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nfsd: track filehandle aliasing in nfs4_files

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It's unusual but possible for multiple filehandles to point to the same
file.  In that case, we may end up with multiple nfs4_files referencing
the same inode.

For delegation purposes it will turn out to be useful to flag those
cases.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This commit is contained in:
J. Bruce Fields 2021-04-16 14:00:16 -04:00 committed by Chuck Lever
parent f9b60e2209
commit a0ce48375a
2 changed files with 30 additions and 9 deletions
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37
fs/nfsd/nfs4state.c
View File

@ -4086,6 +4086,8 @@ static void nfsd4_init_file(struct svc_fh *fh, unsigned int hashval,
fp->fi_share_deny = 0;
memset(fp->fi_fds, 0, sizeof(fp->fi_fds));
memset(fp->fi_access, 0, sizeof(fp->fi_access));
fp->fi_aliased = false;
fp->fi_inode = d_inode(fh->fh_dentry);
#ifdef CONFIG_NFSD_PNFS
INIT_LIST_HEAD(&fp->fi_lo_states);
atomic_set(&fp->fi_lo_recalls, 0);
@ -4438,6 +4440,31 @@ find_file_locked(struct svc_fh *fh, unsigned int hashval)
return NULL;
}
static struct nfs4_file *insert_file(struct nfs4_file *new, struct svc_fh *fh,
unsigned int hashval)
{
struct nfs4_file *fp;
struct nfs4_file *ret = NULL;
bool alias_found = false;
spin_lock(&state_lock);
hlist_for_each_entry_rcu(fp, &file_hashtbl[hashval], fi_hash,
lockdep_is_held(&state_lock)) {
if (fh_match(&fp->fi_fhandle, &fh->fh_handle)) {
if (refcount_inc_not_zero(&fp->fi_ref))
ret = fp;
} else if (d_inode(fh->fh_dentry) == fp->fi_inode)
fp->fi_aliased = alias_found = true;
}
if (likely(ret == NULL)) {
nfsd4_init_file(fh, hashval, new);
new->fi_aliased = alias_found;
ret = new;
}
spin_unlock(&state_lock);
return ret;
}
static struct nfs4_file * find_file(struct svc_fh *fh)
{
struct nfs4_file *fp;
@ -4461,15 +4488,7 @@ find_or_add_file(struct nfs4_file *new, struct svc_fh *fh)
if (fp)
return fp;
spin_lock(&state_lock);
fp = find_file_locked(fh, hashval);
if (likely(fp == NULL)) {
nfsd4_init_file(fh, hashval, new);
fp = new;
}
spin_unlock(&state_lock);
return fp;
return insert_file(new, fh, hashval);
}
/*

2
fs/nfsd/state.h
View File

@ -516,6 +516,8 @@ struct nfs4_clnt_odstate {
*/
struct nfs4_file {
refcount_t fi_ref;
struct inode * fi_inode;
bool fi_aliased;
spinlock_t fi_lock;
struct hlist_node fi_hash; /* hash on fi_fhandle */
struct list_head fi_stateids;