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Subject[PATCH] jffs2: remove fd from the f->dents list immediately.
Date
commit 15953580e79b ("[JFFS2] Improve getdents vs. f_pos handling on NOR flash.")
is introduced to resolve 'rm -r', which cannot remove all files:
http://lists.infradead.org/pipermail/linux-mtd/2007-October/019658.html

However, it can cause the following issues:

1. 'deletion' dirents is alway in the f->dents list, wasting memory
resource. For example:
There is a file named 'file1'. Then we rename it:
mv file1 file2;
mv file2 file3;
...
mv file99999 file1000000

When CONFIG_JFFS2_SUMMARY is not set, file1~file1000000
always in the f->dents list.

2. Since the list become longer and longer, more CPU time is used
to traverse it.

After reverting the commit, we test 'rm -r', which can remove all
files, and all seems OK!

Signed-off-by: Yufen Yu <yuyufen@huawei.com>
---
fs/jffs2/write.c | 33 +++++++++++++++++----------------
1 file changed, 17 insertions(+), 16 deletions(-)

diff --git a/fs/jffs2/write.c b/fs/jffs2/write.c
index cda9a361368e..1deed35beb50 100644
--- a/fs/jffs2/write.c
+++ b/fs/jffs2/write.c
@@ -598,31 +598,32 @@ int jffs2_do_unlink(struct jffs2_sb_info *c, struct jffs2_inode_info *dir_f,
jffs2_add_fd_to_list(c, fd, &dir_f->dents);
mutex_unlock(&dir_f->sem);
} else {
+ struct jffs2_full_dirent **prev = &dir_f->dents;
uint32_t nhash = full_name_hash(NULL, name, namelen);

- fd = dir_f->dents;
/* We don't actually want to reserve any space, but we do
want to be holding the alloc_sem when we write to flash */
mutex_lock(&c->alloc_sem);
mutex_lock(&dir_f->sem);

- for (fd = dir_f->dents; fd; fd = fd->next) {
- if (fd->nhash == nhash &&
- !memcmp(fd->name, name, namelen) &&
- !fd->name[namelen]) {
-
- jffs2_dbg(1, "Marking old dirent node (ino #%u) @%08x obsolete\n",
- fd->ino, ref_offset(fd->raw));
- jffs2_mark_node_obsolete(c, fd->raw);
- /* We don't want to remove it from the list immediately,
- because that screws up getdents()/seek() semantics even
- more than they're screwed already. Turn it into a
- node-less deletion dirent instead -- a placeholder */
- fd->raw = NULL;
- fd->ino = 0;
- break;
+ while ((*prev) && (*prev)->nhash <= nhash) {
+ if ((*prev)->nhash == nhash &&
+ !memcmp((*prev)->name, name, namelen) &&
+ !(*prev)->name[namelen]) {
+
+ struct jffs2_full_dirent *this = *prev;
+
+ jffs2_dbg(1, "Marking old dirent node (ino #%u) @%08x obsolete\n",
+ this->ino, ref_offset(this->raw));
+ *prev = this->next;
+ jffs2_mark_node_obsolete(c, this->raw);
+ jffs2_free_full_dirent(this);
+
+ break;
}
+ prev = &((*prev)->next);
}
+
mutex_unlock(&dir_f->sem);
}

--
2.13.6
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