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authorJosh Hunt <johunt@akamai.com>2011-02-24 11:48:22 +0100
committerJan Kara <jack@suse.cz>2011-03-02 11:03:52 +0100
commite8a80c6f769dd4622d8b211b398452158ee60c0b (patch)
treee538f674c219d98d8829d6286aa9be6feee16c93
parentdd9c1549edef02290edced639f67b54a25abbe0e (diff)
downloadlinux-stericsson-e8a80c6f769dd4622d8b211b398452158ee60c0b.tar.gz
ext2: Fix link count corruption under heavy link+rename load
vfs_rename_other() does not lock renamed inode with i_mutex. Thus changing i_nlink in a non-atomic manner (which happens in ext2_rename()) can corrupt it as reported and analyzed by Josh. In fact, there is no good reason to mess with i_nlink of the moved file. We did it presumably to simulate linking into the new directory and unlinking from an old one. But the practical effect of this is disputable because fsck can possibly treat file as being properly linked into both directories without writing any error which is confusing. So we just stop increment-decrement games with i_nlink which also fixes the corruption. CC: stable@kernel.org CC: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Josh Hunt <johunt@akamai.com> Signed-off-by: Jan Kara <jack@suse.cz>
-rw-r--r--fs/ext2/namei.c9
1 files changed, 2 insertions, 7 deletions
diff --git a/fs/ext2/namei.c b/fs/ext2/namei.c
index 2e1d8341d827..adb91855ccd0 100644
--- a/fs/ext2/namei.c
+++ b/fs/ext2/namei.c
@@ -344,7 +344,6 @@ static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
new_de = ext2_find_entry (new_dir, &new_dentry->d_name, &new_page);
if (!new_de)
goto out_dir;
- inode_inc_link_count(old_inode);
ext2_set_link(new_dir, new_de, new_page, old_inode, 1);
new_inode->i_ctime = CURRENT_TIME_SEC;
if (dir_de)
@@ -356,12 +355,9 @@ static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
if (new_dir->i_nlink >= EXT2_LINK_MAX)
goto out_dir;
}
- inode_inc_link_count(old_inode);
err = ext2_add_link(new_dentry, old_inode);
- if (err) {
- inode_dec_link_count(old_inode);
+ if (err)
goto out_dir;
- }
if (dir_de)
inode_inc_link_count(new_dir);
}
@@ -369,12 +365,11 @@ static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
/*
* Like most other Unix systems, set the ctime for inodes on a
* rename.
- * inode_dec_link_count() will mark the inode dirty.
*/
old_inode->i_ctime = CURRENT_TIME_SEC;
+ mark_inode_dirty(old_inode);
ext2_delete_entry (old_de, old_page);
- inode_dec_link_count(old_inode);
if (dir_de) {
if (old_dir != new_dir)