Commit bd42998a authored by Miklos Szeredi's avatar Miklos Szeredi
Browse files

ext4: add cross rename support



Implement RENAME_EXCHANGE flag in renameat2 syscall.
Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
parent bd1af145
......@@ -3004,6 +3004,8 @@ struct ext4_renament {
struct inode *dir;
struct dentry *dentry;
struct inode *inode;
bool is_dir;
int dir_nlink_delta;
/* entry for "dentry" */
struct buffer_head *bh;
......@@ -3135,6 +3137,17 @@ static void ext4_rename_delete(handle_t *handle, struct ext4_renament *ent)
}
}
static void ext4_update_dir_count(handle_t *handle, struct ext4_renament *ent)
{
if (ent->dir_nlink_delta) {
if (ent->dir_nlink_delta == -1)
ext4_dec_count(handle, ent->dir);
else
ext4_inc_count(handle, ent->dir);
ext4_mark_inode_dirty(handle, ent->dir);
}
}
/*
* Anybody can rename anything with this: the permission checks are left to the
* higher-level routines.
......@@ -3274,13 +3287,137 @@ end_rename:
return retval;
}
static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry)
{
handle_t *handle = NULL;
struct ext4_renament old = {
.dir = old_dir,
.dentry = old_dentry,
.inode = old_dentry->d_inode,
};
struct ext4_renament new = {
.dir = new_dir,
.dentry = new_dentry,
.inode = new_dentry->d_inode,
};
u8 new_file_type;
int retval;
dquot_initialize(old.dir);
dquot_initialize(new.dir);
old.bh = ext4_find_entry(old.dir, &old.dentry->d_name,
&old.de, &old.inlined);
/*
* Check for inode number is _not_ due to possible IO errors.
* We might rmdir the source, keep it as pwd of some process
* and merrily kill the link to whatever was created under the
* same name. Goodbye sticky bit ;-<
*/
retval = -ENOENT;
if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
goto end_rename;
new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
&new.de, &new.inlined);
/* RENAME_EXCHANGE case: old *and* new must both exist */
if (!new.bh || le32_to_cpu(new.de->inode) != new.inode->i_ino)
goto end_rename;
handle = ext4_journal_start(old.dir, EXT4_HT_DIR,
(2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
2 * EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2));
if (IS_ERR(handle))
return PTR_ERR(handle);
if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
ext4_handle_sync(handle);
if (S_ISDIR(old.inode->i_mode)) {
old.is_dir = true;
retval = ext4_rename_dir_prepare(handle, &old);
if (retval)
goto end_rename;
}
if (S_ISDIR(new.inode->i_mode)) {
new.is_dir = true;
retval = ext4_rename_dir_prepare(handle, &new);
if (retval)
goto end_rename;
}
/*
* Other than the special case of overwriting a directory, parents'
* nlink only needs to be modified if this is a cross directory rename.
*/
if (old.dir != new.dir && old.is_dir != new.is_dir) {
old.dir_nlink_delta = old.is_dir ? -1 : 1;
new.dir_nlink_delta = -old.dir_nlink_delta;
retval = -EMLINK;
if ((old.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(old.dir)) ||
(new.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(new.dir)))
goto end_rename;
}
new_file_type = new.de->file_type;
retval = ext4_setent(handle, &new, old.inode->i_ino, old.de->file_type);
if (retval)
goto end_rename;
retval = ext4_setent(handle, &old, new.inode->i_ino, new_file_type);
if (retval)
goto end_rename;
/*
* Like most other Unix systems, set the ctime for inodes on a
* rename.
*/
old.inode->i_ctime = ext4_current_time(old.inode);
new.inode->i_ctime = ext4_current_time(new.inode);
ext4_mark_inode_dirty(handle, old.inode);
ext4_mark_inode_dirty(handle, new.inode);
if (old.dir_bh) {
retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
if (retval)
goto end_rename;
}
if (new.dir_bh) {
retval = ext4_rename_dir_finish(handle, &new, old.dir->i_ino);
if (retval)
goto end_rename;
}
ext4_update_dir_count(handle, &old);
ext4_update_dir_count(handle, &new);
retval = 0;
end_rename:
brelse(old.dir_bh);
brelse(new.dir_bh);
brelse(old.bh);
brelse(new.bh);
if (handle)
ext4_journal_stop(handle);
return retval;
}
static int ext4_rename2(struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry,
unsigned int flags)
{
if (flags & ~RENAME_NOREPLACE)
if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
return -EINVAL;
if (flags & RENAME_EXCHANGE) {
return ext4_cross_rename(old_dir, old_dentry,
new_dir, new_dentry);
}
/*
* Existence checking was done by the VFS, otherwise "RENAME_NOREPLACE"
* is equivalent to regular rename.
*/
return ext4_rename(old_dir, old_dentry, new_dir, new_dentry);
}
......
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