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ext4: don't access the source subdirectory content on same-directory rename

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We can't really afford locking the source on same-directory rename;
currently vfs_rename() tries to do that, but it will have to be changed.
The logics in ext4 is lazy and goes looking for ".." in source even in
same-directory case.  It's not hard to get rid of that, leaving that
behaviour only for cross-directory case; that VFS can get locks safely
(and will keep doing that after the coming changes).

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2023-10-17 14:55:42 -04:00
parent 7307b73fa5
commit 40dbd071f4
1 changed files with 13 additions and 8 deletions
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21
fs/ext4/namei.c
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@ -3591,10 +3591,14 @@ struct ext4_renament {
int dir_inlined;
};
static int ext4_rename_dir_prepare(handle_t *handle, struct ext4_renament *ent)
static int ext4_rename_dir_prepare(handle_t *handle, struct ext4_renament *ent, bool is_cross)
{
int retval;
ent->is_dir = true;
if (!is_cross)
return 0;
ent->dir_bh = ext4_get_first_dir_block(handle, ent->inode,
&retval, &ent->parent_de,
&ent->dir_inlined);
@ -3612,6 +3616,9 @@ static int ext4_rename_dir_finish(handle_t *handle, struct ext4_renament *ent,
{
int retval;
if (!ent->dir_bh)
return 0;
ent->parent_de->inode = cpu_to_le32(dir_ino);
BUFFER_TRACE(ent->dir_bh, "call ext4_handle_dirty_metadata");
if (!ent->dir_inlined) {
@ -3900,7 +3907,7 @@ static int ext4_rename(struct mnt_idmap *idmap, struct inode *old_dir,
if (new.dir != old.dir && EXT4_DIR_LINK_MAX(new.dir))
goto end_rename;
}
retval = ext4_rename_dir_prepare(handle, &old);
retval = ext4_rename_dir_prepare(handle, &old, new.dir != old.dir);
if (retval)
goto end_rename;
}
@ -3964,7 +3971,7 @@ static int ext4_rename(struct mnt_idmap *idmap, struct inode *old_dir,
}
inode_set_mtime_to_ts(old.dir, inode_set_ctime_current(old.dir));
ext4_update_dx_flag(old.dir);
if (old.dir_bh) {
if (old.is_dir) {
retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
if (retval)
goto end_rename;
@ -3987,7 +3994,7 @@ static int ext4_rename(struct mnt_idmap *idmap, struct inode *old_dir,
if (unlikely(retval))
goto end_rename;
if (S_ISDIR(old.inode->i_mode)) {
if (old.is_dir) {
/*
* We disable fast commits here that's because the
* replay code is not yet capable of changing dot dot
@ -4114,14 +4121,12 @@ static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
ext4_handle_sync(handle);
if (S_ISDIR(old.inode->i_mode)) {
old.is_dir = true;
retval = ext4_rename_dir_prepare(handle, &old);
retval = ext4_rename_dir_prepare(handle, &old, new.dir != old.dir);
if (retval)
goto end_rename;
}
if (S_ISDIR(new.inode->i_mode)) {
new.is_dir = true;
retval = ext4_rename_dir_prepare(handle, &new);
retval = ext4_rename_dir_prepare(handle, &new, new.dir != old.dir);
if (retval)
goto end_rename;
}