> > I'm not sure how to resolve it in EROFS itself, anyway...
Instead of allocating the erofs_sb_info in fill_super() allocate it
during erofs_get_tree() and then you can ensure that you always have the
info you need available during erofs_kill_sb(). See the appended
(untested) patch.
>From e4f586a41748b6edc05aca36d49b7b39e55def81 Mon Sep 17 00:00:00 2001
From: Christian Brauner <brau...@kernel.org>
Date: Mon, 15 Apr 2024 20:17:46 +0800
Subject: [PATCH] erofs: reliably distinguish block based and fscache mode
When erofs_kill_sb() is called in block dev based mode, s_bdev may not have
been initialised yet, and if CONFIG_EROFS_FS_ONDEMAND is enabled, it will
be mistaken for fscache mode, and then attempt to free an anon_dev that has
never been allocated, triggering the following warning:
============================================
ida_free called for id=0 which is not allocated.
WARNING: CPU: 14 PID: 926 at lib/idr.c:525 ida_free+0x134/0x140
Modules linked in:
CPU: 14 PID: 926 Comm: mount Not tainted 6.9.0-rc3-dirty #630
RIP: 0010:ida_free+0x134/0x140
Call Trace:
<TASK>
erofs_kill_sb+0x81/0x90
deactivate_locked_super+0x35/0x80
get_tree_bdev+0x136/0x1e0
vfs_get_tree+0x2c/0xf0
do_new_mount+0x190/0x2f0
[...]
============================================
Instead of allocating the erofs_sb_info in fill_super() allocate it
during erofs_get_tree() and ensure that erofs can always have the info
available during erofs_kill_sb().
Signed-off-by: Baokun Li <libaok...@huawei.com>
Signed-off-by: Christian Brauner <brau...@kernel.org>
---
fs/erofs/super.c | 29 ++++++++++++++++-------------
1 file changed, 16 insertions(+), 13 deletions(-)
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index c0eb139adb07..4ed80154edf8 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -581,7 +581,7 @@ static const struct export_operations erofs_export_ops = {
static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
{
struct inode *inode;
- struct erofs_sb_info *sbi;
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
struct erofs_fs_context *ctx = fc->fs_private;
int err;
@@ -590,15 +590,10 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
sb->s_maxbytes = MAX_LFS_FILESIZE;
sb->s_op = &erofs_sops;
- sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
- if (!sbi)
- return -ENOMEM;
-
sb->s_fs_info = sbi;
sbi->opt = ctx->opt;
sbi->devs = ctx->devs;
ctx->devs = NULL;
- sbi->fsid = ctx->fsid;
ctx->fsid = NULL;
sbi->domain_id = ctx->domain_id;
ctx->domain_id = NULL;
@@ -707,8 +702,15 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
static int erofs_fc_get_tree(struct fs_context *fc)
{
struct erofs_fs_context *ctx = fc->fs_private;
+ struct erofs_sb_info *sbi;
+
+ sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
+ if (!sbi)
+ return -ENOMEM;
- if (IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && ctx->fsid)
+ fc->s_fs_info = sbi;
+ sbi->fsid = ctx->fsid;
+ if (IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && sbi->fsid)
return get_tree_nodev(fc, erofs_fc_fill_super);
return get_tree_bdev(fc, erofs_fc_fill_super);
@@ -762,11 +764,15 @@ static void erofs_free_dev_context(struct erofs_dev_context *devs)
static void erofs_fc_free(struct fs_context *fc)
{
struct erofs_fs_context *ctx = fc->fs_private;
+ struct erofs_sb_info *sbi = fc->s_fs_info;
erofs_free_dev_context(ctx->devs);
kfree(ctx->fsid);
kfree(ctx->domain_id);
kfree(ctx);
+
+ if (sbi)
+ kfree(sbi);
}
static const struct fs_context_operations erofs_context_ops = {
@@ -783,6 +789,7 @@ static int erofs_init_fs_context(struct fs_context *fc)
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
+
ctx->devs = kzalloc(sizeof(struct erofs_dev_context), GFP_KERNEL);
if (!ctx->devs) {
kfree(ctx);
@@ -799,17 +806,13 @@ static int erofs_init_fs_context(struct fs_context *fc)
static void erofs_kill_sb(struct super_block *sb)
{
- struct erofs_sb_info *sbi;
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
- if (erofs_is_fscache_mode(sb))
+ if (IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && sbi->fsid)
kill_anon_super(sb);
else
kill_block_super(sb);
- sbi = EROFS_SB(sb);
- if (!sbi)
- return;
-
erofs_free_dev_context(sbi->devs);
fs_put_dax(sbi->dax_dev, NULL);
erofs_fscache_unregister_fs(sb);
--
2.43.0
