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Message-ID: <20090922174838.GC31447@duck.suse.cz>
Date: Tue, 22 Sep 2009 19:48:38 +0200
From: Jan Kara <jack@...e.cz>
To: LKML <linux-kernel@...r.kernel.org>
Cc: npiggin@...e.de, viro@...IV.linux.org.uk,
linux-ext4@...r.kernel.org, hch@...radead.org,
Andrew Morton <akpm@...ux-foundation.org>,
Jan Kara <jack@...e.cz>, tytso@....edu
Subject: Re: [PATCH 5/7] ext4: Convert filesystem to the new truncate
calling convention
Oops, sorry for the subject. It should have been just [PATCH] instead
of [PATCH 5/7]...
On Tue 22-09-09 19:42:05, Jan Kara wrote:
> CC: linux-ext4@...r.kernel.org
> CC: tytso@....edu
> Signed-off-by: Jan Kara <jack@...e.cz>
> ---
> fs/ext4/file.c | 2 +-
> fs/ext4/inode.c | 166 ++++++++++++++++++++++++++++++++----------------------
> 2 files changed, 99 insertions(+), 69 deletions(-)
>
> diff --git a/fs/ext4/file.c b/fs/ext4/file.c
> index 3f1873f..22f49d7 100644
> --- a/fs/ext4/file.c
> +++ b/fs/ext4/file.c
> @@ -198,7 +198,7 @@ const struct file_operations ext4_file_operations = {
> };
>
> const struct inode_operations ext4_file_inode_operations = {
> - .truncate = ext4_truncate,
> + .new_truncate = 1,
> .setattr = ext4_setattr,
> .getattr = ext4_getattr,
> #ifdef CONFIG_EXT4_FS_XATTR
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 58492ab..be25874 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -4682,28 +4686,97 @@ int ext4_write_inode(struct inode *inode, int wait)
> }
>
> /*
> - * ext4_setattr()
> + * ext4_setsize()
> + *
> + * This is a helper for ext4_setattr(). It sets i_size, truncates page cache
> + * and truncates inode blocks if they are over i_size.
> *
> - * Called from notify_change.
> + * We take care of updating i_disksize and adding inode to the orphan list.
> + * That makes sure that we can guarantee that any commit will leave the blocks
> + * being truncated in an unused state on disk. (On recovery, the inode will
> + * get truncated and the blocks will be freed, so we have a strong guarantee
> + * that no future commit will leave these blocks visible to the user.)
> *
> - * We want to trap VFS attempts to truncate the file as soon as
> - * possible. In particular, we want to make sure that when the VFS
> - * shrinks i_size, we put the inode on the orphan list and modify
> - * i_disksize immediately, so that during the subsequent flushing of
> - * dirty pages and freeing of disk blocks, we can guarantee that any
> - * commit will leave the blocks being flushed in an unused state on
> - * disk. (On recovery, the inode will get truncated and the blocks will
> - * be freed, so we have a strong guarantee that no future commit will
> - * leave these blocks visible to the user.)
> + * Another thing we have to assure is that if we are in ordered mode and inode
> + * is still attached to the committing transaction, we must we start writeout
> + * of all the dirty pages which are being truncated. This way we are sure that
> + * all the data written in the previous transaction are already on disk
> + * (truncate waits for pages under writeback).
> + */
> +static int ext4_setsize(struct inode *inode, loff_t newsize)
> +{
> + int error = 0, rc;
> + loff_t oldsize = inode->i_size;
> + handle_t *handle;
> +
> + error = inode_newsize_ok(inode, newsize);
> + if (error)
> + goto out;
> + /* VFS should have checked these and return error... */
> + WARN_ON(!S_ISREG(inode->i_mode) || IS_APPEND(inode) ||
> + IS_IMMUTABLE(inode));
> +
> + if (newsize < oldsize) {
> + handle = ext4_journal_start(inode, 3);
> + if (IS_ERR(handle)) {
> + error = PTR_ERR(handle);
> + goto err_out;
> + }
> +
> + error = ext4_orphan_add(handle, inode);
> + EXT4_I(inode)->i_disksize = newsize;
> + rc = ext4_mark_inode_dirty(handle, inode);
> + if (!error)
> + error = rc;
> + ext4_journal_stop(handle);
> +
> + if (ext4_should_order_data(inode)) {
> + error = ext4_begin_ordered_truncate(inode, newsize);
> + if (error) {
> + /* Do as much error cleanup as possible */
> + handle = ext4_journal_start(inode, 3);
> + if (IS_ERR(handle)) {
> + ext4_orphan_del(NULL, inode);
> + goto err_out;
> + }
> + ext4_orphan_del(handle, inode);
> + ext4_journal_stop(handle);
> + goto err_out;
> + }
> + }
> + } else if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) {
> + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
> +
> + if (newsize > sbi->s_bitmap_maxbytes) {
> + error = -EFBIG;
> + goto out;
> + }
> + }
> +
> + i_size_write(inode, newsize);
> + truncate_pagecache(inode, oldsize, newsize);
> + ext4_truncate(inode);
> +
> + /*
> + * If we failed to get a transaction handle at all, we need to clean up
> + * the in-core orphan list manually.
> + */
> + if (inode->i_nlink)
> + ext4_orphan_del(NULL, inode);
> +err_out:
> + ext4_std_error(inode->i_sb, error);
> +out:
> + return error;
> +}
> +
> +
> +/*
> + * ext4_setattr()
> *
> - * Another thing we have to assure is that if we are in ordered mode
> - * and inode is still attached to the committing transaction, we must
> - * we start writeout of all the dirty pages which are being truncated.
> - * This way we are sure that all the data written in the previous
> - * transaction are already on disk (truncate waits for pages under
> - * writeback).
> + * Handle special things ext4 needs for changing owner of the file, changing
> + * ACLs, or truncating file.
> *
> - * Called with inode->i_mutex down.
> + * Called from notify_change with inode->i_mutex down.
> */
> int ext4_setattr(struct dentry *dentry, struct iattr *attr)
> {
> @@ -4743,61 +4816,18 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
> }
>
> if (attr->ia_valid & ATTR_SIZE) {
> - if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) {
> - struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
> -
> - if (attr->ia_size > sbi->s_bitmap_maxbytes) {
> - error = -EFBIG;
> - goto err_out;
> - }
> - }
> - }
> -
> - if (S_ISREG(inode->i_mode) &&
> - attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
> - handle_t *handle;
> -
> - handle = ext4_journal_start(inode, 3);
> - if (IS_ERR(handle)) {
> - error = PTR_ERR(handle);
> - goto err_out;
> - }
> -
> - error = ext4_orphan_add(handle, inode);
> - EXT4_I(inode)->i_disksize = attr->ia_size;
> - rc = ext4_mark_inode_dirty(handle, inode);
> - if (!error)
> - error = rc;
> - ext4_journal_stop(handle);
> -
> - if (ext4_should_order_data(inode)) {
> - error = ext4_begin_ordered_truncate(inode,
> - attr->ia_size);
> - if (error) {
> - /* Do as much error cleanup as possible */
> - handle = ext4_journal_start(inode, 3);
> - if (IS_ERR(handle)) {
> - ext4_orphan_del(NULL, inode);
> - goto err_out;
> - }
> - ext4_orphan_del(handle, inode);
> - ext4_journal_stop(handle);
> - goto err_out;
> - }
> - }
> + error = ext4_setsize(inode, attr->ia_size);
> + if (error)
> + return error;
> }
>
> - rc = inode_setattr(inode, attr);
> -
> - /* If inode_setattr's call to ext4_truncate failed to get a
> - * transaction handle at all, we need to clean up the in-core
> - * orphan list manually. */
> - if (inode->i_nlink)
> - ext4_orphan_del(NULL, inode);
> + generic_setattr(inode, attr);
>
> - if (!rc && (ia_valid & ATTR_MODE))
> + if (ia_valid & ATTR_MODE)
> rc = ext4_acl_chmod(inode);
>
> + /* Mark inode dirty due to changes done by generic_setattr() */
> + mark_inode_dirty(inode);
> err_out:
> ext4_std_error(inode->i_sb, error);
> if (!error)
> --
> 1.6.0.2
>
--
Jan Kara <jack@...e.cz>
SUSE Labs, CR
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