Linux 4.12 compat: PF_FSTRANS was removed

Change SPL_FSTRANS to optionally contains PF_FSTRANS. Also, add
__spl_pf_fstrans_check for the checks specifically for PF_FSTRANS.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Closes #614

diff --git a/include/sys/kmem.h b/include/sys/kmem.h
index d4b3bf680a454528ec9514258b6d4e193582eaf7..d6b428551fe15d62c3eca8f2d43dda0b4319c9dd 100644 (file)
--- a/include/sys/kmem.h
+++ b/include/sys/kmem.h
@@ -46,6 +46,8 @@ extern void strfree(char *str);
 
 #define        KM_PUBLIC_MASK  (KM_SLEEP | KM_NOSLEEP | KM_PUSHPAGE)
 
+static int spl_fstrans_check(void);
+
 /*
  * Convert a KM_* flags mask to its Linux GFP_* counterpart.  The conversion
  * function is context aware which means that KM_SLEEP allocations can be
@@ -60,7 +62,7 @@ kmem_flags_convert(int flags)
                lflags |= GFP_ATOMIC | __GFP_NORETRY;
        } else {
                lflags |= GFP_KERNEL;
-               if ((current->flags & PF_FSTRANS))
+               if (spl_fstrans_check())
                        lflags &= ~(__GFP_IO|__GFP_FS);
        }
 
@@ -78,17 +80,34 @@ typedef struct {
        unsigned int saved_flags;
 } fstrans_cookie_t;
 
+/*
+ * Introduced in Linux 3.9, however this cannot be solely relied on before
+ * Linux 3.18 as it doesn't turn off __GFP_FS as it should.
+ */
 #ifdef PF_MEMALLOC_NOIO
-#define        SPL_FSTRANS (PF_FSTRANS|PF_MEMALLOC_NOIO)
+#define        __SPL_PF_MEMALLOC_NOIO (PF_MEMALLOC_NOIO)
+#else
+#define        __SPL_PF_MEMALLOC_NOIO (0)
+#endif
+
+/*
+ * PF_FSTRANS is removed from Linux 4.12
+ */
+#ifdef PF_FSTRANS
+#define        __SPL_PF_FSTRANS (PF_FSTRANS)
 #else
-#define        SPL_FSTRANS (PF_FSTRANS)
+#define        __SPL_PF_FSTRANS (0)
 #endif
 
+#define        SPL_FSTRANS (__SPL_PF_FSTRANS|__SPL_PF_MEMALLOC_NOIO)
+
 static inline fstrans_cookie_t
 spl_fstrans_mark(void)
 {
        fstrans_cookie_t cookie;
 
+       BUILD_BUG_ON(SPL_FSTRANS == 0);
+
        cookie.fstrans_thread = current;
        cookie.saved_flags = current->flags & SPL_FSTRANS;
        current->flags |= SPL_FSTRANS;
@@ -109,7 +128,17 @@ spl_fstrans_unmark(fstrans_cookie_t cookie)
 static inline int
 spl_fstrans_check(void)
 {
-       return (current->flags & PF_FSTRANS);
+       return (current->flags & SPL_FSTRANS);
+}
+
+/*
+ * specifically used to check PF_FSTRANS flag, cannot be relied on for
+ * checking spl_fstrans_mark().
+ */
+static inline int
+__spl_pf_fstrans_check(void)
+{
+       return (current->flags & __SPL_PF_FSTRANS);
 }
 
 #ifdef HAVE_ATOMIC64_T

diff --git a/module/spl/spl-vnode.c b/module/spl/spl-vnode.c
index 0902e11618cae09247c8e57b089f85809adfd1c3..346e63c0f1613a4af068338595db08de59fdc439 100644 (file)
--- a/module/spl/spl-vnode.c
+++ b/module/spl/spl-vnode.c
@@ -558,13 +558,13 @@ int vn_fsync(vnode_t *vp, int flags, void *x3, void *x4)
         * May enter XFS which generates a warning when PF_FSTRANS is set.
         * To avoid this the flag is cleared over vfs_sync() and then reset.
         */
-       fstrans = spl_fstrans_check();
+       fstrans = __spl_pf_fstrans_check();
        if (fstrans)
-               current->flags &= ~(PF_FSTRANS);
+               current->flags &= ~(__SPL_PF_FSTRANS);
 
        error = -spl_filp_fsync(vp->v_file, datasync);
        if (fstrans)
-               current->flags |= PF_FSTRANS;
+               current->flags |= __SPL_PF_FSTRANS;
 
        return (error);
 } /* vn_fsync() */
@@ -590,9 +590,9 @@ int vn_space(vnode_t *vp, int cmd, struct flock *bfp, int flag,
         * May enter XFS which generates a warning when PF_FSTRANS is set.
         * To avoid this the flag is cleared over vfs_sync() and then reset.
         */
-       fstrans = spl_fstrans_check();
+       fstrans = __spl_pf_fstrans_check();
        if (fstrans)
-               current->flags &= ~(PF_FSTRANS);
+               current->flags &= ~(__SPL_PF_FSTRANS);
 
        /*
         * When supported by the underlying file system preferentially
@@ -603,7 +603,7 @@ int vn_space(vnode_t *vp, int cmd, struct flock *bfp, int flag,
            bfp->l_start, bfp->l_len);
 
        if (fstrans)
-               current->flags |= PF_FSTRANS;
+               current->flags |= __SPL_PF_FSTRANS;
 
        if (error == 0)
                return (0);