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authorMichael Holzheu <holzheu@de.ibm.com>2007-08-22 15:51:43 +0400
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2007-08-22 15:51:49 +0400
commit9b5a03e198c951225d0deb05f3107a4631791266 (patch)
tree6a70d404272adb8dcdc48f3323f3faa397be9026 /arch/s390
parentcee9e53f59fe1842a7d26fa1e76382fb6ed21048 (diff)
downloadlinux-9b5a03e198c951225d0deb05f3107a4631791266.tar.xz
[S390] hypfs: inode corruption due to missing locking
hypfs removes the whole hypfs directory tree and creates a new one, when a process triggers an update by writing to the "update" attribute. When removing and creating files, it is necessary to lock the inode of the parent directory where the files live. Currently hypfs does not lock the parent inode, which can lead to inode corruption. This patch: * Introduces correct locking * Fixes i_nlink reference counting for inodes, when creating directories * Adds info printk, when hypfs filesystem has been mounted Signed-off-by: Michael Holzheu <holzheu@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/hypfs/inode.c33
1 files changed, 25 insertions, 8 deletions
diff --git a/arch/s390/hypfs/inode.c b/arch/s390/hypfs/inode.c
index ad4ca75c0f04..5245717295b8 100644
--- a/arch/s390/hypfs/inode.c
+++ b/arch/s390/hypfs/inode.c
@@ -60,17 +60,28 @@ static void hypfs_add_dentry(struct dentry *dentry)
hypfs_last_dentry = dentry;
}
+static inline int hypfs_positive(struct dentry *dentry)
+{
+ return dentry->d_inode && !d_unhashed(dentry);
+}
+
static void hypfs_remove(struct dentry *dentry)
{
struct dentry *parent;
parent = dentry->d_parent;
- if (S_ISDIR(dentry->d_inode->i_mode))
- simple_rmdir(parent->d_inode, dentry);
- else
- simple_unlink(parent->d_inode, dentry);
+ if (!parent || !parent->d_inode)
+ return;
+ mutex_lock(&parent->d_inode->i_mutex);
+ if (hypfs_positive(dentry)) {
+ if (S_ISDIR(dentry->d_inode->i_mode))
+ simple_rmdir(parent->d_inode, dentry);
+ else
+ simple_unlink(parent->d_inode, dentry);
+ }
d_delete(dentry);
dput(dentry);
+ mutex_unlock(&parent->d_inode->i_mutex);
}
static void hypfs_delete_tree(struct dentry *root)
@@ -315,6 +326,7 @@ static int hypfs_fill_super(struct super_block *sb, void *data, int silent)
}
hypfs_update_update(sb);
sb->s_root = root_dentry;
+ printk(KERN_INFO "hypfs: Hypervisor filesystem mounted\n");
return 0;
err_tree:
@@ -356,13 +368,17 @@ static struct dentry *hypfs_create_file(struct super_block *sb,
qname.name = name;
qname.len = strlen(name);
qname.hash = full_name_hash(name, qname.len);
+ mutex_lock(&parent->d_inode->i_mutex);
dentry = lookup_one_len(name, parent, strlen(name));
- if (IS_ERR(dentry))
- return ERR_PTR(-ENOMEM);
+ if (IS_ERR(dentry)) {
+ dentry = ERR_PTR(-ENOMEM);
+ goto fail;
+ }
inode = hypfs_make_inode(sb, mode);
if (!inode) {
dput(dentry);
- return ERR_PTR(-ENOMEM);
+ dentry = ERR_PTR(-ENOMEM);
+ goto fail;
}
if (mode & S_IFREG) {
inode->i_fop = &hypfs_file_ops;
@@ -379,6 +395,8 @@ static struct dentry *hypfs_create_file(struct super_block *sb,
inode->i_private = data;
d_instantiate(dentry, inode);
dget(dentry);
+fail:
+ mutex_unlock(&parent->d_inode->i_mutex);
return dentry;
}
@@ -391,7 +409,6 @@ struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent,
if (IS_ERR(dentry))
return dentry;
hypfs_add_dentry(dentry);
- parent->d_inode->i_nlink++;
return dentry;
}