Jeff Layton <jlayton@xxxxxxxxxx> writes: > The MDS reserves a set of inodes for its own usage, and these should > never be accessible to clients. Add a new helper to vet a proposed > inode number against that range, and complain loudly and refuse to > create or look it up if it's in it. We do need to carve out an exception > for the root and the lost+found directories. > > Also, ensure that the MDS doesn't try to delegate that range to us > either. Print a warning if it does, and don't save the range in the > xarray. > > URL: https://tracker.ceph.com/issues/49922 > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> > Signed-off-by: Xiubo Li<xiubli@xxxxxxxxxx> > Reviewed-by: Patrick Donnelly <pdonnell@xxxxxxxxxx> > --- > fs/ceph/export.c | 8 ++++++++ > fs/ceph/inode.c | 3 +++ > fs/ceph/mds_client.c | 7 +++++++ > fs/ceph/super.h | 24 ++++++++++++++++++++++++ > include/linux/ceph/ceph_fs.h | 7 ++++--- > 5 files changed, 46 insertions(+), 3 deletions(-) > > v2: allow lookups of lost+found dir inodes > flesh out and update the CEPH_INO_* definitions > > diff --git a/fs/ceph/export.c b/fs/ceph/export.c > index 17d8c8f4ec89..65540a4429b2 100644 > --- a/fs/ceph/export.c > +++ b/fs/ceph/export.c > @@ -129,6 +129,10 @@ static struct inode *__lookup_inode(struct super_block *sb, u64 ino) > > vino.ino = ino; > vino.snap = CEPH_NOSNAP; > + > + if (ceph_vino_is_reserved(vino)) > + return ERR_PTR(-ESTALE); > + > inode = ceph_find_inode(sb, vino); > if (!inode) { > struct ceph_mds_request *req; > @@ -214,6 +218,10 @@ static struct dentry *__snapfh_to_dentry(struct super_block *sb, > vino.ino = sfh->ino; > vino.snap = sfh->snapid; > } > + > + if (ceph_vino_is_reserved(vino)) > + return ERR_PTR(-ESTALE); > + > inode = ceph_find_inode(sb, vino); > if (inode) > return d_obtain_alias(inode); > diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c > index 14a1f7963625..e1c63adb196d 100644 > --- a/fs/ceph/inode.c > +++ b/fs/ceph/inode.c > @@ -56,6 +56,9 @@ struct inode *ceph_get_inode(struct super_block *sb, struct ceph_vino vino) > { > struct inode *inode; > > + if (ceph_vino_is_reserved(vino)) > + return ERR_PTR(-EREMOTEIO); > + > inode = iget5_locked(sb, (unsigned long)vino.ino, ceph_ino_compare, > ceph_set_ino_cb, &vino); > if (!inode) > diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c > index 63b53098360c..e5af591d3bd4 100644 > --- a/fs/ceph/mds_client.c > +++ b/fs/ceph/mds_client.c > @@ -440,6 +440,13 @@ static int ceph_parse_deleg_inos(void **p, void *end, > > ceph_decode_64_safe(p, end, start, bad); > ceph_decode_64_safe(p, end, len, bad); > + > + /* Don't accept a delegation of system inodes */ > + if (start < CEPH_INO_SYSTEM_BASE) { > + pr_warn_ratelimited("ceph: ignoring reserved inode range delegation (start=0x%llx len=0x%llx)\n", > + start, len); > + continue; > + } > while (len--) { > int err = xa_insert(&s->s_delegated_inos, ino = start++, > DELEGATED_INO_AVAILABLE, > diff --git a/fs/ceph/super.h b/fs/ceph/super.h > index df0851b9240e..f1745403c9b0 100644 > --- a/fs/ceph/super.h > +++ b/fs/ceph/super.h > @@ -529,10 +529,34 @@ static inline int ceph_ino_compare(struct inode *inode, void *data) > ci->i_vino.snap == pvino->snap; > } > > +/* > + * The MDS reserves a set of inodes for its own usage. These should never > + * be accessible by clients, and so the MDS has no reason to ever hand these > + * out. > + * > + * These come from src/mds/mdstypes.h in the ceph sources. > + */ > +#define CEPH_MAX_MDS 0x100 > +#define CEPH_NUM_STRAY 10 > +#define CEPH_INO_SYSTEM_BASE ((6*CEPH_MAX_MDS) + (CEPH_MAX_MDS * CEPH_NUM_STRAY)) > + > +static inline bool ceph_vino_is_reserved(const struct ceph_vino vino) > +{ > + if (vino.ino < CEPH_INO_SYSTEM_BASE && > + vino.ino != CEPH_INO_ROOT && > + vino.ino != CEPH_INO_LOST_AND_FOUND) { > + WARN_RATELIMIT(1, "Attempt to access reserved inode number 0x%llx", vino.ino); This warning is quite easy to hit with inode 0x3, using generic/013. It looks like, while looking for the snaprealm to check quotas, we will eventually get this value from the MDS. So this function should also return 'true' if ino is CEPH_INO_GLOBAL_SNAPREALM. Cheers, -- Luis > + return true; > + } > + return false; > +} > > static inline struct inode *ceph_find_inode(struct super_block *sb, > struct ceph_vino vino) > { > + if (ceph_vino_is_reserved(vino)) > + return NULL; > + > /* > * NB: The hashval will be run through the fs/inode.c hash function > * anyway, so there is no need to squash the inode number down to > diff --git a/include/linux/ceph/ceph_fs.h b/include/linux/ceph/ceph_fs.h > index e41a811026f6..3c90ae21a7e1 100644 > --- a/include/linux/ceph/ceph_fs.h > +++ b/include/linux/ceph/ceph_fs.h > @@ -27,9 +27,10 @@ > #define CEPH_MONC_PROTOCOL 15 /* server/client */ > > > -#define CEPH_INO_ROOT 1 > -#define CEPH_INO_CEPH 2 /* hidden .ceph dir */ > -#define CEPH_INO_DOTDOT 3 /* used by ceph fuse for parent (..) */ > +#define CEPH_INO_ROOT 1 /* root inode number for all cephfs's */ > +#define CEPH_INO_CEPH 2 /* hidden .ceph dir */ > +#define CEPH_INO_GLOBAL_SNAPREALM 3 /* includes all snapshots in the fs */ > +#define CEPH_INO_LOST_AND_FOUND 4 /* lost+found dir */ > > /* arbitrary limit on max # of monitors (cluster of 3 is typical) */ > #define CEPH_MAX_MON 31 > -- > > 2.31.1 >
