From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kara Subject: Re: [PATCH 2/3] dax: use pfn_mkwrite to update c/mtime + freeze protection Date: Tue, 7 Apr 2015 18:28:46 +0200 Message-ID: <20150407162846.GI14897@quack.suse.cz> References: <55239645.9000507@plexistor.com> <552398C6.1010304@plexistor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Dave Chinner , Matthew Wilcox , Andrew Morton , "Kirill A. Shutemov" , Jan Kara , Hugh Dickins , Mel Gorman , linux-mm@kvack.org, linux-nvdimm , linux-fsdevel , Eryu Guan , Christoph Hellwig , Stable Tree To: Boaz Harrosh Return-path: Received: from cantor2.suse.de ([195.135.220.15]:57802 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750997AbbDGQ2v (ORCPT ); Tue, 7 Apr 2015 12:28:51 -0400 Content-Disposition: inline In-Reply-To: <552398C6.1010304@plexistor.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Tue 07-04-15 11:43:50, Boaz Harrosh wrote: > From: Yigal Korman > > [v1] > Without this patch, c/mtime is not updated correctly when mmap'ed page is > first read from and then written to. > > A new xfstest is submitted for testing this (generic/080) > > [v2] > Jan Kara has pointed out that if we add the > sb_start/end_pagefault pair in the new pfn_mkwrite we > are then fixing another bug where: A user could start > writing to the page while filesystem is frozen. The patch looks good to me. You can add: Reviewed-by: Jan Kara Honza > CC: Jan Kara > CC: Matthew Wilcox > CC: Dave Chinner > CC: Stable Tree > > Signed-off-by: Yigal Korman > Signed-off-by: Boaz Harrosh > --- > fs/dax.c | 17 +++++++++++++++++ > fs/ext2/file.c | 1 + > fs/ext4/file.c | 1 + > include/linux/fs.h | 1 + > 4 files changed, 20 insertions(+) > > diff --git a/fs/dax.c b/fs/dax.c > index ed1619e..d0bd1f4 100644 > --- a/fs/dax.c > +++ b/fs/dax.c > @@ -464,6 +464,23 @@ int dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, > EXPORT_SYMBOL_GPL(dax_fault); > > /** > + * dax_pfn_mkwrite - handle first write to DAX page > + * @vma: The virtual memory area where the fault occurred > + * @vmf: The description of the fault > + * > + */ > +int dax_pfn_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) > +{ > + struct super_block *sb = file_inode(vma->vm_file)->i_sb; > + > + sb_start_pagefault(sb); > + file_update_time(vma->vm_file); > + sb_end_pagefault(sb); > + return VM_FAULT_NOPAGE; > +} > +EXPORT_SYMBOL_GPL(dax_pfn_mkwrite); > + > +/** > * dax_zero_page_range - zero a range within a page of a DAX file > * @inode: The file being truncated > * @from: The file offset that is being truncated to > diff --git a/fs/ext2/file.c b/fs/ext2/file.c > index e317017..866a3ce 100644 > --- a/fs/ext2/file.c > +++ b/fs/ext2/file.c > @@ -39,6 +39,7 @@ static int ext2_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) > static const struct vm_operations_struct ext2_dax_vm_ops = { > .fault = ext2_dax_fault, > .page_mkwrite = ext2_dax_mkwrite, > + .pfn_mkwrite = dax_pfn_mkwrite, > }; > > static int ext2_file_mmap(struct file *file, struct vm_area_struct *vma) > diff --git a/fs/ext4/file.c b/fs/ext4/file.c > index 598abbb..aa78c70 100644 > --- a/fs/ext4/file.c > +++ b/fs/ext4/file.c > @@ -206,6 +206,7 @@ static int ext4_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) > static const struct vm_operations_struct ext4_dax_vm_ops = { > .fault = ext4_dax_fault, > .page_mkwrite = ext4_dax_mkwrite, > + .pfn_mkwrite = dax_pfn_mkwrite, > }; > #else > #define ext4_dax_vm_ops ext4_file_vm_ops > diff --git a/include/linux/fs.h b/include/linux/fs.h > index 368e349..394035f 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -2628,6 +2628,7 @@ int dax_clear_blocks(struct inode *, sector_t block, long size); > int dax_zero_page_range(struct inode *, loff_t from, unsigned len, get_block_t); > int dax_truncate_page(struct inode *, loff_t from, get_block_t); > int dax_fault(struct vm_area_struct *, struct vm_fault *, get_block_t); > +int dax_pfn_mkwrite(struct vm_area_struct *, struct vm_fault *); > #define dax_mkwrite(vma, vmf, gb) dax_fault(vma, vmf, gb) > > #ifdef CONFIG_BLOCK > -- > 1.9.3 > > -- Jan Kara SUSE Labs, CR From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Tue, 7 Apr 2015 18:28:46 +0200 From: Jan Kara To: Boaz Harrosh Cc: Dave Chinner , Matthew Wilcox , Andrew Morton , "Kirill A. Shutemov" , Jan Kara , Hugh Dickins , Mel Gorman , linux-mm@kvack.org, linux-nvdimm , linux-fsdevel , Eryu Guan , Christoph Hellwig , Stable Tree Subject: Re: [PATCH 2/3] dax: use pfn_mkwrite to update c/mtime + freeze protection Message-ID: <20150407162846.GI14897@quack.suse.cz> References: <55239645.9000507@plexistor.com> <552398C6.1010304@plexistor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <552398C6.1010304@plexistor.com> Sender: owner-linux-mm@kvack.org List-ID: On Tue 07-04-15 11:43:50, Boaz Harrosh wrote: > From: Yigal Korman > > [v1] > Without this patch, c/mtime is not updated correctly when mmap'ed page is > first read from and then written to. > > A new xfstest is submitted for testing this (generic/080) > > [v2] > Jan Kara has pointed out that if we add the > sb_start/end_pagefault pair in the new pfn_mkwrite we > are then fixing another bug where: A user could start > writing to the page while filesystem is frozen. The patch looks good to me. You can add: Reviewed-by: Jan Kara Honza > CC: Jan Kara > CC: Matthew Wilcox > CC: Dave Chinner > CC: Stable Tree > > Signed-off-by: Yigal Korman > Signed-off-by: Boaz Harrosh > --- > fs/dax.c | 17 +++++++++++++++++ > fs/ext2/file.c | 1 + > fs/ext4/file.c | 1 + > include/linux/fs.h | 1 + > 4 files changed, 20 insertions(+) > > diff --git a/fs/dax.c b/fs/dax.c > index ed1619e..d0bd1f4 100644 > --- a/fs/dax.c > +++ b/fs/dax.c > @@ -464,6 +464,23 @@ int dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, > EXPORT_SYMBOL_GPL(dax_fault); > > /** > + * dax_pfn_mkwrite - handle first write to DAX page > + * @vma: The virtual memory area where the fault occurred > + * @vmf: The description of the fault > + * > + */ > +int dax_pfn_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) > +{ > + struct super_block *sb = file_inode(vma->vm_file)->i_sb; > + > + sb_start_pagefault(sb); > + file_update_time(vma->vm_file); > + sb_end_pagefault(sb); > + return VM_FAULT_NOPAGE; > +} > +EXPORT_SYMBOL_GPL(dax_pfn_mkwrite); > + > +/** > * dax_zero_page_range - zero a range within a page of a DAX file > * @inode: The file being truncated > * @from: The file offset that is being truncated to > diff --git a/fs/ext2/file.c b/fs/ext2/file.c > index e317017..866a3ce 100644 > --- a/fs/ext2/file.c > +++ b/fs/ext2/file.c > @@ -39,6 +39,7 @@ static int ext2_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) > static const struct vm_operations_struct ext2_dax_vm_ops = { > .fault = ext2_dax_fault, > .page_mkwrite = ext2_dax_mkwrite, > + .pfn_mkwrite = dax_pfn_mkwrite, > }; > > static int ext2_file_mmap(struct file *file, struct vm_area_struct *vma) > diff --git a/fs/ext4/file.c b/fs/ext4/file.c > index 598abbb..aa78c70 100644 > --- a/fs/ext4/file.c > +++ b/fs/ext4/file.c > @@ -206,6 +206,7 @@ static int ext4_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) > static const struct vm_operations_struct ext4_dax_vm_ops = { > .fault = ext4_dax_fault, > .page_mkwrite = ext4_dax_mkwrite, > + .pfn_mkwrite = dax_pfn_mkwrite, > }; > #else > #define ext4_dax_vm_ops ext4_file_vm_ops > diff --git a/include/linux/fs.h b/include/linux/fs.h > index 368e349..394035f 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -2628,6 +2628,7 @@ int dax_clear_blocks(struct inode *, sector_t block, long size); > int dax_zero_page_range(struct inode *, loff_t from, unsigned len, get_block_t); > int dax_truncate_page(struct inode *, loff_t from, get_block_t); > int dax_fault(struct vm_area_struct *, struct vm_fault *, get_block_t); > +int dax_pfn_mkwrite(struct vm_area_struct *, struct vm_fault *); > #define dax_mkwrite(vma, vmf, gb) dax_fault(vma, vmf, gb) > > #ifdef CONFIG_BLOCK > -- > 1.9.3 > > -- Jan Kara SUSE Labs, CR -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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