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pNFS: Wait for stale layoutget calls to complete in pnfs_update_layout() 

If the old layout was recalled, and we returned NFS4ERR_NOMATCHINGLAYOUT
then we need to wait for all outstanding layoutget calls to complete
before we can send a new one.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
This commit is contained in:
Trond Myklebust 2018-06-23 22:54:33 -04:00
parent 056f9ad62e
commit 411ae722d1
1 changed files with 31 additions and 5 deletions
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36
fs/nfs/pnfs.c
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@ -1740,6 +1740,17 @@ static bool pnfs_prepare_to_retry_layoutget(struct pnfs_layout_hdr *lo)
TASK_UNINTERRUPTIBLE);
}
static void nfs_layoutget_begin(struct pnfs_layout_hdr *lo)
{
atomic_inc(&lo->plh_outstanding);
}
static void nfs_layoutget_end(struct pnfs_layout_hdr *lo)
{
if (atomic_dec_and_test(&lo->plh_outstanding))
wake_up_var(&lo->plh_outstanding);
}
static void pnfs_clear_first_layoutget(struct pnfs_layout_hdr *lo)
{
unsigned long *bitlock = &lo->plh_flags;
@ -1839,6 +1850,21 @@ lookup_again:
goto out_unlock;
}
/*
* If the layout segment list is empty, but there are outstanding
* layoutget calls, then they might be subject to a layoutrecall.
*/
if (list_empty(&lo->plh_segs) &&
atomic_read(&lo->plh_outstanding) != 0) {
spin_unlock(&ino->i_lock);
if (wait_var_event_killable(&lo->plh_outstanding,
atomic_read(&lo->plh_outstanding) == 0
|| !list_empty(&lo->plh_segs)))
goto out_put_layout_hdr;
pnfs_put_layout_hdr(lo);
goto lookup_again;
}
lseg = pnfs_find_lseg(lo, &arg, strict_iomode);
if (lseg) {
trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
@ -1912,7 +1938,7 @@ lookup_again:
PNFS_UPDATE_LAYOUT_BLOCKED);
goto out_unlock;
}
atomic_inc(&lo->plh_outstanding);
nfs_layoutget_begin(lo);
spin_unlock(&ino->i_lock);
_add_to_server_list(lo, server);
@ -1929,14 +1955,14 @@ lookup_again:
if (!lgp) {
trace_pnfs_update_layout(ino, pos, count, iomode, lo, NULL,
PNFS_UPDATE_LAYOUT_NOMEM);
atomic_dec(&lo->plh_outstanding);
nfs_layoutget_end(lo);
goto out_put_layout_hdr;
}
lseg = nfs4_proc_layoutget(lgp, &timeout);
trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
PNFS_UPDATE_LAYOUT_SEND_LAYOUTGET);
atomic_dec(&lo->plh_outstanding);
nfs_layoutget_end(lo);
if (IS_ERR(lseg)) {
switch(PTR_ERR(lseg)) {
case -EBUSY:
@ -2031,7 +2057,7 @@ _pnfs_grab_empty_layout(struct inode *ino, struct nfs_open_context *ctx)
goto out_unlock;
if (test_and_set_bit(NFS_LAYOUT_FIRST_LAYOUTGET, &lo->plh_flags))
goto out_unlock;
atomic_inc(&lo->plh_outstanding);
nfs_layoutget_begin(lo);
spin_unlock(&ino->i_lock);
_add_to_server_list(lo, NFS_SERVER(ino));
return lo;
@ -2172,8 +2198,8 @@ void nfs4_lgopen_release(struct nfs4_layoutget *lgp)
struct inode *inode = lgp->args.inode;
if (inode) {
struct pnfs_layout_hdr *lo = NFS_I(inode)->layout;
atomic_dec(&lo->plh_outstanding);
pnfs_clear_first_layoutget(lo);
nfs_layoutget_end(lo);
}
pnfs_layoutget_free(lgp);
}