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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, hch@infradead.org
Subject: [PATCH V3 06/10] xfs: Check for extent overflow when writing to unwritten extent
Date: Thu, 20 Aug 2020 11:13:45 +0530	[thread overview]
Message-ID: <20200820054349.5525-7-chandanrlinux@gmail.com> (raw)
In-Reply-To: <20200820054349.5525-1-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 f686c7418d2b..83ff90e2a5fe 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.h
+++ b/fs/xfs/libxfs/xfs_inode_fork.h
@@ -66,6 +66,13 @@ 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 37b0c743c116..694b25fbb4a3 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:[~2020-08-20  5:44 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-20  5:43 [PATCH V3 00/10] Bail out if transaction can cause extent count to overflow Chandan Babu R
2020-08-20  5:43 ` [PATCH V3 01/10] xfs: Add helper for checking per-inode extent count overflow Chandan Babu R
2020-08-31 16:08   ` Darrick J. Wong
2020-08-31 16:44     ` Darrick J. Wong
2020-09-01  9:44       ` Chandan Babu R
2020-08-20  5:43 ` [PATCH V3 02/10] xfs: Check for extent overflow when trivally adding a new extent Chandan Babu R
2020-08-31 16:12   ` Darrick J. Wong
2020-08-20  5:43 ` [PATCH V3 03/10] xfs: Check for extent overflow when deleting an extent Chandan Babu R
2020-08-31 16:34   ` Darrick J. Wong
2020-09-01  9:44     ` Chandan Babu R
2020-08-20  5:43 ` [PATCH V3 04/10] xfs: Check for extent overflow when adding/removing xattrs Chandan Babu R
2020-08-31 16:37   ` Darrick J. Wong
2020-09-01  9:44     ` Chandan Babu R
2020-08-20  5:43 ` [PATCH V3 05/10] xfs: Check for extent overflow when adding/removing dir entries Chandan Babu R
2020-08-31 16:41   ` Darrick J. Wong
2020-08-20  5:43 ` Chandan Babu R [this message]
2020-08-31 16:45   ` [PATCH V3 06/10] xfs: Check for extent overflow when writing to unwritten extent Darrick J. Wong
2020-08-20  5:43 ` [PATCH V3 07/10] xfs: Check for extent overflow when inserting a hole Chandan Babu R
2020-08-31 16:46   ` Darrick J. Wong
2020-09-01  9:44     ` Chandan Babu R
2020-08-20  5:43 ` [PATCH V3 08/10] xfs: Check for extent overflow when moving extent from cow to data fork Chandan Babu R
2020-08-31 16:29   ` Darrick J. Wong
2020-09-01  9:45     ` Chandan Babu R
2020-08-20  5:43 ` [PATCH V3 09/10] xfs: Check for extent overflow when remapping an extent Chandan Babu R
2020-08-31 16:23   ` Darrick J. Wong
2020-09-01  9:45     ` Chandan Babu R
2020-08-20  5:43 ` [PATCH V3 10/10] xfs: Check for extent overflow when swapping extents Chandan Babu R
2020-08-31 16:20   ` Darrick J. Wong
2020-09-01  9:45     ` Chandan Babu R

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