From: "Darrick J. Wong" <darrick.wong@oracle.com> To: ira.weiny@intel.com Cc: linux-kernel@vger.kernel.org, Alexander Viro <viro@zeniv.linux.org.uk>, Dan Williams <dan.j.williams@intel.com>, Dave Chinner <david@fromorbit.com>, Christoph Hellwig <hch@lst.de>, "Theodore Y. Ts'o" <tytso@mit.edu>, Jan Kara <jack@suse.cz>, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [RFC PATCH V2 09/12] fs: Prevent mode change if file is mmap'ed Date: Mon, 13 Jan 2020 14:22:12 -0800 Message-ID: <20200113222212.GO8247@magnolia> (raw) In-Reply-To: <20200110192942.25021-10-ira.weiny@intel.com> On Fri, Jan 10, 2020 at 11:29:39AM -0800, ira.weiny@intel.com wrote: > From: Ira Weiny <ira.weiny@intel.com> > > Page faults need to ensure the inode mode is correct and consistent with > the vmf information at the time of the fault. There is no easy way to > ensure the vmf information is correct if a mode change is in progress. > Furthermore, there is no good use case to require a mode change while > the file is mmap'ed. > > Track mmap's of the file and fail the mode change if the file is > mmap'ed. > > Signed-off-by: Ira Weiny <ira.weiny@intel.com> > --- > fs/inode.c | 2 ++ > fs/xfs/xfs_ioctl.c | 8 ++++++++ > include/linux/fs.h | 1 + > mm/mmap.c | 19 +++++++++++++++++-- > 4 files changed, 28 insertions(+), 2 deletions(-) > > diff --git a/fs/inode.c b/fs/inode.c > index 2b0f51161918..944711aed6f8 100644 > --- a/fs/inode.c > +++ b/fs/inode.c > @@ -245,6 +245,8 @@ static struct inode *alloc_inode(struct super_block *sb) > return NULL; > } > > + atomic64_set(&inode->i_mapped, 0); > + > return inode; > } > > diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c > index bc3654fe3b5d..1ab0906c6c7f 100644 > --- a/fs/xfs/xfs_ioctl.c > +++ b/fs/xfs/xfs_ioctl.c > @@ -1200,6 +1200,14 @@ xfs_ioctl_setattr_dax_invalidate( > goto out_unlock; > } > > + /* > + * If there is a mapping in place we must remain in our current mode. > + */ > + if (atomic64_read(&inode->i_mapped)) { Urk, should we really be messing around with the address space internals? > + error = -EBUSY; > + goto out_unlock; > + } > + > error = filemap_write_and_wait(inode->i_mapping); > if (error) > goto out_unlock; > diff --git a/include/linux/fs.h b/include/linux/fs.h > index 631f11d6246e..6e7dc626b657 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -740,6 +740,7 @@ struct inode { > #endif > > void *i_private; /* fs or device private pointer */ > + atomic64_t i_mapped; I would have expected to find this in struct address_space since the mapping count is a function of the address space, right? --D > } __randomize_layout; > > struct timespec64 timestamp_truncate(struct timespec64 t, struct inode *inode); > diff --git a/mm/mmap.c b/mm/mmap.c > index dfaf1130e706..e6b68924b7ca 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -171,12 +171,17 @@ void unlink_file_vma(struct vm_area_struct *vma) > static struct vm_area_struct *remove_vma(struct vm_area_struct *vma) > { > struct vm_area_struct *next = vma->vm_next; > + struct file *f = vma->vm_file; > > might_sleep(); > if (vma->vm_ops && vma->vm_ops->close) > vma->vm_ops->close(vma); > - if (vma->vm_file) > - fput(vma->vm_file); > + if (f) { > + struct inode *inode = file_inode(f); > + if (inode) > + atomic64_dec(&inode->i_mapped); > + fput(f); > + } > mpol_put(vma_policy(vma)); > vm_area_free(vma); > return next; > @@ -1837,6 +1842,16 @@ unsigned long mmap_region(struct file *file, unsigned long addr, > > vma_set_page_prot(vma); > > + /* > + * Track if there is mapping in place such that a mode change > + * does not occur on a file which is mapped > + */ > + if (file) { > + struct inode *inode = file_inode(file); > + > + atomic64_inc(&inode->i_mapped); > + } > + > return addr; > > unmap_and_free_vma: > -- > 2.21.0 >
next prev parent reply index Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-01-10 19:29 [RFC PATCH V2 00/12] Enable per-file/directory DAX operations V2 ira.weiny 2020-01-10 19:29 ` [RFC PATCH V2 01/12] fs/stat: Define DAX statx attribute ira.weiny 2020-01-15 11:37 ` Jan Kara 2020-01-15 17:38 ` Darrick J. Wong 2020-01-15 19:45 ` Ira Weiny 2020-01-15 20:10 ` Dan Williams 2020-01-15 22:38 ` Ira Weiny 2020-01-16 5:39 ` Darrick J. Wong 2020-01-16 6:05 ` Dan Williams 2020-01-16 6:18 ` Darrick J. Wong 2020-01-16 6:25 ` Dan Williams 2020-01-18 9:11 ` Dave Chinner 2020-01-16 17:55 ` Ira Weiny 2020-01-16 18:04 ` Darrick J. Wong 2020-01-16 18:52 ` Ira Weiny 2020-01-16 22:19 ` Darrick J. Wong 2020-01-17 11:58 ` Jan Kara 2020-01-10 19:29 ` [RFC PATCH V2 02/12] fs/xfs: Isolate the physical DAX flag from effective ira.weiny 2020-01-10 19:29 ` [RFC PATCH V2 03/12] fs/xfs: Separate functionality of xfs_inode_supports_dax() ira.weiny 2020-01-10 19:29 ` [RFC PATCH V2 04/12] fs/xfs: Clean up DAX support check ira.weiny 2020-01-10 19:29 ` [RFC PATCH V2 05/12] fs: remove unneeded IS_DAX() check ira.weiny 2020-01-16 9:38 ` Jan Kara 2020-01-16 18:47 ` Ira Weiny 2020-01-10 19:29 ` [RFC PATCH V2 06/12] fs/xfs: Check if the inode supports DAX under lock ira.weiny 2020-01-10 19:29 ` [RFC PATCH V2 07/12] fs: Add locking for a dynamic inode 'mode' ira.weiny 2020-01-13 22:12 ` Darrick J. Wong 2020-01-14 0:20 ` Ira Weiny 2020-01-14 1:03 ` Darrick J. Wong 2020-01-15 19:08 ` Ira Weiny 2020-01-16 5:40 ` Darrick J. Wong 2020-01-16 18:54 ` Ira Weiny 2020-01-10 19:29 ` [RFC PATCH V2 08/12] fs/xfs: Add lock/unlock mode to xfs ira.weiny 2020-01-13 22:19 ` Darrick J. Wong 2020-01-14 0:35 ` Ira Weiny 2020-01-15 0:57 ` Ira Weiny 2020-01-15 23:52 ` Ira Weiny 2020-01-16 9:24 ` Jan Kara 2020-01-16 19:12 ` Ira Weiny 2020-01-10 19:29 ` [RFC PATCH V2 09/12] fs: Prevent mode change if file is mmap'ed ira.weiny 2020-01-13 22:22 ` Darrick J. Wong [this message] 2020-01-14 0:46 ` Ira Weiny 2020-01-14 1:30 ` Darrick J. Wong 2020-01-14 17:53 ` Ira Weiny 2020-01-15 11:34 ` Jan Kara 2020-01-15 18:24 ` Ira Weiny 2020-01-15 10:21 ` David Laight 2020-01-15 17:53 ` Ira Weiny 2020-01-10 19:29 ` [RFC PATCH V2 10/12] fs/xfs: Fix truncate up ira.weiny 2020-01-13 22:27 ` Darrick J. Wong 2020-01-14 0:40 ` Ira Weiny 2020-01-14 1:14 ` Darrick J. Wong 2020-01-14 19:00 ` Ira Weiny 2020-01-14 19:39 ` Ira Weiny 2020-01-10 19:29 ` [RFC PATCH V2 11/12] fs/xfs: Clean up locking in dax invalidate ira.weiny 2020-01-10 19:29 ` [RFC PATCH V2 12/12] fs/xfs: Allow toggle of effective DAX flag ira.weiny
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20200113222212.GO8247@magnolia \ --to=darrick.wong@oracle.com \ --cc=dan.j.williams@intel.com \ --cc=david@fromorbit.com \ --cc=hch@lst.de \ --cc=ira.weiny@intel.com \ --cc=jack@suse.cz \ --cc=linux-ext4@vger.kernel.org \ --cc=linux-fsdevel@vger.kernel.org \ --cc=linux-kernel@vger.kernel.org \ --cc=linux-xfs@vger.kernel.org \ --cc=tytso@mit.edu \ --cc=viro@zeniv.linux.org.uk \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: link
Linux-XFS Archive on lore.kernel.org Archives are clonable: git clone --mirror https://lore.kernel.org/linux-xfs/0 linux-xfs/git/0.git # If you have public-inbox 1.1+ installed, you may # initialize and index your mirror using the following commands: public-inbox-init -V2 linux-xfs linux-xfs/ https://lore.kernel.org/linux-xfs \ linux-xfs@vger.kernel.org public-inbox-index linux-xfs Example config snippet for mirrors Newsgroup available over NNTP: nntp://nntp.lore.kernel.org/org.kernel.vger.linux-xfs AGPL code for this site: git clone https://public-inbox.org/public-inbox.git