[PATCH V7 10/14] xfs: Introduce error injection to reduce maximum inode fork extent count

Chandan Babu R
2020-10-19T06:41:42Z

This commit adds XFS_ERRTAG_REDUCE_MAX_IEXTENTS error tag which enables
userspace programs to test "Inode fork extent count overflow detection"
by reducing maximum possible inode fork extent count to 10.

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_errortag.h | 4 +++-
fs/xfs/libxfs/xfs_inode_fork.c | 4 ++++
fs/xfs/xfs_error.c | 3 +++
3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/libxfs/xfs_errortag.h b/fs/xfs/libxfs/xfs_errortag.h
index 53b305dea381..1c56fcceeea6 100644
--- a/fs/xfs/libxfs/xfs_errortag.h
+++ b/fs/xfs/libxfs/xfs_errortag.h
@@ -56,7 +56,8 @@
#define XFS_ERRTAG_FORCE_SUMMARY_RECALC 33
#define XFS_ERRTAG_IUNLINK_FALLBACK 34
#define XFS_ERRTAG_BUF_IOERROR 35
-#define XFS_ERRTAG_MAX 36
+#define XFS_ERRTAG_REDUCE_MAX_IEXTENTS 36
+#define XFS_ERRTAG_MAX 37

/*
* Random factors for above tags, 1 means always, 2 means 1/2 time, etc.
@@ -97,5 +98,6 @@
#define XFS_RANDOM_FORCE_SUMMARY_RECALC 1
#define XFS_RANDOM_IUNLINK_FALLBACK (XFS_RANDOM_DEFAULT/10)
#define XFS_RANDOM_BUF_IOERROR XFS_RANDOM_DEFAULT
+#define XFS_RANDOM_REDUCE_MAX_IEXTENTS 1

#endif /* __XFS_ERRORTAG_H_ */
diff --git a/fs/xfs/libxfs/xfs_inode_fork.c b/fs/xfs/libxfs/xfs_inode_fork.c
index 8d48716547e5..e080d7e07643 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.c
+++ b/fs/xfs/libxfs/xfs_inode_fork.c
@@ -24,6 +24,7 @@
#include "xfs_dir2_priv.h"
#include "xfs_attr_leaf.h"
#include "xfs_types.h"
+#include "xfs_errortag.h"

kmem_zone_t *xfs_ifork_zone;

@@ -745,6 +746,9 @@ xfs_iext_count_may_overflow(

max_exts = (whichfork == XFS_ATTR_FORK) ? MAXAEXTNUM : MAXEXTNUM;

+ if (XFS_TEST_ERROR(false, ip->i_mount, XFS_ERRTAG_REDUCE_MAX_IEXTENTS))
+ max_exts = 10;
+
nr_exts = ifp->if_nextents + nr_to_add;
if (nr_exts < ifp->if_nextents || nr_exts > max_exts)
return -EFBIG;
diff --git a/fs/xfs/xfs_error.c b/fs/xfs/xfs_error.c
index 7f6e20899473..3780b118cc47 100644
--- a/fs/xfs/xfs_error.c
+++ b/fs/xfs/xfs_error.c
@@ -54,6 +54,7 @@ static unsigned int xfs_errortag_random_default[] = {
XFS_RANDOM_FORCE_SUMMARY_RECALC,
XFS_RANDOM_IUNLINK_FALLBACK,
XFS_RANDOM_BUF_IOERROR,
+ XFS_RANDOM_REDUCE_MAX_IEXTENTS,
};

struct xfs_errortag_attr {
@@ -164,6 +165,7 @@ XFS_ERRORTAG_ATTR_RW(force_repair, XFS_ERRTAG_FORCE_SCRUB_REPAIR);
XFS_ERRORTAG_ATTR_RW(bad_summary, XFS_ERRTAG_FORCE_SUMMARY_RECALC);
XFS_ERRORTAG_ATTR_RW(iunlink_fallback, XFS_ERRTAG_IUNLINK_FALLBACK);
XFS_ERRORTAG_ATTR_RW(buf_ioerror, XFS_ERRTAG_BUF_IOERROR);
+XFS_ERRORTAG_ATTR_RW(reduce_max_iextents, XFS_ERRTAG_REDUCE_MAX_IEXTENTS);

static struct attribute *xfs_errortag_attrs[] = {
XFS_ERRORTAG_ATTR_LIST(noerror),
@@ -202,6 +204,7 @@ static struct attribute *xfs_errortag_attrs[] = {
XFS_ERRORTAG_ATTR_LIST(bad_summary),
XFS_ERRORTAG_ATTR_LIST(iunlink_fallback),
XFS_ERRORTAG_ATTR_LIST(buf_ioerror),
+ XFS_ERRORTAG_ATTR_LIST(reduce_max_iextents),
NULL,
};

--
2.28.0