This is a note to let you know that I've just added the patch titled
nfsd: fix handling of cached open files in nfsd4_open codepath
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nfsd-fix-handling-of-cached-open-files-in-nfsd4_open.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 235d56c9844bbf63bfa3d6ae463d2904a8828558
Author: Jeff Layton <jlayton@xxxxxxxxxx>
Date: Thu Jan 5 14:55:56 2023 -0500
nfsd: fix handling of cached open files in nfsd4_open codepath
[ Upstream commit 0b3a551fa58b4da941efeb209b3770868e2eddd7 ]
Commit fb70bf124b05 ("NFSD: Instantiate a struct file when creating a
regular NFSv4 file") added the ability to cache an open fd over a
compound. There are a couple of problems with the way this currently
works:
It's racy, as a newly-created nfsd_file can end up with its PENDING bit
cleared while the nf is hashed, and the nf_file pointer is still zeroed
out. Other tasks can find it in this state and they expect to see a
valid nf_file, and can oops if nf_file is NULL.
Also, there is no guarantee that we'll end up creating a new nfsd_file
if one is already in the hash. If an extant entry is in the hash with a
valid nf_file, nfs4_get_vfs_file will clobber its nf_file pointer with
the value of op_file and the old nf_file will leak.
Fix both issues by making a new nfsd_file_acquirei_opened variant that
takes an optional file pointer. If one is present when this is called,
we'll take a new reference to it instead of trying to open the file. If
the nfsd_file already has a valid nf_file, we'll just ignore the
optional file and pass the nfsd_file back as-is.
Also rework the tracepoints a bit to allow for an "opened" variant and
don't try to avoid counting acquisitions in the case where we already
have a cached open file.
Fixes: fb70bf124b05 ("NFSD: Instantiate a struct file when creating a regular NFSv4 file")
Cc: Trond Myklebust <trondmy@xxxxxxxxxxxxxxx>
Reported-by: Stanislav Saner <ssaner@xxxxxxxxxx>
Reported-and-Tested-by: Ruben Vestergaard <rubenv@xxxxxxxx>
Reported-and-Tested-by: Torkil Svensgaard <torkil@xxxxxxxx>
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
index 140094a44cc40..6a62d95d5ce64 100644
--- a/fs/nfsd/filecache.c
+++ b/fs/nfsd/filecache.c
@@ -1070,8 +1070,8 @@ nfsd_file_is_cached(struct inode *inode)
static __be32
nfsd_file_do_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
- unsigned int may_flags, struct nfsd_file **pnf,
- bool open, bool want_gc)
+ unsigned int may_flags, struct file *file,
+ struct nfsd_file **pnf, bool want_gc)
{
struct nfsd_file_lookup_key key = {
.type = NFSD_FILE_KEY_FULL,
@@ -1146,8 +1146,7 @@ nfsd_file_do_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
status = nfserrno(nfsd_open_break_lease(file_inode(nf->nf_file), may_flags));
out:
if (status == nfs_ok) {
- if (open)
- this_cpu_inc(nfsd_file_acquisitions);
+ this_cpu_inc(nfsd_file_acquisitions);
*pnf = nf;
} else {
if (refcount_dec_and_test(&nf->nf_ref))
@@ -1157,20 +1156,23 @@ nfsd_file_do_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
out_status:
put_cred(key.cred);
- if (open)
- trace_nfsd_file_acquire(rqstp, key.inode, may_flags, nf, status);
+ trace_nfsd_file_acquire(rqstp, key.inode, may_flags, nf, status);
return status;
open_file:
trace_nfsd_file_alloc(nf);
nf->nf_mark = nfsd_file_mark_find_or_create(nf, key.inode);
if (nf->nf_mark) {
- if (open) {
+ if (file) {
+ get_file(file);
+ nf->nf_file = file;
+ status = nfs_ok;
+ trace_nfsd_file_opened(nf, status);
+ } else {
status = nfsd_open_verified(rqstp, fhp, may_flags,
&nf->nf_file);
trace_nfsd_file_open(nf, status);
- } else
- status = nfs_ok;
+ }
} else
status = nfserr_jukebox;
/*
@@ -1206,7 +1208,7 @@ __be32
nfsd_file_acquire_gc(struct svc_rqst *rqstp, struct svc_fh *fhp,
unsigned int may_flags, struct nfsd_file **pnf)
{
- return nfsd_file_do_acquire(rqstp, fhp, may_flags, pnf, true, true);
+ return nfsd_file_do_acquire(rqstp, fhp, may_flags, NULL, pnf, true);
}
/**
@@ -1227,28 +1229,30 @@ __be32
nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
unsigned int may_flags, struct nfsd_file **pnf)
{
- return nfsd_file_do_acquire(rqstp, fhp, may_flags, pnf, true, false);
+ return nfsd_file_do_acquire(rqstp, fhp, may_flags, NULL, pnf, false);
}
/**
- * nfsd_file_create - Get a struct nfsd_file, do not open
+ * nfsd_file_acquire_opened - Get a struct nfsd_file using existing open file
* @rqstp: the RPC transaction being executed
* @fhp: the NFS filehandle of the file just created
* @may_flags: NFSD_MAY_ settings for the file
+ * @file: cached, already-open file (may be NULL)
* @pnf: OUT: new or found "struct nfsd_file" object
*
- * The nfsd_file_object returned by this API is reference-counted
- * but not garbage-collected. The object is released immediately
- * one RCU grace period after the final nfsd_file_put().
+ * Acquire a nfsd_file object that is not GC'ed. If one doesn't already exist,
+ * and @file is non-NULL, use it to instantiate a new nfsd_file instead of
+ * opening a new one.
*
* Returns nfs_ok and sets @pnf on success; otherwise an nfsstat in
* network byte order is returned.
*/
__be32
-nfsd_file_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
- unsigned int may_flags, struct nfsd_file **pnf)
+nfsd_file_acquire_opened(struct svc_rqst *rqstp, struct svc_fh *fhp,
+ unsigned int may_flags, struct file *file,
+ struct nfsd_file **pnf)
{
- return nfsd_file_do_acquire(rqstp, fhp, may_flags, pnf, false, false);
+ return nfsd_file_do_acquire(rqstp, fhp, may_flags, file, pnf, false);
}
/*
diff --git a/fs/nfsd/filecache.h b/fs/nfsd/filecache.h
index b7efb2c3ddb18..41516a4263ea5 100644
--- a/fs/nfsd/filecache.h
+++ b/fs/nfsd/filecache.h
@@ -60,7 +60,8 @@ __be32 nfsd_file_acquire_gc(struct svc_rqst *rqstp, struct svc_fh *fhp,
unsigned int may_flags, struct nfsd_file **nfp);
__be32 nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
unsigned int may_flags, struct nfsd_file **nfp);
-__be32 nfsd_file_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
- unsigned int may_flags, struct nfsd_file **nfp);
+__be32 nfsd_file_acquire_opened(struct svc_rqst *rqstp, struct svc_fh *fhp,
+ unsigned int may_flags, struct file *file,
+ struct nfsd_file **nfp);
int nfsd_file_cache_stats_show(struct seq_file *m, void *v);
#endif /* _FS_NFSD_FILECACHE_H */
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 8bb75adbd4e6a..485e7055e52ec 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -5262,18 +5262,10 @@ static __be32 nfs4_get_vfs_file(struct svc_rqst *rqstp, struct nfs4_file *fp,
if (!fp->fi_fds[oflag]) {
spin_unlock(&fp->fi_lock);
- if (!open->op_filp) {
- status = nfsd_file_acquire(rqstp, cur_fh, access, &nf);
- if (status != nfs_ok)
- goto out_put_access;
- } else {
- status = nfsd_file_create(rqstp, cur_fh, access, &nf);
- if (status != nfs_ok)
- goto out_put_access;
- nf->nf_file = open->op_filp;
- open->op_filp = NULL;
- trace_nfsd_file_create(rqstp, access, nf);
- }
+ status = nfsd_file_acquire_opened(rqstp, cur_fh, access,
+ open->op_filp, &nf);
+ if (status != nfs_ok)
+ goto out_put_access;
spin_lock(&fp->fi_lock);
if (!fp->fi_fds[oflag]) {
diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h
index 48943b84b930a..1b50a0ee7a7a0 100644
--- a/fs/nfsd/trace.h
+++ b/fs/nfsd/trace.h
@@ -980,43 +980,6 @@ TRACE_EVENT(nfsd_file_acquire,
)
);
-TRACE_EVENT(nfsd_file_create,
- TP_PROTO(
- const struct svc_rqst *rqstp,
- unsigned int may_flags,
- const struct nfsd_file *nf
- ),
-
- TP_ARGS(rqstp, may_flags, nf),
-
- TP_STRUCT__entry(
- __field(const void *, nf_inode)
- __field(const void *, nf_file)
- __field(unsigned long, may_flags)
- __field(unsigned long, nf_flags)
- __field(unsigned long, nf_may)
- __field(unsigned int, nf_ref)
- __field(u32, xid)
- ),
-
- TP_fast_assign(
- __entry->nf_inode = nf->nf_inode;
- __entry->nf_file = nf->nf_file;
- __entry->may_flags = may_flags;
- __entry->nf_flags = nf->nf_flags;
- __entry->nf_may = nf->nf_may;
- __entry->nf_ref = refcount_read(&nf->nf_ref);
- __entry->xid = be32_to_cpu(rqstp->rq_xid);
- ),
-
- TP_printk("xid=0x%x inode=%p may_flags=%s ref=%u nf_flags=%s nf_may=%s nf_file=%p",
- __entry->xid, __entry->nf_inode,
- show_nfsd_may_flags(__entry->may_flags),
- __entry->nf_ref, show_nf_flags(__entry->nf_flags),
- show_nfsd_may_flags(__entry->nf_may), __entry->nf_file
- )
-);
-
TRACE_EVENT(nfsd_file_insert_err,
TP_PROTO(
const struct svc_rqst *rqstp,
@@ -1078,8 +1041,8 @@ TRACE_EVENT(nfsd_file_cons_err,
)
);
-TRACE_EVENT(nfsd_file_open,
- TP_PROTO(struct nfsd_file *nf, __be32 status),
+DECLARE_EVENT_CLASS(nfsd_file_open_class,
+ TP_PROTO(const struct nfsd_file *nf, __be32 status),
TP_ARGS(nf, status),
TP_STRUCT__entry(
__field(void *, nf_inode) /* cannot be dereferenced */
@@ -1103,6 +1066,17 @@ TRACE_EVENT(nfsd_file_open,
__entry->nf_file)
)
+#define DEFINE_NFSD_FILE_OPEN_EVENT(name) \
+DEFINE_EVENT(nfsd_file_open_class, name, \
+ TP_PROTO( \
+ const struct nfsd_file *nf, \
+ __be32 status \
+ ), \
+ TP_ARGS(nf, status))
+
+DEFINE_NFSD_FILE_OPEN_EVENT(nfsd_file_open);
+DEFINE_NFSD_FILE_OPEN_EVENT(nfsd_file_opened);
+
TRACE_EVENT(nfsd_file_is_cached,
TP_PROTO(
const struct inode *inode,
