From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: Chandan Babu R <chandanrlinux@gmail.com>
Cc: linux-xfs@vger.kernel.org, david@fromorbit.com
Subject: Re: [PATCH V2 08/10] xfs: Check for extent overflow when moving extent from cow to data fork
Date: Tue, 18 Aug 2020 15:03:07 -0700 [thread overview]
Message-ID: <20200818220307.GA6096@magnolia> (raw)
In-Reply-To: <20200814080833.84760-9-chandanrlinux@gmail.com>
On Fri, Aug 14, 2020 at 01:38:31PM +0530, Chandan Babu R wrote:
> Moving an extent to data fork can cause a sub-interval of an existing
> extent to be unmapped. This will increase extent count by 1. Mapping in
> the new extent can increase the extent count by 1 again i.e.
> | Old extent | New extent | Old extent |
> Hence number of extents increases by 2.
>
> Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
> ---
> fs/xfs/libxfs/xfs_inode_fork.h | 10 +++++++++-
> fs/xfs/xfs_reflink.c | 6 ++++++
> 2 files changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/fs/xfs/libxfs/xfs_inode_fork.h b/fs/xfs/libxfs/xfs_inode_fork.h
> index 63f83a13e0a8..d750bdff17c9 100644
> --- a/fs/xfs/libxfs/xfs_inode_fork.h
> +++ b/fs/xfs/libxfs/xfs_inode_fork.h
> @@ -76,7 +76,15 @@ struct xfs_ifork {
> * increase by 1.
> */
> #define XFS_IEXT_INSERT_HOLE_CNT 1
> -
> +/*
> + * Moving an extent to data fork can cause a sub-interval of an
> + * existing extent to be unmapped. This will increase extent count by
> + * 1. Mapping in the new extent can increase the extent count by 1
> + * again i.e.
> + * | Old extent | New extent | Old extent |
This comment is a little oddly formatted, mostly because my brain
thought that the line starting with "1. Mapping" was a numbered bullet
list. If you reflow the comment further outward, you can get it to look
like this:
/*
* Moving an extent to data fork can cause a sub-interval of an existing
* extent to be unmapped, increasing extent count by 1. Mapping in the
* new extent can also increase the extent count by 1:
* | Old extent | New extent | Old extent |
* Hence number of extents increases by 2.
*/
#define XFS_IEXT_REFLINK_END_COW_CNT 2
--D
> + * Hence number of extents increases by 2.
> + */
> +#define XFS_IEXT_REFLINK_END_COW_CNT 2
> /*
> * Fork handling.
> */
> diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
> index aac83f9d6107..04a7754ee681 100644
> --- a/fs/xfs/xfs_reflink.c
> +++ b/fs/xfs/xfs_reflink.c
> @@ -29,6 +29,7 @@
> #include "xfs_iomap.h"
> #include "xfs_sb.h"
> #include "xfs_ag_resv.h"
> +#include "xfs_trans_resv.h"
>
> /*
> * Copy on Write of Shared Blocks
> @@ -628,6 +629,11 @@ xfs_reflink_end_cow_extent(
> xfs_ilock(ip, XFS_ILOCK_EXCL);
> xfs_trans_ijoin(tp, ip, 0);
>
> + error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
> + XFS_IEXT_REFLINK_END_COW_CNT);
> + if (error)
> + goto out_cancel;
> +
> /*
> * In case of racing, overlapping AIO writes no COW extents might be
> * left by the time I/O completes for the loser of the race. In that
> --
> 2.28.0
>
next prev parent reply other threads:[~2020-08-18 22:03 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-14 8:08 [PATCH V2 00/10] Bail out if transaction can cause extent count to overflow Chandan Babu R
2020-08-14 8:08 ` [PATCH V2 01/10] xfs: Add helper for checking per-inode extent count overflow Chandan Babu R
2020-08-17 6:51 ` Christoph Hellwig
2020-08-17 7:44 ` Chandan Babu R
2020-08-14 8:08 ` [PATCH V2 02/10] xfs: Check for extent overflow when trivally adding a new extent Chandan Babu R
2020-08-17 6:53 ` Christoph Hellwig
2020-08-17 7:44 ` Chandan Babu R
2020-08-27 8:09 ` Christoph Hellwig
2020-08-27 13:51 ` Chandan Babu R
2020-08-18 21:49 ` Dave Chinner
2020-08-18 21:57 ` Darrick J. Wong
2020-08-19 4:43 ` Chandan Babu R
2020-08-14 8:08 ` [PATCH V2 03/10] xfs: Check for extent overflow when deleting an extent Chandan Babu R
2020-08-14 8:08 ` [PATCH V2 04/10] xfs: Check for extent overflow when adding/removing xattrs Chandan Babu R
2020-08-14 8:08 ` [PATCH V2 05/10] xfs: Check for extent overflow when adding/removing dir entries Chandan Babu R
2020-08-14 8:08 ` [PATCH V2 06/10] xfs: Check for extent overflow when writing to unwritten extent Chandan Babu R
2020-08-14 8:08 ` [PATCH V2 07/10] xfs: Check for extent overflow when inserting a hole Chandan Babu R
2020-08-14 8:08 ` [PATCH V2 08/10] xfs: Check for extent overflow when moving extent from cow to data fork Chandan Babu R
2020-08-18 22:03 ` Darrick J. Wong [this message]
2020-08-19 5:04 ` Chandan Babu R
2020-08-14 8:08 ` [PATCH V2 09/10] xfs: Check for extent overflow when remapping an extent Chandan Babu R
2020-08-14 8:08 ` [PATCH V2 10/10] xfs: Check for extent overflow when swapping extents Chandan Babu R
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=20200818220307.GA6096@magnolia \
--to=darrick.wong@oracle.com \
--cc=chandanrlinux@gmail.com \
--cc=david@fromorbit.com \
--cc=linux-xfs@vger.kernel.org \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox