Home » Mailing lists » Devel » [PATCH] ext3: ext3_symlink should use GFP_NOFS allocations inside
| [PATCH] ext3: ext3_symlink should use GFP_NOFS allocations inside [message #1957] |
Fri, 10 March 2006 08:03  |
Kirill Korotaev
Messages: 137
Registered: January 2006
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Senior Member |
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Andrew,
Resending a patch with a separate helper as requested by Al Viro:
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, GFP_KERNEL);
+}
+
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 [message #1959 is a reply to message #1957] |
Fri, 10 March 2006 08:41  |
dev
Messages: 1693
Registered: September 2005
Location: Moscow
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Senior Member |
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>>+ page = find_or_create_page(mapping, 0,
>>+ mapping_gfp_mask(mapping) | gfp_mask);
>
>
>>+int page_symlink(struct inode *inode, const char *symname, int len)
>>+{
>>+ return __page_symlink(inode, symname, len, GFP_KERNEL);
>
>
> s/GFP_KERNEL/0/; if somebody has e.g. GFP_NOFS in their mapping flags,
> you end up breaking their code. We really pass extra flags to be added
> to default ones; page_symlink() should pass 0.
thanks for noticing this.
fixed and resend.
Thanks,
Kirill
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| Re: [PATCH] ext3: ext3_symlink should use GFP_NOFS allocations inside [message #1960 is a reply to message #1957] |
Fri, 10 March 2006 08:31 |
Al Viro
Messages: 5
Registered: March 2006
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Junior Member |
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On Fri, Mar 10, 2006 at 11:08:29AM +0300, Kirill Korotaev wrote:
> + page = find_or_create_page(mapping, 0,
> + mapping_gfp_mask(mapping) | gfp_mask);
> +int page_symlink(struct inode *inode, const char *symname, int len)
> +{
> + return __page_symlink(inode, symname, len, GFP_KERNEL);
s/GFP_KERNEL/0/; if somebody has e.g. GFP_NOFS in their mapping flags,
you end up breaking their code. We really pass extra flags to be added
to default ones; page_symlink() should pass 0.
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