd Bergmann wrote:
> 
> The trouble is that detecting the erase block size requires us to
> write specific patterns to the device, which is generally a bad
> idea after the file system has been created.

How much space do you need?  It's not hard to allocate a bunch of
space, in a file, use FIEMAP ioctl to verify that you have a
contiguous range of blocks, and then do direct I/O into that region.

> I think the best we can do is
> 
> * default to "unspecified" as before
> * if "unspecified", make the file system ask the block device. in
>   case of eMMC, that will usually be reliable
> * Add an option to mkfs and tunefs to hardcode a specific size for
>   users that know the size and can't rely on the blockdev reporting
>   it correctly to the file system.
> * Add an option to mkfs to autodetect the size for the drive it's
>   run on.

Well, I think we can do better; the question is whether or not it's
worth the effort.  It may not be....

				- Ted

  reply	other threads:[~2012-06-15 21:30 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-11 10:46 [PATCH 1/3] block: Context support Saugata Das
2012-06-11 10:46 ` [PATCH 2/3] ext4: " Saugata Das
2012-06-11 11:41   ` Artem Bityutskiy
2012-06-11 12:27     ` Ted Ts'o
2012-06-12 12:21       ` Saugata Das
2012-06-12 12:32         ` Ted Ts'o
2012-06-12 13:29         ` Arnd Bergmann
2012-06-12 14:26           ` Saugata Das
2012-06-12 14:55             ` Arnd Bergmann
2012-06-12 18:19               ` Ted Ts'o
2012-06-12 20:07                 ` Arnd Bergmann
2012-06-12 20:41                   ` Ted Ts'o
2012-06-13 19:44                     ` Arnd Bergmann
2012-06-13 20:00                       ` Ted Ts'o
2012-06-13 20:43                         ` Arnd Bergmann
2012-06-14  2:07                           ` Ted Ts'o
2012-06-14 16:14                             ` Nicolas Pitre
2012-06-14 16:24                               ` Artem Bityutskiy
2012-06-14 17:05                               ` Ted Ts'o
2012-06-14 19:08                                 ` Nicolas Pitre
2012-06-15  9:19                                   ` Arnd Bergmann
2012-06-15 21:30                                     ` Ted Ts'o [this message]
2012-06-16  6:49                                       ` Arnd Bergmann
2012-06-14 21:55                             ` Arnd Bergmann
2012-06-15  5:18                               ` Andreas Dilger
2012-06-15  9:25                                 ` Arnd Bergmann
2012-06-15  9:40                                   ` Andreas Dilger
2012-06-15 10:54                                     ` Arnd Bergmann
2012-06-15 22:04                               ` Ted Ts'o
2012-06-15 22:25                                 ` Andreas Dilger
2012-06-16  7:14                                   ` Arnd Bergmann
2012-06-16  7:28                                     ` Arnd Bergmann
2012-06-16  7:26                                 ` Arnd Bergmann
2012-06-16 13:49                                   ` Ted Ts'o
2012-06-16 17:41                                     ` Arnd Bergmann
2012-06-18 17:42                                       ` Ted Ts'o
2012-06-19 15:17                                         ` Arnd Bergmann
2012-06-20 15:09                                           ` Luca Porzio (lporzio)
2012-06-20 15:46                                             ` Arnd Bergmann
2012-06-22 13:29                       ` Artem Bityutskiy
2012-06-22 14:07                         ` Luca Porzio (lporzio)
2012-06-11 10:46 ` [PATCH 3/3] mmc: " Saugata Das

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