Fix: writeback probe on RHEL >= 3.10.0-327.10.1

[lttng-modules.git] / instrumentation / events / lttng-module / writeback.h

diff --git a/instrumentation/events/lttng-module/writeback.h b/instrumentation/events/lttng-module/writeback.h
index 225940c90d67ce71ad718b879eb8ee1ed8266e7b..6006c2945fecdc61f71bc62afdba025f0aaf98cb 100644 (file)
--- a/instrumentation/events/lttng-module/writeback.h
+++ b/instrumentation/events/lttng-module/writeback.h
@@ -4,7 +4,7 @@
 #if !defined(LTTNG_TRACE_WRITEBACK_H) || defined(TRACE_HEADER_MULTI_READ)
 #define LTTNG_TRACE_WRITEBACK_H
 
-#include "../../../probes/lttng-tracepoint-event.h"
+#include <probes/lttng-tracepoint-event.h>
 #include <linux/tracepoint.h>
 #include <linux/backing-dev.h>
 #include <linux/writeback.h>
@@ -13,16 +13,34 @@
 #ifndef _TRACE_WRITEBACK_DEF_
 #define _TRACE_WRITEBACK_DEF_
 
+/*
+ * Vanilla kernels before 4.0 do not implement inode_to_bdi
+ * RHEL kernels before 3.10.0-327.10.1 do not implement inode_to_bdi
+ * RHEL kernel 3.10.0-327.10.1 has inode_to_bdi
+ * RHEL kernel 3.10.0-327.13.1 includes a partial merge of upstream
+ *  commit a212b105b07d75b48b1a166378282e8a77fbf53d which inlines
+ *  inode_to_bdi but not sb_is_blkdev_sb making it unusable by modules.
+ */
 #if (LINUX_VERSION_CODE < KERNEL_VERSION(4,0,0))
-static inline struct backing_dev_info *inode_to_bdi(struct inode *inode)
+static inline struct backing_dev_info *lttng_inode_to_bdi(struct inode *inode)
 {
-       struct super_block *sb = inode->i_sb;
+       struct super_block *sb;
+
+       if (!inode)
+               return &noop_backing_dev_info;
+
+       sb = inode->i_sb;
 
        if (strcmp(sb->s_type->name, "bdev") == 0)
                return inode->i_mapping->backing_dev_info;
 
        return sb->s_bdi;
 }
+#else
+static inline struct backing_dev_info *lttng_inode_to_bdi(struct inode *inode)
+{
+       return inode_to_bdi(inode);
+}
 #endif /* #if (LINUX_VERSION_CODE < KERNEL_VERSION(4,0,0)) */
 
 #endif
@@ -64,7 +82,7 @@ LTTNG_TRACEPOINT_EVENT(writeback_dirty_page,
        TP_ARGS(page, mapping),
        TP_FIELDS(
                ctf_array_text(char, name,
-                       mapping ? dev_name(inode_to_bdi(mapping->host)->dev) : "(unknown)", 32)
+                       mapping ? dev_name(lttng_inode_to_bdi(mapping->host)->dev) : "(unknown)", 32)
                ctf_integer(unsigned long, ino, mapping ? mapping->host->i_ino : 0)
                ctf_integer(pgoff_t, index, page->index)
        )
@@ -76,8 +94,8 @@ LTTNG_TRACEPOINT_EVENT_CLASS(writeback_dirty_inode_template,
        TP_FIELDS(
                /* may be called for files on pseudo FSes w/ unregistered bdi */
                ctf_array_text(char, name,
-                       inode_to_bdi(inode)->dev ?
-                               dev_name(inode_to_bdi(inode)->dev) : "(unknown)", 32)
+                       lttng_inode_to_bdi(inode)->dev ?
+                               dev_name(lttng_inode_to_bdi(inode)->dev) : "(unknown)", 32)
                ctf_integer(unsigned long, ino, inode->i_ino)
                ctf_integer(unsigned long, state, inode->i_state)
                ctf_integer(unsigned long, flags, flags)
@@ -96,7 +114,7 @@ LTTNG_TRACEPOINT_EVENT_CLASS(writeback_write_inode_template,
        TP_ARGS(inode, wbc),
        TP_FIELDS(
                ctf_array_text(char, name,
-                       dev_name(inode_to_bdi(inode)->dev), 32)
+                       dev_name(lttng_inode_to_bdi(inode)->dev), 32)
                ctf_integer(unsigned long, ino, inode->i_ino)
                ctf_integer(int, sync_mode, wbc->sync_mode)
        )
@@ -608,7 +626,7 @@ LTTNG_TRACEPOINT_EVENT(writeback_sb_inodes_requeue,
 
        TP_FIELDS(
                ctf_array_text(char, name,
-                       dev_name(inode_to_bdi(inode)->dev), 32)
+                       dev_name(lttng_inode_to_bdi(inode)->dev), 32)
                ctf_integer(unsigned long, ino, inode->i_ino)
                ctf_integer(unsigned long, state, inode->i_state)
                ctf_integer(unsigned long, dirtied_when, inode->dirtied_when)
@@ -656,7 +674,7 @@ LTTNG_TRACEPOINT_EVENT_CLASS(writeback_single_inode_template,
 
        TP_FIELDS(
                ctf_array_text(char, name,
-                       dev_name(inode_to_bdi(inode)->dev), 32)
+                       dev_name(lttng_inode_to_bdi(inode)->dev), 32)
                ctf_integer(unsigned long, ino, inode->i_ino)
                ctf_integer(unsigned long, state, inode->i_state)
                ctf_integer(unsigned long, dirtied_when, inode->dirtied_when)
@@ -688,4 +706,4 @@ LTTNG_TRACEPOINT_EVENT_INSTANCE(writeback_single_inode_template, writeback_singl
 #endif /* LTTNG_TRACE_WRITEBACK_H */
 
 /* This part must be outside protection */
-#include "../../../probes/define_trace.h"
+#include <probes/define_trace.h>