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NFSd: fix locking in nfsd_forget_delegations()

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This patch adds recall_lock hold to nfsd_forget_delegations() to protect
nfsd_process_n_delegations() call.
Also, looks like it would be better to collect delegations to some local
on-stack list, and then unhash collected list. This split allows to
simplify locking, because delegation traversing is protected by recall_lock,
when delegation unhash is protected by client_mutex.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
Stanislav Kinsbursky 2012-05-25 18:38:50 +04:00 committed by J. Bruce Fields
parent 5559b50acd
commit a6d88f293e
1 changed files with 17 additions and 6 deletions
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23
fs/nfsd/nfs4state.c
View file

@ -4575,7 +4575,7 @@ void nfsd_forget_openowners(u64 num)
printk(KERN_INFO "NFSD: Forgot %d open owners", count);
}
int nfsd_process_n_delegations(u64 num, void (*deleg_func)(struct nfs4_delegation *))
int nfsd_process_n_delegations(u64 num, struct list_head *list)
{
int i, count = 0;
struct nfs4_file *fp, *fnext;
@ -4584,7 +4584,7 @@ int nfsd_process_n_delegations(u64 num, void (*deleg_func)(struct nfs4_delegatio
for (i = 0; i < FILE_HASH_SIZE; i++) {
list_for_each_entry_safe(fp, fnext, &file_hashtbl[i], fi_hash) {
list_for_each_entry_safe(dp, dnext, &fp->fi_delegations, dl_perfile) {
deleg_func(dp);
list_move(&dp->dl_recall_lru, list);
if (++count == num)
return count;
}
@ -4597,9 +4597,16 @@ int nfsd_process_n_delegations(u64 num, void (*deleg_func)(struct nfs4_delegatio
void nfsd_forget_delegations(u64 num)
{
unsigned int count;
LIST_HEAD(victims);
struct nfs4_delegation *dp, *dnext;
spin_lock(&recall_lock);
count = nfsd_process_n_delegations(num, &victims);
spin_unlock(&recall_lock);
nfs4_lock_state();
count = nfsd_process_n_delegations(num, unhash_delegation);
list_for_each_entry_safe(dp, dnext, &victims, dl_recall_lru)
unhash_delegation(dp);
nfs4_unlock_state();
printk(KERN_INFO "NFSD: Forgot %d delegations", count);
@ -4608,12 +4615,16 @@ void nfsd_forget_delegations(u64 num)
void nfsd_recall_delegations(u64 num)
{
unsigned int count;
LIST_HEAD(victims);
struct nfs4_delegation *dp, *dnext;
nfs4_lock_state();
spin_lock(&recall_lock);
count = nfsd_process_n_delegations(num, nfsd_break_one_deleg);
count = nfsd_process_n_delegations(num, &victims);
list_for_each_entry_safe(dp, dnext, &victims, dl_recall_lru) {
list_del(&dp->dl_recall_lru);
nfsd_break_one_deleg(dp);
}
spin_unlock(&recall_lock);
nfs4_unlock_state();
printk(KERN_INFO "NFSD: Recalled %d delegations", count);
}