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zfs: getnewvnode_reserve must be called outside of a zfs transaction

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Otherwise we could run into the following deadlock.
A thread has a transaction open and assigned to a transaction group.
That would prevent the transaction group from be quiesced and synced.
The thread is blocked in getnewvnode_reserve waiting for a vnode to
a be reclaimed.  vnlru thread is blocked trying to enter ZFS VOP because
a filesystem is suspended by an ongoing rollback or receive operation.
In its turn the operation is waiting for the current transaction group
to be synced.

zfs_zget is always used outside of active transactions, but zfs_mknode
is always used in a transaction context.  Thus, we hoist
getnewvnode_reserve from zfs_mknode to its callers.

While there, assert that ZFS always calls getnewvnode while having
a vnode reserved.

Reported by:	adrian
Tested by:	adrian
MFC after:	17 days
Sponsored by:	HybridCluster
This commit is contained in:
avg 2014-01-16 12:22:46 +00:00
parent f9bc6dc89c
commit 97986ccb0b
3 changed files with 30 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_dir.c
View File

@ -951,6 +951,8 @@ zfs_make_xattrdir(znode_t *zp, vattr_t *vap, vnode_t **xvpp, cred_t *cr)
return (SET_ERROR(EDQUOT));
}
getnewvnode_reserve(1);
tx = dmu_tx_create(zfsvfs->z_os);
dmu_tx_hold_sa_create(tx, acl_ids.z_aclp->z_acl_bytes +
ZFS_SA_BASE_ATTR_SIZE);
@ -985,6 +987,8 @@ zfs_make_xattrdir(znode_t *zp, vattr_t *vap, vnode_t **xvpp, cred_t *cr)
zfs_acl_ids_free(&acl_ids);
dmu_tx_commit(tx);
getnewvnode_drop_reserve();
*xvpp = ZTOV(xzp);
return (0);

24
sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
View File

@ -1625,6 +1625,9 @@ zfs_create(vnode_t *dvp, char *name, vattr_t *vap, int excl, int mode,
return (error);
}
}
getnewvnode_reserve(1);
top:
*vpp = NULL;
@ -1653,6 +1656,7 @@ top:
zfs_acl_ids_free(&acl_ids);
if (strcmp(name, "..") == 0)
error = SET_ERROR(EISDIR);
getnewvnode_drop_reserve();
ZFS_EXIT(zfsvfs);
return (error);
}
@ -1721,6 +1725,7 @@ top:
}
zfs_acl_ids_free(&acl_ids);
dmu_tx_abort(tx);
getnewvnode_drop_reserve();
ZFS_EXIT(zfsvfs);
return (error);
}
@ -1787,6 +1792,7 @@ top:
}
}
out:
getnewvnode_drop_reserve();
if (dl)
zfs_dirent_unlock(dl);
@ -2130,6 +2136,9 @@ zfs_mkdir(vnode_t *dvp, char *dirname, vattr_t *vap, vnode_t **vpp, cred_t *cr,
ZFS_EXIT(zfsvfs);
return (error);
}
getnewvnode_reserve(1);
/*
* First make sure the new directory doesn't exist.
*
@ -2143,6 +2152,7 @@ top:
if (error = zfs_dirent_lock(&dl, dzp, dirname, &zp, zf,
NULL, NULL)) {
zfs_acl_ids_free(&acl_ids);
getnewvnode_drop_reserve();
ZFS_EXIT(zfsvfs);
return (error);
}
@ -2150,6 +2160,7 @@ top:
if (error = zfs_zaccess(dzp, ACE_ADD_SUBDIRECTORY, 0, B_FALSE, cr)) {
zfs_acl_ids_free(&acl_ids);
zfs_dirent_unlock(dl);
getnewvnode_drop_reserve();
ZFS_EXIT(zfsvfs);
return (error);
}
@ -2157,6 +2168,7 @@ top:
if (zfs_acl_ids_overquota(zfsvfs, &acl_ids)) {
zfs_acl_ids_free(&acl_ids);
zfs_dirent_unlock(dl);
getnewvnode_drop_reserve();
ZFS_EXIT(zfsvfs);
return (SET_ERROR(EDQUOT));
}
@ -2189,6 +2201,7 @@ top:
}
zfs_acl_ids_free(&acl_ids);
dmu_tx_abort(tx);
getnewvnode_drop_reserve();
ZFS_EXIT(zfsvfs);
return (error);
}
@ -2218,6 +2231,8 @@ top:
dmu_tx_commit(tx);
getnewvnode_drop_reserve();
zfs_dirent_unlock(dl);
if (zfsvfs->z_os->os_sync == ZFS_SYNC_ALWAYS)
@ -4109,6 +4124,9 @@ zfs_symlink(vnode_t *dvp, vnode_t **vpp, char *name, vattr_t *vap, char *link,
ZFS_EXIT(zfsvfs);
return (error);
}
getnewvnode_reserve(1);
top:
/*
* Attempt to lock directory; fail if entry already exists.
@ -4116,6 +4134,7 @@ top:
error = zfs_dirent_lock(&dl, dzp, name, &zp, zflg, NULL, NULL);
if (error) {
zfs_acl_ids_free(&acl_ids);
getnewvnode_drop_reserve();
ZFS_EXIT(zfsvfs);
return (error);
}
@ -4123,6 +4142,7 @@ top:
if (error = zfs_zaccess(dzp, ACE_ADD_FILE, 0, B_FALSE, cr)) {
zfs_acl_ids_free(&acl_ids);
zfs_dirent_unlock(dl);
getnewvnode_drop_reserve();
ZFS_EXIT(zfsvfs);
return (error);
}
@ -4130,6 +4150,7 @@ top:
if (zfs_acl_ids_overquota(zfsvfs, &acl_ids)) {
zfs_acl_ids_free(&acl_ids);
zfs_dirent_unlock(dl);
getnewvnode_drop_reserve();
ZFS_EXIT(zfsvfs);
return (SET_ERROR(EDQUOT));
}
@ -4157,6 +4178,7 @@ top:
}
zfs_acl_ids_free(&acl_ids);
dmu_tx_abort(tx);
getnewvnode_drop_reserve();
ZFS_EXIT(zfsvfs);
return (error);
}
@ -4195,6 +4217,8 @@ top:
dmu_tx_commit(tx);
getnewvnode_drop_reserve();
zfs_dirent_unlock(dl);
if (zfsvfs->z_os->os_sync == ZFS_SYNC_ALWAYS)

4
sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_znode.c
View File

@ -624,6 +624,8 @@ zfs_znode_alloc(zfsvfs_t *zfsvfs, dmu_buf_t *db, int blksz,
zp = kmem_cache_alloc(znode_cache, KM_SLEEP);
KASSERT(td->td_vp_reserv > 0,
("zfs_znode_alloc: getnewvnode without any vnodes reserved"));
error = getnewvnode("zfs", zfsvfs->z_parent->z_vfs, &zfs_vnodeops, &vp);
if (error != 0) {
kmem_cache_free(znode_cache, zp);
@ -830,7 +832,6 @@ zfs_mknode(znode_t *dzp, vattr_t *vap, dmu_tx_t *tx, cred_t *cr,
}
}
getnewvnode_reserve(1);
ZFS_OBJ_HOLD_ENTER(zfsvfs, obj);
VERIFY(0 == sa_buf_hold(zfsvfs->z_os, obj, NULL, &db));
@ -1016,7 +1017,6 @@ zfs_mknode(znode_t *dzp, vattr_t *vap, dmu_tx_t *tx, cred_t *cr,
KASSERT(err == 0, ("insmntque() failed: error %d", err));
}
ZFS_OBJ_HOLD_EXIT(zfsvfs, obj);
getnewvnode_drop_reserve();
}
/*