Hi,
we ran into a problem, while using filesystem snapshots on a GPFS-filesystem.
With this we want to give the users the opportunity to restore Mailboxes from
this snapshots in case they deleted mail by accident.
For each snapshot we create a namespace via a postlogin skript (with
INDEX=MEMORY to avoid writing index files to a ro filesystem). The snapshot are
of course read only.
When accessing the mailboxes in the namespaces, dovecot generates an error (ro
filesystem):
Error: Mailbox #backup20/Mail/deleted-messages: open() failed with mbox:
Read-only file system
We tracked that down to a problem in src/lib-storage/index/mbox/mbox-file.c
(yes, we are still using mbox ;) )
fd = open(mailbox_get_path(&mbox->box),
mbox_is_backend_readonly(mbox) ? O_RDONLY : O_RDWR);
if (fd == -1 && errno == EACCES &&
!mbox->backend_readonly) {
mbox->backend_readonly = TRUE;
fd = open(mailbox_get_path(&mbox->box), O_RDONLY);
}
Here the mailbox is opened and it is checked wether the file is ro or rw.
Since the snapshot contains the original file permissions, the file is of course
rw, but the filesystem is ro.
Unfortunately the code only checks for file permissions (errno == EACCES), which
doesn?t catch our error condition (FS ro).
We think that exchanging this to (errno == EACCESS || errno == EROFS) would
catch the file system ro error correctly and set the readonly flag correctly and
open the mailbox ro.
(this probably hast to be done for other mailbox formats in the corresponding
files too)
What do you think? Is there a chance to implement that in an upcoming release?
Best regards
Damian
?
Postmaster at WWU
WWU IT
Westf?lische Wilhelms-Universit?t (WWU) M?nster
R?ntgenstr. 7-13, 48149 M?nster
mailto:postmaster at uni-muenster.de
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Hi! This is on our backlog already as DOP-2294, lets see if we get it forward at some point. Aki> On 29/06/2021 12:48 Bucher, Dr. Damian <bucher at uni-muenster.de> wrote: > > > Hi, > > we ran into a problem, while using filesystem snapshots on a GPFS-filesystem. With this we want to give the users the opportunity to restore Mailboxes from this snapshots in case they deleted mail by accident. > > For each snapshot we create a namespace via a postlogin skript (with INDEX=MEMORY to avoid writing index files to a ro filesystem). The snapshot are of course read only. > When accessing the mailboxes in the namespaces, dovecot generates an error (ro filesystem): > Error: Mailbox #backup20/Mail/deleted-messages: open() failed with mbox: Read-only file system > > > We tracked that down to a problem in src/lib-storage/index/mbox/mbox-file.c (yes, we are still using mbox ;) ) > > fd = open(mailbox_get_path(&mbox->box), > mbox_is_backend_readonly(mbox) ? O_RDONLY : O_RDWR); > if (fd == -1 && errno == EACCES && !mbox->backend_readonly) { > mbox->backend_readonly = TRUE; > fd = open(mailbox_get_path(&mbox->box), O_RDONLY); > } > > Here the mailbox is opened and it is checked wether the file is ro or rw. > Since the snapshot contains the original file permissions, the file is of course rw, but the filesystem is ro. > Unfortunately the code only checks for file permissions (errno == EACCES), which doesn?t catch our error condition (FS ro). > > We think that exchanging this to (errno == EACCESS || errno == EROFS) would catch the file system ro error correctly and set the readonly flag correctly and open the mailbox ro. > (this probably hast to be done for other mailbox formats in the corresponding files too) > > What do you think? Is there a chance to implement that in an upcoming release? > > Best regards > Damian > > ? > Postmaster at WWU > WWU IT > Westf?lische Wilhelms-Universit?t (WWU) M?nster > R?ntgenstr. 7-13, 48149 M?nster > > mailto:postmaster at uni-muenster.de