From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Matthew Wilcox <matthew@wil.cx>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>,
linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org,
linux-mm@kvack.org, Andrea Arcangeli <aarcange@redhat.com>
Subject: Re: [PATCH v4 21/22] Add support for pmd_faults
Date: Mon, 23 Dec 2013 20:54:33 +0200 [thread overview]
Message-ID: <20131223185433.GA18067@node.dhcp.inet.fi> (raw)
In-Reply-To: <20131223184222.GE11091@parisc-linux.org>
On Mon, Dec 23, 2013 at 11:42:22AM -0700, Matthew Wilcox wrote:
> > Do you know anyone who relay on SIGBUS for correctness?
>
> Oh, I remember the real reason now. If we install a PMD that hangs off
> the end of the file then by reading past i_size, we can read the blocks of
> whatever happens to be in storage after the end of the file, which could
> be another file's data. This doesn't happen for the PTE case because the
> existing code only works for filesystems with a block size == PAGE_SIZE.
I see. It's valid reason. Probably, it's better to add comment there.
--
Kirill A. Shutemov
WARNING: multiple messages have this Message-ID (diff)
From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Matthew Wilcox <matthew@wil.cx>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>,
linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org,
linux-mm@kvack.org, Andrea Arcangeli <aarcange@redhat.com>
Subject: Re: [PATCH v4 21/22] Add support for pmd_faults
Date: Mon, 23 Dec 2013 20:54:33 +0200 [thread overview]
Message-ID: <20131223185433.GA18067@node.dhcp.inet.fi> (raw)
In-Reply-To: <20131223184222.GE11091@parisc-linux.org>
On Mon, Dec 23, 2013 at 11:42:22AM -0700, Matthew Wilcox wrote:
> > Do you know anyone who relay on SIGBUS for correctness?
>
> Oh, I remember the real reason now. If we install a PMD that hangs off
> the end of the file then by reading past i_size, we can read the blocks of
> whatever happens to be in storage after the end of the file, which could
> be another file's data. This doesn't happen for the PTE case because the
> existing code only works for filesystems with a block size == PAGE_SIZE.
I see. It's valid reason. Probably, it's better to add comment there.
--
Kirill A. Shutemov
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next prev parent reply other threads:[~2013-12-23 18:54 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-22 21:49 [PATCH v4 00/22] Add XIP support to ext4 Matthew Wilcox
2013-12-22 21:49 ` [PATCH v4 01/22] Fix XIP fault vs truncate race Matthew Wilcox
2013-12-22 21:49 ` [PATCH v4 02/22] Simplify COW of XIP mappings Matthew Wilcox
2013-12-22 21:49 ` [PATCH v4 03/22] axonram: Fix bug in direct_access Matthew Wilcox
2013-12-22 21:49 ` [PATCH v4 04/22] Change direct_access calling convention Matthew Wilcox
2013-12-22 21:49 ` [PATCH v4 05/22] Introduce IS_XIP(inode) Matthew Wilcox
2013-12-22 21:49 ` [PATCH v4 06/22] Treat XIP like O_DIRECT Matthew Wilcox
2013-12-22 21:49 ` [PATCH v4 07/22] Rewrite XIP page fault handling Matthew Wilcox
2013-12-22 21:49 ` [PATCH v4 08/22] Change xip_truncate_page to take a get_block parameter Matthew Wilcox
2013-12-22 21:49 ` [PATCH v4 09/22] Remove mm/filemap_xip.c Matthew Wilcox
2013-12-22 21:49 ` [PATCH v4 10/22] Remove get_xip_mem Matthew Wilcox
2013-12-22 21:49 ` [PATCH v4 11/22] Replace ext2_clear_xip_target with xip_clear_blocks Matthew Wilcox
2013-12-22 21:49 ` [PATCH v4 12/22] ext2: Remove ext2_xip_verify_sb() Matthew Wilcox
2013-12-22 21:49 ` [PATCH v4 13/22] ext2: Remove ext2_use_xip Matthew Wilcox
2013-12-22 21:49 ` [PATCH v4 14/22] ext2: Remove xip.c and xip.h Matthew Wilcox
2013-12-22 21:49 ` [PATCH v4 15/22] Remove CONFIG_EXT2_FS_XIP Matthew Wilcox
2013-12-22 21:49 ` [PATCH v4 16/22] ext2: Remove ext2_aops_xip Matthew Wilcox
2013-12-22 21:49 ` [PATCH v4 17/22] xip: Add xip_zero_page_range Matthew Wilcox
2013-12-22 21:49 ` [PATCH v4 18/22] ext4: Make ext4_block_zero_page_range static Matthew Wilcox
2013-12-22 21:49 ` [PATCH v4 19/22] ext4: Add XIP functionality Matthew Wilcox
2013-12-22 21:49 ` [PATCH v4 20/22] ext4: Fix typos Matthew Wilcox
2013-12-22 21:49 ` [PATCH v4 21/22] Add support for pmd_faults Matthew Wilcox
2013-12-23 13:41 ` Kirill A. Shutemov
2013-12-23 14:50 ` Matthew Wilcox
2013-12-23 15:04 ` Matthew Wilcox
2013-12-23 15:11 ` Kirill A. Shutemov
2013-12-23 15:10 ` Kirill A. Shutemov
2013-12-23 18:42 ` Matthew Wilcox
2013-12-23 18:42 ` Matthew Wilcox
2013-12-23 18:54 ` Kirill A. Shutemov [this message]
2013-12-23 18:54 ` Kirill A. Shutemov
2013-12-22 21:49 ` [PATCH v4 22/22] xip: Add reporting of major faults Matthew Wilcox
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