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From: Chandan Babu R <chandanrlinux@gmail.com>
To: linux-xfs@vger.kernel.org
Cc: Chandan Babu R <chandanrlinux@gmail.com>,
	darrick.wong@oracle.com, david@fromorbit.com
Subject: [PATCH V6 06/11] xfs: Check for extent overflow when writing to unwritten extent
Date: Mon, 12 Oct 2020 14:59:33 +0530	[thread overview]
Message-ID: <20201012092938.50946-7-chandanrlinux@gmail.com> (raw)
In-Reply-To: <20201012092938.50946-1-chandanrlinux@gmail.com>

A write to a sub-interval of an existing unwritten extent causes
the original extent to be split into 3 extents
i.e. | Unwritten | Real | Unwritten |
Hence extent count can increase by 2.

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
---
 fs/xfs/libxfs/xfs_inode_fork.h | 8 ++++++++
 fs/xfs/xfs_iomap.c             | 5 +++++
 2 files changed, 13 insertions(+)

diff --git a/fs/xfs/libxfs/xfs_inode_fork.h b/fs/xfs/libxfs/xfs_inode_fork.h
index fd93fdc67ee4..afb647e1e3fa 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.h
+++ b/fs/xfs/libxfs/xfs_inode_fork.h
@@ -70,6 +70,14 @@ struct xfs_ifork {
 #define XFS_IEXT_DIR_MANIP_CNT(mp) \
 	((XFS_DA_NODE_MAXDEPTH + 1 + 1) * (mp)->m_dir_geo->fsbcount)
 
+/*
+ * A write to a sub-interval of an existing unwritten extent causes the original
+ * extent to be split into 3 extents
+ * i.e. | Unwritten | Real | Unwritten |
+ * Hence extent count can increase by 2.
+ */
+#define XFS_IEXT_WRITE_UNWRITTEN_CNT	(2)
+
 /*
  * Fork handling.
  */
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index a302a96823b8..2aa788379611 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -566,6 +566,11 @@ xfs_iomap_write_unwritten(
 		if (error)
 			goto error_on_bmapi_transaction;
 
+		error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
+				XFS_IEXT_WRITE_UNWRITTEN_CNT);
+		if (error)
+			goto error_on_bmapi_transaction;
+
 		/*
 		 * Modify the unwritten extent state of the buffer.
 		 */
-- 
2.28.0


  parent reply	other threads:[~2020-10-12  9:30 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-12  9:29 [PATCH V6 00/11] Bail out if transaction can cause extent count to overflow Chandan Babu R
2020-10-12  9:29 ` [PATCH V6 01/11] xfs: Add helper for checking per-inode extent count overflow Chandan Babu R
2020-10-15  8:34   ` Christoph Hellwig
2020-10-12  9:29 ` [PATCH V6 02/11] xfs: Check for extent overflow when trivally adding a new extent Chandan Babu R
2020-10-15  8:34   ` Christoph Hellwig
2020-10-12  9:29 ` [PATCH V6 03/11] xfs: Check for extent overflow when punching a hole Chandan Babu R
2020-10-15  8:35   ` Christoph Hellwig
2020-10-12  9:29 ` [PATCH V6 04/11] xfs: Check for extent overflow when adding/removing xattrs Chandan Babu R
2020-10-15  8:36   ` Christoph Hellwig
2020-10-12  9:29 ` [PATCH V6 05/11] xfs: Check for extent overflow when adding/removing dir entries Chandan Babu R
2020-10-15  8:36   ` Christoph Hellwig
2020-10-12  9:29 ` Chandan Babu R [this message]
2020-10-15  8:36   ` [PATCH V6 06/11] xfs: Check for extent overflow when writing to unwritten extent Christoph Hellwig
2020-10-12  9:29 ` [PATCH V6 07/11] xfs: Check for extent overflow when moving extent from cow to data fork Chandan Babu R
2020-10-15  8:37   ` Christoph Hellwig
2020-10-12  9:29 ` [PATCH V6 08/11] xfs: Check for extent overflow when remapping an extent Chandan Babu R
2020-10-15  8:39   ` Christoph Hellwig
2020-10-15 10:01     ` Chandan Babu R
2020-10-15 18:45       ` Darrick J. Wong
2020-10-16  4:27         ` Chandan Babu R
2020-10-16  7:04       ` Christoph Hellwig
2020-10-16 11:28         ` Chandan Babu R
2020-10-16 15:29           ` Darrick J. Wong
2020-10-17  2:55             ` Chandan Babu R
2020-10-12  9:29 ` [PATCH V6 09/11] xfs: Check for extent overflow when swapping extents Chandan Babu R
2020-10-12  9:29 ` [PATCH V6 10/11] xfs: Introduce error injection to reduce maximum inode fork extent count Chandan Babu R
2020-10-15  8:40   ` Christoph Hellwig
2020-10-12  9:29 ` [PATCH V6 11/11] xfs: Introduce error injection to allocate only minlen size extents for files Chandan Babu R
2020-10-15  8:41   ` Christoph Hellwig
2020-10-15 10:02     ` Chandan Babu R
2020-10-15 18:41       ` Darrick J. Wong
2020-10-16 11:31         ` Chandan Babu R

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