6.6-stable review patch. If anyone has any objections, please let me know.
------------------ From: Amir Goldstein <[email protected]> [ Upstream commit 880bd496ec72a6dcb00cb70c430ef752ba242ae7 ] In preparation to adding LSM blob to backing_file struct, factor out helpers init_backing_file() and backing_file_free(). Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Signed-off-by: Amir Goldstein <[email protected]> Reviewed-by: Serge Hallyn <[email protected]> [PM: use the term "LSM blob", fix comment style to match file] Signed-off-by: Paul Moore <[email protected]> [1. The commit def3ae83da02 ("fs: store real path instead of fake path in backing file f_path") is not merged, The 6.6 LTS version accordingly operates on &ff->real_path instead of &ff->user_path. 2. Mainline's file_free() does both the backing_file cleanup and the kmem_cache_free() synchronously. Linux 6.6.y defers the actual kfree() to file_free_rcu() via call_rcu(), so only path_put() is done synchronously in file_free().] Signed-off-by: Cai Xinchen <[email protected]> Signed-off-by: Sasha Levin <[email protected]> --- fs/file_table.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) diff --git a/fs/file_table.c b/fs/file_table.c index 234284ef72a9a5..b4c208a771539d 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -72,11 +72,16 @@ static void file_free_rcu(struct rcu_head *head) kmem_cache_free(filp_cachep, f); } +static inline void backing_file_free(struct backing_file *ff) +{ + path_put(&ff->real_path); +} + static inline void file_free(struct file *f) { security_file_free(f); if (unlikely(f->f_mode & FMODE_BACKING)) - path_put(backing_file_real_path(f)); + backing_file_free(backing_file(f)); if (likely(!(f->f_mode & FMODE_NOACCOUNT))) percpu_counter_dec(&nr_files); call_rcu(&f->f_rcuhead, file_free_rcu); @@ -252,6 +257,12 @@ struct file *alloc_empty_file_noaccount(int flags, const struct cred *cred) return f; } +static int init_backing_file(struct backing_file *ff) +{ + memset(&ff->real_path, 0, sizeof(ff->real_path)); + return 0; +} + /* * Variant of alloc_empty_file() that allocates a backing_file container * and doesn't check and modify nr_files. @@ -274,7 +285,14 @@ struct file *alloc_empty_backing_file(int flags, const struct cred *cred) return ERR_PTR(error); } + /* The f_mode flags must be set before fput(). */ ff->file.f_mode |= FMODE_BACKING | FMODE_NOACCOUNT; + error = init_backing_file(ff); + if (unlikely(error)) { + fput(&ff->file); + return ERR_PTR(error); + } + return &ff->file; } -- 2.53.0
