[34-longterm 023/260] ext4: restart ext4_ext_remove_space() after transaction restart

Paul Gortmaker
2011-01-02T08:07:57Z

From: Dmitry Monakhov <dmonakhov@openvz.org>

commit 0617b83fa239db9743a18ce6cc0e556f4d0fd567 upstream.

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: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
fs/ext4/extents.c | 16 +++++++++-------
1 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 5e663a7..bb03109 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -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;
}
@@ -2361,7 +2358,7 @@ 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);

@@ -2370,23 +2367,26 @@ 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) {
@@ -2480,6 +2480,8 @@ 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;
--
1.7.3.3