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ANDROID: fuse-bpf: Fix RCU/reference issue

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094905c877 ("ANDROID: fuse-bpf: Always call revalidate for backing")
called dget_parent/dput improperly within an RCU context. Additionally,
it failed to free/put some references.

Fixes: 094905c877 ("ANDROID: fuse-bpf: Always call revalidate for backing")
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Change-Id: Iedeee7550ff88366bc5310eedece285019336814
This commit is contained in:
Daniel Rosenberg
2022-07-25 14:28:33 -07:00
parent 1f44e4411f
commit f2cf53322f
1 changed files with 10 additions and 15 deletions
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25
fs/fuse/dir.c
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@@ -243,14 +243,6 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
goto out; goto out;
} }
} }
/* TODO: Respect timeouts for lookups with backing inodes */
parent = dget_parent(entry);
if (get_fuse_inode(d_inode_rcu(parent))->backing_inode) {
dput(parent);
ret = 1;
goto out;
}
dput(parent);
#endif #endif
if (time_before64(fuse_dentry_time(entry), get_jiffies_64()) || if (time_before64(fuse_dentry_time(entry), get_jiffies_64()) ||
(flags & LOOKUP_REVAL)) { (flags & LOOKUP_REVAL)) {
@@ -269,23 +261,26 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
goto out; goto out;
fm = get_fuse_mount(inode); fm = get_fuse_mount(inode);
forget = fuse_alloc_forget();
ret = -ENOMEM;
if (!forget)
goto out;
attr_version = fuse_get_attr_version(fm->fc);
parent = dget_parent(entry); parent = dget_parent(entry);
/* TODO: Once we're handling timeouts for backing inodes, do a /* TODO: Once we're handling timeouts for backing inodes, do a
* bpf based lookup_revalidate here. * bpf based lookup_revalidate here.
*/ */
if (get_fuse_inode(parent->d_inode)->backing_inode) { if (get_fuse_inode(parent->d_inode)->backing_inode) {
dput(parent);
ret = 1; ret = 1;
goto out; goto out;
} }
forget = fuse_alloc_forget();
ret = -ENOMEM;
if (!forget) {
dput(parent);
goto out;
}
attr_version = fuse_get_attr_version(fm->fc);
fuse_lookup_init(fm->fc, &args, get_node_id(d_inode(parent)), fuse_lookup_init(fm->fc, &args, get_node_id(d_inode(parent)),
&entry->d_name, &outarg, &bpf_arg.out); &entry->d_name, &outarg, &bpf_arg.out);
ret = fuse_simple_request(fm, &args); ret = fuse_simple_request(fm, &args);