linux.git/fs/cifs/dfs_cache.c, branch v5.14

cifs: support share failover when remounting

2021-07-22T16:43:23+00:00

When remouting a DFS share, force a new DFS referral of the path and
if the currently cached targets do not match any of the new targets or
there was no cached targets, then mark it for reconnect.

For example:

    $ mount //dom/dfs/link /mnt -o username=foo,password=bar
    $ ls /mnt
    oldfile.txt

    change target share of 'link' in server settings

    $ mount /mnt -o remount,username=foo,password=bar
    $ ls /mnt
    newfile.txt

Signed-off-by: Paulo Alcantara (SUSE) 
Signed-off-by: Steve French

cifs: fix check of dfs interlinks

2021-06-21T02:28:17+00:00

Interlink is a special type of DFS link that resolves to a different
DFS domain-based namespace.  To determine whether it is an interlink
or not, check if ReferralServers and StorageServers bits are set to 1
and 0 respectively in ReferralHeaderFlags, as specified in MS-DFSC
3.1.5.4.5 Determining Whether a Referral Response is an Interlink.

Signed-off-by: Paulo Alcantara (SUSE) 
Reviewed-by: Aurelien Aptel 
Signed-off-by: Steve French

cifs: avoid starvation when refreshing dfs cache

2021-06-21T02:28:17+00:00

When refreshing the DFS cache, keep SMB2 IOCTL calls as much outside
critical sections as possible and avoid read/write starvation when
getting new DFS referrals by using broken or slow connections.

Signed-off-by: Paulo Alcantara (SUSE) 
Reviewed-by: Aurelien Aptel 
Signed-off-by: Steve French

cifs: set a minimum of 2 minutes for refreshing dfs cache

2021-06-21T02:28:17+00:00

We don't want to refresh the dfs cache in very short intervals, so
setting a minimum interval of 2 minutes is OK.

If it needs to be refreshed immediately, one could have the cache
cleared with

	$ echo 0 > /proc/fs/cifs/dfscache

and then remounting the dfs share.

Signed-off-by: Paulo Alcantara (SUSE) 
Reviewed-by: Aurelien Aptel 
Signed-off-by: Steve French

cifs: fix path comparison and hash calc

2021-06-21T02:28:17+00:00

Fix cache lookup and hash calculations when handling paths with
different cases.

Signed-off-by: Paulo Alcantara (SUSE) 
Reviewed-by: Aurelien Aptel 
Signed-off-by: Steve French

cifs: handle different charsets in dfs cache

2021-06-21T02:28:16+00:00

Convert all dfs paths to dfs cache's local codepage (@cache_cp) and
avoid mixing them with different charsets.

Signed-off-by: Paulo Alcantara (SUSE) 
Reviewed-by: Aurelien Aptel 
Signed-off-by: Steve French

cifs: keep referral server sessions alive

2021-06-21T02:28:16+00:00

At every mount, keep all sessions alive that were used for chasing the
DFS referrals as long as the dfs mounts are active.

Use those sessions in DFS cache to refresh all active tcons as well as
cached entries.  They will be managed by a list of mount_group
structures that will be indexed by a randomly generated uuid at mount
time, so we can put all the sessions related to specific dfs mounts
and avoid leaking them.

Signed-off-by: Paulo Alcantara (SUSE) 
Reviewed-by: Aurelien Aptel 
Signed-off-by: Steve French

cifs: get rid of @noreq param in __dfs_cache_find()

2021-06-21T02:28:16+00:00

@noreq param isn't used anywhere, so just remove it.

Signed-off-by: Paulo Alcantara (SUSE) 
Reviewed-by: Aurelien Aptel 
Signed-off-by: Steve French

cifs: Remove unused inline function is_sysvol_or_netlogon()

2021-06-21T02:28:16+00:00

is_sysvol_or_netlogon() is never used, so can remove it.

Signed-off-by: YueHaibing 
Reviewed-by: Paulo Alcantara (SUSE) 
Signed-off-by: Steve French

cifs: constify get_normalized_path() properly

2021-04-25T21:28:23+00:00

As it is, it takes const char * and, in some cases, stores it in
caller's variable that is plain char *.  Fortunately, none of the
callers actually proceeded to modify the string via now-non-const
alias, but that's trouble waiting to happen.

It's easy to do properly, anyway...

Signed-off-by: Al Viro 
Signed-off-by: Steve French