Home » Mailing lists » Devel » [PATCH] ext3: ext3_symlink should use GFP_NOFS allocations inside (ver. 3)
| [PATCH] ext3: ext3_symlink should use GFP_NOFS allocations inside (ver. 3) [message #1958] |
Fri, 10 March 2006 08:41  |
Kirill Korotaev
Messages: 137
Registered: January 2006
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Senior Member |
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Andrew,
Fixed both comments from Al Viro (thanks, Al):
- should have a separate helper
- should pass 0 instead of GFP_KERNEL in page_symlink()
This patch fixes illegal __GFP_FS allocation inside ext3
transaction in ext3_symlink().
Such allocation may re-enter ext3 code from
try_to_free_pages. But JBD/ext3 code keeps a pointer to current
journal handle in task_struct and, hence, is not reentrable.
This bug led to "Assertion failure in journal_dirty_metadata()" messages.
http://bugzilla.openvz.org/show_bug.cgi?id=115
Signed-Off-By: Andrey Savochkin <saw@saw.sw.com.sg>
Signed-Off-By: Kirill Korotaev <dev@openvz.org>
Thanks,
Kirill
P.S. against 2.6.16-rc5
--- ./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);
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| Re: [PATCH] ext3: ext3_symlink should use GFP_NOFS allocations inside (ver. 3) [message #1964 is a reply to message #1962] |
Fri, 10 March 2006 08:56  |
Andrew Morton
Messages: 127
Registered: December 2005
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Senior Member |
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Arjan van de Ven <arjan@infradead.org> 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.
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| Re: [PATCH] ext3: ext3_symlink should use GFP_NOFS allocations inside (ver. 3) [message #1965 is a reply to message #1962] |
Fri, 10 March 2006 08:59 |
Al Viro
Messages: 5
Registered: March 2006
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Junior Member |
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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...
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| Re: [PATCH] ext3: ext3_symlink should use GFP_NOFS allocations inside (ver. 3) [message #1966 is a reply to message #1964] |
Fri, 10 March 2006 09:06 |
dev
Messages: 1693
Registered: September 2005
Location: Moscow
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Senior Member |
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>>>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.
This looks reasonable.
See the patch attached.
Thanks,
Kirill
--- ./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);
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| Re: [PATCH] ext3: ext3_symlink should use GFP_NOFS allocations inside (ver. 3) [message #1967 is a reply to message #1965] |
Fri, 10 March 2006 09:40 |
Arjan van de Ven
Messages: 14
Registered: March 2006
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Junior Member |
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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
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