diff options
Diffstat (limited to 'fs/afs/validation.c')
| -rw-r--r-- | fs/afs/validation.c | 199 |
1 files changed, 197 insertions, 2 deletions
diff --git a/fs/afs/validation.c b/fs/afs/validation.c index 18ba2c5e8ead..6aadd5e075e4 100644 --- a/fs/afs/validation.c +++ b/fs/afs/validation.c @@ -11,6 +11,201 @@ #include "internal.h" /* + * See if the server we've just talked to is currently excluded. + */ +static bool __afs_is_server_excluded(struct afs_operation *op, struct afs_volume *volume) +{ + const struct afs_server_entry *se; + const struct afs_server_list *slist; + bool is_excluded = true; + int i; + + rcu_read_lock(); + + slist = rcu_dereference(volume->servers); + for (i = 0; i < slist->nr_servers; i++) { + se = &slist->servers[i]; + if (op->server == se->server) { + is_excluded = test_bit(AFS_SE_EXCLUDED, &se->flags); + break; + } + } + + rcu_read_unlock(); + return is_excluded; +} + +/* + * Update the volume's server list when the creation time changes and see if + * the server we've just talked to is currently excluded. + */ +static int afs_is_server_excluded(struct afs_operation *op, struct afs_volume *volume) +{ + int ret; + + if (__afs_is_server_excluded(op, volume)) + return 1; + + set_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags); + ret = afs_check_volume_status(op->volume, op); + if (ret < 0) + return ret; + + return __afs_is_server_excluded(op, volume); +} + +/* + * Handle a change to the volume creation time in the VolSync record. + */ +static int afs_update_volume_creation_time(struct afs_operation *op, struct afs_volume *volume) +{ + unsigned int snap; + time64_t cur = volume->creation_time; + time64_t old = op->pre_volsync.creation; + time64_t new = op->volsync.creation; + int ret; + + _enter("%llx,%llx,%llx->%llx", volume->vid, cur, old, new); + + if (cur == TIME64_MIN) { + volume->creation_time = new; + return 0; + } + + if (new == cur) + return 0; + + /* Try to advance the creation timestamp from what we had before the + * operation to what we got back from the server. This should + * hopefully ensure that in a race between multiple operations only one + * of them will do this. + */ + if (cur != old) + return 0; + + /* If the creation time changes in an unexpected way, we need to scrub + * our caches. For a RW vol, this will only change if the volume is + * restored from a backup; for a RO/Backup vol, this will advance when + * the volume is updated to a new snapshot (eg. "vos release"). + */ + if (volume->type == AFSVL_RWVOL) + goto regressed; + if (volume->type == AFSVL_BACKVOL) { + if (new < old) + goto regressed; + goto advance; + } + + /* We have an RO volume, we need to query the VL server and look at the + * server flags to see if RW->RO replication is in progress. + */ + ret = afs_is_server_excluded(op, volume); + if (ret < 0) + return ret; + if (ret > 0) { + snap = atomic_read(&volume->cb_ro_snapshot); + trace_afs_cb_v_break(volume->vid, snap, afs_cb_break_volume_excluded); + return ret; + } + +advance: + snap = atomic_inc_return(&volume->cb_ro_snapshot); + trace_afs_cb_v_break(volume->vid, snap, afs_cb_break_for_vos_release); + volume->creation_time = new; + return 0; + +regressed: + atomic_inc(&volume->cb_scrub); + trace_afs_cb_v_break(volume->vid, 0, afs_cb_break_for_creation_regress); + volume->creation_time = new; + return 0; +} + +/* + * Handle a change to the volume update time in the VolSync record. + */ +static void afs_update_volume_update_time(struct afs_operation *op, struct afs_volume *volume) +{ + enum afs_cb_break_reason reason = afs_cb_break_no_break; + time64_t cur = volume->update_time; + time64_t old = op->pre_volsync.update; + time64_t new = op->volsync.update; + + _enter("%llx,%llx,%llx->%llx", volume->vid, cur, old, new); + + if (cur == TIME64_MIN) { + volume->update_time = new; + return; + } + + if (new == cur) + return; + + /* If the volume update time changes in an unexpected way, we need to + * scrub our caches. For a RW vol, this will advance on every + * modification op; for a RO/Backup vol, this will advance when the + * volume is updated to a new snapshot (eg. "vos release"). + */ + if (new < old) + reason = afs_cb_break_for_update_regress; + + /* Try to advance the update timestamp from what we had before the + * operation to what we got back from the server. This should + * hopefully ensure that in a race between multiple operations only one + * of them will do this. + */ + if (cur == old) { + if (reason == afs_cb_break_for_update_regress) { + atomic_inc(&volume->cb_scrub); + trace_afs_cb_v_break(volume->vid, 0, reason); + } + volume->update_time = new; + } +} + +static int afs_update_volume_times(struct afs_operation *op, struct afs_volume *volume) +{ + int ret = 0; + + if (likely(op->volsync.creation == volume->creation_time && + op->volsync.update == volume->update_time)) + return 0; + + mutex_lock(&volume->volsync_lock); + if (op->volsync.creation != volume->creation_time) { + ret = afs_update_volume_creation_time(op, volume); + if (ret < 0) + goto out; + } + if (op->volsync.update != volume->update_time) + afs_update_volume_update_time(op, volume); +out: + mutex_unlock(&volume->volsync_lock); + return ret; +} + +/* + * Update the state of a volume. Returns 1 to redo the operation from the start. + */ +int afs_update_volume_state(struct afs_operation *op) +{ + struct afs_volume *volume = op->volume; + int ret; + + _enter("%llx", op->volume->vid); + + if (op->volsync.creation != TIME64_MIN || op->volsync.update != TIME64_MIN) { + ret = afs_update_volume_times(op, volume); + if (ret != 0) { + _leave(" = %d", ret); + return ret; + } + } + + return 0; +} + +/* * mark the data attached to an inode as obsolete due to a write on the server * - might also want to ditch all the outstanding writes and dirty pages */ @@ -74,7 +269,7 @@ bool afs_check_validity(struct afs_vnode *vnode) cb_break = vnode->cb_break; if (test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) { - if (vnode->cb_v_break != vnode->volume->cb_v_break) + if (vnode->cb_v_break != atomic_read(&vnode->volume->cb_v_break)) need_clear = afs_cb_break_for_v_break; else if (!afs_check_server_good(vnode)) need_clear = afs_cb_break_for_s_reinit; @@ -95,7 +290,7 @@ bool afs_check_validity(struct afs_vnode *vnode) write_seqlock(&vnode->cb_lock); if (need_clear == afs_cb_break_no_promise) - vnode->cb_v_break = vnode->volume->cb_v_break; + vnode->cb_v_break = atomic_read(&vnode->volume->cb_v_break); else if (cb_break == vnode->cb_break) __afs_break_callback(vnode, need_clear); else |