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do d_instantiate/unlock_new_inode combinations safely

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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>
This commit is contained in:
Al Viro 2018-05-04 08:23:01 -04:00
parent d7760d638b
commit 1e2e547a93
14 changed files with 57 additions and 72 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
fs/btrfs/inode.c
View File

@ -6575,8 +6575,7 @@ static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
goto out_unlock_inode;
} else {
btrfs_update_inode(trans, root, inode);
unlock_new_inode(inode);
d_instantiate(dentry, inode);
d_instantiate_new(dentry, inode);
}
out_unlock:
@ -6652,8 +6651,7 @@ static int btrfs_create(struct inode *dir, struct dentry *dentry,
goto out_unlock_inode;
BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
unlock_new_inode(inode);
d_instantiate(dentry, inode);
d_instantiate_new(dentry, inode);
out_unlock:
btrfs_end_transaction(trans);
@ -6798,12 +6796,7 @@ static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
if (err)
goto out_fail_inode;
d_instantiate(dentry, inode);
/*
* mkdir is special. We're unlocking after we call d_instantiate
* to avoid a race with nfsd calling d_instantiate.
*/
unlock_new_inode(inode);
d_instantiate_new(dentry, inode);
drop_on_err = 0;
out_fail:
@ -10246,8 +10239,7 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
goto out_unlock_inode;
}
unlock_new_inode(inode);
d_instantiate(dentry, inode);
d_instantiate_new(dentry, inode);
out_unlock:
btrfs_end_transaction(trans);

22
fs/dcache.c
View File

@ -1899,6 +1899,28 @@ void d_instantiate(struct dentry *entry, struct inode * inode)
}
EXPORT_SYMBOL(d_instantiate);
/*
* This should be equivalent to d_instantiate() + unlock_new_inode(),
* with lockdep-related part of unlock_new_inode() done before
* anything else. Use that instead of open-coding d_instantiate()/
* unlock_new_inode() combinations.
*/
void d_instantiate_new(struct dentry *entry, struct inode *inode)
{
BUG_ON(!hlist_unhashed(&entry->d_u.d_alias));
BUG_ON(!inode);
lockdep_annotate_inode_mutex_key(inode);
security_d_instantiate(entry, inode);
spin_lock(&inode->i_lock);
__d_instantiate(entry, inode);
WARN_ON(!(inode->i_state & I_NEW));
inode->i_state &= ~I_NEW;
smp_mb();
wake_up_bit(&inode->i_state, __I_NEW);
spin_unlock(&inode->i_lock);
}
EXPORT_SYMBOL(d_instantiate_new);
/**
* d_instantiate_no_diralias - instantiate a non-aliased dentry
* @entry: dentry to complete

3
fs/ecryptfs/inode.c
View File

@ -283,8 +283,7 @@ ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
iget_failed(ecryptfs_inode);
goto out;
}
unlock_new_inode(ecryptfs_inode);
d_instantiate(ecryptfs_dentry, ecryptfs_inode);
d_instantiate_new(ecryptfs_dentry, ecryptfs_inode);
out:
return rc;
}

6
fs/ext2/namei.c
View File

@ -41,8 +41,7 @@ static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode)
{
int err = ext2_add_link(dentry, inode);
if (!err) {
unlock_new_inode(inode);
d_instantiate(dentry, inode);
d_instantiate_new(dentry, inode);
return 0;
}
inode_dec_link_count(inode);
@ -255,8 +254,7 @@ static int ext2_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode)
if (err)
goto out_fail;
unlock_new_inode(inode);
d_instantiate(dentry, inode);
d_instantiate_new(dentry, inode);
out:
return err;

6
fs/ext4/namei.c
View File

@ -2411,8 +2411,7 @@ static int ext4_add_nondir(handle_t *handle,
int err = ext4_add_entry(handle, dentry, inode);
if (!err) {
ext4_mark_inode_dirty(handle, inode);
unlock_new_inode(inode);
d_instantiate(dentry, inode);
d_instantiate_new(dentry, inode);
return 0;
}
drop_nlink(inode);
@ -2651,8 +2650,7 @@ out_clear_inode:
err = ext4_mark_inode_dirty(handle, dir);
if (err)
goto out_clear_inode;
unlock_new_inode(inode);
d_instantiate(dentry, inode);
d_instantiate_new(dentry, inode);
if (IS_DIRSYNC(dir))
ext4_handle_sync(handle);

12
fs/f2fs/namei.c
View File

@ -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);

12
fs/jffs2/dir.c
View File

@ -209,8 +209,7 @@ static int jffs2_create(struct inode *dir_i, struct dentry *dentry,
__func__, inode->i_ino, inode->i_mode, inode->i_nlink,
f->inocache->pino_nlink, inode->i_mapping->nrpages);
unlock_new_inode(inode);
d_instantiate(dentry, inode);
d_instantiate_new(dentry, inode);
return 0;
fail:
@ -430,8 +429,7 @@ static int jffs2_symlink (struct inode *dir_i, struct dentry *dentry, const char
mutex_unlock(&dir_f->sem);
jffs2_complete_reservation(c);
unlock_new_inode(inode);
d_instantiate(dentry, inode);
d_instantiate_new(dentry, inode);
return 0;
fail:
@ -575,8 +573,7 @@ static int jffs2_mkdir (struct inode *dir_i, struct dentry *dentry, umode_t mode
mutex_unlock(&dir_f->sem);
jffs2_complete_reservation(c);
unlock_new_inode(inode);
d_instantiate(dentry, inode);
d_instantiate_new(dentry, inode);
return 0;
fail:
@ -747,8 +744,7 @@ static int jffs2_mknod (struct inode *dir_i, struct dentry *dentry, umode_t mode
mutex_unlock(&dir_f->sem);
jffs2_complete_reservation(c);
unlock_new_inode(inode);
d_instantiate(dentry, inode);
d_instantiate_new(dentry, inode);
return 0;
fail:

12
fs/jfs/namei.c
View File

@ -178,8 +178,7 @@ static int jfs_create(struct inode *dip, struct dentry *dentry, umode_t mode,
unlock_new_inode(ip);
iput(ip);
} else {
unlock_new_inode(ip);
d_instantiate(dentry, ip);
d_instantiate_new(dentry, ip);
}
out2:
@ -313,8 +312,7 @@ static int jfs_mkdir(struct inode *dip, struct dentry *dentry, umode_t mode)
unlock_new_inode(ip);
iput(ip);
} else {
unlock_new_inode(ip);
d_instantiate(dentry, ip);
d_instantiate_new(dentry, ip);
}
out2:
@ -1059,8 +1057,7 @@ static int jfs_symlink(struct inode *dip, struct dentry *dentry,
unlock_new_inode(ip);
iput(ip);
} else {
unlock_new_inode(ip);
d_instantiate(dentry, ip);
d_instantiate_new(dentry, ip);
}
out2:
@ -1447,8 +1444,7 @@ static int jfs_mknod(struct inode *dir, struct dentry *dentry,
unlock_new_inode(ip);
iput(ip);
} else {
unlock_new_inode(ip);
d_instantiate(dentry, ip);
d_instantiate_new(dentry, ip);
}
out1:

6
fs/nilfs2/namei.c
View File

@ -46,8 +46,7 @@ static inline int nilfs_add_nondir(struct dentry *dentry, struct inode *inode)
int err = nilfs_add_link(dentry, inode);
if (!err) {
d_instantiate(dentry, inode);
unlock_new_inode(inode);
d_instantiate_new(dentry, inode);
return 0;
}
inode_dec_link_count(inode);
@ -243,8 +242,7 @@ static int nilfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
goto out_fail;
nilfs_mark_inode_dirty(inode);
d_instantiate(dentry, inode);
unlock_new_inode(inode);
d_instantiate_new(dentry, inode);
out:
if (!err)
err = nilfs_transaction_commit(dir->i_sb);

9
fs/orangefs/namei.c
View File

@ -75,8 +75,7 @@ static int orangefs_create(struct inode *dir,
get_khandle_from_ino(inode),
dentry);
d_instantiate(dentry, inode);
unlock_new_inode(inode);
d_instantiate_new(dentry, inode);
orangefs_set_timeout(dentry);
ORANGEFS_I(inode)->getattr_time = jiffies - 1;
ORANGEFS_I(inode)->getattr_mask = STATX_BASIC_STATS;
@ -332,8 +331,7 @@ static int orangefs_symlink(struct inode *dir,
"Assigned symlink inode new number of %pU\n",
get_khandle_from_ino(inode));
d_instantiate(dentry, inode);
unlock_new_inode(inode);
d_instantiate_new(dentry, inode);
orangefs_set_timeout(dentry);
ORANGEFS_I(inode)->getattr_time = jiffies - 1;
ORANGEFS_I(inode)->getattr_mask = STATX_BASIC_STATS;
@ -402,8 +400,7 @@ static int orangefs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode
"Assigned dir inode new number of %pU\n",
get_khandle_from_ino(inode));
d_instantiate(dentry, inode);
unlock_new_inode(inode);
d_instantiate_new(dentry, inode);
orangefs_set_timeout(dentry);
ORANGEFS_I(inode)->getattr_time = jiffies - 1;
ORANGEFS_I(inode)->getattr_mask = STATX_BASIC_STATS;

12
fs/reiserfs/namei.c
View File

@ -687,8 +687,7 @@ static int reiserfs_create(struct inode *dir, struct dentry *dentry, umode_t mod
reiserfs_update_inode_transaction(inode);
reiserfs_update_inode_transaction(dir);
unlock_new_inode(inode);
d_instantiate(dentry, inode);
d_instantiate_new(dentry, inode);
retval = journal_end(&th);
out_failed:
@ -771,8 +770,7 @@ static int reiserfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode
goto out_failed;
}
unlock_new_inode(inode);
d_instantiate(dentry, inode);
d_instantiate_new(dentry, inode);
retval = journal_end(&th);
out_failed:
@ -871,8 +869,7 @@ static int reiserfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode
/* the above add_entry did not update dir's stat data */
reiserfs_update_sd(&th, dir);
unlock_new_inode(inode);
d_instantiate(dentry, inode);
d_instantiate_new(dentry, inode);
retval = journal_end(&th);
out_failed:
reiserfs_write_unlock(dir->i_sb);
@ -1187,8 +1184,7 @@ static int reiserfs_symlink(struct inode *parent_dir,
goto out_failed;
}
unlock_new_inode(inode);
d_instantiate(dentry, inode);
d_instantiate_new(dentry, inode);
retval = journal_end(&th);
out_failed:
reiserfs_write_unlock(parent_dir->i_sb);

6
fs/udf/namei.c
View File

@ -622,8 +622,7 @@ static int udf_add_nondir(struct dentry *dentry, struct inode *inode)
if (fibh.sbh != fibh.ebh)
brelse(fibh.ebh);
brelse(fibh.sbh);
unlock_new_inode(inode);
d_instantiate(dentry, inode);
d_instantiate_new(dentry, inode);
return 0;
}
@ -733,8 +732,7 @@ static int udf_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
inc_nlink(dir);
dir->i_ctime = dir->i_mtime = current_time(dir);
mark_inode_dirty(dir);
unlock_new_inode(inode);
d_instantiate(dentry, inode);
d_instantiate_new(dentry, inode);
if (fibh.sbh != fibh.ebh)
brelse(fibh.ebh);
brelse(fibh.sbh);

6
fs/ufs/namei.c
View File

@ -39,8 +39,7 @@ static inline int ufs_add_nondir(struct dentry *dentry, struct inode *inode)
{
int err = ufs_add_link(dentry, inode);
if (!err) {
unlock_new_inode(inode);
d_instantiate(dentry, inode);
d_instantiate_new(dentry, inode);
return 0;
}
inode_dec_link_count(inode);
@ -193,8 +192,7 @@ static int ufs_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode)
if (err)
goto out_fail;
unlock_new_inode(inode);
d_instantiate(dentry, inode);
d_instantiate_new(dentry, inode);
return 0;
out_fail:

1
include/linux/dcache.h
View File

@ -224,6 +224,7 @@ extern seqlock_t rename_lock;
* These are the low-level FS interfaces to the dcache..
*/
extern void d_instantiate(struct dentry *, struct inode *);
extern void d_instantiate_new(struct dentry *, struct inode *);
extern struct dentry * d_instantiate_unique(struct dentry *, struct inode *);
extern struct dentry * d_instantiate_anon(struct dentry *, struct inode *);
extern int d_instantiate_no_diralias(struct dentry *, struct inode *);