* [PATCH] cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occurs
@ 2019-10-24 2:08 Dave Wysochanski
2019-10-24 2:57 ` Ronnie Sahlberg
2019-10-24 22:22 ` Pavel Shilovsky
0 siblings, 2 replies; 7+ messages in thread
From: Dave Wysochanski @ 2019-10-24 2:08 UTC (permalink / raw)
To: linux-cifs
There's a deadlock that is possible and can easily be seen with
a test where multiple readers open/read/close of the same file
and a disruption occurs causing reconnect. The deadlock is due
a reader thread inside cifs_strict_readv calling down_read and
obtaining lock_sem, and then after reconnect inside
cifs_reopen_file calling down_read a second time. If in
between the two down_read calls, a down_write comes from
another process, deadlock occurs.
CPU0 CPU1
---- ----
cifs_strict_readv()
down_read(&cifsi->lock_sem);
_cifsFileInfo_put
OR
cifs_new_fileinfo
down_write(&cifsi->lock_sem);
cifs_reopen_file()
down_read(&cifsi->lock_sem);
Fix the above by changing all down_write(lock_sem) calls to
down_write_trylock(lock_sem)/msleep() loop, which in turn
makes the second down_read call benign since it will never
block behind the writer while holding lock_sem.
Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Suggested-by: Ronnie Sahlberg <lsahlber@redhat.com>
---
fs/cifs/cifsglob.h | 5 +++++
fs/cifs/file.c | 24 ++++++++++++++++--------
fs/cifs/smb2file.c | 3 ++-
3 files changed, 23 insertions(+), 9 deletions(-)
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 50dfd9049370..2c4a7adbcb4e 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -1391,6 +1391,11 @@ struct cifs_writedata {
struct cifsInodeInfo {
bool can_cache_brlcks;
struct list_head llist; /* locks helb by this inode */
+ /*
+ * NOTE: Some code paths call down_read(lock_sem) twice, so
+ * we must always use use down_write_trylock()/msleep() loop
+ * to avoid deadlock.
+ */
struct rw_semaphore lock_sem; /* protect the fields above */
/* BB add in lists for dirty pages i.e. write caching info for oplock */
struct list_head openFileList;
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 5ad15de2bb4f..52454df5ae39 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -306,7 +306,8 @@ struct cifsFileInfo *
INIT_LIST_HEAD(&fdlocks->locks);
fdlocks->cfile = cfile;
cfile->llist = fdlocks;
- down_write(&cinode->lock_sem);
+ while (!down_write_trylock(&cinode->lock_sem))
+ msleep(125);
list_add(&fdlocks->llist, &cinode->llist);
up_write(&cinode->lock_sem);
@@ -464,7 +465,8 @@ void _cifsFileInfo_put(struct cifsFileInfo *cifs_file, bool wait_oplock_handler)
* Delete any outstanding lock records. We'll lose them when the file
* is closed anyway.
*/
- down_write(&cifsi->lock_sem);
+ while (!down_write_trylock(&cifsi->lock_sem))
+ msleep(125);
list_for_each_entry_safe(li, tmp, &cifs_file->llist->locks, llist) {
list_del(&li->llist);
cifs_del_lock_waiters(li);
@@ -1027,7 +1029,8 @@ int cifs_closedir(struct inode *inode, struct file *file)
cifs_lock_add(struct cifsFileInfo *cfile, struct cifsLockInfo *lock)
{
struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
- down_write(&cinode->lock_sem);
+ while (!down_write_trylock(&cinode->lock_sem))
+ msleep(125);
list_add_tail(&lock->llist, &cfile->llist->locks);
up_write(&cinode->lock_sem);
}
@@ -1049,7 +1052,8 @@ int cifs_closedir(struct inode *inode, struct file *file)
try_again:
exist = false;
- down_write(&cinode->lock_sem);
+ while (!down_write_trylock(&cinode->lock_sem))
+ msleep(125);
exist = cifs_find_lock_conflict(cfile, lock->offset, lock->length,
lock->type, lock->flags, &conf_lock,
@@ -1072,7 +1076,8 @@ int cifs_closedir(struct inode *inode, struct file *file)
(lock->blist.next == &lock->blist));
if (!rc)
goto try_again;
- down_write(&cinode->lock_sem);
+ while (!down_write_trylock(&cinode->lock_sem))
+ msleep(125);
list_del_init(&lock->blist);
}
@@ -1125,7 +1130,8 @@ int cifs_closedir(struct inode *inode, struct file *file)
return rc;
try_again:
- down_write(&cinode->lock_sem);
+ while (!down_write_trylock(&cinode->lock_sem))
+ msleep(125);
if (!cinode->can_cache_brlcks) {
up_write(&cinode->lock_sem);
return rc;
@@ -1331,7 +1337,8 @@ struct lock_to_push {
int rc = 0;
/* we are going to update can_cache_brlcks here - need a write access */
- down_write(&cinode->lock_sem);
+ while (!down_write_trylock(&cinode->lock_sem))
+ msleep(125);
if (!cinode->can_cache_brlcks) {
up_write(&cinode->lock_sem);
return rc;
@@ -1522,7 +1529,8 @@ struct lock_to_push {
if (!buf)
return -ENOMEM;
- down_write(&cinode->lock_sem);
+ while (!down_write_trylock(&cinode->lock_sem))
+ msleep(125);
for (i = 0; i < 2; i++) {
cur = buf;
num = 0;
diff --git a/fs/cifs/smb2file.c b/fs/cifs/smb2file.c
index e6a1fc72018f..61f6cc8d9cc9 100644
--- a/fs/cifs/smb2file.c
+++ b/fs/cifs/smb2file.c
@@ -145,7 +145,8 @@
cur = buf;
- down_write(&cinode->lock_sem);
+ while (!down_write_trylock(&cinode->lock_sem))
+ msleep(125);
list_for_each_entry_safe(li, tmp, &cfile->llist->locks, llist) {
if (flock->fl_start > li->offset ||
(flock->fl_start + length) <
--
1.8.3.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occurs
2019-10-24 2:08 [PATCH] cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occurs Dave Wysochanski
@ 2019-10-24 2:57 ` Ronnie Sahlberg
2019-10-24 22:22 ` Pavel Shilovsky
1 sibling, 0 replies; 7+ messages in thread
From: Ronnie Sahlberg @ 2019-10-24 2:57 UTC (permalink / raw)
To: Dave Wysochanski; +Cc: linux-cifs
Reviewed-by me
----- Original Message -----
From: "Dave Wysochanski" <dwysocha@redhat.com>
To: linux-cifs@vger.kernel.org
Sent: Thursday, 24 October, 2019 12:08:22 PM
Subject: [PATCH] cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occurs
There's a deadlock that is possible and can easily be seen with
a test where multiple readers open/read/close of the same file
and a disruption occurs causing reconnect. The deadlock is due
a reader thread inside cifs_strict_readv calling down_read and
obtaining lock_sem, and then after reconnect inside
cifs_reopen_file calling down_read a second time. If in
between the two down_read calls, a down_write comes from
another process, deadlock occurs.
CPU0 CPU1
---- ----
cifs_strict_readv()
down_read(&cifsi->lock_sem);
_cifsFileInfo_put
OR
cifs_new_fileinfo
down_write(&cifsi->lock_sem);
cifs_reopen_file()
down_read(&cifsi->lock_sem);
Fix the above by changing all down_write(lock_sem) calls to
down_write_trylock(lock_sem)/msleep() loop, which in turn
makes the second down_read call benign since it will never
block behind the writer while holding lock_sem.
Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Suggested-by: Ronnie Sahlberg <lsahlber@redhat.com>
---
fs/cifs/cifsglob.h | 5 +++++
fs/cifs/file.c | 24 ++++++++++++++++--------
fs/cifs/smb2file.c | 3 ++-
3 files changed, 23 insertions(+), 9 deletions(-)
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 50dfd9049370..2c4a7adbcb4e 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -1391,6 +1391,11 @@ struct cifs_writedata {
struct cifsInodeInfo {
bool can_cache_brlcks;
struct list_head llist; /* locks helb by this inode */
+ /*
+ * NOTE: Some code paths call down_read(lock_sem) twice, so
+ * we must always use use down_write_trylock()/msleep() loop
+ * to avoid deadlock.
+ */
struct rw_semaphore lock_sem; /* protect the fields above */
/* BB add in lists for dirty pages i.e. write caching info for oplock */
struct list_head openFileList;
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 5ad15de2bb4f..52454df5ae39 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -306,7 +306,8 @@ struct cifsFileInfo *
INIT_LIST_HEAD(&fdlocks->locks);
fdlocks->cfile = cfile;
cfile->llist = fdlocks;
- down_write(&cinode->lock_sem);
+ while (!down_write_trylock(&cinode->lock_sem))
+ msleep(125);
list_add(&fdlocks->llist, &cinode->llist);
up_write(&cinode->lock_sem);
@@ -464,7 +465,8 @@ void _cifsFileInfo_put(struct cifsFileInfo *cifs_file, bool wait_oplock_handler)
* Delete any outstanding lock records. We'll lose them when the file
* is closed anyway.
*/
- down_write(&cifsi->lock_sem);
+ while (!down_write_trylock(&cifsi->lock_sem))
+ msleep(125);
list_for_each_entry_safe(li, tmp, &cifs_file->llist->locks, llist) {
list_del(&li->llist);
cifs_del_lock_waiters(li);
@@ -1027,7 +1029,8 @@ int cifs_closedir(struct inode *inode, struct file *file)
cifs_lock_add(struct cifsFileInfo *cfile, struct cifsLockInfo *lock)
{
struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
- down_write(&cinode->lock_sem);
+ while (!down_write_trylock(&cinode->lock_sem))
+ msleep(125);
list_add_tail(&lock->llist, &cfile->llist->locks);
up_write(&cinode->lock_sem);
}
@@ -1049,7 +1052,8 @@ int cifs_closedir(struct inode *inode, struct file *file)
try_again:
exist = false;
- down_write(&cinode->lock_sem);
+ while (!down_write_trylock(&cinode->lock_sem))
+ msleep(125);
exist = cifs_find_lock_conflict(cfile, lock->offset, lock->length,
lock->type, lock->flags, &conf_lock,
@@ -1072,7 +1076,8 @@ int cifs_closedir(struct inode *inode, struct file *file)
(lock->blist.next == &lock->blist));
if (!rc)
goto try_again;
- down_write(&cinode->lock_sem);
+ while (!down_write_trylock(&cinode->lock_sem))
+ msleep(125);
list_del_init(&lock->blist);
}
@@ -1125,7 +1130,8 @@ int cifs_closedir(struct inode *inode, struct file *file)
return rc;
try_again:
- down_write(&cinode->lock_sem);
+ while (!down_write_trylock(&cinode->lock_sem))
+ msleep(125);
if (!cinode->can_cache_brlcks) {
up_write(&cinode->lock_sem);
return rc;
@@ -1331,7 +1337,8 @@ struct lock_to_push {
int rc = 0;
/* we are going to update can_cache_brlcks here - need a write access */
- down_write(&cinode->lock_sem);
+ while (!down_write_trylock(&cinode->lock_sem))
+ msleep(125);
if (!cinode->can_cache_brlcks) {
up_write(&cinode->lock_sem);
return rc;
@@ -1522,7 +1529,8 @@ struct lock_to_push {
if (!buf)
return -ENOMEM;
- down_write(&cinode->lock_sem);
+ while (!down_write_trylock(&cinode->lock_sem))
+ msleep(125);
for (i = 0; i < 2; i++) {
cur = buf;
num = 0;
diff --git a/fs/cifs/smb2file.c b/fs/cifs/smb2file.c
index e6a1fc72018f..61f6cc8d9cc9 100644
--- a/fs/cifs/smb2file.c
+++ b/fs/cifs/smb2file.c
@@ -145,7 +145,8 @@
cur = buf;
- down_write(&cinode->lock_sem);
+ while (!down_write_trylock(&cinode->lock_sem))
+ msleep(125);
list_for_each_entry_safe(li, tmp, &cfile->llist->locks, llist) {
if (flock->fl_start > li->offset ||
(flock->fl_start + length) <
--
1.8.3.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occurs
2019-10-24 2:08 [PATCH] cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occurs Dave Wysochanski
2019-10-24 2:57 ` Ronnie Sahlberg
@ 2019-10-24 22:22 ` Pavel Shilovsky
1 sibling, 0 replies; 7+ messages in thread
From: Pavel Shilovsky @ 2019-10-24 22:22 UTC (permalink / raw)
To: Dave Wysochanski; +Cc: linux-cifs
чт, 24 окт. 2019 г. в 04:04, Dave Wysochanski <dwysocha@redhat.com>:
>
> There's a deadlock that is possible and can easily be seen with
> a test where multiple readers open/read/close of the same file
> and a disruption occurs causing reconnect. The deadlock is due
> a reader thread inside cifs_strict_readv calling down_read and
> obtaining lock_sem, and then after reconnect inside
> cifs_reopen_file calling down_read a second time. If in
> between the two down_read calls, a down_write comes from
> another process, deadlock occurs.
>
> CPU0 CPU1
> ---- ----
> cifs_strict_readv()
> down_read(&cifsi->lock_sem);
> _cifsFileInfo_put
> OR
> cifs_new_fileinfo
> down_write(&cifsi->lock_sem);
> cifs_reopen_file()
> down_read(&cifsi->lock_sem);
>
> Fix the above by changing all down_write(lock_sem) calls to
> down_write_trylock(lock_sem)/msleep() loop, which in turn
> makes the second down_read call benign since it will never
> block behind the writer while holding lock_sem.
>
> Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
> Suggested-by: Ronnie Sahlberg <lsahlber@redhat.com>
> ---
> fs/cifs/cifsglob.h | 5 +++++
> fs/cifs/file.c | 24 ++++++++++++++++--------
> fs/cifs/smb2file.c | 3 ++-
> 3 files changed, 23 insertions(+), 9 deletions(-)
>
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> index 50dfd9049370..2c4a7adbcb4e 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -1391,6 +1391,11 @@ struct cifs_writedata {
> struct cifsInodeInfo {
> bool can_cache_brlcks;
> struct list_head llist; /* locks helb by this inode */
> + /*
> + * NOTE: Some code paths call down_read(lock_sem) twice, so
> + * we must always use use down_write_trylock()/msleep() loop
> + * to avoid deadlock.
> + */
> struct rw_semaphore lock_sem; /* protect the fields above */
> /* BB add in lists for dirty pages i.e. write caching info for oplock */
> struct list_head openFileList;
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> index 5ad15de2bb4f..52454df5ae39 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -306,7 +306,8 @@ struct cifsFileInfo *
> INIT_LIST_HEAD(&fdlocks->locks);
> fdlocks->cfile = cfile;
> cfile->llist = fdlocks;
> - down_write(&cinode->lock_sem);
> + while (!down_write_trylock(&cinode->lock_sem))
> + msleep(125);
> list_add(&fdlocks->llist, &cinode->llist);
> up_write(&cinode->lock_sem);
>
> @@ -464,7 +465,8 @@ void _cifsFileInfo_put(struct cifsFileInfo *cifs_file, bool wait_oplock_handler)
> * Delete any outstanding lock records. We'll lose them when the file
> * is closed anyway.
> */
> - down_write(&cifsi->lock_sem);
> + while (!down_write_trylock(&cifsi->lock_sem))
> + msleep(125);
Please wrap the above code into a helper function e.g.
cifs_acquire_lock_sem(struct cifsInodeInfo *cinode) or any other name
you like.
Other than that it looks good.
--
Best regards,
Pavel Shilovsky
^ permalink raw reply [flat|nested] 7+ messages in thread
* RE: [PATCH] cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occurs
2019-10-25 15:38 ` Pavel Shilovskiy
@ 2019-10-25 15:41 ` Pavel Shilovskiy
0 siblings, 0 replies; 7+ messages in thread
From: Pavel Shilovskiy @ 2019-10-25 15:41 UTC (permalink / raw)
To: Pavel Shilovskiy, David Wysochanski, Ronnie Sahlberg; +Cc: linux-cifs
...continuing my email:
"I still think the right way to fix it would be to put "reconnected" file handles into a new queue and make another thread to "relock" the file."
But this approach requires much more work and it will involve more regression risks. So, I think the current patch is good for now.
-----Original Message-----
From: linux-cifs-owner@vger.kernel.org <linux-cifs-owner@vger.kernel.org> On Behalf Of Pavel Shilovskiy
Sent: Friday, October 25, 2019 8:39 AM
To: David Wysochanski <dwysocha@redhat.com>; Ronnie Sahlberg <lsahlber@redhat.com>
Cc: linux-cifs <linux-cifs@vger.kernel.org>
Subject: RE: [PATCH] cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occurs
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
I still think the right way to fix it would be to put "reconnected" file handles into a new queue and make another thread to "relock" the file.
It seems like a stable kernel candidate but I would hold off and let it bake a little bit in the mainline before we consider doing that.
Best regards,
Pavel Shilovsky
-----Original Message-----
From: linux-cifs-owner@vger.kernel.org <linux-cifs-owner@vger.kernel.org> On Behalf Of David Wysochanski
Sent: Thursday, October 24, 2019 6:23 PM
To: Ronnie Sahlberg <lsahlber@redhat.com>
Cc: linux-cifs <linux-cifs@vger.kernel.org>
Subject: Re: [PATCH] cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occurs
On Thu, Oct 24, 2019 at 7:51 PM Ronnie Sahlberg <lsahlber@redhat.com> wrote:
>
> From: Dave Wysochanski <dwysocha@redhat.com>
>
> There's a deadlock that is possible and can easily be seen with a test
> where multiple readers open/read/close of the same file and a
> disruption occurs causing reconnect. The deadlock is due a reader
> thread inside cifs_strict_readv calling down_read and obtaining
> lock_sem, and then after reconnect inside cifs_reopen_file calling
> down_read a second time. If in between the two down_read calls, a
> down_write comes from another process, deadlock occurs.
>
> CPU0 CPU1
> ---- ----
> cifs_strict_readv()
> down_read(&cifsi->lock_sem);
> _cifsFileInfo_put
> OR
> cifs_new_fileinfo
> down_write(&cifsi->lock_sem);
> cifs_reopen_file()
> down_read(&cifsi->lock_sem);
>
> Fix the above by changing all down_write(lock_sem) calls to
> down_write_trylock(lock_sem)/msleep() loop, which in turn makes the
> second down_read call benign since it will never block behind the
> writer while holding lock_sem.
>
> Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
> Suggested-by: Ronnie Sahlberg <lsahlber@redhat.com>
> ---
> fs/cifs/cifsglob.h | 5 +++++
> fs/cifs/cifsproto.h | 1 +
> fs/cifs/file.c | 23 +++++++++++++++--------
> fs/cifs/smb2file.c | 2 +-
> 4 files changed, 22 insertions(+), 9 deletions(-)
>
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h index
> 50dfd9049370..d78bfcc19156 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -1391,6 +1391,11 @@ void cifsFileInfo_put(struct cifsFileInfo
> *cifs_file); struct cifsInodeInfo {
> bool can_cache_brlcks;
> struct list_head llist; /* locks helb by this inode */
> + /*
> + * NOTE: Some code paths call down_read(lock_sem) twice, so
> + * we must always use use cifs_down_write() instead of down_write()
> + * for this semaphore to avoid deadlocks.
> + */
> struct rw_semaphore lock_sem; /* protect the fields above */
> /* BB add in lists for dirty pages i.e. write caching info for oplock */
> struct list_head openFileList; diff --git
> a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h index
> e53e9f62b87b..fe597d3d5208 100644
> --- a/fs/cifs/cifsproto.h
> +++ b/fs/cifs/cifsproto.h
> @@ -170,6 +170,7 @@ extern int cifs_unlock_range(struct cifsFileInfo *cfile,
> struct file_lock *flock, const unsigned
> int xid); extern int cifs_push_mandatory_locks(struct cifsFileInfo
> *cfile);
>
> +extern void cifs_down_write(struct rw_semaphore *sem);
> extern struct cifsFileInfo *cifs_new_fileinfo(struct cifs_fid *fid,
> struct file *file,
> struct tcon_link *tlink,
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c index
> 0e0217641de1..a80ec683ea32 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -281,6 +281,13 @@ cifs_has_mand_locks(struct cifsInodeInfo *cinode)
> return has_locks;
> }
>
> +void
> +cifs_down_write(struct rw_semaphore *sem) {
> + while (!down_write_trylock(sem))
> + msleep(10);
> +}
> +
> struct cifsFileInfo *
> cifs_new_fileinfo(struct cifs_fid *fid, struct file *file,
> struct tcon_link *tlink, __u32 oplock) @@ -306,7
> +313,7 @@ cifs_new_fileinfo(struct cifs_fid *fid, struct file *file,
> INIT_LIST_HEAD(&fdlocks->locks);
> fdlocks->cfile = cfile;
> cfile->llist = fdlocks;
> - down_write(&cinode->lock_sem);
> + cifs_down_write(&cinode->lock_sem);
> list_add(&fdlocks->llist, &cinode->llist);
> up_write(&cinode->lock_sem);
>
> @@ -464,7 +471,7 @@ void _cifsFileInfo_put(struct cifsFileInfo *cifs_file, bool wait_oplock_handler)
> * Delete any outstanding lock records. We'll lose them when the file
> * is closed anyway.
> */
> - down_write(&cifsi->lock_sem);
> + cifs_down_write(&cifsi->lock_sem);
> list_for_each_entry_safe(li, tmp, &cifs_file->llist->locks, llist) {
> list_del(&li->llist);
> cifs_del_lock_waiters(li); @@ -1027,7 +1034,7 @@
> static void cifs_lock_add(struct cifsFileInfo *cfile, struct
> cifsLockInfo *lock) {
> struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
> - down_write(&cinode->lock_sem);
> + cifs_down_write(&cinode->lock_sem);
> list_add_tail(&lock->llist, &cfile->llist->locks);
> up_write(&cinode->lock_sem);
> }
> @@ -1049,7 +1056,7 @@ cifs_lock_add_if(struct cifsFileInfo *cfile,
> struct cifsLockInfo *lock,
>
> try_again:
> exist = false;
> - down_write(&cinode->lock_sem);
> + cifs_down_write(&cinode->lock_sem);
>
> exist = cifs_find_lock_conflict(cfile, lock->offset, lock->length,
> lock->type, lock->flags,
> &conf_lock, @@ -1072,7 +1079,7 @@ cifs_lock_add_if(struct cifsFileInfo *cfile, struct cifsLockInfo *lock,
> (lock->blist.next == &lock->blist));
> if (!rc)
> goto try_again;
> - down_write(&cinode->lock_sem);
> + cifs_down_write(&cinode->lock_sem);
> list_del_init(&lock->blist);
> }
>
> @@ -1125,7 +1132,7 @@ cifs_posix_lock_set(struct file *file, struct file_lock *flock)
> return rc;
>
> try_again:
> - down_write(&cinode->lock_sem);
> + cifs_down_write(&cinode->lock_sem);
> if (!cinode->can_cache_brlcks) {
> up_write(&cinode->lock_sem);
> return rc;
> @@ -1331,7 +1338,7 @@ cifs_push_locks(struct cifsFileInfo *cfile)
> int rc = 0;
>
> /* we are going to update can_cache_brlcks here - need a write access */
> - down_write(&cinode->lock_sem);
> + cifs_down_write(&cinode->lock_sem);
> if (!cinode->can_cache_brlcks) {
> up_write(&cinode->lock_sem);
> return rc;
> @@ -1522,7 +1529,7 @@ cifs_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
> if (!buf)
> return -ENOMEM;
>
> - down_write(&cinode->lock_sem);
> + cifs_down_write(&cinode->lock_sem);
> for (i = 0; i < 2; i++) {
> cur = buf;
> num = 0;
> diff --git a/fs/cifs/smb2file.c b/fs/cifs/smb2file.c index
> e6a1fc72018f..8b0b512c5792 100644
> --- a/fs/cifs/smb2file.c
> +++ b/fs/cifs/smb2file.c
> @@ -145,7 +145,7 @@ smb2_unlock_range(struct cifsFileInfo *cfile,
> struct file_lock *flock,
>
> cur = buf;
>
> - down_write(&cinode->lock_sem);
> + cifs_down_write(&cinode->lock_sem);
> list_for_each_entry_safe(li, tmp, &cfile->llist->locks, llist) {
> if (flock->fl_start > li->offset ||
> (flock->fl_start + length) <
> --
> 2.13.6
>
Thanks for doing this! Looks fine to me.
I'm not loving this approach to solve this problem but I understand why it may be preferred right now.
I note that trylock with a sleep / retry loop is not often used in filesystems that I could tell (though it is used in drivers), so maybe this can be improved another day.
^ permalink raw reply [flat|nested] 7+ messages in thread
* RE: [PATCH] cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occurs
2019-10-25 1:23 ` David Wysochanski
@ 2019-10-25 15:38 ` Pavel Shilovskiy
2019-10-25 15:41 ` Pavel Shilovskiy
0 siblings, 1 reply; 7+ messages in thread
From: Pavel Shilovskiy @ 2019-10-25 15:38 UTC (permalink / raw)
To: David Wysochanski, Ronnie Sahlberg; +Cc: linux-cifs
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
I still think the right way to fix it would be to put "reconnected" file handles into a new queue and make another thread to "relock" the file.
It seems like a stable kernel candidate but I would hold off and let it bake a little bit in the mainline before we consider doing that.
Best regards,
Pavel Shilovsky
-----Original Message-----
From: linux-cifs-owner@vger.kernel.org <linux-cifs-owner@vger.kernel.org> On Behalf Of David Wysochanski
Sent: Thursday, October 24, 2019 6:23 PM
To: Ronnie Sahlberg <lsahlber@redhat.com>
Cc: linux-cifs <linux-cifs@vger.kernel.org>
Subject: Re: [PATCH] cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occurs
On Thu, Oct 24, 2019 at 7:51 PM Ronnie Sahlberg <lsahlber@redhat.com> wrote:
>
> From: Dave Wysochanski <dwysocha@redhat.com>
>
> There's a deadlock that is possible and can easily be seen with a test
> where multiple readers open/read/close of the same file and a
> disruption occurs causing reconnect. The deadlock is due a reader
> thread inside cifs_strict_readv calling down_read and obtaining
> lock_sem, and then after reconnect inside cifs_reopen_file calling
> down_read a second time. If in between the two down_read calls, a
> down_write comes from another process, deadlock occurs.
>
> CPU0 CPU1
> ---- ----
> cifs_strict_readv()
> down_read(&cifsi->lock_sem);
> _cifsFileInfo_put
> OR
> cifs_new_fileinfo
> down_write(&cifsi->lock_sem);
> cifs_reopen_file()
> down_read(&cifsi->lock_sem);
>
> Fix the above by changing all down_write(lock_sem) calls to
> down_write_trylock(lock_sem)/msleep() loop, which in turn makes the
> second down_read call benign since it will never block behind the
> writer while holding lock_sem.
>
> Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
> Suggested-by: Ronnie Sahlberg <lsahlber@redhat.com>
> ---
> fs/cifs/cifsglob.h | 5 +++++
> fs/cifs/cifsproto.h | 1 +
> fs/cifs/file.c | 23 +++++++++++++++--------
> fs/cifs/smb2file.c | 2 +-
> 4 files changed, 22 insertions(+), 9 deletions(-)
>
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h index
> 50dfd9049370..d78bfcc19156 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -1391,6 +1391,11 @@ void cifsFileInfo_put(struct cifsFileInfo
> *cifs_file); struct cifsInodeInfo {
> bool can_cache_brlcks;
> struct list_head llist; /* locks helb by this inode */
> + /*
> + * NOTE: Some code paths call down_read(lock_sem) twice, so
> + * we must always use use cifs_down_write() instead of down_write()
> + * for this semaphore to avoid deadlocks.
> + */
> struct rw_semaphore lock_sem; /* protect the fields above */
> /* BB add in lists for dirty pages i.e. write caching info for oplock */
> struct list_head openFileList; diff --git
> a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h index
> e53e9f62b87b..fe597d3d5208 100644
> --- a/fs/cifs/cifsproto.h
> +++ b/fs/cifs/cifsproto.h
> @@ -170,6 +170,7 @@ extern int cifs_unlock_range(struct cifsFileInfo *cfile,
> struct file_lock *flock, const unsigned
> int xid); extern int cifs_push_mandatory_locks(struct cifsFileInfo
> *cfile);
>
> +extern void cifs_down_write(struct rw_semaphore *sem);
> extern struct cifsFileInfo *cifs_new_fileinfo(struct cifs_fid *fid,
> struct file *file,
> struct tcon_link *tlink,
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c index
> 0e0217641de1..a80ec683ea32 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -281,6 +281,13 @@ cifs_has_mand_locks(struct cifsInodeInfo *cinode)
> return has_locks;
> }
>
> +void
> +cifs_down_write(struct rw_semaphore *sem) {
> + while (!down_write_trylock(sem))
> + msleep(10);
> +}
> +
> struct cifsFileInfo *
> cifs_new_fileinfo(struct cifs_fid *fid, struct file *file,
> struct tcon_link *tlink, __u32 oplock) @@ -306,7
> +313,7 @@ cifs_new_fileinfo(struct cifs_fid *fid, struct file *file,
> INIT_LIST_HEAD(&fdlocks->locks);
> fdlocks->cfile = cfile;
> cfile->llist = fdlocks;
> - down_write(&cinode->lock_sem);
> + cifs_down_write(&cinode->lock_sem);
> list_add(&fdlocks->llist, &cinode->llist);
> up_write(&cinode->lock_sem);
>
> @@ -464,7 +471,7 @@ void _cifsFileInfo_put(struct cifsFileInfo *cifs_file, bool wait_oplock_handler)
> * Delete any outstanding lock records. We'll lose them when the file
> * is closed anyway.
> */
> - down_write(&cifsi->lock_sem);
> + cifs_down_write(&cifsi->lock_sem);
> list_for_each_entry_safe(li, tmp, &cifs_file->llist->locks, llist) {
> list_del(&li->llist);
> cifs_del_lock_waiters(li); @@ -1027,7 +1034,7 @@
> static void cifs_lock_add(struct cifsFileInfo *cfile, struct
> cifsLockInfo *lock) {
> struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
> - down_write(&cinode->lock_sem);
> + cifs_down_write(&cinode->lock_sem);
> list_add_tail(&lock->llist, &cfile->llist->locks);
> up_write(&cinode->lock_sem);
> }
> @@ -1049,7 +1056,7 @@ cifs_lock_add_if(struct cifsFileInfo *cfile,
> struct cifsLockInfo *lock,
>
> try_again:
> exist = false;
> - down_write(&cinode->lock_sem);
> + cifs_down_write(&cinode->lock_sem);
>
> exist = cifs_find_lock_conflict(cfile, lock->offset, lock->length,
> lock->type, lock->flags,
> &conf_lock, @@ -1072,7 +1079,7 @@ cifs_lock_add_if(struct cifsFileInfo *cfile, struct cifsLockInfo *lock,
> (lock->blist.next == &lock->blist));
> if (!rc)
> goto try_again;
> - down_write(&cinode->lock_sem);
> + cifs_down_write(&cinode->lock_sem);
> list_del_init(&lock->blist);
> }
>
> @@ -1125,7 +1132,7 @@ cifs_posix_lock_set(struct file *file, struct file_lock *flock)
> return rc;
>
> try_again:
> - down_write(&cinode->lock_sem);
> + cifs_down_write(&cinode->lock_sem);
> if (!cinode->can_cache_brlcks) {
> up_write(&cinode->lock_sem);
> return rc;
> @@ -1331,7 +1338,7 @@ cifs_push_locks(struct cifsFileInfo *cfile)
> int rc = 0;
>
> /* we are going to update can_cache_brlcks here - need a write access */
> - down_write(&cinode->lock_sem);
> + cifs_down_write(&cinode->lock_sem);
> if (!cinode->can_cache_brlcks) {
> up_write(&cinode->lock_sem);
> return rc;
> @@ -1522,7 +1529,7 @@ cifs_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
> if (!buf)
> return -ENOMEM;
>
> - down_write(&cinode->lock_sem);
> + cifs_down_write(&cinode->lock_sem);
> for (i = 0; i < 2; i++) {
> cur = buf;
> num = 0;
> diff --git a/fs/cifs/smb2file.c b/fs/cifs/smb2file.c index
> e6a1fc72018f..8b0b512c5792 100644
> --- a/fs/cifs/smb2file.c
> +++ b/fs/cifs/smb2file.c
> @@ -145,7 +145,7 @@ smb2_unlock_range(struct cifsFileInfo *cfile,
> struct file_lock *flock,
>
> cur = buf;
>
> - down_write(&cinode->lock_sem);
> + cifs_down_write(&cinode->lock_sem);
> list_for_each_entry_safe(li, tmp, &cfile->llist->locks, llist) {
> if (flock->fl_start > li->offset ||
> (flock->fl_start + length) <
> --
> 2.13.6
>
Thanks for doing this! Looks fine to me.
I'm not loving this approach to solve this problem but I understand why it may be preferred right now.
I note that trylock with a sleep / retry loop is not often used in filesystems that I could tell (though it is used in drivers), so maybe this can be improved another day.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occurs
2019-10-24 23:51 ` [PATCH] cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occurs Ronnie Sahlberg
@ 2019-10-25 1:23 ` David Wysochanski
2019-10-25 15:38 ` Pavel Shilovskiy
0 siblings, 1 reply; 7+ messages in thread
From: David Wysochanski @ 2019-10-25 1:23 UTC (permalink / raw)
To: Ronnie Sahlberg; +Cc: linux-cifs
On Thu, Oct 24, 2019 at 7:51 PM Ronnie Sahlberg <lsahlber@redhat.com> wrote:
>
> From: Dave Wysochanski <dwysocha@redhat.com>
>
> There's a deadlock that is possible and can easily be seen with
> a test where multiple readers open/read/close of the same file
> and a disruption occurs causing reconnect. The deadlock is due
> a reader thread inside cifs_strict_readv calling down_read and
> obtaining lock_sem, and then after reconnect inside
> cifs_reopen_file calling down_read a second time. If in
> between the two down_read calls, a down_write comes from
> another process, deadlock occurs.
>
> CPU0 CPU1
> ---- ----
> cifs_strict_readv()
> down_read(&cifsi->lock_sem);
> _cifsFileInfo_put
> OR
> cifs_new_fileinfo
> down_write(&cifsi->lock_sem);
> cifs_reopen_file()
> down_read(&cifsi->lock_sem);
>
> Fix the above by changing all down_write(lock_sem) calls to
> down_write_trylock(lock_sem)/msleep() loop, which in turn
> makes the second down_read call benign since it will never
> block behind the writer while holding lock_sem.
>
> Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
> Suggested-by: Ronnie Sahlberg <lsahlber@redhat.com>
> ---
> fs/cifs/cifsglob.h | 5 +++++
> fs/cifs/cifsproto.h | 1 +
> fs/cifs/file.c | 23 +++++++++++++++--------
> fs/cifs/smb2file.c | 2 +-
> 4 files changed, 22 insertions(+), 9 deletions(-)
>
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> index 50dfd9049370..d78bfcc19156 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -1391,6 +1391,11 @@ void cifsFileInfo_put(struct cifsFileInfo *cifs_file);
> struct cifsInodeInfo {
> bool can_cache_brlcks;
> struct list_head llist; /* locks helb by this inode */
> + /*
> + * NOTE: Some code paths call down_read(lock_sem) twice, so
> + * we must always use use cifs_down_write() instead of down_write()
> + * for this semaphore to avoid deadlocks.
> + */
> struct rw_semaphore lock_sem; /* protect the fields above */
> /* BB add in lists for dirty pages i.e. write caching info for oplock */
> struct list_head openFileList;
> diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
> index e53e9f62b87b..fe597d3d5208 100644
> --- a/fs/cifs/cifsproto.h
> +++ b/fs/cifs/cifsproto.h
> @@ -170,6 +170,7 @@ extern int cifs_unlock_range(struct cifsFileInfo *cfile,
> struct file_lock *flock, const unsigned int xid);
> extern int cifs_push_mandatory_locks(struct cifsFileInfo *cfile);
>
> +extern void cifs_down_write(struct rw_semaphore *sem);
> extern struct cifsFileInfo *cifs_new_fileinfo(struct cifs_fid *fid,
> struct file *file,
> struct tcon_link *tlink,
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> index 0e0217641de1..a80ec683ea32 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -281,6 +281,13 @@ cifs_has_mand_locks(struct cifsInodeInfo *cinode)
> return has_locks;
> }
>
> +void
> +cifs_down_write(struct rw_semaphore *sem)
> +{
> + while (!down_write_trylock(sem))
> + msleep(10);
> +}
> +
> struct cifsFileInfo *
> cifs_new_fileinfo(struct cifs_fid *fid, struct file *file,
> struct tcon_link *tlink, __u32 oplock)
> @@ -306,7 +313,7 @@ cifs_new_fileinfo(struct cifs_fid *fid, struct file *file,
> INIT_LIST_HEAD(&fdlocks->locks);
> fdlocks->cfile = cfile;
> cfile->llist = fdlocks;
> - down_write(&cinode->lock_sem);
> + cifs_down_write(&cinode->lock_sem);
> list_add(&fdlocks->llist, &cinode->llist);
> up_write(&cinode->lock_sem);
>
> @@ -464,7 +471,7 @@ void _cifsFileInfo_put(struct cifsFileInfo *cifs_file, bool wait_oplock_handler)
> * Delete any outstanding lock records. We'll lose them when the file
> * is closed anyway.
> */
> - down_write(&cifsi->lock_sem);
> + cifs_down_write(&cifsi->lock_sem);
> list_for_each_entry_safe(li, tmp, &cifs_file->llist->locks, llist) {
> list_del(&li->llist);
> cifs_del_lock_waiters(li);
> @@ -1027,7 +1034,7 @@ static void
> cifs_lock_add(struct cifsFileInfo *cfile, struct cifsLockInfo *lock)
> {
> struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
> - down_write(&cinode->lock_sem);
> + cifs_down_write(&cinode->lock_sem);
> list_add_tail(&lock->llist, &cfile->llist->locks);
> up_write(&cinode->lock_sem);
> }
> @@ -1049,7 +1056,7 @@ cifs_lock_add_if(struct cifsFileInfo *cfile, struct cifsLockInfo *lock,
>
> try_again:
> exist = false;
> - down_write(&cinode->lock_sem);
> + cifs_down_write(&cinode->lock_sem);
>
> exist = cifs_find_lock_conflict(cfile, lock->offset, lock->length,
> lock->type, lock->flags, &conf_lock,
> @@ -1072,7 +1079,7 @@ cifs_lock_add_if(struct cifsFileInfo *cfile, struct cifsLockInfo *lock,
> (lock->blist.next == &lock->blist));
> if (!rc)
> goto try_again;
> - down_write(&cinode->lock_sem);
> + cifs_down_write(&cinode->lock_sem);
> list_del_init(&lock->blist);
> }
>
> @@ -1125,7 +1132,7 @@ cifs_posix_lock_set(struct file *file, struct file_lock *flock)
> return rc;
>
> try_again:
> - down_write(&cinode->lock_sem);
> + cifs_down_write(&cinode->lock_sem);
> if (!cinode->can_cache_brlcks) {
> up_write(&cinode->lock_sem);
> return rc;
> @@ -1331,7 +1338,7 @@ cifs_push_locks(struct cifsFileInfo *cfile)
> int rc = 0;
>
> /* we are going to update can_cache_brlcks here - need a write access */
> - down_write(&cinode->lock_sem);
> + cifs_down_write(&cinode->lock_sem);
> if (!cinode->can_cache_brlcks) {
> up_write(&cinode->lock_sem);
> return rc;
> @@ -1522,7 +1529,7 @@ cifs_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
> if (!buf)
> return -ENOMEM;
>
> - down_write(&cinode->lock_sem);
> + cifs_down_write(&cinode->lock_sem);
> for (i = 0; i < 2; i++) {
> cur = buf;
> num = 0;
> diff --git a/fs/cifs/smb2file.c b/fs/cifs/smb2file.c
> index e6a1fc72018f..8b0b512c5792 100644
> --- a/fs/cifs/smb2file.c
> +++ b/fs/cifs/smb2file.c
> @@ -145,7 +145,7 @@ smb2_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
>
> cur = buf;
>
> - down_write(&cinode->lock_sem);
> + cifs_down_write(&cinode->lock_sem);
> list_for_each_entry_safe(li, tmp, &cfile->llist->locks, llist) {
> if (flock->fl_start > li->offset ||
> (flock->fl_start + length) <
> --
> 2.13.6
>
Thanks for doing this! Looks fine to me.
I'm not loving this approach to solve this problem but I understand
why it may be preferred right now.
I note that trylock with a sleep / retry loop is not often used in
filesystems that I could tell (though it is used in drivers), so maybe
this can be improved another day.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH] cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occurs
2019-10-24 23:51 Updated patch for the the lock_sem deadlock Ronnie Sahlberg
@ 2019-10-24 23:51 ` Ronnie Sahlberg
2019-10-25 1:23 ` David Wysochanski
0 siblings, 1 reply; 7+ messages in thread
From: Ronnie Sahlberg @ 2019-10-24 23:51 UTC (permalink / raw)
To: linux-cifs; +Cc: Dave Wysochanski
From: Dave Wysochanski <dwysocha@redhat.com>
There's a deadlock that is possible and can easily be seen with
a test where multiple readers open/read/close of the same file
and a disruption occurs causing reconnect. The deadlock is due
a reader thread inside cifs_strict_readv calling down_read and
obtaining lock_sem, and then after reconnect inside
cifs_reopen_file calling down_read a second time. If in
between the two down_read calls, a down_write comes from
another process, deadlock occurs.
CPU0 CPU1
---- ----
cifs_strict_readv()
down_read(&cifsi->lock_sem);
_cifsFileInfo_put
OR
cifs_new_fileinfo
down_write(&cifsi->lock_sem);
cifs_reopen_file()
down_read(&cifsi->lock_sem);
Fix the above by changing all down_write(lock_sem) calls to
down_write_trylock(lock_sem)/msleep() loop, which in turn
makes the second down_read call benign since it will never
block behind the writer while holding lock_sem.
Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Suggested-by: Ronnie Sahlberg <lsahlber@redhat.com>
---
fs/cifs/cifsglob.h | 5 +++++
fs/cifs/cifsproto.h | 1 +
fs/cifs/file.c | 23 +++++++++++++++--------
fs/cifs/smb2file.c | 2 +-
4 files changed, 22 insertions(+), 9 deletions(-)
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 50dfd9049370..d78bfcc19156 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -1391,6 +1391,11 @@ void cifsFileInfo_put(struct cifsFileInfo *cifs_file);
struct cifsInodeInfo {
bool can_cache_brlcks;
struct list_head llist; /* locks helb by this inode */
+ /*
+ * NOTE: Some code paths call down_read(lock_sem) twice, so
+ * we must always use use cifs_down_write() instead of down_write()
+ * for this semaphore to avoid deadlocks.
+ */
struct rw_semaphore lock_sem; /* protect the fields above */
/* BB add in lists for dirty pages i.e. write caching info for oplock */
struct list_head openFileList;
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index e53e9f62b87b..fe597d3d5208 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -170,6 +170,7 @@ extern int cifs_unlock_range(struct cifsFileInfo *cfile,
struct file_lock *flock, const unsigned int xid);
extern int cifs_push_mandatory_locks(struct cifsFileInfo *cfile);
+extern void cifs_down_write(struct rw_semaphore *sem);
extern struct cifsFileInfo *cifs_new_fileinfo(struct cifs_fid *fid,
struct file *file,
struct tcon_link *tlink,
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 0e0217641de1..a80ec683ea32 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -281,6 +281,13 @@ cifs_has_mand_locks(struct cifsInodeInfo *cinode)
return has_locks;
}
+void
+cifs_down_write(struct rw_semaphore *sem)
+{
+ while (!down_write_trylock(sem))
+ msleep(10);
+}
+
struct cifsFileInfo *
cifs_new_fileinfo(struct cifs_fid *fid, struct file *file,
struct tcon_link *tlink, __u32 oplock)
@@ -306,7 +313,7 @@ cifs_new_fileinfo(struct cifs_fid *fid, struct file *file,
INIT_LIST_HEAD(&fdlocks->locks);
fdlocks->cfile = cfile;
cfile->llist = fdlocks;
- down_write(&cinode->lock_sem);
+ cifs_down_write(&cinode->lock_sem);
list_add(&fdlocks->llist, &cinode->llist);
up_write(&cinode->lock_sem);
@@ -464,7 +471,7 @@ void _cifsFileInfo_put(struct cifsFileInfo *cifs_file, bool wait_oplock_handler)
* Delete any outstanding lock records. We'll lose them when the file
* is closed anyway.
*/
- down_write(&cifsi->lock_sem);
+ cifs_down_write(&cifsi->lock_sem);
list_for_each_entry_safe(li, tmp, &cifs_file->llist->locks, llist) {
list_del(&li->llist);
cifs_del_lock_waiters(li);
@@ -1027,7 +1034,7 @@ static void
cifs_lock_add(struct cifsFileInfo *cfile, struct cifsLockInfo *lock)
{
struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
- down_write(&cinode->lock_sem);
+ cifs_down_write(&cinode->lock_sem);
list_add_tail(&lock->llist, &cfile->llist->locks);
up_write(&cinode->lock_sem);
}
@@ -1049,7 +1056,7 @@ cifs_lock_add_if(struct cifsFileInfo *cfile, struct cifsLockInfo *lock,
try_again:
exist = false;
- down_write(&cinode->lock_sem);
+ cifs_down_write(&cinode->lock_sem);
exist = cifs_find_lock_conflict(cfile, lock->offset, lock->length,
lock->type, lock->flags, &conf_lock,
@@ -1072,7 +1079,7 @@ cifs_lock_add_if(struct cifsFileInfo *cfile, struct cifsLockInfo *lock,
(lock->blist.next == &lock->blist));
if (!rc)
goto try_again;
- down_write(&cinode->lock_sem);
+ cifs_down_write(&cinode->lock_sem);
list_del_init(&lock->blist);
}
@@ -1125,7 +1132,7 @@ cifs_posix_lock_set(struct file *file, struct file_lock *flock)
return rc;
try_again:
- down_write(&cinode->lock_sem);
+ cifs_down_write(&cinode->lock_sem);
if (!cinode->can_cache_brlcks) {
up_write(&cinode->lock_sem);
return rc;
@@ -1331,7 +1338,7 @@ cifs_push_locks(struct cifsFileInfo *cfile)
int rc = 0;
/* we are going to update can_cache_brlcks here - need a write access */
- down_write(&cinode->lock_sem);
+ cifs_down_write(&cinode->lock_sem);
if (!cinode->can_cache_brlcks) {
up_write(&cinode->lock_sem);
return rc;
@@ -1522,7 +1529,7 @@ cifs_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
if (!buf)
return -ENOMEM;
- down_write(&cinode->lock_sem);
+ cifs_down_write(&cinode->lock_sem);
for (i = 0; i < 2; i++) {
cur = buf;
num = 0;
diff --git a/fs/cifs/smb2file.c b/fs/cifs/smb2file.c
index e6a1fc72018f..8b0b512c5792 100644
--- a/fs/cifs/smb2file.c
+++ b/fs/cifs/smb2file.c
@@ -145,7 +145,7 @@ smb2_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
cur = buf;
- down_write(&cinode->lock_sem);
+ cifs_down_write(&cinode->lock_sem);
list_for_each_entry_safe(li, tmp, &cfile->llist->locks, llist) {
if (flock->fl_start > li->offset ||
(flock->fl_start + length) <
--
2.13.6
^ permalink raw reply related [flat|nested] 7+ messages in thread
end of thread, other threads:[~2019-10-25 15:41 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-10-24 2:08 [PATCH] cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occurs Dave Wysochanski
2019-10-24 2:57 ` Ronnie Sahlberg
2019-10-24 22:22 ` Pavel Shilovsky
2019-10-24 23:51 Updated patch for the the lock_sem deadlock Ronnie Sahlberg
2019-10-24 23:51 ` [PATCH] cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occurs Ronnie Sahlberg
2019-10-25 1:23 ` David Wysochanski
2019-10-25 15:38 ` Pavel Shilovskiy
2019-10-25 15:41 ` Pavel Shilovskiy
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