On Sat, 2011-07-30 at 14:33 -0400, Trond Myklebust wrote: > On Fri, 2011-07-29 at 14:50 +0100, Sachin Prabhu wrote: > > When you normally attempt to mount a share twice on the same mountpoint, > > a check in do_add_mount causes it to return an error > > > > # mount localhost:/nfsv3 /mnt > > # mount localhost:/nfsv3 /mnt > > mount.nfs: /mnt is already mounted or busy > > > > However when using the option 'noac', the user is able to mount the same > > share on the same mountpoint multiple times. This happens because a > > share mounted with the noac option is automatically assigned the 'sync' > > flag MS_SYNCHRONOUS in nfs_initialise_sb(). This flag is set after the > > check for already existing superblocks is done in sget(). The check for > > the mount flags in nfs_compare_mount_options() does not take into > > account the 'sync' flag applied later on in the code path. This means > > that when using 'noac', a new superblock structure is assigned for every > > new mount of the same share and multiple shares on the same mountpoint > > are allowed. > > > > ie. > > # mount -onoac localhost:/nfsv3 /mnt > > can be run multiple times. > > > > The patch checks for noac and assigns the sync flag before sget() is > > called to obtain an already existing superblock structure. > > > > > > Signed-off-by: Sachin Prabhu <sprabhu@xxxxxxxxxx> > > Hi Sachin, > > This patch fails to apply with the error 'corrupt patch at line 6'. It > looks to me as if your mailer has reformatted it for you. > > Cheers > Trond Hello Trond, Sorry about that. I have re-posted the patch. Sachin Prabhu -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
