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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 V2 06/10] xfs: Check for extent overflow when writing to unwritten extent
Date: Fri, 14 Aug 2020 13:38:29 +0530	[thread overview]
Message-ID: <20200814080833.84760-7-chandanrlinux@gmail.com> (raw)
In-Reply-To: <20200814080833.84760-1-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.

Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
---
 fs/xfs/libxfs/xfs_inode_fork.h | 7 +++++++
 fs/xfs/xfs_iomap.c             | 5 +++++
 2 files changed, 12 insertions(+)

diff --git a/fs/xfs/libxfs/xfs_inode_fork.h b/fs/xfs/libxfs/xfs_inode_fork.h
index e39ce09a824f..a929fa094cf6 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.h
+++ b/fs/xfs/libxfs/xfs_inode_fork.h
@@ -63,6 +63,13 @@ 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 0af679ef9a33..81cccd4abcc6 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:[~2020-08-14  8:09 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 ` Chandan Babu R [this message]
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
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

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