On Wed, May 26, 2010 at 10:45:45AM -0400, tytso@xxxxxxx wrote: > OK, but why not have the truncate *always* restart its job after > restarting the transaction? #1, it's relatively rare in most > workloads that we need to restart the transaction at all in the first > place, and #2, it's easier to test if we always restart the truncate, > and #3, it's not like we'll be doing that much extra work if we > restart the truncate and the file wasn't extended significantly... > Like this.... (note how much simpler this patch is compared to earlier versions) - Ted ext4: restart ext4_ext_remove_space() after transaction restart From: Dmitry Monakhov <dmonakhov@xxxxxxxxxx> 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@xxxxxxxxxx> Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx> Acked-by: Jan Kara <jack@xxxxxxx> --- 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 ffcaa11..0a47bec 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; } @@ -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; -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
