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Subject[PATCH v2] CIFS: Print message when attempting a mount
Date
Currently, no messages are printed when mounting a CIFS filesystem and
no debug configuration is enabled.

However, a CIFS mount information is valuable when troubleshooting
and/or forensic analyzing a system and finding out if was a CIFS
endpoint mount attempted.

Other filesystems such as XFS, EXT* does issue a printk() when mounting
their filesystems.

A terse log message is printed only if cifsFYI is not enabled.

Sample mount operations:

[root@corinthians ~]# mount -o user=administrator //172.25.250.18/c$ /mnt
(non-existent system)

[root@corinthians ~]# mount -o user=administrator //172.25.250.19/c$ /mnt
(Valid system)

Kernel message log for the mount operations:

[ 450.464543] CIFS VFS: Attempting to mount //172.25.250.18/c$
[ 456.478186] CIFS VFS: Error connecting to socket. Aborting operation.
[ 456.478381] CIFS VFS: cifs_mount failed w/return code = -113
[ 467.688866] CIFS VFS: Attempting to mount //172.25.250.19/c$

v2: Created a loop to select the right cifs_dbg message to be printed,
considering the current system's scenario, in order to avoid a
duplicate message or stripping out important information in
debug.

Signed-off-by: Rodrigo Freire <rfreire@redhat.com>
---
fs/cifs/cifsfs.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 7065426..7fde6bc 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -707,7 +707,11 @@ static int cifs_set_super(struct super_block *sb, void *data)
struct cifs_mnt_data mnt_data;
struct dentry *root;

- cifs_dbg(FYI, "Devname: %s flags: %d\n", dev_name, flags);
+ /* Prints in Kernel / CIFS log the attempted mount operation */
+ if (cifsFYI)
+ cifs_dbg(FYI, "Devname: %s flags: %d\n", dev_name, flags);
+ else
+ cifs_dbg(VFS, "Attempting to mount %s\n", dev_name);

volume_info = cifs_get_volume_info((char *)data, dev_name, is_smb3);
if (IS_ERR(volume_info))
--
1.8.3.1
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