HAMMER VFS: Correct a ref count leak in the recent I/O invalidation work

Correct a ref count leak in the recent I/O invalidation work.  This could
lead to permanently referenced hammer_buffers and prevent reservations
from terminating.

Reported-by: Michael Neumann <mneumann@ntecs.de>

diff --git a/sys/vfs/hammer/hammer_ondisk.c b/sys/vfs/hammer/hammer_ondisk.c
index 44e4e00..711fe65 100644 (file)
--- a/sys/vfs/hammer/hammer_ondisk.c
+++ b/sys/vfs/hammer/hammer_ondisk.c
@@ -736,8 +736,10 @@ hammer_del_buffers(hammer_mount_t hmp, hammer_off_t base_offset,
                                   base_offset);
                if (buffer) {
                        error = hammer_ref_buffer(buffer);
-                       if (error == 0 && buffer->io.lock.refs != 1)
+                       if (error == 0 && buffer->io.lock.refs != 1) {
                                error = EAGAIN;
+                               hammer_rel_buffer(buffer, 0);
+                       }
                        if (error == 0) {
                                KKASSERT(buffer->zone2_offset == zone2_offset);
                                hammer_io_clear_modify(&buffer->io, 1);
@@ -752,7 +754,7 @@ hammer_del_buffers(hammer_mount_t hmp, hammer_off_t base_offset,
                if (error) {
                        ret_error = error;
                        if (report_conflicts || (hammer_debug_general & 0x8000))
-                               kprintf("hammer_del_buffers: unable to invalidate %016llx rep=%d\n", base_offset, report_conflicts);
+                               kprintf("hammer_del_buffers: unable to invalidate %016llx buffer=%p rep=%d\n", base_offset, buffer, report_conflicts);
                }
                base_offset += HAMMER_BUFSIZE;
                zone2_offset += HAMMER_BUFSIZE;