Changes since v5:
In cachefiles_daemon_poll(), replace xa_for_each_marked with xas_for_each_marked.
[Background]
============
In ondemand read mode, if user daemon closes anonymous fd(e.g. daemon
crashes), subsequent read and inflight requests based on these fd will
return -EIO.
Even if above mentioned case is tolerable for some individual users, but
when it happenens in real cloud service production environment, such IO
errors will be passed to cloud service users and impact its working jobs.
It's terrible for cloud service stability.
[Design]
========
The main idea of daemon failover is reopen the inflight req related object,
thus the newly started daemon could process the req as usual.
To implement that, we need to support:
1. Store inflight requests during daemon crash.
2. Hold the handle of /dev/cachefiles(by container snapshotter/systemd).
BTW, if user chooses not to keep /dev/cachefiles fd, failover is not enabled.
Inflight requests return error and passed it to container.(same behavior as now).
[Flow Path]
===========
This patchset introduce three states for ondemand object:
CLOSE: Object which just be allocated or closed by user daemon.
OPEN: Object which related OPEN request has been processed correctly.
REOPENING: Object which has been closed, and is drived to open by a read
request.
1. Daemon use UDS send/receive fd to keep and pass the fd reference of
"/dev/cachefiles".
2. User daemon crashes -> restart and recover dev fd's reference.
3. User daemon write "restore" to device.
2.1 Reset the object's state from CLOSE to REOPENING.
2.2 Init a work which reinit the object and add it to wq. (daemon can
get rid of kernel space and handle that open request).
4. The user of upper filesystem won't notice that the daemon ever crashed
since the inflight IO is restored and handled correctly.
[Test]
======
There is a testcase for above mentioned scenario.
A user process read the file by fscache ondemand reading.
At the same time, we kill the daemon constantly.
The expected result is that the file read by user is consistent with
original, and the user doesn't notice that daemon has ever been killed.
https://github.com/userzj/demand-read-cachefilesd/commits/failover-test
[GitWeb]
========
https://github.com/userzj/linux/tree/fscache-failover-v6
RFC: https://lore.kernel.org/all/[email protected]/
V1: https://lore.kernel.org/all/[email protected]/
V2: https://lore.kernel.org/all/[email protected]/
V3: https://lore.kernel.org/all/[email protected]/
V4: https://lore.kernel.org/all/[email protected]/
V5: https://lore.kernel.org/all/[email protected]/
Jia Zhu (5):
cachefiles: introduce object ondemand state
cachefiles: extract ondemand info field from cachefiles_object
cachefiles: resend an open request if the read request's object is
closed
cachefiles: narrow the scope of triggering EPOLLIN events in ondemand
mode
cachefiles: add restore command to recover inflight ondemand read
requests
fs/cachefiles/daemon.c | 15 +++-
fs/cachefiles/interface.c | 7 +-
fs/cachefiles/internal.h | 59 +++++++++++++-
fs/cachefiles/ondemand.c | 166 ++++++++++++++++++++++++++++----------
4 files changed, 201 insertions(+), 46 deletions(-)
--
2.20.1
Previously, @ondemand_id field was used not only to identify ondemand
state of the object, but also to represent the index of the xarray.
This commit introduces @state field to decouple the role of @ondemand_id
and adds helpers to access it.
Signed-off-by: Jia Zhu <[email protected]>
---
fs/cachefiles/internal.h | 21 +++++++++++++++++++++
fs/cachefiles/ondemand.c | 21 +++++++++------------
2 files changed, 30 insertions(+), 12 deletions(-)
diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
index 2ad58c4652084..00beedeaec183 100644
--- a/fs/cachefiles/internal.h
+++ b/fs/cachefiles/internal.h
@@ -44,6 +44,11 @@ struct cachefiles_volume {
struct dentry *fanout[256]; /* Fanout subdirs */
};
+enum cachefiles_object_state {
+ CACHEFILES_ONDEMAND_OBJSTATE_CLOSE, /* Anonymous fd closed by daemon or initial state */
+ CACHEFILES_ONDEMAND_OBJSTATE_OPEN, /* Anonymous fd associated with object is available */
+};
+
/*
* Backing file state.
*/
@@ -62,6 +67,7 @@ struct cachefiles_object {
#define CACHEFILES_OBJECT_USING_TMPFILE 0 /* Have an unlinked tmpfile */
#ifdef CONFIG_CACHEFILES_ONDEMAND
int ondemand_id;
+ enum cachefiles_object_state state;
#endif
};
@@ -296,6 +302,21 @@ extern void cachefiles_ondemand_clean_object(struct cachefiles_object *object);
extern int cachefiles_ondemand_read(struct cachefiles_object *object,
loff_t pos, size_t len);
+#define CACHEFILES_OBJECT_STATE_FUNCS(_state, _STATE) \
+static inline bool \
+cachefiles_ondemand_object_is_##_state(const struct cachefiles_object *object) \
+{ \
+ return object->state == CACHEFILES_ONDEMAND_OBJSTATE_##_STATE; \
+} \
+ \
+static inline void \
+cachefiles_ondemand_set_object_##_state(struct cachefiles_object *object) \
+{ \
+ object->state = CACHEFILES_ONDEMAND_OBJSTATE_##_STATE; \
+}
+
+CACHEFILES_OBJECT_STATE_FUNCS(open, OPEN);
+CACHEFILES_OBJECT_STATE_FUNCS(close, CLOSE);
#else
static inline ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache,
char __user *_buffer, size_t buflen)
diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c
index 0254ed39f68ce..90456b8a4b3e0 100644
--- a/fs/cachefiles/ondemand.c
+++ b/fs/cachefiles/ondemand.c
@@ -15,6 +15,7 @@ static int cachefiles_ondemand_fd_release(struct inode *inode,
xa_lock(&cache->reqs);
object->ondemand_id = CACHEFILES_ONDEMAND_ID_CLOSED;
+ cachefiles_ondemand_set_object_close(object);
/*
* Flush all pending READ requests since their completion depends on
@@ -176,6 +177,8 @@ int cachefiles_ondemand_copen(struct cachefiles_cache *cache, char *args)
set_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags);
trace_cachefiles_ondemand_copen(req->object, id, size);
+ cachefiles_ondemand_set_object_open(req->object);
+
out:
complete(&req->done);
return ret;
@@ -363,7 +366,8 @@ static int cachefiles_ondemand_send_req(struct cachefiles_object *object,
/* coupled with the barrier in cachefiles_flush_reqs() */
smp_mb();
- if (opcode != CACHEFILES_OP_OPEN && object->ondemand_id <= 0) {
+ if (opcode != CACHEFILES_OP_OPEN &&
+ !cachefiles_ondemand_object_is_open(object)) {
WARN_ON_ONCE(object->ondemand_id == 0);
xas_unlock(&xas);
ret = -EIO;
@@ -430,18 +434,11 @@ static int cachefiles_ondemand_init_close_req(struct cachefiles_req *req,
void *private)
{
struct cachefiles_object *object = req->object;
- int object_id = object->ondemand_id;
- /*
- * It's possible that object id is still 0 if the cookie looking up
- * phase failed before OPEN request has ever been sent. Also avoid
- * sending CLOSE request for CACHEFILES_ONDEMAND_ID_CLOSED, which means
- * anon_fd has already been closed.
- */
- if (object_id <= 0)
+ if (!cachefiles_ondemand_object_is_open(object))
return -ENOENT;
- req->msg.object_id = object_id;
+ req->msg.object_id = object->ondemand_id;
trace_cachefiles_ondemand_close(object, &req->msg);
return 0;
}
@@ -460,7 +457,7 @@ static int cachefiles_ondemand_init_read_req(struct cachefiles_req *req,
int object_id = object->ondemand_id;
/* Stop enqueuing requests when daemon has closed anon_fd. */
- if (object_id <= 0) {
+ if (!cachefiles_ondemand_object_is_open(object)) {
WARN_ON_ONCE(object_id == 0);
pr_info_once("READ: anonymous fd closed prematurely.\n");
return -EIO;
@@ -485,7 +482,7 @@ int cachefiles_ondemand_init_object(struct cachefiles_object *object)
* creating a new tmpfile as the cache file. Reuse the previously
* allocated object ID if any.
*/
- if (object->ondemand_id > 0)
+ if (cachefiles_ondemand_object_is_open(object))
return 0;
volume_key_size = volume->key[0] + 1;
--
2.20.1
Don't trigger EPOLLIN when there are only reopening read requests in
xarray.
Suggested-by: Xin Yin <[email protected]>
Signed-off-by: Jia Zhu <[email protected]>
---
fs/cachefiles/daemon.c | 14 ++++++++++++--
fs/cachefiles/internal.h | 12 ++++++++++++
2 files changed, 24 insertions(+), 2 deletions(-)
diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c
index aa4efcabb5e37..70caa1946207d 100644
--- a/fs/cachefiles/daemon.c
+++ b/fs/cachefiles/daemon.c
@@ -355,14 +355,24 @@ static __poll_t cachefiles_daemon_poll(struct file *file,
struct poll_table_struct *poll)
{
struct cachefiles_cache *cache = file->private_data;
+ XA_STATE(xas, &cache->reqs, 0);
+ struct cachefiles_req *req;
__poll_t mask;
poll_wait(file, &cache->daemon_pollwq, poll);
mask = 0;
if (cachefiles_in_ondemand_mode(cache)) {
- if (!xa_empty(&cache->reqs))
- mask |= EPOLLIN;
+ if (!xa_empty(&cache->reqs)) {
+ rcu_read_lock();
+ xas_for_each_marked(&xas, req, ULONG_MAX, CACHEFILES_REQ_NEW) {
+ if (!cachefiles_ondemand_is_reopening_read(req)) {
+ mask |= EPOLLIN;
+ break;
+ }
+ }
+ rcu_read_unlock();
+ }
} else {
if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags))
mask |= EPOLLIN;
diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
index b9a90f1a0c015..26e5f8f123ef1 100644
--- a/fs/cachefiles/internal.h
+++ b/fs/cachefiles/internal.h
@@ -329,6 +329,13 @@ cachefiles_ondemand_set_object_##_state(struct cachefiles_object *object) \
CACHEFILES_OBJECT_STATE_FUNCS(open, OPEN);
CACHEFILES_OBJECT_STATE_FUNCS(close, CLOSE);
CACHEFILES_OBJECT_STATE_FUNCS(reopening, REOPENING);
+
+static inline bool cachefiles_ondemand_is_reopening_read(struct cachefiles_req *req)
+{
+ return cachefiles_ondemand_object_is_reopening(req->object) &&
+ req->msg.opcode == CACHEFILES_OP_READ;
+}
+
#else
static inline ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache,
char __user *_buffer, size_t buflen)
@@ -359,6 +366,11 @@ static inline int cachefiles_ondemand_init_obj_info(struct cachefiles_object *ob
static inline void cachefiles_ondemand_deinit_obj_info(struct cachefiles_object *obj)
{
}
+
+static inline bool cachefiles_ondemand_is_reopening_read(struct cachefiles_req *req)
+{
+ return false;
+}
#endif
/*
--
2.20.1
We'll introduce a @work_struct field for @object in subsequent patches,
it will enlarge the size of @object.
As the result of that, this commit extracts ondemand info field from
@object.
Signed-off-by: Jia Zhu <[email protected]>
---
fs/cachefiles/interface.c | 7 ++++++-
fs/cachefiles/internal.h | 26 ++++++++++++++++++++++----
fs/cachefiles/ondemand.c | 34 ++++++++++++++++++++++++++++------
3 files changed, 56 insertions(+), 11 deletions(-)
diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c
index 40052bdb33655..35ba2117a6f65 100644
--- a/fs/cachefiles/interface.c
+++ b/fs/cachefiles/interface.c
@@ -31,6 +31,11 @@ struct cachefiles_object *cachefiles_alloc_object(struct fscache_cookie *cookie)
if (!object)
return NULL;
+ if (cachefiles_ondemand_init_obj_info(object, volume)) {
+ kmem_cache_free(cachefiles_object_jar, object);
+ return NULL;
+ }
+
refcount_set(&object->ref, 1);
spin_lock_init(&object->lock);
@@ -88,7 +93,7 @@ void cachefiles_put_object(struct cachefiles_object *object,
ASSERTCMP(object->file, ==, NULL);
kfree(object->d_name);
-
+ cachefiles_ondemand_deinit_obj_info(object);
cache = object->volume->cache->cache;
fscache_put_cookie(object->cookie, fscache_cookie_put_object);
object->cookie = NULL;
diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
index 00beedeaec183..b0fe76964bc0d 100644
--- a/fs/cachefiles/internal.h
+++ b/fs/cachefiles/internal.h
@@ -49,6 +49,12 @@ enum cachefiles_object_state {
CACHEFILES_ONDEMAND_OBJSTATE_OPEN, /* Anonymous fd associated with object is available */
};
+struct cachefiles_ondemand_info {
+ int ondemand_id;
+ enum cachefiles_object_state state;
+ struct cachefiles_object *object;
+};
+
/*
* Backing file state.
*/
@@ -66,8 +72,7 @@ struct cachefiles_object {
unsigned long flags;
#define CACHEFILES_OBJECT_USING_TMPFILE 0 /* Have an unlinked tmpfile */
#ifdef CONFIG_CACHEFILES_ONDEMAND
- int ondemand_id;
- enum cachefiles_object_state state;
+ struct cachefiles_ondemand_info *ondemand;
#endif
};
@@ -302,17 +307,21 @@ extern void cachefiles_ondemand_clean_object(struct cachefiles_object *object);
extern int cachefiles_ondemand_read(struct cachefiles_object *object,
loff_t pos, size_t len);
+extern int cachefiles_ondemand_init_obj_info(struct cachefiles_object *obj,
+ struct cachefiles_volume *volume);
+extern void cachefiles_ondemand_deinit_obj_info(struct cachefiles_object *obj);
+
#define CACHEFILES_OBJECT_STATE_FUNCS(_state, _STATE) \
static inline bool \
cachefiles_ondemand_object_is_##_state(const struct cachefiles_object *object) \
{ \
- return object->state == CACHEFILES_ONDEMAND_OBJSTATE_##_STATE; \
+ return object->ondemand->state == CACHEFILES_ONDEMAND_OBJSTATE_##_STATE; \
} \
\
static inline void \
cachefiles_ondemand_set_object_##_state(struct cachefiles_object *object) \
{ \
- object->state = CACHEFILES_ONDEMAND_OBJSTATE_##_STATE; \
+ object->ondemand->state = CACHEFILES_ONDEMAND_OBJSTATE_##_STATE; \
}
CACHEFILES_OBJECT_STATE_FUNCS(open, OPEN);
@@ -338,6 +347,15 @@ static inline int cachefiles_ondemand_read(struct cachefiles_object *object,
{
return -EOPNOTSUPP;
}
+
+static inline int cachefiles_ondemand_init_obj_info(struct cachefiles_object *obj,
+ struct cachefiles_volume *volume)
+{
+ return 0;
+}
+static inline void cachefiles_ondemand_deinit_obj_info(struct cachefiles_object *obj)
+{
+}
#endif
/*
diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c
index 90456b8a4b3e0..deb7e3007aa1d 100644
--- a/fs/cachefiles/ondemand.c
+++ b/fs/cachefiles/ondemand.c
@@ -9,12 +9,13 @@ static int cachefiles_ondemand_fd_release(struct inode *inode,
{
struct cachefiles_object *object = file->private_data;
struct cachefiles_cache *cache = object->volume->cache;
- int object_id = object->ondemand_id;
+ struct cachefiles_ondemand_info *info = object->ondemand;
+ int object_id = info->ondemand_id;
struct cachefiles_req *req;
XA_STATE(xas, &cache->reqs, 0);
xa_lock(&cache->reqs);
- object->ondemand_id = CACHEFILES_ONDEMAND_ID_CLOSED;
+ info->ondemand_id = CACHEFILES_ONDEMAND_ID_CLOSED;
cachefiles_ondemand_set_object_close(object);
/*
@@ -222,7 +223,7 @@ static int cachefiles_ondemand_get_fd(struct cachefiles_req *req)
load = (void *)req->msg.data;
load->fd = fd;
req->msg.object_id = object_id;
- object->ondemand_id = object_id;
+ object->ondemand->ondemand_id = object_id;
cachefiles_get_unbind_pincount(cache);
trace_cachefiles_ondemand_open(object, &req->msg, load);
@@ -368,7 +369,7 @@ static int cachefiles_ondemand_send_req(struct cachefiles_object *object,
if (opcode != CACHEFILES_OP_OPEN &&
!cachefiles_ondemand_object_is_open(object)) {
- WARN_ON_ONCE(object->ondemand_id == 0);
+ WARN_ON_ONCE(object->ondemand->ondemand_id == 0);
xas_unlock(&xas);
ret = -EIO;
goto out;
@@ -438,7 +439,7 @@ static int cachefiles_ondemand_init_close_req(struct cachefiles_req *req,
if (!cachefiles_ondemand_object_is_open(object))
return -ENOENT;
- req->msg.object_id = object->ondemand_id;
+ req->msg.object_id = object->ondemand->ondemand_id;
trace_cachefiles_ondemand_close(object, &req->msg);
return 0;
}
@@ -454,7 +455,7 @@ static int cachefiles_ondemand_init_read_req(struct cachefiles_req *req,
struct cachefiles_object *object = req->object;
struct cachefiles_read *load = (void *)req->msg.data;
struct cachefiles_read_ctx *read_ctx = private;
- int object_id = object->ondemand_id;
+ int object_id = object->ondemand->ondemand_id;
/* Stop enqueuing requests when daemon has closed anon_fd. */
if (!cachefiles_ondemand_object_is_open(object)) {
@@ -500,6 +501,27 @@ void cachefiles_ondemand_clean_object(struct cachefiles_object *object)
cachefiles_ondemand_init_close_req, NULL);
}
+int cachefiles_ondemand_init_obj_info(struct cachefiles_object *object,
+ struct cachefiles_volume *volume)
+{
+ if (!cachefiles_in_ondemand_mode(volume->cache))
+ return 0;
+
+ object->ondemand = kzalloc(sizeof(struct cachefiles_ondemand_info),
+ GFP_KERNEL);
+ if (!object->ondemand)
+ return -ENOMEM;
+
+ object->ondemand->object = object;
+ return 0;
+}
+
+void cachefiles_ondemand_deinit_obj_info(struct cachefiles_object *object)
+{
+ kfree(object->ondemand);
+ object->ondemand = NULL;
+}
+
int cachefiles_ondemand_read(struct cachefiles_object *object,
loff_t pos, size_t len)
{
--
2.20.1
Previously, in ondemand read scenario, if the anonymous fd was closed by
user daemon, inflight and subsequent read requests would return EIO.
As long as the device connection is not released, user daemon can hold
and restore inflight requests by setting the request flag to
CACHEFILES_REQ_NEW.
Suggested-by: Gao Xiang <[email protected]>
Signed-off-by: Jia Zhu <[email protected]>
Signed-off-by: Xin Yin <[email protected]>
Reviewed-by: Jingbo Xu <[email protected]>
---
fs/cachefiles/daemon.c | 1 +
fs/cachefiles/internal.h | 3 +++
fs/cachefiles/ondemand.c | 23 +++++++++++++++++++++++
3 files changed, 27 insertions(+)
diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c
index 70caa1946207d..3f24905f40661 100644
--- a/fs/cachefiles/daemon.c
+++ b/fs/cachefiles/daemon.c
@@ -77,6 +77,7 @@ static const struct cachefiles_daemon_cmd cachefiles_daemon_cmds[] = {
{ "tag", cachefiles_daemon_tag },
#ifdef CONFIG_CACHEFILES_ONDEMAND
{ "copen", cachefiles_ondemand_copen },
+ { "restore", cachefiles_ondemand_restore },
#endif
{ "", NULL }
};
diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
index 26e5f8f123ef1..4a87c9d714a94 100644
--- a/fs/cachefiles/internal.h
+++ b/fs/cachefiles/internal.h
@@ -303,6 +303,9 @@ extern ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache,
extern int cachefiles_ondemand_copen(struct cachefiles_cache *cache,
char *args);
+extern int cachefiles_ondemand_restore(struct cachefiles_cache *cache,
+ char *args);
+
extern int cachefiles_ondemand_init_object(struct cachefiles_object *object);
extern void cachefiles_ondemand_clean_object(struct cachefiles_object *object);
diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c
index 8e130de952f7d..b8fbbb1961bbc 100644
--- a/fs/cachefiles/ondemand.c
+++ b/fs/cachefiles/ondemand.c
@@ -182,6 +182,29 @@ int cachefiles_ondemand_copen(struct cachefiles_cache *cache, char *args)
return ret;
}
+int cachefiles_ondemand_restore(struct cachefiles_cache *cache, char *args)
+{
+ struct cachefiles_req *req;
+
+ XA_STATE(xas, &cache->reqs, 0);
+
+ if (!test_bit(CACHEFILES_ONDEMAND_MODE, &cache->flags))
+ return -EOPNOTSUPP;
+
+ /*
+ * Reset the requests to CACHEFILES_REQ_NEW state, so that the
+ * requests have been processed halfway before the crash of the
+ * user daemon could be reprocessed after the recovery.
+ */
+ xas_lock(&xas);
+ xas_for_each(&xas, req, ULONG_MAX)
+ xas_set_mark(&xas, CACHEFILES_REQ_NEW);
+ xas_unlock(&xas);
+
+ wake_up_all(&cache->daemon_pollwq);
+ return 0;
+}
+
static int cachefiles_ondemand_get_fd(struct cachefiles_req *req)
{
struct cachefiles_object *object;
--
2.20.1
When an anonymous fd is closed by user daemon, if there is a new read
request for this file comes up, the anonymous fd should be re-opened
to handle that read request rather than fail it directly.
1. Introduce reopening state for objects that are closed but have
inflight/subsequent read requests.
2. No longer flush READ requests but only CLOSE requests when anonymous
fd is closed.
3. Enqueue the reopen work to workqueue, thus user daemon could get rid
of daemon_read context and handle that request smoothly. Otherwise,
the user daemon will send a reopen request and wait for itself to
process the request.
Signed-off-by: Jia Zhu <[email protected]>
---
fs/cachefiles/internal.h | 3 ++
fs/cachefiles/ondemand.c | 98 ++++++++++++++++++++++++++++------------
2 files changed, 72 insertions(+), 29 deletions(-)
diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
index b0fe76964bc0d..b9a90f1a0c015 100644
--- a/fs/cachefiles/internal.h
+++ b/fs/cachefiles/internal.h
@@ -47,9 +47,11 @@ struct cachefiles_volume {
enum cachefiles_object_state {
CACHEFILES_ONDEMAND_OBJSTATE_CLOSE, /* Anonymous fd closed by daemon or initial state */
CACHEFILES_ONDEMAND_OBJSTATE_OPEN, /* Anonymous fd associated with object is available */
+ CACHEFILES_ONDEMAND_OBJSTATE_REOPENING, /* Object that was closed and is being reopened. */
};
struct cachefiles_ondemand_info {
+ struct work_struct ondemand_work;
int ondemand_id;
enum cachefiles_object_state state;
struct cachefiles_object *object;
@@ -326,6 +328,7 @@ cachefiles_ondemand_set_object_##_state(struct cachefiles_object *object) \
CACHEFILES_OBJECT_STATE_FUNCS(open, OPEN);
CACHEFILES_OBJECT_STATE_FUNCS(close, CLOSE);
+CACHEFILES_OBJECT_STATE_FUNCS(reopening, REOPENING);
#else
static inline ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache,
char __user *_buffer, size_t buflen)
diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c
index deb7e3007aa1d..8e130de952f7d 100644
--- a/fs/cachefiles/ondemand.c
+++ b/fs/cachefiles/ondemand.c
@@ -18,14 +18,10 @@ static int cachefiles_ondemand_fd_release(struct inode *inode,
info->ondemand_id = CACHEFILES_ONDEMAND_ID_CLOSED;
cachefiles_ondemand_set_object_close(object);
- /*
- * Flush all pending READ requests since their completion depends on
- * anon_fd.
- */
- xas_for_each(&xas, req, ULONG_MAX) {
+ /* Only flush CACHEFILES_REQ_NEW marked req to avoid race with daemon_read */
+ xas_for_each_marked(&xas, req, ULONG_MAX, CACHEFILES_REQ_NEW) {
if (req->msg.object_id == object_id &&
- req->msg.opcode == CACHEFILES_OP_READ) {
- req->error = -EIO;
+ req->msg.opcode == CACHEFILES_OP_CLOSE) {
complete(&req->done);
xas_store(&xas, NULL);
}
@@ -179,6 +175,7 @@ int cachefiles_ondemand_copen(struct cachefiles_cache *cache, char *args)
trace_cachefiles_ondemand_copen(req->object, id, size);
cachefiles_ondemand_set_object_open(req->object);
+ wake_up_all(&cache->daemon_pollwq);
out:
complete(&req->done);
@@ -222,7 +219,6 @@ static int cachefiles_ondemand_get_fd(struct cachefiles_req *req)
load = (void *)req->msg.data;
load->fd = fd;
- req->msg.object_id = object_id;
object->ondemand->ondemand_id = object_id;
cachefiles_get_unbind_pincount(cache);
@@ -238,6 +234,43 @@ static int cachefiles_ondemand_get_fd(struct cachefiles_req *req)
return ret;
}
+static void ondemand_object_worker(struct work_struct *work)
+{
+ struct cachefiles_ondemand_info *info =
+ container_of(work, struct cachefiles_ondemand_info, ondemand_work);
+
+ cachefiles_ondemand_init_object(info->object);
+}
+
+/*
+ * If there are any inflight or subsequent READ requests on the
+ * closed object, reopen it.
+ * Skip read requests whose related object is reopening.
+ */
+static struct cachefiles_req *cachefiles_ondemand_select_req(struct xa_state *xas,
+ unsigned long xa_max)
+{
+ struct cachefiles_req *req;
+ struct cachefiles_object *object;
+ struct cachefiles_ondemand_info *info;
+
+ xas_for_each_marked(xas, req, xa_max, CACHEFILES_REQ_NEW) {
+ if (req->msg.opcode != CACHEFILES_OP_READ)
+ return req;
+ object = req->object;
+ info = object->ondemand;
+ if (cachefiles_ondemand_object_is_close(object)) {
+ cachefiles_ondemand_set_object_reopening(object);
+ queue_work(fscache_wq, &info->ondemand_work);
+ continue;
+ }
+ if (cachefiles_ondemand_object_is_reopening(object))
+ continue;
+ return req;
+ }
+ return NULL;
+}
+
ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache,
char __user *_buffer, size_t buflen)
{
@@ -248,16 +281,16 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache,
int ret = 0;
XA_STATE(xas, &cache->reqs, cache->req_id_next);
+ xa_lock(&cache->reqs);
/*
* Cyclically search for a request that has not ever been processed,
* to prevent requests from being processed repeatedly, and make
* request distribution fair.
*/
- xa_lock(&cache->reqs);
- req = xas_find_marked(&xas, UINT_MAX, CACHEFILES_REQ_NEW);
+ req = cachefiles_ondemand_select_req(&xas, ULONG_MAX);
if (!req && cache->req_id_next > 0) {
xas_set(&xas, 0);
- req = xas_find_marked(&xas, cache->req_id_next - 1, CACHEFILES_REQ_NEW);
+ req = cachefiles_ondemand_select_req(&xas, cache->req_id_next - 1);
}
if (!req) {
xa_unlock(&cache->reqs);
@@ -277,14 +310,18 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache,
xa_unlock(&cache->reqs);
id = xas.xa_index;
- msg->msg_id = id;
if (msg->opcode == CACHEFILES_OP_OPEN) {
ret = cachefiles_ondemand_get_fd(req);
- if (ret)
+ if (ret) {
+ cachefiles_ondemand_set_object_close(req->object);
goto error;
+ }
}
+ msg->msg_id = id;
+ msg->object_id = req->object->ondemand->ondemand_id;
+
if (copy_to_user(_buffer, msg, n) != 0) {
ret = -EFAULT;
goto err_put_fd;
@@ -317,19 +354,23 @@ static int cachefiles_ondemand_send_req(struct cachefiles_object *object,
void *private)
{
struct cachefiles_cache *cache = object->volume->cache;
- struct cachefiles_req *req;
+ struct cachefiles_req *req = NULL;
XA_STATE(xas, &cache->reqs, 0);
int ret;
if (!test_bit(CACHEFILES_ONDEMAND_MODE, &cache->flags))
return 0;
- if (test_bit(CACHEFILES_DEAD, &cache->flags))
- return -EIO;
+ if (test_bit(CACHEFILES_DEAD, &cache->flags)) {
+ ret = -EIO;
+ goto out;
+ }
req = kzalloc(sizeof(*req) + data_len, GFP_KERNEL);
- if (!req)
- return -ENOMEM;
+ if (!req) {
+ ret = -ENOMEM;
+ goto out;
+ }
req->object = object;
init_completion(&req->done);
@@ -367,7 +408,7 @@ static int cachefiles_ondemand_send_req(struct cachefiles_object *object,
/* coupled with the barrier in cachefiles_flush_reqs() */
smp_mb();
- if (opcode != CACHEFILES_OP_OPEN &&
+ if (opcode == CACHEFILES_OP_CLOSE &&
!cachefiles_ondemand_object_is_open(object)) {
WARN_ON_ONCE(object->ondemand->ondemand_id == 0);
xas_unlock(&xas);
@@ -392,7 +433,15 @@ static int cachefiles_ondemand_send_req(struct cachefiles_object *object,
wake_up_all(&cache->daemon_pollwq);
wait_for_completion(&req->done);
ret = req->error;
+ kfree(req);
+ return ret;
out:
+ /* Reset the object to close state in error handling path.
+ * If error occurs after creating the anonymous fd,
+ * cachefiles_ondemand_fd_release() will set object to close.
+ */
+ if (opcode == CACHEFILES_OP_OPEN)
+ cachefiles_ondemand_set_object_close(object);
kfree(req);
return ret;
}
@@ -439,7 +488,6 @@ static int cachefiles_ondemand_init_close_req(struct cachefiles_req *req,
if (!cachefiles_ondemand_object_is_open(object))
return -ENOENT;
- req->msg.object_id = object->ondemand->ondemand_id;
trace_cachefiles_ondemand_close(object, &req->msg);
return 0;
}
@@ -455,16 +503,7 @@ static int cachefiles_ondemand_init_read_req(struct cachefiles_req *req,
struct cachefiles_object *object = req->object;
struct cachefiles_read *load = (void *)req->msg.data;
struct cachefiles_read_ctx *read_ctx = private;
- int object_id = object->ondemand->ondemand_id;
-
- /* Stop enqueuing requests when daemon has closed anon_fd. */
- if (!cachefiles_ondemand_object_is_open(object)) {
- WARN_ON_ONCE(object_id == 0);
- pr_info_once("READ: anonymous fd closed prematurely.\n");
- return -EIO;
- }
- req->msg.object_id = object_id;
load->off = read_ctx->off;
load->len = read_ctx->len;
trace_cachefiles_ondemand_read(object, &req->msg, load);
@@ -513,6 +552,7 @@ int cachefiles_ondemand_init_obj_info(struct cachefiles_object *object,
return -ENOMEM;
object->ondemand->object = object;
+ INIT_WORK(&object->ondemand->ondemand_work, ondemand_object_worker);
return 0;
}
--
2.20.1