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Further refine r352393, only call vnode_pager_setsize() outside the

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node lock when shrinking.

This is similar to r252528, applied to the above commit.

Apparently there is a race which makes necessary at least to keep the
n_size and pager size consistent when extending.  Current suspect is
that iod threads perform vnode_pager_setsize() without taking the
vnode lock, which corrupts the file content.

Reported and tested by:	Masachika ISHIZUKA <ish@amail.plala.or.jp>
Discussed with:	rmacklem (related issues)
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
This commit is contained in:
kib 2019-09-17 18:41:39 +00:00
parent 53e898f9eb
commit 82f8cfda99
1 changed files with 22 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

41
sys/fs/nfsclient/nfs_clport.c
View File

@ -414,12 +414,12 @@ nfscl_loadattrcache(struct vnode **vpp, struct nfsvattr *nap, void *nvaper,
struct nfsnode *np; struct nfsnode *np;
struct nfsmount *nmp; struct nfsmount *nmp;
struct timespec mtime_save; struct timespec mtime_save;
vm_object_t object;
u_quad_t nsize; u_quad_t nsize;
int setnsize, error, force_fid_err; int error, force_fid_err;
bool setnsize;
error = 0; error = 0;
setnsize = 0;
nsize = 0;
/* /*
* If v_type == VNON it is a new node, so fill in the v_type, * If v_type == VNON it is a new node, so fill in the v_type,
@ -511,8 +511,7 @@ nfscl_loadattrcache(struct vnode **vpp, struct nfsvattr *nap, void *nvaper,
* zero np->n_attrstamp to indicate that * zero np->n_attrstamp to indicate that
* the attributes are stale. * the attributes are stale.
*/ */
nsize = vap->va_size = np->n_size; vap->va_size = np->n_size;
setnsize = 1;
np->n_attrstamp = 0; np->n_attrstamp = 0;
KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp); KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
} else if (np->n_flag & NMODIFIED) { } else if (np->n_flag & NMODIFIED) {
@ -526,22 +525,9 @@ nfscl_loadattrcache(struct vnode **vpp, struct nfsvattr *nap, void *nvaper,
np->n_size = vap->va_size; np->n_size = vap->va_size;
np->n_flag |= NSIZECHANGED; np->n_flag |= NSIZECHANGED;
} }
nsize = np->n_size;
setnsize = 1;
} else if (vap->va_size < np->n_size) {
/*
* When shrinking the size, the call to
* vnode_pager_setsize() cannot be done
* with the mutex held, so delay it until
* after the mtx_unlock call.
*/
nsize = np->n_size = vap->va_size;
np->n_flag |= NSIZECHANGED;
setnsize = 1;
} else { } else {
nsize = np->n_size = vap->va_size; np->n_size = vap->va_size;
np->n_flag |= NSIZECHANGED; np->n_flag |= NSIZECHANGED;
setnsize = 1;
} }
} else { } else {
np->n_size = vap->va_size; np->n_size = vap->va_size;
@ -579,6 +565,23 @@ nfscl_loadattrcache(struct vnode **vpp, struct nfsvattr *nap, void *nvaper,
if (np->n_attrstamp != 0) if (np->n_attrstamp != 0)
KDTRACE_NFS_ATTRCACHE_LOAD_DONE(vp, vap, error); KDTRACE_NFS_ATTRCACHE_LOAD_DONE(vp, vap, error);
#endif #endif
nsize = vap->va_size;
object = vp->v_object;
setnsize = false;
if (object != NULL) {
if (OFF_TO_IDX(nsize + PAGE_MASK) < object->size) {
/*
* When shrinking the size, the call to
* vnode_pager_setsize() cannot be done with
* the mutex held, because we might need to
* wait for a busy page. Delay it until after
* the node is unlocked.
*/
setnsize = true;
} else {
vnode_pager_setsize(vp, nsize);
}
}
NFSUNLOCKNODE(np); NFSUNLOCKNODE(np);
if (setnsize) if (setnsize)
vnode_pager_setsize(vp, nsize); vnode_pager_setsize(vp, nsize);