From bfcd17a6c5529bc37234cfa720a047cf9397bcfc Mon Sep 17 00:00:00 2001 From: Thomas Petazzoni Date: Wed, 6 Aug 2008 15:12:22 +0200 Subject: [PATCH] Configure out file locking features This patch adds the CONFIG_FILE_LOCKING option which allows to remove support for advisory locks. With this patch enabled, the flock() system call, the F_GETLK, F_SETLK and F_SETLKW operations of fcntl() and NFS support are disabled. These features are not necessarly needed on embedded systems. It allows to save ~11 Kb of kernel code and data: text data bss dec hex filename 1125436 118764 212992 1457192 163c28 vmlinux.old 1114299 118564 212992 1445855 160fdf vmlinux -11137 -200 0 -11337 -2C49 +/- This patch has originally been written by Matt Mackall , and is part of the Linux Tiny project. Signed-off-by: Thomas Petazzoni Signed-off-by: Matt Mackall Cc: matthew@wil.cx Cc: linux-fsdevel@vger.kernel.org Cc: mpm@selenic.com Cc: akpm@linux-foundation.org Signed-off-by: J. Bruce Fields --- fs/Kconfig | 8 +++++++ fs/Makefile | 3 ++- fs/proc/proc_misc.c | 4 ++++ include/linux/fs.h | 57 +++++++++++++++++++++++++++++++++++++++------ kernel/sys_ni.c | 1 + kernel/sysctl.c | 6 ++++- 6 files changed, 70 insertions(+), 9 deletions(-) diff --git a/fs/Kconfig b/fs/Kconfig index abccb5dab9a8..c6ae4d4842eb 100644 --- a/fs/Kconfig +++ b/fs/Kconfig @@ -419,6 +419,14 @@ config FS_POSIX_ACL bool default n +config FILE_LOCKING + bool "Enable POSIX file locking API" if EMBEDDED + default y + help + This option enables standard file locking support, required + for filesystems like NFS and for the flock() system + call. Disabling this option saves about 11k. + source "fs/xfs/Kconfig" source "fs/gfs2/Kconfig" diff --git a/fs/Makefile b/fs/Makefile index a1482a5eff15..4b86d433baaf 100644 --- a/fs/Makefile +++ b/fs/Makefile @@ -7,7 +7,7 @@ obj-y := open.o read_write.o file_table.o super.o \ char_dev.o stat.o exec.o pipe.o namei.o fcntl.o \ - ioctl.o readdir.o select.o fifo.o locks.o dcache.o inode.o \ + ioctl.o readdir.o select.o fifo.o dcache.o inode.o \ attr.o bad_inode.o file.o filesystems.o namespace.o aio.o \ seq_file.o xattr.o libfs.o fs-writeback.o \ pnode.o drop_caches.o splice.o sync.o utimes.o \ @@ -27,6 +27,7 @@ obj-$(CONFIG_ANON_INODES) += anon_inodes.o obj-$(CONFIG_SIGNALFD) += signalfd.o obj-$(CONFIG_TIMERFD) += timerfd.o obj-$(CONFIG_EVENTFD) += eventfd.o +obj-$(CONFIG_FILE_LOCKING) += locks.o obj-$(CONFIG_COMPAT) += compat.o compat_ioctl.o nfsd-$(CONFIG_NFSD) := nfsctl.o diff --git a/fs/proc/proc_misc.c b/fs/proc/proc_misc.c index 29e20c6b1f7f..1aabbe2592e1 100644 --- a/fs/proc/proc_misc.c +++ b/fs/proc/proc_misc.c @@ -684,6 +684,7 @@ static int cmdline_read_proc(char *page, char **start, off_t off, return proc_calc_metrics(page, start, off, count, eof, len); } +#ifdef CONFIG_FILE_LOCKING static int locks_open(struct inode *inode, struct file *filp) { return seq_open(filp, &locks_seq_operations); @@ -695,6 +696,7 @@ static const struct file_operations proc_locks_operations = { .llseek = seq_lseek, .release = seq_release, }; +#endif /* CONFIG_FILE_LOCKING */ static int execdomains_read_proc(char *page, char **start, off_t off, int count, int *eof, void *data) @@ -888,7 +890,9 @@ void __init proc_misc_init(void) #ifdef CONFIG_PRINTK proc_create("kmsg", S_IRUSR, NULL, &proc_kmsg_operations); #endif +#ifdef CONFIG_FILE_LOCKING proc_create("locks", 0, NULL, &proc_locks_operations); +#endif proc_create("devices", 0, NULL, &proc_devinfo_operations); proc_create("cpuinfo", 0, NULL, &proc_cpuinfo_operations); #ifdef CONFIG_BLOCK diff --git a/include/linux/fs.h b/include/linux/fs.h index 580b513668fe..9f540165a078 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -983,6 +983,13 @@ struct file_lock { #include +extern void send_sigio(struct fown_struct *fown, int fd, int band); + +/* fs/sync.c */ +extern int do_sync_mapping_range(struct address_space *mapping, loff_t offset, + loff_t endbyte, unsigned int flags); + +#ifdef CONFIG_FILE_LOCKING extern int fcntl_getlk(struct file *, struct flock __user *); extern int fcntl_setlk(unsigned int, struct file *, unsigned int, struct flock __user *); @@ -993,14 +1000,9 @@ extern int fcntl_setlk64(unsigned int, struct file *, unsigned int, struct flock64 __user *); #endif -extern void send_sigio(struct fown_struct *fown, int fd, int band); extern int fcntl_setlease(unsigned int fd, struct file *filp, long arg); extern int fcntl_getlease(struct file *filp); -/* fs/sync.c */ -extern int do_sync_mapping_range(struct address_space *mapping, loff_t offset, - loff_t endbyte, unsigned int flags); - /* fs/locks.c */ extern void locks_init_lock(struct file_lock *); extern void locks_copy_lock(struct file_lock *, struct file_lock *); @@ -1023,6 +1025,37 @@ extern int lease_modify(struct file_lock **, int); extern int lock_may_read(struct inode *, loff_t start, unsigned long count); extern int lock_may_write(struct inode *, loff_t start, unsigned long count); extern struct seq_operations locks_seq_operations; +#else /* !CONFIG_FILE_LOCKING */ +#define fcntl_getlk(a, b) ({ -EINVAL; }) +#define fcntl_setlk(a, b, c, d) ({ -EACCES; }) +#if BITS_PER_LONG == 32 +#define fcntl_getlk64(a, b) ({ -EINVAL; }) +#define fcntl_setlk64(a, b, c, d) ({ -EACCES; }) +#endif +#define fcntl_setlease(a, b, c) ({ 0; }) +#define fcntl_getlease(a) ({ 0; }) +#define locks_init_lock(a) ({ }) +#define __locks_copy_lock(a, b) ({ }) +#define locks_copy_lock(a, b) ({ }) +#define locks_remove_posix(a, b) ({ }) +#define locks_remove_flock(a) ({ }) +#define posix_test_lock(a, b) ({ 0; }) +#define posix_lock_file(a, b, c) ({ -ENOLCK; }) +#define posix_lock_file_wait(a, b) ({ -ENOLCK; }) +#define posix_unblock_lock(a, b) (-ENOENT) +#define vfs_test_lock(a, b) ({ 0; }) +#define vfs_lock_file(a, b, c, d) (-ENOLCK) +#define vfs_cancel_lock(a, b) ({ 0; }) +#define flock_lock_file_wait(a, b) ({ -ENOLCK; }) +#define __break_lease(a, b) ({ 0; }) +#define lease_get_mtime(a, b) ({ }) +#define generic_setlease(a, b, c) ({ -EINVAL; }) +#define vfs_setlease(a, b, c) ({ -EINVAL; }) +#define lease_modify(a, b) ({ -EINVAL; }) +#define lock_may_read(a, b, c) ({ 1; }) +#define lock_may_write(a, b, c) ({ 1; }) +#endif /* !CONFIG_FILE_LOCKING */ + struct fasync_struct { int magic; @@ -1554,9 +1587,12 @@ extern int vfs_statfs(struct dentry *, struct kstatfs *); /* /sys/fs */ extern struct kobject *fs_kobj; +extern int rw_verify_area(int, struct file *, loff_t *, size_t); + #define FLOCK_VERIFY_READ 1 #define FLOCK_VERIFY_WRITE 2 +#ifdef CONFIG_FILE_LOCKING extern int locks_mandatory_locked(struct inode *); extern int locks_mandatory_area(int, struct inode *, struct file *, loff_t, size_t); @@ -1587,8 +1623,6 @@ static inline int locks_verify_locked(struct inode *inode) return 0; } -extern int rw_verify_area(int, struct file *, loff_t *, size_t); - static inline int locks_verify_truncate(struct inode *inode, struct file *filp, loff_t size) @@ -1609,6 +1643,15 @@ static inline int break_lease(struct inode *inode, unsigned int mode) return __break_lease(inode, mode); return 0; } +#else /* !CONFIG_FILE_LOCKING */ +#define locks_mandatory_locked(a) ({ 0; }) +#define locks_mandatory_area(a, b, c, d, e) ({ 0; }) +#define __mandatory_lock(a) ({ 0; }) +#define mandatory_lock(a) ({ 0; }) +#define locks_verify_locked(a) ({ 0; }) +#define locks_verify_truncate(a, b, c) ({ 0; }) +#define break_lease(a, b) ({ 0; }) +#endif /* CONFIG_FILE_LOCKING */ /* fs/open.c */ diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index 08d6e1bb99ac..503d8d4eb80a 100644 --- a/kernel/sys_ni.c +++ b/kernel/sys_ni.c @@ -125,6 +125,7 @@ cond_syscall(sys_vm86old); cond_syscall(sys_vm86); cond_syscall(compat_sys_ipc); cond_syscall(compat_sys_sysctl); +cond_syscall(sys_flock); /* arch-specific weak syscall entries */ cond_syscall(sys_pciconfig_read); diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 50ec0886fa3d..4588b2cf2ecb 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -97,7 +97,7 @@ static int sixty = 60; static int neg_one = -1; #endif -#ifdef CONFIG_MMU +#if defined(CONFIG_MMU) && defined(CONFIG_FILE_LOCKING) static int two = 2; #endif @@ -1261,6 +1261,7 @@ static struct ctl_table fs_table[] = { .extra1 = &minolduid, .extra2 = &maxolduid, }, +#ifdef CONFIG_FILE_LOCKING { .ctl_name = FS_LEASES, .procname = "leases-enable", @@ -1269,6 +1270,7 @@ static struct ctl_table fs_table[] = { .mode = 0644, .proc_handler = &proc_dointvec, }, +#endif #ifdef CONFIG_DNOTIFY { .ctl_name = FS_DIR_NOTIFY, @@ -1280,6 +1282,7 @@ static struct ctl_table fs_table[] = { }, #endif #ifdef CONFIG_MMU +#ifdef CONFIG_FILE_LOCKING { .ctl_name = FS_LEASE_TIME, .procname = "lease-break-time", @@ -1291,6 +1294,7 @@ static struct ctl_table fs_table[] = { .extra1 = &zero, .extra2 = &two, }, +#endif { .procname = "aio-nr", .data = &aio_nr,