xfs: Introduce error injection to reduce maximum inode fork extent count

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>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

diff --git a/fs/xfs/libxfs/xfs_errortag.h b/fs/xfs/libxfs/xfs_errortag.h
index 53b305d..1c56fcc 100644 (file)
--- 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 8d48716..e080d7e 100644 (file)
--- 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 7f6e208..3780b11 100644 (file)
--- 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,
 };