Messages in this thread | | | Date | Mon, 20 Mar 2006 14:20:05 +0100 | From | Aurelien Degremont <> | Subject | Re: NFS superblock sharing implies mount flags bug |
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Nobody is interested by this issue ? It could be easily reproduced. All recent versions are concerned.
Aurelien
Aurelien Degremont wrote: > Hello > > I'm facing incorrect using of mount flags when dealing with NFS mounts > and I think it could be seen as a bug. > > The error occurs when mounting the same NFS export many times, on the > same machine but *with different mount flags*, particularly concerning > RO/RW flags. > > As the NFS client code re-uses superblocks when it detects that it is > the same export (same server/same port/same exported directory) and that > the read-only flag is managed as a per-superblock flag, if a NFS exports > is mounted a second time, the superblock of the first mount is re-used > and the specified mount flag is ignored. > > # mount foo:/bar /bar_ro -o ro > # mount foo:/bar /bar_rw -o rw > $ touch /bar_rw/bar > touch: cannot touch `/bar_rw/bar': Read-only file system > > Ideally, the best solution to fix this is to move the RDONLY flag from > its per-superblock basis to a per-mountpoint (vfsmount) basis. I do not > know is there is a something that prevent that except that this implies > many changes as many codes do not use macros but access s_flags directly. > > It seems quite clear that the superblock sharing couldn't be changed (to > avoid incoherency, inode aliasing and so on...) ? > > Do you have a (better) solution ? > I can help if needed. > > > Cordially >
-- Aurelien Degremont CEA/DAM - DIF/DSSI/SISR - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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