2006-03-10 08:41:34

by Kirill Korotaev

[permalink] [raw]
Subject: [PATCH] ext3: ext3_symlink should use GFP_NOFS allocations inside (ver. 3)

--- ./fs/ext3/namei.c.symlnkfix 2006-03-10 10:24:05.000000000 +0300
+++ ./fs/ext3/namei.c 2006-03-10 10:24:49.000000000 +0300
@@ -2141,7 +2141,7 @@ retry:
* We have a transaction open. All is sweetness. It also sets
* i_size in generic_commit_write().
*/
- err = page_symlink(inode, symname, l);
+ err = __page_symlink(inode, symname, l, GFP_NOFS);
if (err) {
ext3_dec_count(handle, inode);
ext3_mark_inode_dirty(handle, inode);
--- ./fs/namei.c.symlnkfix 2006-03-10 10:24:05.000000000 +0300
+++ ./fs/namei.c 2006-03-10 10:34:58.000000000 +0300
@@ -2613,13 +2613,16 @@ void page_put_link(struct dentry *dentry
}
}

-int page_symlink(struct inode *inode, const char *symname, int len)
+int __page_symlink(struct inode *inode, const char *symname, int len,
+ gfp_t gfp_mask)
{
struct address_space *mapping = inode->i_mapping;
- struct page *page = grab_cache_page(mapping, 0);
+ struct page *page;
int err = -ENOMEM;
char *kaddr;

+ page = find_or_create_page(mapping, 0,
+ mapping_gfp_mask(mapping) | gfp_mask);
if (!page)
goto fail;
err = mapping->a_ops->prepare_write(NULL, page, 0, len-1);
@@ -2654,6 +2657,11 @@ fail:
return err;
}

+int page_symlink(struct inode *inode, const char *symname, int len)
+{
+ return __page_symlink(inode, symname, len, 0);
+}
+
struct inode_operations page_symlink_inode_operations = {
.readlink = generic_readlink,
.follow_link = page_follow_link_light,
@@ -2672,6 +2680,7 @@ EXPORT_SYMBOL(lookup_one_len);
EXPORT_SYMBOL(page_follow_link_light);
EXPORT_SYMBOL(page_put_link);
EXPORT_SYMBOL(page_readlink);
+EXPORT_SYMBOL(__page_symlink);
EXPORT_SYMBOL(page_symlink);
EXPORT_SYMBOL(page_symlink_inode_operations);
EXPORT_SYMBOL(path_lookup);
--- ./include/linux/fs.h.symlnkfix 2006-03-10 10:24:05.000000000 +0300
+++ ./include/linux/fs.h 2006-03-10 10:27:40.000000000 +0300
@@ -1669,6 +1669,8 @@ extern int vfs_follow_link(struct nameid
extern int page_readlink(struct dentry *, char __user *, int);
extern void *page_follow_link_light(struct dentry *, struct nameidata *);
extern void page_put_link(struct dentry *, struct nameidata *, void *);
+extern int __page_symlink(struct inode *inode, const char *symname, int len,
+ gfp_t gfp_mask);
extern int page_symlink(struct inode *inode, const char *symname, int len);
extern struct inode_operations page_symlink_inode_operations;
extern int generic_readlink(struct dentry *, char __user *, int);


Attachments:
diff-ext3-nofssymlink-20060210 (2.40 kB)

2006-03-10 08:46:31

by Arjan van de Ven

[permalink] [raw]
Subject: Re: [PATCH] ext3: ext3_symlink should use GFP_NOFS allocations inside (ver. 3)

On Fri, 2006-03-10 at 11:46 +0300, Kirill Korotaev wrote:
> Andrew,
>
> Fixed both comments from Al Viro (thanks, Al):
> - should have a separate helper
> - should pass 0 instead of GFP_KERNEL in page_symlink()

>
> + page = find_or_create_page(mapping, 0,
> + mapping_gfp_mask(mapping) | gfp_mask);



this does not work; GFP_NOFS has a bit *LESS* than GFP_KERNEL, not a bit
more. As such a | operation isn't going to be useful....

(So I think that while Al's intention was good, the implication of it
isn't ;)


2006-03-10 08:53:27

by Kirill Korotaev

[permalink] [raw]
Subject: Re: [PATCH] ext3: ext3_symlink should use GFP_NOFS allocations inside (ver. 3)

>>Andrew,
>>
>>Fixed both comments from Al Viro (thanks, Al):
>>- should have a separate helper
>>- should pass 0 instead of GFP_KERNEL in page_symlink()
>
>
>>
>>+ page = find_or_create_page(mapping, 0,
>>+ mapping_gfp_mask(mapping) | gfp_mask);
>
>
>
>
> this does not work; GFP_NOFS has a bit *LESS* than GFP_KERNEL, not a bit
> more. As such a | operation isn't going to be useful....
>
> (So I think that while Al's intention was good, the implication of it
> isn't ;)
Oh no... Had to sleep well today... :/
Al, are you agree with the original patch then?
I don't think it is a good idea to introduce AND mask instead :)

Thanks,
Kirill

2006-03-10 08:58:54

by Andrew Morton

[permalink] [raw]
Subject: Re: [PATCH] ext3: ext3_symlink should use GFP_NOFS allocations inside (ver. 3)

Arjan van de Ven <[email protected]> wrote:
>
> On Fri, 2006-03-10 at 11:46 +0300, Kirill Korotaev wrote:
> > Andrew,
> >
> > Fixed both comments from Al Viro (thanks, Al):
> > - should have a separate helper
> > - should pass 0 instead of GFP_KERNEL in page_symlink()
>
> >
> > + page = find_or_create_page(mapping, 0,
> > + mapping_gfp_mask(mapping) | gfp_mask);
>
>
>
> this does not work; GFP_NOFS has a bit *LESS* than GFP_KERNEL, not a bit
> more. As such a | operation isn't going to be useful....
>
> (So I think that while Al's intention was good, the implication of it
> isn't ;)

Yup. page_symlink() needs to pass in mapping_gfp_mask(inode->i_mapping)
and ext3 needs to pass in, umm,

mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS

or

GFP_NOFS|__GFP_HIGHMEM.

preferably the former I guess.

2006-03-10 08:59:06

by Al Viro

[permalink] [raw]
Subject: Re: [PATCH] ext3: ext3_symlink should use GFP_NOFS allocations inside (ver. 3)

On Fri, Mar 10, 2006 at 09:46:25AM +0100, Arjan van de Ven wrote:
> On Fri, 2006-03-10 at 11:46 +0300, Kirill Korotaev wrote:
> > Andrew,
> >
> > Fixed both comments from Al Viro (thanks, Al):
> > - should have a separate helper
> > - should pass 0 instead of GFP_KERNEL in page_symlink()
>
> >
> > + page = find_or_create_page(mapping, 0,
> > + mapping_gfp_mask(mapping) | gfp_mask);
>
>
>
> this does not work; GFP_NOFS has a bit *LESS* than GFP_KERNEL, not a bit
> more. As such a | operation isn't going to be useful....
>
> (So I think that while Al's intention was good, the implication of it
> isn't ;)

s/|/^/ and accept my apologies...

2006-03-10 09:06:36

by Kirill Korotaev

[permalink] [raw]
Subject: Re: [PATCH] ext3: ext3_symlink should use GFP_NOFS allocations inside (ver. 3)

--- ./fs/ext3/namei.c.symlnkfix 2006-03-10 10:24:05.000000000 +0300
+++ ./fs/ext3/namei.c 2006-03-10 12:06:00.000000000 +0300
@@ -2141,7 +2141,8 @@ retry:
* We have a transaction open. All is sweetness. It also sets
* i_size in generic_commit_write().
*/
- err = page_symlink(inode, symname, l);
+ err = __page_symlink(inode, symname, l,
+ mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS);
if (err) {
ext3_dec_count(handle, inode);
ext3_mark_inode_dirty(handle, inode);
--- ./fs/namei.c.symlnkfix 2006-03-10 10:24:05.000000000 +0300
+++ ./fs/namei.c 2006-03-10 12:07:47.000000000 +0300
@@ -2613,13 +2613,15 @@ void page_put_link(struct dentry *dentry
}
}

-int page_symlink(struct inode *inode, const char *symname, int len)
+int __page_symlink(struct inode *inode, const char *symname, int len,
+ gfp_t gfp_mask)
{
struct address_space *mapping = inode->i_mapping;
- struct page *page = grab_cache_page(mapping, 0);
+ struct page *page;
int err = -ENOMEM;
char *kaddr;

+ page = find_or_create_page(mapping, 0, gfp_mask);
if (!page)
goto fail;
err = mapping->a_ops->prepare_write(NULL, page, 0, len-1);
@@ -2654,6 +2656,12 @@ fail:
return err;
}

+int page_symlink(struct inode *inode, const char *symname, int len)
+{
+ return __page_symlink(inode, symname, len,
+ mapping_gfp_mask(inode->i_mapping));
+}
+
struct inode_operations page_symlink_inode_operations = {
.readlink = generic_readlink,
.follow_link = page_follow_link_light,
@@ -2672,6 +2680,7 @@ EXPORT_SYMBOL(lookup_one_len);
EXPORT_SYMBOL(page_follow_link_light);
EXPORT_SYMBOL(page_put_link);
EXPORT_SYMBOL(page_readlink);
+EXPORT_SYMBOL(__page_symlink);
EXPORT_SYMBOL(page_symlink);
EXPORT_SYMBOL(page_symlink_inode_operations);
EXPORT_SYMBOL(path_lookup);
--- ./include/linux/fs.h.symlnkfix 2006-03-10 10:24:05.000000000 +0300
+++ ./include/linux/fs.h 2006-03-10 10:27:40.000000000 +0300
@@ -1669,6 +1669,8 @@ extern int vfs_follow_link(struct nameid
extern int page_readlink(struct dentry *, char __user *, int);
extern void *page_follow_link_light(struct dentry *, struct nameidata *);
extern void page_put_link(struct dentry *, struct nameidata *, void *);
+extern int __page_symlink(struct inode *inode, const char *symname, int len,
+ gfp_t gfp_mask);
extern int page_symlink(struct inode *inode, const char *symname, int len);
extern struct inode_operations page_symlink_inode_operations;
extern int generic_readlink(struct dentry *, char __user *, int);


Attachments:
diff-ext3-nofssymlink-20060210 (2.44 kB)

2006-03-10 09:40:33

by Arjan van de Ven

[permalink] [raw]
Subject: Re: [PATCH] ext3: ext3_symlink should use GFP_NOFS allocations inside (ver. 3)

On Fri, 2006-03-10 at 08:59 +0000, Al Viro wrote:
> On Fri, Mar 10, 2006 at 09:46:25AM +0100, Arjan van de Ven wrote:
> > On Fri, 2006-03-10 at 11:46 +0300, Kirill Korotaev wrote:
> > > Andrew,
> > >
> > > Fixed both comments from Al Viro (thanks, Al):
> > > - should have a separate helper
> > > - should pass 0 instead of GFP_KERNEL in page_symlink()
> >
> > >
> > > + page = find_or_create_page(mapping, 0,
> > > + mapping_gfp_mask(mapping) | gfp_mask);
> >
> >
> >
> > this does not work; GFP_NOFS has a bit *LESS* than GFP_KERNEL, not a bit
> > more. As such a | operation isn't going to be useful....
> >
> > (So I think that while Al's intention was good, the implication of it
> > isn't ;)
>
> s/|/^/ and accept my apologies...

I think you mean
& ~()

since xor... can flip it on if it was off after all