Date: Thu, 21 Sep 2006 16:46:30 +0100 From: Alasdair G Kergon <agk@redhat.com> Subject: [RHEL5 PATCH 10/30] dm snapshot: make read and write exception functions void read_exception() and write_exception() only return an error if supplied with an out-of-range index. If this ever happens it's the result of a bug in the calling code so we handle this with an assertion and remove the error handling in the callers. Index: linux-2.6.18.noarch/drivers/md/dm-exception-store.c =================================================================== --- linux-2.6.18.noarch.orig/drivers/md/dm-exception-store.c +++ linux-2.6.18.noarch/drivers/md/dm-exception-store.c @@ -296,42 +296,29 @@ static int write_header(struct pstore *p */ static struct disk_exception *get_exception(struct pstore *ps, uint32_t index) { - if (index >= ps->exceptions_per_area) - return NULL; + BUG_ON(index >= ps->exceptions_per_area); return ((struct disk_exception *) ps->area) + index; } -static int read_exception(struct pstore *ps, - uint32_t index, struct disk_exception *result) +static void read_exception(struct pstore *ps, + uint32_t index, struct disk_exception *result) { - struct disk_exception *e; - - e = get_exception(ps, index); - if (!e) - return -EINVAL; + struct disk_exception *e = get_exception(ps, index); /* copy it */ result->old_chunk = le64_to_cpu(e->old_chunk); result->new_chunk = le64_to_cpu(e->new_chunk); - - return 0; } -static int write_exception(struct pstore *ps, - uint32_t index, struct disk_exception *de) +static void write_exception(struct pstore *ps, + uint32_t index, struct disk_exception *de) { - struct disk_exception *e; - - e = get_exception(ps, index); - if (!e) - return -EINVAL; + struct disk_exception *e = get_exception(ps, index); /* copy it */ e->old_chunk = cpu_to_le64(de->old_chunk); e->new_chunk = cpu_to_le64(de->new_chunk); - - return 0; } /* @@ -349,10 +336,7 @@ static int insert_exceptions(struct psto *full = 1; for (i = 0; i < ps->exceptions_per_area; i++) { - r = read_exception(ps, i, &de); - - if (r) - return r; + read_exception(ps, i, &de); /* * If the new_chunk is pointing at the start of Date: Thu, 21 Sep 2006 16:46:48 +0100 From: Alasdair G Kergon <agk@redhat.com> Subject: [RHEL5 PATCH 11/30] dm snapshot: fix metadata writing when suspending When suspending a device-mapper device, dm_suspend() sleeps until all necessary I/O is completed. This state is triggered by a callback from persistent_commit(). But some I/O can still be issued *after* the callback (to prepare the next metadata area for use if the current one is full). This patch delays the callback until after that I/O is complete. Index: linux-2.6.18.noarch/drivers/md/dm-exception-store.c =================================================================== --- linux-2.6.18.noarch.orig/drivers/md/dm-exception-store.c +++ linux-2.6.18.noarch/drivers/md/dm-exception-store.c @@ -536,6 +536,16 @@ static void persistent_commit(struct exc if (r) ps->valid = 0; + /* + * Have we completely filled the current area ? + */ + if (ps->current_committed == ps->exceptions_per_area) { + ps->current_committed = 0; + r = zero_area(ps, ps->current_area + 1); + if (r) + ps->valid = 0; + } + for (i = 0; i < ps->callback_count; i++) { cb = ps->callbacks + i; cb->callback(cb->context, r == 0 ? 1 : 0); @@ -543,16 +553,6 @@ static void persistent_commit(struct exc ps->callback_count = 0; } - - /* - * Have we completely filled the current area ? - */ - if (ps->current_committed == ps->exceptions_per_area) { - ps->current_committed = 0; - r = zero_area(ps, ps->current_area + 1); - if (r) - ps->valid = 0; - } } static void persistent_drop(struct exception_store *store)