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fs: use debug-only asserts around fd allocation and install

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This also restores the check which got removed in 52732bb9abc9ee5b
("fs/file.c: remove sanity_check and add likely/unlikely in alloc_fd()")
for performance reasons -- they no longer apply with a debug-only
variant.

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://lore.kernel.org/r/20250312161941.1261615-1-mjguzik@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Mateusz Guzik 2025-03-12 17:19:41 +01:00 committed by Christian Brauner
parent 86f40fa6a4
commit dc530c44cd
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GPG Key ID: 91C61BC06578DCA2
1 changed files with 3 additions and 2 deletions
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5
fs/file.c
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@ -577,6 +577,7 @@ static int alloc_fd(unsigned start, unsigned end, unsigned flags)
__set_open_fd(fd, fdt, flags & O_CLOEXEC);
error = fd;
VFS_BUG_ON(rcu_access_pointer(fdt->fd[fd]) != NULL);
out:
spin_unlock(&files->file_lock);
@ -642,7 +643,7 @@ void fd_install(unsigned int fd, struct file *file)
rcu_read_unlock_sched();
spin_lock(&files->file_lock);
fdt = files_fdtable(files);
WARN_ON(fdt->fd[fd] != NULL);
VFS_BUG_ON(rcu_access_pointer(fdt->fd[fd]) != NULL);
rcu_assign_pointer(fdt->fd[fd], file);
spin_unlock(&files->file_lock);
return;
@ -650,7 +651,7 @@ void fd_install(unsigned int fd, struct file *file)
/* coupled with smp_wmb() in expand_fdtable() */
smp_rmb();
fdt = rcu_dereference_sched(files->fdt);
BUG_ON(fdt->fd[fd] != NULL);
VFS_BUG_ON(rcu_access_pointer(fdt->fd[fd]) != NULL);
rcu_assign_pointer(fdt->fd[fd], file);
rcu_read_unlock_sched();
}