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Use both va_gen and va_filerev to validate cache entries.
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Various filesystems implement one or another of these with varying
semantics so check both otherwise the cache does not operate corectly.
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@DanielO
Robin Geuze authored and DanielO committed Oct 12, 2022
1 parent 7e65358 commit aa7f151
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Showing 3 changed files with 41 additions and 23 deletions.
2 changes: 2 additions & 0 deletions sys/fs/pefs/pefs_dircache.c
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Original file line number Diff line number Diff line change
Expand Up @@ -319,6 +319,7 @@ pefs_dircache_purge(struct pefs_dircache *pd)
// ASSERT_VOP_ELOCKED
mtx_lock(&pd->pd_mtx);
atomic_store_rel_long(&pd->pd_gen, 0);
atomic_store_rel_64(&pd->pd_filerev, 0);
LIST_FOREACH_SAFE(pde, &pd->pd_activehead, pde_dir_entry, tmp) {
dircache_entry_expire_locked(pde);
}
Expand All @@ -337,6 +338,7 @@ pefs_dircache_expire(struct pefs_dircache_entry *pde, u_int dflags)
return;
mtx_lock(&pd->pd_mtx);
atomic_store_rel_long(&pd->pd_gen, 0);
atomic_store_rel_64(&pd->pd_filerev, 0);
dircache_retry_clear(pd);
if (pde->pde_dircache != NULL) {
dircache_entry_expire_locked(pde);
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15 changes: 10 additions & 5 deletions sys/fs/pefs/pefs_dircache.h
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Original file line number Diff line number Diff line change
Expand Up @@ -42,7 +42,8 @@ struct pefs_dircache {
struct mtx pd_mtx;
struct pefs_dircache_listhead pd_activehead;
struct pefs_dircache_listhead pd_stalehead;
volatile u_long pd_gen;
volatile u_long pd_gen;
volatile u_quad_t pd_filerev;
struct pefs_dircache_pool *pd_pool;
struct pefs_dircache_entry *pd_retry[PEFS_DIRCACHE_RETRY_COUNT];
};
Expand Down Expand Up @@ -89,14 +90,17 @@ void pefs_dircache_expire_encname(struct pefs_dircache *pd,
void pefs_dircache_gc(struct pefs_dircache *pd);

static __inline int
pefs_dircache_valid(struct pefs_dircache *pd, u_long gen)
pefs_dircache_valid(struct pefs_dircache *pd, u_long gen, u_quad_t filerev)
{
u_long pd_gen;
u_quad_t pd_filerev;

if (gen == 0)
if (filerev == 0 && gen == 0)
return 0;

pd_gen = atomic_load_acq_long(&pd->pd_gen);
return (gen == pd_gen);
pd_filerev = atomic_load_acq_64(&pd->pd_filerev);
return ((filerev == pd_filerev || filerev == 0) && (gen == pd_gen || gen == 0));
}

static __inline void
Expand All @@ -105,9 +109,10 @@ pefs_dircache_beginupdate(struct pefs_dircache *pd)
}

static __inline void
pefs_dircache_endupdate(struct pefs_dircache *pd, u_long gen)
pefs_dircache_endupdate(struct pefs_dircache *pd, u_long gen, u_quad_t filerev)
{
atomic_store_rel_long(&pd->pd_gen, gen);
atomic_store_rel_64(&pd->pd_filerev, filerev);
}

static __inline void
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47 changes: 29 additions & 18 deletions sys/fs/pefs/pefs_vnops.c
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Original file line number Diff line number Diff line change
Expand Up @@ -108,21 +108,28 @@ static int pefs_read_int(struct vnode *vp, struct uio *uio, int ioflag,
static int pefs_write_int(struct vnode *vp, struct uio *uio, int ioflag,
struct ucred *cred, u_quad_t nsize);

static __inline u_long
pefs_getgen(struct vnode *vp, struct ucred *cred)
static __inline void
pefs_getgen_and_filerev(struct vnode *vp, struct ucred *cred, u_long *gen, u_quad_t *filerev)
{
struct vattr va;
int error;

if (!pefs_dircache_enable ||
((VFS_TO_PEFS(vp->v_mount)->pm_flags & PM_DIRCACHE) == 0))
return (0);
((VFS_TO_PEFS(vp->v_mount)->pm_flags & PM_DIRCACHE) == 0)) {
*gen = 0;
*filerev = 0;
return;
}

error = VOP_GETATTR(PEFS_LOWERVP(vp), &va, cred);
if (error != 0)
return (0);
if (error != 0) {
*gen = 0;
*filerev = 0;
return;
}

return (va.va_gen);
*gen = va.va_gen;
*filerev = va.va_filerev;
}

static __inline int
Expand Down Expand Up @@ -439,7 +446,7 @@ pefs_lookup_parsedir(struct pefs_dircache *pd, struct pefs_ctx *ctx,
}

static int
pefs_lookup_readdir(struct pefs_enccn *pec, u_long gen, struct vnode *dvp,
pefs_lookup_readdir(struct pefs_enccn *pec, u_long gen, u_quad_t filerev, struct vnode *dvp,
struct componentname *cnp)
{
struct uio *uio;
Expand Down Expand Up @@ -485,7 +492,7 @@ pefs_lookup_readdir(struct pefs_enccn *pec, u_long gen, struct vnode *dvp,
pefs_chunk_restore(&pc);
}
if (eofflag != 0 && error == 0)
pefs_dircache_endupdate(dpn->pn_dircache, gen);
pefs_dircache_endupdate(dpn->pn_dircache, gen, filerev);
else
pefs_dircache_abortupdate(dpn->pn_dircache);

Expand Down Expand Up @@ -534,7 +541,7 @@ pefs_lookup_lower(struct vnode *dvp, struct vnode **lvpp,
}

static int
pefs_lookup_dircache(struct pefs_enccn *enccn, u_long gen, struct vnode *dvp,
pefs_lookup_dircache(struct pefs_enccn *enccn, u_long gen, u_quad_t filerev , struct vnode *dvp,
struct vnode **lvpp, struct componentname *cnp)
{
struct pefs_dircache *pd;
Expand All @@ -546,7 +553,7 @@ pefs_lookup_dircache(struct pefs_enccn *enccn, u_long gen, struct vnode *dvp,
cache = pefs_dircache_lookup(pd, cnp->cn_nameptr,
cnp->cn_namelen);
if (cache == NULL) {
if (pefs_dircache_valid(pd, gen))
if (pefs_dircache_valid(pd, gen, filerev))
return (ENOENT);
return (EINVAL);
}
Expand Down Expand Up @@ -578,6 +585,7 @@ pefs_lookup(struct vop_cachedlookup_args *ap)
struct mount *mp;
uint64_t flags;
u_long gen;
u_quad_t filerev;
int nokey_lookup, skip_lookup;
int error;

Expand Down Expand Up @@ -613,10 +621,10 @@ pefs_lookup(struct vop_cachedlookup_args *ap)

if (!nokey_lookup) {
lvp = NULL;
gen = pefs_getgen(dvp, cnp->cn_cred);
error = pefs_lookup_dircache(&enccn, gen, dvp, &lvp, cnp);
pefs_getgen_and_filerev(dvp, cnp->cn_cred, &gen, &filerev);
error = pefs_lookup_dircache(&enccn, gen, filerev, dvp, &lvp, cnp);
if (error != 0 && error != ENOENT)
error = pefs_lookup_readdir(&enccn, gen, dvp, cnp);
error = pefs_lookup_readdir(&enccn, gen, filerev, dvp, cnp);
if (error == ENOENT && (cnp->cn_flags & ISLASTCN) &&
(cnp->cn_nameiop == CREATE || cnp->cn_nameiop == RENAME ||
(cnp->cn_nameiop == DELETE &&
Expand Down Expand Up @@ -1680,6 +1688,7 @@ pefs_readdir(struct vop_readdir_args *ap)
struct pefs_ctx *ctx;
size_t mem_size;
u_long gen;
u_quad_t filerev;
int error;
int r_ncookies = 0, r_ncookies_max = 0, ncookies = 0;
u_long *r_cookies = NULL, *cookies = NULL;
Expand All @@ -1703,13 +1712,15 @@ pefs_readdir(struct vop_readdir_args *ap)
a_cookies = &cookies;
}

gen = pefs_getgen(vp, cred);
pefs_getgen_and_filerev(vp, cred, &gen, &filerev);
ctx = pefs_ctx_get();
pefs_chunk_create(&pc, pn, qmin(uio->uio_resid, DFLTPHYS));
pn_key = pefs_node_key(pn);
pefs_dircache_beginupdate(pn->pn_dircache);
if (!pefs_dircache_valid(pn->pn_dircache, gen) || uio->uio_offset != 0)
if (!pefs_dircache_valid(pn->pn_dircache, gen, filerev) || uio->uio_offset != 0) {
gen = 0;
filerev = 0;
}
while (1) {
if (uio->uio_resid < pc.pc_size)
pefs_chunk_setsize(&pc, uio->uio_resid);
Expand Down Expand Up @@ -1766,8 +1777,8 @@ pefs_readdir(struct vop_readdir_args *ap)

pefs_chunk_restore(&pc);
}
if (*eofflag != 0 && error == 0 && gen != 0)
pefs_dircache_endupdate(pn->pn_dircache, gen);
if (*eofflag != 0 && error == 0 && gen != 0 && filerev != 0)
pefs_dircache_endupdate(pn->pn_dircache, gen, filerev);
else
pefs_dircache_abortupdate(pn->pn_dircache);

Expand Down

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