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authorFrank van der Linden <fllinden@amazon.com>2020-06-23 22:39:18 +0000
committerChuck Lever <chuck.lever@oracle.com>2020-07-13 17:27:03 -0400
commit08b5d5014a27e717826999ad20e394a8811aae92 (patch)
tree9ad6215f9a0716012bf842c10d95e021d79be880 /fs/xattr.c
parentc1326210477ecc06c53221f0005c64419aba30d6 (diff)
xattr: break delegations in {set,remove}xattr
set/removexattr on an exported filesystem should break NFS delegations. This is true in general, but also for the upcoming support for RFC 8726 (NFSv4 extended attribute support). Make sure that they do. Additionally, they need to grow a _locked variant, since callers might call this with i_rwsem held (like the NFS server code). Cc: stable@vger.kernel.org # v4.9+ Cc: linux-fsdevel@vger.kernel.org Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Frank van der Linden <fllinden@amazon.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Diffstat (limited to 'fs/xattr.c')
-rw-r--r--fs/xattr.c84
1 files changed, 77 insertions, 7 deletions
diff --git a/fs/xattr.c b/fs/xattr.c
index 91608d9bfc6a..95f38f57347f 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -204,10 +204,22 @@ int __vfs_setxattr_noperm(struct dentry *dentry, const char *name,
return error;
}
-
+/**
+ * __vfs_setxattr_locked: set an extended attribute while holding the inode
+ * lock
+ *
+ * @dentry - object to perform setxattr on
+ * @name - xattr name to set
+ * @value - value to set @name to
+ * @size - size of @value
+ * @flags - flags to pass into filesystem operations
+ * @delegated_inode - on return, will contain an inode pointer that
+ * a delegation was broken on, NULL if none.
+ */
int
-vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
- size_t size, int flags)
+__vfs_setxattr_locked(struct dentry *dentry, const char *name,
+ const void *value, size_t size, int flags,
+ struct inode **delegated_inode)
{
struct inode *inode = dentry->d_inode;
int error;
@@ -216,15 +228,40 @@ vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
if (error)
return error;
- inode_lock(inode);
error = security_inode_setxattr(dentry, name, value, size, flags);
if (error)
goto out;
+ error = try_break_deleg(inode, delegated_inode);
+ if (error)
+ goto out;
+
error = __vfs_setxattr_noperm(dentry, name, value, size, flags);
out:
+ return error;
+}
+EXPORT_SYMBOL_GPL(__vfs_setxattr_locked);
+
+int
+vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
+ size_t size, int flags)
+{
+ struct inode *inode = dentry->d_inode;
+ struct inode *delegated_inode = NULL;
+ int error;
+
+retry_deleg:
+ inode_lock(inode);
+ error = __vfs_setxattr_locked(dentry, name, value, size, flags,
+ &delegated_inode);
inode_unlock(inode);
+
+ if (delegated_inode) {
+ error = break_deleg_wait(&delegated_inode);
+ if (!error)
+ goto retry_deleg;
+ }
return error;
}
EXPORT_SYMBOL_GPL(vfs_setxattr);
@@ -378,8 +415,18 @@ __vfs_removexattr(struct dentry *dentry, const char *name)
}
EXPORT_SYMBOL(__vfs_removexattr);
+/**
+ * __vfs_removexattr_locked: set an extended attribute while holding the inode
+ * lock
+ *
+ * @dentry - object to perform setxattr on
+ * @name - name of xattr to remove
+ * @delegated_inode - on return, will contain an inode pointer that
+ * a delegation was broken on, NULL if none.
+ */
int
-vfs_removexattr(struct dentry *dentry, const char *name)
+__vfs_removexattr_locked(struct dentry *dentry, const char *name,
+ struct inode **delegated_inode)
{
struct inode *inode = dentry->d_inode;
int error;
@@ -388,11 +435,14 @@ vfs_removexattr(struct dentry *dentry, const char *name)
if (error)
return error;
- inode_lock(inode);
error = security_inode_removexattr(dentry, name);
if (error)
goto out;
+ error = try_break_deleg(inode, delegated_inode);
+ if (error)
+ goto out;
+
error = __vfs_removexattr(dentry, name);
if (!error) {
@@ -401,12 +451,32 @@ vfs_removexattr(struct dentry *dentry, const char *name)
}
out:
+ return error;
+}
+EXPORT_SYMBOL_GPL(__vfs_removexattr_locked);
+
+int
+vfs_removexattr(struct dentry *dentry, const char *name)
+{
+ struct inode *inode = dentry->d_inode;
+ struct inode *delegated_inode = NULL;
+ int error;
+
+retry_deleg:
+ inode_lock(inode);
+ error = __vfs_removexattr_locked(dentry, name, &delegated_inode);
inode_unlock(inode);
+
+ if (delegated_inode) {
+ error = break_deleg_wait(&delegated_inode);
+ if (!error)
+ goto retry_deleg;
+ }
+
return error;
}
EXPORT_SYMBOL_GPL(vfs_removexattr);
-
/*
* Extended attribute SET operations
*/