Currently xfs_logprint doesn't show detailed data about AGF and AGI
buffers and instead always shows "Out of space". This is because
xfs_agf_t has additional fields and padding which we never read from
disk and thus buffer length is always smaller than the size of
xfs_agf_t or xfs_agi_t respectively.
Fix the problem by only making sure we have enough data in the buffer
to contain all the information we want to print.
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
logprint/log_misc.c | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)
diff --git a/logprint/log_misc.c b/logprint/log_misc.c
index d482cf3fba57..c9286c67b913 100644
--- a/logprint/log_misc.c
+++ b/logprint/log_misc.c
@@ -325,7 +325,15 @@ xlog_print_trans_buffer(xfs_caddr_t *ptr, int len, int *i, int num_ops)
} else if (be32_to_cpu(*(__be32 *)(*ptr)) == XFS_AGI_MAGIC) {
agi = (xfs_agi_t *)(*ptr);
printf(_("AGI Buffer: XAGI "));
- if (be32_to_cpu(head->oh_len) < sizeof(xfs_agi_t) -
+ /*
+ * v4 filesystems only contain the fields before the uuid.
+ * Even v5 filesystems don't log any field beneath it. That
+ * means that the size that is logged is almost always going to
+ * be smaller than the structure itself. Hence we need to make
+ * sure that the buffer contains all the data we want to print
+ * rather than just check against the structure size.
+ */
+ if (be32_to_cpu(head->oh_len) < offsetof(xfs_agi_t, agi_uuid) -
XFS_AGI_UNLINKED_BUCKETS*sizeof(xfs_agino_t)) {
printf(_("out of space\n"));
} else {
@@ -367,7 +375,15 @@ xlog_print_trans_buffer(xfs_caddr_t *ptr, int len, int *i, int num_ops)
} else if (be32_to_cpu(*(__be32 *)(*ptr)) == XFS_AGF_MAGIC) {
agf = (xfs_agf_t *)(*ptr);
printf(_("AGF Buffer: XAGF "));
- if (be32_to_cpu(head->oh_len) < sizeof(xfs_agf_t)) {
+ /*
+ * v4 filesystems only contain the fields before the uuid.
+ * Even v5 filesystems don't log any field beneath it. That
+ * means that the size that is logged is almost always going to
+ * be smaller than the structure itself. Hence we need to make
+ * sure that the buffer contains all the data we want to print
+ * rather than just check against the structure size.
+ */
+ if (be32_to_cpu(head->oh_len) < offsetof(xfs_agf_t, agf_uuid)) {
printf(_("Out of space\n"));
} else {
printf("\n");
--
1.8.1.4
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