ext4: add cross rename support
Implement RENAME_EXCHANGE flag in renameat2 syscall. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Jan Kara <jack@suse.cz>hifive-unleashed-5.1
Miklos Szeredi
parent
bd1af145b9
commit
bd42998a6b
139
fs/ext4/namei.c
139
fs/ext4/namei.c
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@ -3004,6 +3004,8 @@ struct ext4_renament {
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struct inode *dir;
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struct dentry *dentry;
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struct inode *inode;
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bool is_dir;
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int dir_nlink_delta;
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/* entry for "dentry" */
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struct buffer_head *bh;
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@ -3135,6 +3137,17 @@ static void ext4_rename_delete(handle_t *handle, struct ext4_renament *ent)
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}
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}
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static void ext4_update_dir_count(handle_t *handle, struct ext4_renament *ent)
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{
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if (ent->dir_nlink_delta) {
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if (ent->dir_nlink_delta == -1)
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ext4_dec_count(handle, ent->dir);
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else
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ext4_inc_count(handle, ent->dir);
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ext4_mark_inode_dirty(handle, ent->dir);
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}
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}
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/*
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* Anybody can rename anything with this: the permission checks are left to the
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* higher-level routines.
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@ -3274,13 +3287,137 @@ end_rename:
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return retval;
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}
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static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
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struct inode *new_dir, struct dentry *new_dentry)
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{
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handle_t *handle = NULL;
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struct ext4_renament old = {
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.dir = old_dir,
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.dentry = old_dentry,
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.inode = old_dentry->d_inode,
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};
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struct ext4_renament new = {
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.dir = new_dir,
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.dentry = new_dentry,
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.inode = new_dentry->d_inode,
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};
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u8 new_file_type;
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int retval;
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dquot_initialize(old.dir);
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dquot_initialize(new.dir);
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old.bh = ext4_find_entry(old.dir, &old.dentry->d_name,
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&old.de, &old.inlined);
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/*
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* Check for inode number is _not_ due to possible IO errors.
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* We might rmdir the source, keep it as pwd of some process
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* and merrily kill the link to whatever was created under the
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* same name. Goodbye sticky bit ;-<
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*/
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retval = -ENOENT;
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if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
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goto end_rename;
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new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
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&new.de, &new.inlined);
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/* RENAME_EXCHANGE case: old *and* new must both exist */
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if (!new.bh || le32_to_cpu(new.de->inode) != new.inode->i_ino)
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goto end_rename;
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handle = ext4_journal_start(old.dir, EXT4_HT_DIR,
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(2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
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2 * EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2));
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if (IS_ERR(handle))
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return PTR_ERR(handle);
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if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
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ext4_handle_sync(handle);
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if (S_ISDIR(old.inode->i_mode)) {
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old.is_dir = true;
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retval = ext4_rename_dir_prepare(handle, &old);
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if (retval)
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goto end_rename;
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}
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if (S_ISDIR(new.inode->i_mode)) {
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new.is_dir = true;
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retval = ext4_rename_dir_prepare(handle, &new);
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if (retval)
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goto end_rename;
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}
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/*
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* Other than the special case of overwriting a directory, parents'
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* nlink only needs to be modified if this is a cross directory rename.
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*/
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if (old.dir != new.dir && old.is_dir != new.is_dir) {
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old.dir_nlink_delta = old.is_dir ? -1 : 1;
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new.dir_nlink_delta = -old.dir_nlink_delta;
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retval = -EMLINK;
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if ((old.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(old.dir)) ||
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(new.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(new.dir)))
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goto end_rename;
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}
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new_file_type = new.de->file_type;
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retval = ext4_setent(handle, &new, old.inode->i_ino, old.de->file_type);
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if (retval)
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goto end_rename;
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retval = ext4_setent(handle, &old, new.inode->i_ino, new_file_type);
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if (retval)
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goto end_rename;
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/*
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* Like most other Unix systems, set the ctime for inodes on a
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* rename.
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*/
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old.inode->i_ctime = ext4_current_time(old.inode);
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new.inode->i_ctime = ext4_current_time(new.inode);
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ext4_mark_inode_dirty(handle, old.inode);
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ext4_mark_inode_dirty(handle, new.inode);
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if (old.dir_bh) {
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retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
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if (retval)
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goto end_rename;
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}
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if (new.dir_bh) {
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retval = ext4_rename_dir_finish(handle, &new, old.dir->i_ino);
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if (retval)
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goto end_rename;
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}
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ext4_update_dir_count(handle, &old);
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ext4_update_dir_count(handle, &new);
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retval = 0;
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end_rename:
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brelse(old.dir_bh);
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brelse(new.dir_bh);
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brelse(old.bh);
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brelse(new.bh);
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if (handle)
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ext4_journal_stop(handle);
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return retval;
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}
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static int ext4_rename2(struct inode *old_dir, struct dentry *old_dentry,
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struct inode *new_dir, struct dentry *new_dentry,
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unsigned int flags)
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{
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if (flags & ~RENAME_NOREPLACE)
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if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
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return -EINVAL;
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if (flags & RENAME_EXCHANGE) {
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return ext4_cross_rename(old_dir, old_dentry,
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new_dir, new_dentry);
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}
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/*
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* Existence checking was done by the VFS, otherwise "RENAME_NOREPLACE"
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* is equivalent to regular rename.
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*/
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return ext4_rename(old_dir, old_dentry, new_dir, new_dentry);
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}
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