2015-04-10 13:01:30

by Kinglong Mee

Subject: [PATCH] fscache: put reference of parent's usage and n_children

If netfs exist, fscache must put the reference of parent's
usage and n_children, otherwise, never be decreased.

Signed-off-by: Kinglong Mee <[email protected]>
---
fs/fscache/netfs.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/fscache/netfs.c b/fs/fscache/netfs.c
index 6d941f5..b16afba 100644
--- a/fs/fscache/netfs.c
+++ b/fs/fscache/netfs.c
@@ -71,8 +71,7 @@ already_registered:
up_write(&fscache_addremove_sem);

if (ret < 0) {
- netfs->primary_index->parent = NULL;
- __fscache_cookie_put(netfs->primary_index);
+ fscache_relinquish_cookie(netfs->primary_index, 0);
netfs->primary_index = NULL;
}

--
2.3.5

2015-04-13 11:33:49

by David Howells

Subject: Re: [PATCH] fscache: put reference of parent's usage and n_children

Kinglong Mee <[email protected]> wrote:

> If netfs exist, fscache must put the reference of parent's
> usage and n_children, otherwise, never be decreased.

Good catch. Though it might be preferable to only increment the counters if
the list_add() is done.

David

2015-04-13 12:23:19

by Kinglong Mee

Subject: Re: [PATCH] fscache: put reference of parent's usage and n_children

On 4/13/2015 7:33 PM, David Howells wrote:
> Kinglong Mee <[email protected]> wrote:
>
>> If netfs exist, fscache must put the reference of parent's
>> usage and n_children, otherwise, never be decreased.
>
> Good catch. Though it might be preferable to only increment the counters if
> the list_add() is done.

Thanks for your comments, that's great.
I will update and resend those two patch.

Thanks,
Kinglong Mee

2015-04-13 12:44:30

by David Howells

Subject: Re: [PATCH] fscache: put reference of parent's usage and n_children

Kinglong Mee <[email protected]> wrote:

> > Good catch. Though it might be preferable to only increment the counters if
> > the list_add() is done.
>
> Thanks for your comments, that's great.
> I will update and resend those two patch.

In fact, kmem_cache_free() can be called instead of
fscache_relinquish_cookie() in that case.

David

2015-04-13 13:01:41

by Kinglong Mee

Subject: [PATCH v2 1/2] FSCACHE: Increase reference of parent after registering netfs success

If netfs exist, fscache should not increase the reference of parent's
usage and n_children, otherwise, never be decreased.

v2: thanks David's suggest,
move increasing reference of parent if success
use kmem_cache_free() freeing primary_index directly

Signed-off-by: Kinglong Mee <[email protected]>
---
fs/fscache/netfs.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/fs/fscache/netfs.c b/fs/fscache/netfs.c
index 6d941f5..bea1f2e 100644
--- a/fs/fscache/netfs.c
+++ b/fs/fscache/netfs.c
@@ -43,13 +43,9 @@ int __fscache_register_netfs(struct fscache_netfs *netfs)
atomic_set(&netfs->primary_index->n_active, 1);

netfs->primary_index->def = &fscache_fsdef_netfs_def;
- netfs->primary_index->parent = &fscache_fsdef_index;
netfs->primary_index->netfs_data = netfs;
netfs->primary_index->flags = 1 << FSCACHE_COOKIE_ENABLED;

- atomic_inc(&netfs->primary_index->parent->usage);
- atomic_inc(&netfs->primary_index->parent->n_children);
-
spin_lock_init(&netfs->primary_index->lock);
INIT_HLIST_HEAD(&netfs->primary_index->backing_objects);

@@ -62,6 +58,10 @@ int __fscache_register_netfs(struct fscache_netfs *netfs)
goto already_registered;
}

+ netfs->primary_index->parent = &fscache_fsdef_index;
+ atomic_inc(&netfs->primary_index->parent->usage);
+ atomic_inc(&netfs->primary_index->parent->n_children);
+
list_add(&netfs->link, &fscache_netfs_list);
ret = 0;

@@ -71,8 +71,7 @@ already_registered:
up_write(&fscache_addremove_sem);

if (ret < 0) {
- netfs->primary_index->parent = NULL;
- __fscache_cookie_put(netfs->primary_index);
+ kmem_cache_free(fscache_cookie_jar, netfs->primary_index);
netfs->primary_index = NULL;
}

--
2.3.5

2015-04-13 13:01:49

by Kinglong Mee

Subject: [PATCH v2 2/2] FSCACHE: Don't override netfs's primary_index if registering failed

Only override netfs->primary_index when registering success.

v2: according to the change of 1/2

Signed-off-by: Kinglong Mee <[email protected]>
---
fs/fscache/netfs.c | 35 +++++++++++++++++------------------
1 file changed, 17 insertions(+), 18 deletions(-)

diff --git a/fs/fscache/netfs.c b/fs/fscache/netfs.c
index bea1f2e..166fdc3 100644
--- a/fs/fscache/netfs.c
+++ b/fs/fscache/netfs.c
@@ -22,6 +22,7 @@ static LIST_HEAD(fscache_netfs_list);
int __fscache_register_netfs(struct fscache_netfs *netfs)
{
struct fscache_netfs *ptr;
+ struct fscache_cookie *cookie;
int ret;

_enter("{%s}", netfs->name);
@@ -29,25 +30,24 @@ int __fscache_register_netfs(struct fscache_netfs *netfs)
INIT_LIST_HEAD(&netfs->link);

/* allocate a cookie for the primary index */
- netfs->primary_index =
- kmem_cache_zalloc(fscache_cookie_jar, GFP_KERNEL);
+ cookie = kmem_cache_zalloc(fscache_cookie_jar, GFP_KERNEL);

- if (!netfs->primary_index) {
+ if (!cookie) {
_leave(" = -ENOMEM");
return -ENOMEM;
}

/* initialise the primary index cookie */
- atomic_set(&netfs->primary_index->usage, 1);
- atomic_set(&netfs->primary_index->n_children, 0);
- atomic_set(&netfs->primary_index->n_active, 1);
+ atomic_set(&cookie->usage, 1);
+ atomic_set(&cookie->n_children, 0);
+ atomic_set(&cookie->n_active, 1);

- netfs->primary_index->def = &fscache_fsdef_netfs_def;
- netfs->primary_index->netfs_data = netfs;
- netfs->primary_index->flags = 1 << FSCACHE_COOKIE_ENABLED;
+ cookie->def = &fscache_fsdef_netfs_def;
+ cookie->netfs_data = netfs;
+ cookie->flags = 1 << FSCACHE_COOKIE_ENABLED;

- spin_lock_init(&netfs->primary_index->lock);
- INIT_HLIST_HEAD(&netfs->primary_index->backing_objects);
+ spin_lock_init(&cookie->lock);
+ INIT_HLIST_HEAD(&cookie->backing_objects);

/* check the netfs type is not already present */
down_write(&fscache_addremove_sem);
@@ -58,10 +58,11 @@ int __fscache_register_netfs(struct fscache_netfs *netfs)
goto already_registered;
}

- netfs->primary_index->parent = &fscache_fsdef_index;
- atomic_inc(&netfs->primary_index->parent->usage);
- atomic_inc(&netfs->primary_index->parent->n_children);
+ cookie->parent = &fscache_fsdef_index;
+ atomic_inc(&cookie->parent->usage);
+ atomic_inc(&cookie->parent->n_children);

+ netfs->primary_index = cookie;
list_add(&netfs->link, &fscache_netfs_list);
ret = 0;

@@ -70,10 +71,8 @@ int __fscache_register_netfs(struct fscache_netfs *netfs)
already_registered:
up_write(&fscache_addremove_sem);

- if (ret < 0) {
- kmem_cache_free(fscache_cookie_jar, netfs->primary_index);
- netfs->primary_index = NULL;
- }
+ if (ret < 0)
+ kmem_cache_free(fscache_cookie_jar, cookie);

_leave(" = %d", ret);
return ret;
--
2.3.5

2015-04-13 13:12:43

by David Howells

Subject: Re: [PATCH v2 1/2] FSCACHE: Increase reference of parent after registering netfs success

Kinglong Mee <[email protected]> wrote:

> - netfs->primary_index->parent = &fscache_fsdef_index;

fscache_fsdef_index is a static variable so leave this where it is.

David

2015-04-13 13:35:52

by Kinglong Mee

Subject: [PATCH v3 1/2] FSCACHE: Increase reference of parent after registering, netfs success

If netfs exist, fscache should not increase the reference of parent's
usage and n_children, otherwise, never be decreased.

v2: thanks David's suggest,
move increasing reference of parent if success
use kmem_cache_free() freeing primary_index directly

v3: don't move "netfs->primary_index->parent = &fscache_fsdef_index;"

Signed-off-by: Kinglong Mee <[email protected]>
---
fs/fscache/netfs.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/fs/fscache/netfs.c b/fs/fscache/netfs.c
index 6d941f5..458cc96 100644
--- a/fs/fscache/netfs.c
+++ b/fs/fscache/netfs.c
@@ -47,9 +47,6 @@ int __fscache_register_netfs(struct fscache_netfs *netfs)
netfs->primary_index->netfs_data = netfs;
netfs->primary_index->flags = 1 << FSCACHE_COOKIE_ENABLED;

- atomic_inc(&netfs->primary_index->parent->usage);
- atomic_inc(&netfs->primary_index->parent->n_children);
-
spin_lock_init(&netfs->primary_index->lock);
INIT_HLIST_HEAD(&netfs->primary_index->backing_objects);

@@ -62,6 +59,9 @@ int __fscache_register_netfs(struct fscache_netfs *netfs)
goto already_registered;
}

+ atomic_inc(&netfs->primary_index->parent->usage);
+ atomic_inc(&netfs->primary_index->parent->n_children);
+
list_add(&netfs->link, &fscache_netfs_list);
ret = 0;

@@ -71,8 +71,7 @@ already_registered:
up_write(&fscache_addremove_sem);

if (ret < 0) {
- netfs->primary_index->parent = NULL;
- __fscache_cookie_put(netfs->primary_index);
+ kmem_cache_free(fscache_cookie_jar, netfs->primary_index);
netfs->primary_index = NULL;
}

--
2.3.5

2015-04-13 13:35:58

by Kinglong Mee

Subject: [PATCH v3 2/2] FSCACHE: Don't override netfs's primary_index if registering failed

Only override netfs->primary_index when registering success.

v2,v3: according to the change of [PATH 1/2]

Signed-off-by: Kinglong Mee <[email protected]>
---
fs/fscache/netfs.c | 35 +++++++++++++++++------------------
1 file changed, 17 insertions(+), 18 deletions(-)

diff --git a/fs/fscache/netfs.c b/fs/fscache/netfs.c
index 458cc96..9b28649 100644
--- a/fs/fscache/netfs.c
+++ b/fs/fscache/netfs.c
@@ -22,6 +22,7 @@ static LIST_HEAD(fscache_netfs_list);
int __fscache_register_netfs(struct fscache_netfs *netfs)
{
struct fscache_netfs *ptr;
+ struct fscache_cookie *cookie;
int ret;

_enter("{%s}", netfs->name);
@@ -29,26 +30,25 @@ int __fscache_register_netfs(struct fscache_netfs *netfs)
INIT_LIST_HEAD(&netfs->link);

/* allocate a cookie for the primary index */
- netfs->primary_index =
- kmem_cache_zalloc(fscache_cookie_jar, GFP_KERNEL);
+ cookie = kmem_cache_zalloc(fscache_cookie_jar, GFP_KERNEL);

- if (!netfs->primary_index) {
+ if (!cookie) {
_leave(" = -ENOMEM");
return -ENOMEM;
}

/* initialise the primary index cookie */
- atomic_set(&netfs->primary_index->usage, 1);
- atomic_set(&netfs->primary_index->n_children, 0);
- atomic_set(&netfs->primary_index->n_active, 1);
+ atomic_set(&cookie->usage, 1);
+ atomic_set(&cookie->n_children, 0);
+ atomic_set(&cookie->n_active, 1);

- netfs->primary_index->def = &fscache_fsdef_netfs_def;
- netfs->primary_index->parent = &fscache_fsdef_index;
- netfs->primary_index->netfs_data = netfs;
- netfs->primary_index->flags = 1 << FSCACHE_COOKIE_ENABLED;
+ cookie->def = &fscache_fsdef_netfs_def;
+ cookie->parent = &fscache_fsdef_index;
+ cookie->netfs_data = netfs;
+ cookie->flags = 1 << FSCACHE_COOKIE_ENABLED;

- spin_lock_init(&netfs->primary_index->lock);
- INIT_HLIST_HEAD(&netfs->primary_index->backing_objects);
+ spin_lock_init(&cookie->lock);
+ INIT_HLIST_HEAD(&cookie->backing_objects);

/* check the netfs type is not already present */
down_write(&fscache_addremove_sem);
@@ -59,9 +59,10 @@ int __fscache_register_netfs(struct fscache_netfs *netfs)
goto already_registered;
}

- atomic_inc(&netfs->primary_index->parent->usage);
- atomic_inc(&netfs->primary_index->parent->n_children);
+ atomic_inc(&cookie->parent->usage);
+ atomic_inc(&cookie->parent->n_children);

+ netfs->primary_index = cookie;
list_add(&netfs->link, &fscache_netfs_list);
ret = 0;

@@ -70,10 +71,8 @@ int __fscache_register_netfs(struct fscache_netfs *netfs)
already_registered:
up_write(&fscache_addremove_sem);

- if (ret < 0) {
- kmem_cache_free(fscache_cookie_jar, netfs->primary_index);
- netfs->primary_index = NULL;
- }
+ if (ret < 0)
+ kmem_cache_free(fscache_cookie_jar, cookie);

_leave(" = %d", ret);
return ret;
--
2.3.5

2015-04-14 09:34:15

by David Howells

Subject: Re: [PATCH v3 1/2] FSCACHE: Increase reference of parent after registering, netfs success

Applied here:

http://git.kernel.org/cgit/linux/kernel/git/dhowells/linux-fs.git/log/?h=fscache

David