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pNFS: Fix a deadlock when returning a delegation during open()
Ben Coddington reports seeing a hang in the following stack trace:
0 [ffffd0b50e1774e0] __schedule at ffffffff9ca05415
1 [ffffd0b50e177548] schedule at ffffffff9ca05717
2 [ffffd0b50e177558] bit_wait at ffffffff9ca061e1
3 [ffffd0b50e177568] __wait_on_bit at ffffffff9ca05cfb
4 [ffffd0b50e1775c8] out_of_line_wait_on_bit at ffffffff9ca05ea5
5 [ffffd0b50e177618] pnfs_roc at ffffffffc154207b [nfsv4]
6 [ffffd0b50e1776b8] _nfs4_proc_delegreturn at ffffffffc1506586 [nfsv4]
7 [ffffd0b50e177788] nfs4_proc_delegreturn at ffffffffc1507480 [nfsv4]
8 [ffffd0b50e1777f8] nfs_do_return_delegation at ffffffffc1523e41 [nfsv4]
9 [ffffd0b50e177838] nfs_inode_set_delegation at ffffffffc1524a75 [nfsv4]
10 [ffffd0b50e177888] nfs4_process_delegation at ffffffffc14f41dd [nfsv4]
11 [ffffd0b50e1778a0] _nfs4_opendata_to_nfs4_state at ffffffffc1503edf [nfsv4]
12 [ffffd0b50e1778c0] _nfs4_open_and_get_state at ffffffffc1504e56 [nfsv4]
13 [ffffd0b50e177978] _nfs4_do_open at ffffffffc15051b8 [nfsv4]
14 [ffffd0b50e1779f8] nfs4_do_open at ffffffffc150559c [nfsv4]
15 [ffffd0b50e177a80] nfs4_atomic_open at ffffffffc15057fb [nfsv4]
16 [ffffd0b50e177ad0] nfs4_file_open at ffffffffc15219be [nfsv4]
17 [ffffd0b50e177b78] do_dentry_open at ffffffff9c09e6ea
18 [ffffd0b50e177ba8] vfs_open at ffffffff9c0a082e
19 [ffffd0b50e177bd0] dentry_open at ffffffff9c0a0935
The issue is that the delegreturn is being asked to wait for a layout
return that cannot complete because a state recovery was initiated. The
state recovery cannot complete until the open() finishes processing the
delegations it was given.
The solution is to propagate the existing flags that indicate a
non-blocking call to the function pnfs_roc(), so that it knows not to
wait in this situation.
Reported-by: Benjamin Coddington <bcodding@hammerspace.com>
Fixes: 29ade5db12 ("pNFS: Wait on outstanding layoutreturns to complete in pnfs_roc()")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
This commit is contained in:
Trond Myklebust
parent
3609fa95fb
commit
857bf90562
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@ -3894,8 +3894,8 @@ int nfs4_do_close(struct nfs4_state *state, gfp_t gfp_mask, int wait)
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calldata->res.seqid = calldata->arg.seqid;
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calldata->res.server = server;
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calldata->res.lr_ret = -NFS4ERR_NOMATCHING_LAYOUT;
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calldata->lr.roc = pnfs_roc(state->inode,
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&calldata->lr.arg, &calldata->lr.res, msg.rpc_cred);
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calldata->lr.roc = pnfs_roc(state->inode, &calldata->lr.arg,
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&calldata->lr.res, msg.rpc_cred, wait);
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if (calldata->lr.roc) {
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calldata->arg.lr_args = &calldata->lr.arg;
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calldata->res.lr_res = &calldata->lr.res;
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@ -7005,7 +7005,7 @@ static int _nfs4_proc_delegreturn(struct inode *inode, const struct cred *cred,
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data->inode = nfs_igrab_and_active(inode);
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if (data->inode || issync) {
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data->lr.roc = pnfs_roc(inode, &data->lr.arg, &data->lr.res,
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cred);
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cred, issync);
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if (data->lr.roc) {
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data->args.lr_args = &data->lr.arg;
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data->res.lr_res = &data->lr.res;
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@ -1533,10 +1533,9 @@ static int pnfs_layout_return_on_reboot(struct pnfs_layout_hdr *lo)
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PNFS_FL_LAYOUTRETURN_PRIVILEGED);
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}
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bool pnfs_roc(struct inode *ino,
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struct nfs4_layoutreturn_args *args,
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struct nfs4_layoutreturn_res *res,
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const struct cred *cred)
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bool pnfs_roc(struct inode *ino, struct nfs4_layoutreturn_args *args,
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struct nfs4_layoutreturn_res *res, const struct cred *cred,
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bool sync)
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{
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struct nfs_inode *nfsi = NFS_I(ino);
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struct nfs_open_context *ctx;
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@ -1547,7 +1546,7 @@ bool pnfs_roc(struct inode *ino,
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nfs4_stateid stateid;
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enum pnfs_iomode iomode = 0;
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bool layoutreturn = false, roc = false;
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bool skip_read = false;
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bool skip_read;
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if (!nfs_have_layout(ino))
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return false;
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@ -1560,20 +1559,14 @@ bool pnfs_roc(struct inode *ino,
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lo = NULL;
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goto out_noroc;
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}
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pnfs_get_layout_hdr(lo);
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if (test_bit(NFS_LAYOUT_RETURN_LOCK, &lo->plh_flags)) {
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spin_unlock(&ino->i_lock);
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rcu_read_unlock();
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wait_on_bit(&lo->plh_flags, NFS_LAYOUT_RETURN,
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TASK_UNINTERRUPTIBLE);
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pnfs_put_layout_hdr(lo);
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goto retry;
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}
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/* no roc if we hold a delegation */
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skip_read = false;
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if (nfs4_check_delegation(ino, FMODE_READ)) {
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if (nfs4_check_delegation(ino, FMODE_WRITE))
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if (nfs4_check_delegation(ino, FMODE_WRITE)) {
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lo = NULL;
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goto out_noroc;
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}
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skip_read = true;
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}
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@ -1582,12 +1575,43 @@ bool pnfs_roc(struct inode *ino,
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if (state == NULL)
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continue;
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/* Don't return layout if there is open file state */
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if (state->state & FMODE_WRITE)
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if (state->state & FMODE_WRITE) {
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lo = NULL;
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goto out_noroc;
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}
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if (state->state & FMODE_READ)
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skip_read = true;
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}
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if (skip_read) {
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bool writes = false;
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list_for_each_entry(lseg, &lo->plh_segs, pls_list) {
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if (lseg->pls_range.iomode != IOMODE_READ) {
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writes = true;
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break;
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}
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}
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if (!writes) {
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lo = NULL;
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goto out_noroc;
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}
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}
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pnfs_get_layout_hdr(lo);
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if (test_bit(NFS_LAYOUT_RETURN_LOCK, &lo->plh_flags)) {
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if (!sync) {
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pnfs_set_plh_return_info(
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lo, skip_read ? IOMODE_RW : IOMODE_ANY, 0);
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goto out_noroc;
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}
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spin_unlock(&ino->i_lock);
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rcu_read_unlock();
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wait_on_bit(&lo->plh_flags, NFS_LAYOUT_RETURN,
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TASK_UNINTERRUPTIBLE);
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pnfs_put_layout_hdr(lo);
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goto retry;
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}
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list_for_each_entry_safe(lseg, next, &lo->plh_segs, pls_list) {
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if (skip_read && lseg->pls_range.iomode == IOMODE_READ)
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@ -1627,7 +1651,7 @@ bool pnfs_roc(struct inode *ino,
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out_noroc:
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spin_unlock(&ino->i_lock);
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rcu_read_unlock();
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pnfs_layoutcommit_inode(ino, true);
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pnfs_layoutcommit_inode(ino, sync);
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if (roc) {
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struct pnfs_layoutdriver_type *ld = NFS_SERVER(ino)->pnfs_curr_ld;
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if (ld->prepare_layoutreturn)
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@ -303,10 +303,9 @@ int pnfs_mark_matching_lsegs_return(struct pnfs_layout_hdr *lo,
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u32 seq);
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int pnfs_mark_layout_stateid_invalid(struct pnfs_layout_hdr *lo,
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struct list_head *lseg_list);
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bool pnfs_roc(struct inode *ino,
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struct nfs4_layoutreturn_args *args,
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struct nfs4_layoutreturn_res *res,
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const struct cred *cred);
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bool pnfs_roc(struct inode *ino, struct nfs4_layoutreturn_args *args,
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struct nfs4_layoutreturn_res *res, const struct cred *cred,
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bool sync);
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int pnfs_roc_done(struct rpc_task *task, struct nfs4_layoutreturn_args **argpp,
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struct nfs4_layoutreturn_res **respp, int *ret);
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void pnfs_roc_release(struct nfs4_layoutreturn_args *args,
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@ -773,12 +772,10 @@ pnfs_layoutcommit_outstanding(struct inode *inode)
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return false;
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}
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static inline bool
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pnfs_roc(struct inode *ino,
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struct nfs4_layoutreturn_args *args,
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struct nfs4_layoutreturn_res *res,
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const struct cred *cred)
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static inline bool pnfs_roc(struct inode *ino,
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struct nfs4_layoutreturn_args *args,
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struct nfs4_layoutreturn_res *res,
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const struct cred *cred, bool sync)
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{
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return false;
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}
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