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Commit 0617b83f authored by Dmitry Monakhov's avatar Dmitry Monakhov Committed by Theodore Ts'o
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ext4: restart ext4_ext_remove_space() after transaction restart 

If i_data_sem was internally dropped due to transaction restart, it is
necessary to restart path look-up because extents tree was possibly
modified by ext4_get_block().

https://bugzilla.kernel.org/show_bug.cgi?id=15827



Signed-off-by: default avatarDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
Acked-by: default avatarJan Kara <jack@suse.cz>
parent 786ec791

fs/ext4/extents.c

+9 −7
Original line number Diff line number Diff line
@@ -107,11 +107,8 @@ static int ext4_ext_truncate_extend_restart(handle_t *handle, 
	if (err <= 0)

		return err;

	err = ext4_truncate_restart_trans(handle, inode, needed);

	/*

	 * We have dropped i_data_sem so someone might have cached again

	 * an extent we are going to truncate.

	 */

	ext4_ext_invalidate_cache(inode);

	if (err == 0)

		err = -EAGAIN;



	return err;

}
@@ -2359,7 +2356,7 @@ static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start) 
	int depth = ext_depth(inode);

	struct ext4_ext_path *path;

	handle_t *handle;

	int i = 0, err = 0;

	int i, err;



	ext_debug("truncate since %u\n", start);
@@ -2368,23 +2365,26 @@ static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start) 
	if (IS_ERR(handle))

		return PTR_ERR(handle);



again:

	ext4_ext_invalidate_cache(inode);



	/*

	 * We start scanning from right side, freeing all the blocks

	 * after i_size and walking into the tree depth-wise.

	 */

	depth = ext_depth(inode);

	path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_NOFS);

	if (path == NULL) {

		ext4_journal_stop(handle);

		return -ENOMEM;

	}

	path[0].p_depth = depth;

	path[0].p_hdr = ext_inode_hdr(inode);

	if (ext4_ext_check(inode, path[0].p_hdr, depth)) {

		err = -EIO;

		goto out;

	}

	path[0].p_depth = depth;

	i = err = 0;



	while (i >= 0 && err == 0) {

		if (i == depth) {
@@ -2478,6 +2478,8 @@ static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start) 
out:

	ext4_ext_drop_refs(path);

	kfree(path);

	if (err == -EAGAIN)

		goto again;

	ext4_journal_stop(handle);



	return err;