[PATCH V7 02/14] xfs: Check for extent overflow when trivally adding a new extent

Chandan Babu R
2020-10-19T06:41:18Z

When adding a new data extent (without modifying an inode's existing
extents) the extent count increases only by 1. This commit checks for
extent count overflow in such cases.

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
---
fs/xfs/libxfs/xfs_bmap.c | 6 ++++++
fs/xfs/libxfs/xfs_inode_fork.h | 6 ++++++
fs/xfs/xfs_bmap_item.c | 7 +++++++
fs/xfs/xfs_bmap_util.c | 5 +++++
fs/xfs/xfs_dquot.c | 8 +++++++-
fs/xfs/xfs_iomap.c | 5 +++++
fs/xfs/xfs_rtalloc.c | 5 +++++
7 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index d9a692484eae..505358839d2f 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -4527,6 +4527,12 @@ xfs_bmapi_convert_delalloc(
return error;

xfs_ilock(ip, XFS_ILOCK_EXCL);
+
+ error = xfs_iext_count_may_overflow(ip, whichfork,
+ XFS_IEXT_ADD_NOSPLIT_CNT);
+ if (error)
+ goto out_trans_cancel;
+
xfs_trans_ijoin(tp, ip, 0);

if (!xfs_iext_lookup_extent(ip, ifp, offset_fsb, &bma.icur, &bma.got) ||
diff --git a/fs/xfs/libxfs/xfs_inode_fork.h b/fs/xfs/libxfs/xfs_inode_fork.h
index 0beb8e2a00be..7fc2b129a2e7 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.h
+++ b/fs/xfs/libxfs/xfs_inode_fork.h
@@ -34,6 +34,12 @@ struct xfs_ifork {
#define XFS_IFEXTENTS 0x02 /* All extent pointers are read in */
#define XFS_IFBROOT 0x04 /* i_broot points to the bmap b-tree root */

+/*
+ * Worst-case increase in the fork extent count when we're adding a single
+ * extent to a fork and there's no possibility of splitting an existing mapping.
+ */
+#define XFS_IEXT_ADD_NOSPLIT_CNT (1)
+
/*
* Fork handling.
*/
diff --git a/fs/xfs/xfs_bmap_item.c b/fs/xfs/xfs_bmap_item.c
index 9e16a4d0f97c..1610d6ad089b 100644
--- a/fs/xfs/xfs_bmap_item.c
+++ b/fs/xfs/xfs_bmap_item.c
@@ -497,6 +497,13 @@ xfs_bui_item_recover(
xfs_ilock(ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip, 0);

+ if (bui_type == XFS_BMAP_MAP) {
+ error = xfs_iext_count_may_overflow(ip, whichfork,
+ XFS_IEXT_ADD_NOSPLIT_CNT);
+ if (error)
+ goto err_cancel;
+ }
+
count = bmap->me_len;
error = xfs_trans_log_finish_bmap_update(tp, budp, bui_type, ip,
whichfork, bmap->me_startoff, bmap->me_startblock,
diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index f2a8a0e75e1f..dcd6e61df711 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -822,6 +822,11 @@ xfs_alloc_file_space(
if (error)
goto error1;

+ error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
+ XFS_IEXT_ADD_NOSPLIT_CNT);
+ if (error)
+ goto error0;
+
xfs_trans_ijoin(tp, ip, 0);

error = xfs_bmapi_write(tp, ip, startoffset_fsb,
diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c
index 1d95ed387d66..175f544f7c45 100644
--- a/fs/xfs/xfs_dquot.c
+++ b/fs/xfs/xfs_dquot.c
@@ -314,8 +314,14 @@ xfs_dquot_disk_alloc(
return -ESRCH;
}

- /* Create the block mapping. */
xfs_trans_ijoin(tp, quotip, XFS_ILOCK_EXCL);
+
+ error = xfs_iext_count_may_overflow(quotip, XFS_DATA_FORK,
+ XFS_IEXT_ADD_NOSPLIT_CNT);
+ if (error)
+ return error;
+
+ /* Create the block mapping. */
error = xfs_bmapi_write(tp, quotip, dqp->q_fileoffset,
XFS_DQUOT_CLUSTER_SIZE_FSB, XFS_BMAPI_METADATA, 0, &map,
&nmaps);
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 3abb8b9d6f4c..a302a96823b8 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -250,6 +250,11 @@ xfs_iomap_write_direct(
if (error)
goto out_trans_cancel;

+ error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
+ XFS_IEXT_ADD_NOSPLIT_CNT);
+ if (error)
+ goto out_trans_cancel;
+
xfs_trans_ijoin(tp, ip, 0);

/*
diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
index 9d4e33d70d2a..3e841a75f272 100644
--- a/fs/xfs/xfs_rtalloc.c
+++ b/fs/xfs/xfs_rtalloc.c
@@ -804,6 +804,11 @@ xfs_growfs_rt_alloc(
xfs_ilock(ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);

+ error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
+ XFS_IEXT_ADD_NOSPLIT_CNT);
+ if (error)
+ goto out_trans_cancel;
+
/*
* Allocate blocks to the bitmap file.
*/
--
2.28.0