ext4: support RENAME_WHITEOUT
Add whiteout support to ext4_rename(). A whiteout inode (chrdev/0,0) is created before the rename takes place. The whiteout inode is added to the old entry instead of deleting it. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
This commit is contained in:
Miklos Szeredi
Родитель
0d7a855526
Коммит
cd808deced
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@ -3190,6 +3190,39 @@ static void ext4_update_dir_count(handle_t *handle, struct ext4_renament *ent)
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}
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}
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static struct inode *ext4_whiteout_for_rename(struct ext4_renament *ent,
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int credits, handle_t **h)
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{
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struct inode *wh;
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handle_t *handle;
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int retries = 0;
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/*
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* for inode block, sb block, group summaries,
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* and inode bitmap
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*/
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credits += (EXT4_MAXQUOTAS_TRANS_BLOCKS(ent->dir->i_sb) +
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EXT4_XATTR_TRANS_BLOCKS + 4);
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retry:
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wh = ext4_new_inode_start_handle(ent->dir, S_IFCHR | WHITEOUT_MODE,
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&ent->dentry->d_name, 0, NULL,
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EXT4_HT_DIR, credits);
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handle = ext4_journal_current_handle();
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if (IS_ERR(wh)) {
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if (handle)
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ext4_journal_stop(handle);
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if (PTR_ERR(wh) == -ENOSPC &&
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ext4_should_retry_alloc(ent->dir->i_sb, &retries))
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goto retry;
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} else {
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*h = handle;
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init_special_inode(wh, wh->i_mode, WHITEOUT_DEV);
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wh->i_op = &ext4_special_inode_operations;
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}
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return wh;
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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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@ -3199,7 +3232,8 @@ static void ext4_update_dir_count(handle_t *handle, struct ext4_renament *ent)
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* This comes from rename(const char *oldpath, const char *newpath)
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*/
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static int ext4_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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struct inode *new_dir, struct dentry *new_dentry,
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unsigned int flags)
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{
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handle_t *handle = NULL;
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struct ext4_renament old = {
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@ -3214,6 +3248,9 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
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};
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int force_reread;
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int retval;
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struct inode *whiteout = NULL;
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int credits;
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u8 old_file_type;
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dquot_initialize(old.dir);
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dquot_initialize(new.dir);
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@ -3252,11 +3289,17 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
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if (new.inode && !test_opt(new.dir->i_sb, NO_AUTO_DA_ALLOC))
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ext4_alloc_da_blocks(old.inode);
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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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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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credits = (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
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EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2);
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if (!(flags & RENAME_WHITEOUT)) {
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handle = ext4_journal_start(old.dir, EXT4_HT_DIR, credits);
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if (IS_ERR(handle))
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return PTR_ERR(handle);
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} else {
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whiteout = ext4_whiteout_for_rename(&old, credits, &handle);
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if (IS_ERR(whiteout))
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return PTR_ERR(whiteout);
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}
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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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@ -3284,13 +3327,26 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
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*/
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force_reread = (new.dir->i_ino == old.dir->i_ino &&
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ext4_test_inode_flag(new.dir, EXT4_INODE_INLINE_DATA));
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old_file_type = old.de->file_type;
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if (whiteout) {
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/*
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* Do this before adding a new entry, so the old entry is sure
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* to be still pointing to the valid old entry.
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*/
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retval = ext4_setent(handle, &old, whiteout->i_ino,
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EXT4_FT_CHRDEV);
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if (retval)
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goto end_rename;
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ext4_mark_inode_dirty(handle, whiteout);
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}
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if (!new.bh) {
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retval = ext4_add_entry(handle, new.dentry, old.inode);
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if (retval)
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goto end_rename;
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} else {
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retval = ext4_setent(handle, &new,
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old.inode->i_ino, old.de->file_type);
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old.inode->i_ino, old_file_type);
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if (retval)
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goto end_rename;
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}
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@ -3305,10 +3361,12 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
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old.inode->i_ctime = ext4_current_time(old.inode);
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ext4_mark_inode_dirty(handle, old.inode);
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/*
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* ok, that's it
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*/
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ext4_rename_delete(handle, &old, force_reread);
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if (!whiteout) {
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/*
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* ok, that's it
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*/
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ext4_rename_delete(handle, &old, force_reread);
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}
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if (new.inode) {
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ext4_dec_count(handle, new.inode);
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@ -3344,6 +3402,12 @@ end_rename:
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brelse(old.dir_bh);
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brelse(old.bh);
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brelse(new.bh);
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if (whiteout) {
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if (retval)
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drop_nlink(whiteout);
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unlock_new_inode(whiteout);
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iput(whiteout);
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}
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if (handle)
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ext4_journal_stop(handle);
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return retval;
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@ -3476,18 +3540,15 @@ 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 | RENAME_EXCHANGE))
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if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
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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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return ext4_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
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}
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/*
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