Author: kib
Date: Sat Feb 22 20:50:30 2020
New Revision: 358252
URL: https://svnweb.freebsd.org/changeset/base/358252
Log:
Fix NFS client deadlock when read reports truncated node.
If node attribute returned in the reply for read rpc indicate
truncation, and it happens that the vnode is exclusively locked,
update of the node attributes would try to shrink vnode size. Since
during the read some vnode pages were busied by the reading thread,
vnode_pager_setsize() deadlocks waiting for the busy state owned by
the caller.
Use a thread-local flag to indicate that NFS read owns some (s)busy
pages states and postpone the call to vnode_pager_setsize() until the
thread relinguishes the ownership.
Diagnosed by: rlibby
Tested by: pho, rlibby
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Modified:
head/sys/fs/nfsclient/nfs_clbio.c
head/sys/fs/nfsclient/nfs_clport.c
head/sys/sys/proc.h
Modified: head/sys/fs/nfsclient/nfs_clbio.c
==============================================================================
--- head/sys/fs/nfsclient/nfs_clbio.c Sat Feb 22 20:43:04 2020
(r358251)
+++ head/sys/fs/nfsclient/nfs_clbio.c Sat Feb 22 20:50:30 2020
(r358252)
@@ -425,14 +425,11 @@ int
ncl_bioread(struct vnode *vp, struct uio *uio, int ioflag, struct ucred *cred)
{
struct nfsnode *np = VTONFS(vp);
- int biosize, i;
struct buf *bp, *rabp;
struct thread *td;
struct nfsmount *nmp = VFSTONFS(vp->v_mount);
daddr_t lbn, rabn;
- int bcount;
- int seqcount;
- int nra, error = 0, n = 0, on = 0;
+ int biosize, bcount, error, i, n, nra, on, save2, seqcount;
off_t tmp_off;
KASSERT(uio->uio_rw == UIO_READ, ("ncl_read mode"));
@@ -464,6 +461,8 @@ ncl_bioread(struct vnode *vp, struct uio *uio, int iof
/* No caching/ no readaheads. Just read data into the user
buffer */
return ncl_readrpc(vp, uio, cred);
+ n = 0;
+ on = 0;
biosize = vp->v_bufobj.bo_bsize;
seqcount = (int)((off_t)(ioflag >> IO_SEQSHIFT) * biosize / BKVASIZE);
@@ -471,6 +470,7 @@ ncl_bioread(struct vnode *vp, struct uio *uio, int iof
if (error)
return error;
+ save2 = curthread_pflags2_set(TDP2_SBPAGES);
do {
u_quad_t nsize;
@@ -495,7 +495,9 @@ ncl_bioread(struct vnode *vp, struct uio *uio, int iof
rabp = nfs_getcacheblk(vp, rabn, biosize, td);
if (!rabp) {
error = newnfs_sigintr(nmp, td);
- return (error ? error : EINTR);
+ if (error == 0)
+ error = EINTR;
+ goto out;
}
if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
rabp->b_flags |= B_ASYNC;
@@ -526,7 +528,9 @@ ncl_bioread(struct vnode *vp, struct uio *uio, int iof
if (!bp) {
error = newnfs_sigintr(nmp, td);
- return (error ? error : EINTR);
+ if (error == 0)
+ error = EINTR;
+ goto out;
}
/*
@@ -540,7 +544,7 @@ ncl_bioread(struct vnode *vp, struct uio *uio, int iof
error = ncl_doio(vp, bp, cred, td, 0);
if (error) {
brelse(bp);
- return (error);
+ goto out;
}
}
@@ -561,7 +565,9 @@ ncl_bioread(struct vnode *vp, struct uio *uio, int iof
bp = nfs_getcacheblk(vp, (daddr_t)0, NFS_MAXPATHLEN, td);
if (!bp) {
error = newnfs_sigintr(nmp, td);
- return (error ? error : EINTR);
+ if (error == 0)
+ error = EINTR;
+ goto out;
}
if ((bp->b_flags & B_CACHE) == 0) {
bp->b_iocmd = BIO_READ;
@@ -570,7 +576,7 @@ ncl_bioread(struct vnode *vp, struct uio *uio, int iof
if (error) {
bp->b_ioflags |= BIO_ERROR;
brelse(bp);
- return (error);
+ goto out;
}
}
n = MIN(uio->uio_resid, NFS_MAXPATHLEN - bp->b_resid);
@@ -580,14 +586,17 @@ ncl_bioread(struct vnode *vp, struct uio *uio, int iof
NFSINCRGLOBAL(nfsstatsv1.biocache_readdirs);
if (np->n_direofoffset
&& uio->uio_offset >= np->n_direofoffset) {
- return (0);
+ error = 0;
+ goto out;
}
lbn = (uoff_t)uio->uio_offset / NFS_DIRBLKSIZ;
on = uio->uio_offset & (NFS_DIRBLKSIZ - 1);
bp = nfs_getcacheblk(vp, lbn, NFS_DIRBLKSIZ, td);
if (!bp) {
- error = newnfs_sigintr(nmp, td);
- return (error ? error : EINTR);
+ error = newnfs_sigintr(nmp, td);
+ if (error == 0)
+ error = EINTR;
+ goto out;
}
if ((bp->b_flags & B_CACHE) == 0) {
bp->b_iocmd = BIO_READ;
@@ -612,12 +621,16 @@ ncl_bioread(struct vnode *vp, struct uio *uio, int iof
*/
for (i = 0; i <= lbn && !error; i++) {
if (np->n_direofoffset
- && (i * NFS_DIRBLKSIZ) >= np->n_direofoffset)
- return (0);
+ && (i * NFS_DIRBLKSIZ) >= np->n_direofoffset) {
+ error = 0;
+ goto out;
+ }
bp = nfs_getcacheblk(vp, i, NFS_DIRBLKSIZ, td);
if (!bp) {
error = newnfs_sigintr(nmp, td);
- return (error ? error : EINTR);
+ if (error == 0)
+ error = EINTR;
+ goto out;
}
if ((bp->b_flags & B_CACHE) == 0) {
bp->b_iocmd = BIO_READ;
@@ -646,7 +659,7 @@ ncl_bioread(struct vnode *vp, struct uio *uio, int iof
* we give up.
*/
if (error)
- return (error);
+ goto out;
}
/*
@@ -706,6 +719,12 @@ ncl_bioread(struct vnode *vp, struct uio *uio, int iof
if (bp != NULL)
brelse(bp);
} while (error == 0 && uio->uio_resid > 0 && n > 0);
+out:
+ curthread_pflags2_restore(save2);
+ if ((curthread->td_pflags2 & TDP2_SBPAGES) == 0) {
+ NFSLOCKNODE(np);
+ ncl_pager_setsize(vp, NULL);
+ }
return (error);
}
Modified: head/sys/fs/nfsclient/nfs_clport.c
==============================================================================
--- head/sys/fs/nfsclient/nfs_clport.c Sat Feb 22 20:43:04 2020
(r358251)
+++ head/sys/fs/nfsclient/nfs_clport.c Sat Feb 22 20:50:30 2020
(r358252)
@@ -597,7 +597,8 @@ ncl_pager_setsize(struct vnode *vp, u_quad_t *nsizep)
setnsize = false;
if (object != NULL && nsize != object->un_pager.vnp.vnp_size) {
- if (VOP_ISLOCKED(vp) == LK_EXCLUSIVE)
+ if (VOP_ISLOCKED(vp) == LK_EXCLUSIVE &&
+ (curthread->td_pflags2 & TDP2_SBPAGES) == 0)
setnsize = true;
else
np->n_flag |= NVNSETSZSKIP;
Modified: head/sys/sys/proc.h
==============================================================================
--- head/sys/sys/proc.h Sat Feb 22 20:43:04 2020 (r358251)
+++ head/sys/sys/proc.h Sat Feb 22 20:50:30 2020 (r358252)
@@ -515,6 +515,8 @@ do {
\
#define TDP_EXECVMSPC 0x40000000 /* Execve destroyed old vmspace */
#define TDP_SIGFASTPENDING 0x80000000 /* Pending signal due to
sigfastblock */
+#define TDP2_SBPAGES 0x00000001 /* Owns sbusy on some pages */
+
/*
* Reasons that the current thread can not be run yet.
* More than one may apply.
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