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authorAl Viro <viro@zeniv.linux.org.uk>2018-05-04 08:23:01 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2018-05-11 15:36:37 -0400
commit1e2e547a93a00ebc21582c06ca3c6cfea2a309ee (patch)
treee31468774e0543997a15daa0409ef79a02d1438c /fs/f2fs
parentd7760d638b140d53c6390a2fbee9b06460b43e9e (diff)
do d_instantiate/unlock_new_inode combinations safely
For anything NFS-exported we do _not_ want to unlock new inode before it has grown an alias; original set of fixes got the ordering right, but missed the nasty complication in case of lockdep being enabled - unlock_new_inode() does lockdep_annotate_inode_mutex_key(inode) which can only be done before anyone gets a chance to touch ->i_mutex. Unfortunately, flipping the order and doing unlock_new_inode() before d_instantiate() opens a window when mkdir can race with open-by-fhandle on a guessed fhandle, leading to multiple aliases for a directory inode and all the breakage that follows from that. Correct solution: a new primitive (d_instantiate_new()) combining these two in the right order - lockdep annotate, then d_instantiate(), then the rest of unlock_new_inode(). All combinations of d_instantiate() with unlock_new_inode() should be converted to that. Cc: stable@kernel.org # 2.6.29 and later Tested-by: Mike Marshall <hubcap@omnibond.com> Reviewed-by: Andreas Dilger <adilger@dilger.ca> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/f2fs')
-rw-r--r--fs/f2fs/namei.c12
1 files changed, 4 insertions, 8 deletions
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index d5098efe577c..75e37fd720b2 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -294,8 +294,7 @@ static int f2fs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
alloc_nid_done(sbi, ino);
- d_instantiate(dentry, inode);
- unlock_new_inode(inode);
+ d_instantiate_new(dentry, inode);
if (IS_DIRSYNC(dir))
f2fs_sync_fs(sbi->sb, 1);
@@ -597,8 +596,7 @@ static int f2fs_symlink(struct inode *dir, struct dentry *dentry,
err = page_symlink(inode, disk_link.name, disk_link.len);
err_out:
- d_instantiate(dentry, inode);
- unlock_new_inode(inode);
+ d_instantiate_new(dentry, inode);
/*
* Let's flush symlink data in order to avoid broken symlink as much as
@@ -661,8 +659,7 @@ static int f2fs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
alloc_nid_done(sbi, inode->i_ino);
- d_instantiate(dentry, inode);
- unlock_new_inode(inode);
+ d_instantiate_new(dentry, inode);
if (IS_DIRSYNC(dir))
f2fs_sync_fs(sbi->sb, 1);
@@ -713,8 +710,7 @@ static int f2fs_mknod(struct inode *dir, struct dentry *dentry,
alloc_nid_done(sbi, inode->i_ino);
- d_instantiate(dentry, inode);
- unlock_new_inode(inode);
+ d_instantiate_new(dentry, inode);
if (IS_DIRSYNC(dir))
f2fs_sync_fs(sbi->sb, 1);