Commit 0adb25d2 authored by Kirill Korotaev's avatar Kirill Korotaev Committed by Linus Torvalds
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[PATCH] ext3: ext3_symlink should use GFP_NOFS allocations inside 

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: default avatarAndrey Savochkin <saw@saw.sw.com.sg>
Signed-off-by: default avatarKirill Korotaev <dev@openvz.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 8bd0ee93

fs/ext3/namei.c

+2 −1
Original line number Diff line number Diff line
@@ -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

+11 −2
Original line number Diff line number Diff line
@@ -2613,13 +2613,15 @@ void page_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) 
	}

}



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

+2 −0
Original line number Diff line number Diff line
@@ -1664,6 +1664,8 @@ extern int vfs_follow_link(struct nameidata *, const char *); 
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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