On Mon, Nov 22, 2010 at 03:36:07PM +0100, Sébastien Michel wrote:
> > > You have got to be kidding me. Unless there's actually something which
> > > requires the files to be rewritten (i.e. an expunge event) then this
> > > should not happen. Again, Cyrus 2.4.x will be much more efficient in
> > > this regard, only rewriting if you have explicitly enable immediate
> > > expunge rather than "default" expunge.
> >
> It is a 2.3.16. Tu be sure I have tested again with a fresh downloaded
> tarball. Just sending a mail in LMTP and opening the mailbox several times
> (SELECT/CLOSE only)
> A binary diff indicated that Generation Number is incremented but nothing
> else.
Ok - that's definitely fixed in 2.4. I'm also attaching some patches
against 2.4 if anyone else wants to have a play with them. The first
makes Cyrus open the index and cache files O_RDONLY if the index is
locked in shared mode (which implies a read-only session).
The second patch then makes index EXAMINE commands use a shared lock!
Bron.
>From 2b358b943677bc50830774e465537fc040917dde Mon Sep 17 00:00:00 2001
From: Bron Gondwana <brong@xxxxxxxxx>
Date: Tue, 23 Nov 2010 00:26:40 +1100
Subject: [PATCH 2/5] Open Files Readonly - mailbox_open_irl => read only filehandles
---
imap/mailbox.c | 26 ++++++++++++++++++++------
imap/mailbox.h | 1 +
2 files changed, 21 insertions(+), 6 deletions(-)
diff --git a/imap/mailbox.c b/imap/mailbox.c
index 1f2bbb0..8a1cafc 100644
--- a/imap/mailbox.c
+++ b/imap/mailbox.c
@@ -456,6 +456,7 @@ int mailbox_open_cache(struct mailbox *mailbox)
struct stat sbuf;
unsigned generation;
int retry = 0;
+ int openflags = mailbox->is_readonly ? O_RDONLY : O_RDWR;
/* already got everything? great */
if (mailbox->cache_fd != -1 && !mailbox->need_cache_refresh)
@@ -471,7 +472,7 @@ int mailbox_open_cache(struct mailbox *mailbox)
abort();
fname = mailbox_meta_fname(mailbox, META_CACHE);
- mailbox->cache_fd = open(fname, O_RDWR, 0);
+ mailbox->cache_fd = open(fname, openflags, 0);
if (mailbox->cache_fd == -1)
goto fail;
}
@@ -573,6 +574,8 @@ int mailbox_append_cache(struct mailbox *mailbox,
{
int r;
+ assert(mailbox_index_islocked(mailbox, 1));
+
/* no cache content */
if (!record->crec.len)
return 0;
@@ -852,6 +855,9 @@ int mailbox_open_advanced(const char *name,
mailbox->acl = xstrdup(mbentry.acl);
mailbox->mbtype = mbentry.mbtype;
+ if (index_locktype == LOCK_SHARED)
+ mailbox->is_readonly = 1;
+
r = mailbox_open_index(mailbox);
if (r) {
syslog(LOG_ERR, "IOERROR: opening index %s: %m", mailbox->name);
@@ -901,6 +907,7 @@ int mailbox_open_index(struct mailbox *mailbox)
{
struct stat sbuf;
char *fname;
+ int openflags = mailbox->is_readonly ? O_RDONLY : O_RDWR;
if (mailbox->i.dirty || mailbox->cache_dirty)
abort();
@@ -924,7 +931,7 @@ int mailbox_open_index(struct mailbox *mailbox)
if (!fname)
return IMAP_MAILBOX_BADNAME;
- mailbox->index_fd = open(fname, O_RDWR, 0);
+ mailbox->index_fd = open(fname, openflags, 0);
if (mailbox->index_fd == -1)
return IMAP_IOERROR;
@@ -1445,12 +1452,19 @@ int mailbox_lock_index(struct mailbox *mailbox, int locktype)
restart:
- if (locktype == LOCK_EXCLUSIVE)
- r = lock_blocking(mailbox->index_fd);
- else
+ if (locktype == LOCK_EXCLUSIVE) {
+ /* handle read-only case cleanly - we need to re-open read-write first! */
+ if (mailbox->is_readonly) {
+ mailbox->is_readonly = 0;
+ r = mailbox_open_index(mailbox);
+ }
+ if (!r) r = lock_blocking(mailbox->index_fd);
+ }
+ else {
r = lock_shared(mailbox->index_fd);
+ }
- if (r == -1) {
+ if (r) {
syslog(LOG_ERR, "IOERROR: locking index for %s: %m",
mailbox->name);
return IMAP_IOERROR;
diff --git a/imap/mailbox.h b/imap/mailbox.h
index 77bcc1b..1f2aca3 100644
--- a/imap/mailbox.h
+++ b/imap/mailbox.h
@@ -194,6 +194,7 @@ struct mailbox {
unsigned long cache_len; /* mapped size */
int index_locktype; /* 0 = none, 1 = shared, 2 = exclusive */
+ int is_readonly; /* true = open index and cache files readonly */
ino_t header_file_ino;
bit32 header_file_crc;
--
1.7.2.3
>From 49e4793e97559d750571d9252074aeb388c73dab Mon Sep 17 00:00:00 2001
From: Bron Gondwana <brong@xxxxxxxxx>
Date: Tue, 23 Nov 2010 13:34:12 +1100
Subject: [PATCH 3/5] Open with read lock in EXAMINE
---
imap/index.c | 15 +++++++++++----
1 files changed, 11 insertions(+), 4 deletions(-)
diff --git a/imap/index.c b/imap/index.c
index a00dbef..77664c8 100644
--- a/imap/index.c
+++ b/imap/index.c
@@ -214,13 +214,16 @@ int index_open(const char *name, struct index_init *init,
struct index_state *state = xzmalloc(sizeof(struct index_state));
struct seqset *vanishedlist = NULL;
- r = mailbox_open_iwl(name, &state->mailbox);
- if (r) goto fail;
-
if (init) {
state->myrights = cyrus_acl_myrights(init->authstate, state->mailbox->acl);
- if (init->examine_mode)
+ if (init->examine_mode) {
state->myrights &= ~ACL_READ_WRITE;
+ r = mailbox_open_irl(name, &state->mailbox);
+ if (r) goto fail;
+ } else {
+ r = mailbox_open_iwl(name, &state->mailbox);
+ if (r) goto fail;
+ }
state->authstate = init->authstate;
state->userid = init->userid ? xstrdup(init->userid) : NULL;
@@ -232,6 +235,10 @@ int index_open(const char *name, struct index_init *init,
state->out = init->out;
state->qresync = init->qresync;
}
+ else {
+ r = mailbox_open_iwl(name, &state->mailbox);
+ if (r) goto fail;
+ }
/* initialise the index_state */
index_refresh(state);
--
1.7.2.3
----
Cyrus Home Page: http://www.cyrusimap.org/
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