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Linux 4.7 compat: inode_lock() and friends 

Linux 4.7 changes i_mutex to i_rwsem, and we should used inode_lock and
inode_lock_shared to do exclusive and shared lock respectively.

We use spl_inode_lock{,_shared}() to hide the difference. Note that on older
kernel you'll always take an exclusive lock.

We also add all other inode_lock friends. And nested users now should
explicitly call spl_inode_lock_nested with correct subclass.

Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue zfsonlinux/zfs#4665
Closes #549
This commit is contained in:
Chunwei Chen 2016-05-18 11:28:46 -07:00 committed by Brian Behlendorf
parent 39cd90ef08
commit fdbc1ba99d
3 changed files with 45 additions and 2 deletions
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25
config/spl-build.m4
View File

@ -45,6 +45,7 @@ AC_DEFUN([SPL_AC_CONFIG_KERNEL], [
SPL_AC_KMEM_CACHE_ALLOCFLAGS
SPL_AC_WAIT_ON_BIT
SPL_AC_MUTEX_OWNER
SPL_AC_INODE_LOCK
])
AC_DEFUN([SPL_AC_MODULE_SYMVERS], [
@ -1476,3 +1477,27 @@ AC_DEFUN([SPL_AC_MUTEX_OWNER], [
])
EXTRA_KCFLAGS="$tmp_flags"
])
dnl #
dnl # 4.7 API change
dnl # i_mutex is changed to i_rwsem. Instead of directly using
dnl # i_mutex/i_rwsem, we should use inode_lock() and inode_lock_shared()
dnl # We test inode_lock_shared because inode_lock is introduced earlier.
dnl #
AC_DEFUN([SPL_AC_INODE_LOCK], [
AC_MSG_CHECKING([whether inode_lock_shared() exists])
tmp_flags="$EXTRA_KCFLAGS"
EXTRA_KCFLAGS="-Werror"
SPL_LINUX_TRY_COMPILE([
#include <linux/fs.h>
],[
struct inode *inode = NULL;
inode_lock_shared(inode);
],[
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_INODE_LOCK_SHARED, 1, [yes])
],[
AC_MSG_RESULT(no)
])
EXTRA_KCFLAGS="$tmp_flags"
])

19
include/linux/file_compat.h
View File

@ -76,8 +76,25 @@ spl_filp_fallocate(struct file *fp, int mode, loff_t offset, loff_t len)
#define spl_filp_fsync(fp, sync) vfs_fsync(fp, (fp)->f_dentry, sync)
#endif /* HAVE_2ARGS_VFS_FSYNC */
#define spl_inode_lock(ip) mutex_lock_nested(&(ip)->i_mutex, I_MUTEX_PARENT)
#ifdef HAVE_INODE_LOCK_SHARED
#define spl_inode_lock(ip) inode_lock(ip)
#define spl_inode_unlock(ip) inode_unlock(ip)
#define spl_inode_lock_shared(ip) inode_lock_shared(ip)
#define spl_inode_unlock_shared(ip) inode_unlock_shared(ip)
#define spl_inode_trylock(ip) inode_trylock(ip)
#define spl_inode_trylock_shared(ip) inode_trylock_shared(ip)
#define spl_inode_is_locked(ip) inode_is_locked(ip)
#define spl_inode_lock_nested(ip, s) inode_lock_nested(ip, s)
#else
#define spl_inode_lock(ip) mutex_lock(&(ip)->i_mutex)
#define spl_inode_unlock(ip) mutex_unlock(&(ip)->i_mutex)
#define spl_inode_lock_shared(ip) mutex_lock(&(ip)->i_mutex)
#define spl_inode_unlock_shared(ip) mutex_unlock(&(ip)->i_mutex)
#define spl_inode_trylock(ip) mutex_trylock(&(ip)->i_mutex)
#define spl_inode_trylock_shared(ip) mutex_trylock(&(ip)->i_mutex)
#define spl_inode_is_locked(ip) mutex_is_locked(&(ip)->i_mutex)
#define spl_inode_lock_nested(ip, s) mutex_lock_nested(&(ip)->i_mutex, s)
#endif
#endif /* SPL_FILE_COMPAT_H */

3
module/spl/spl-vnode.c
View File

@ -352,7 +352,8 @@ spl_kern_path_locked(const char *name, struct path *path)
if (rc)
return (ERR_PTR(rc));
spl_inode_lock(parent.dentry->d_inode);
/* use I_MUTEX_PARENT because vfs_unlink needs it */
spl_inode_lock_nested(parent.dentry->d_inode, I_MUTEX_PARENT);
dentry = lookup_one_len(basename, parent.dentry, len);
if (IS_ERR(dentry)) {