Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:

 * Fix include order for bison/flex-generated C files, from Ben Hutchings

 * Build fixes and documentation corrections from David Ahern

 * Group parsing support, from Jiri Olsa

 * UI/gtk refactorings and improvements from Namhyung Kim

 * NULL deref fix for perf script, from Namhyung Kim

 * Assorted cleanups from Robert Richter

 * Let O= makes handle relative paths, from Steven Rostedt

 * perf script python fixes, from Feng Tang.

 * Improve 'perf lock' error message when the needed tracepoints
   are not present, from David Ahern.

 * Initial bash completion support, from Frederic Weisbecker

 * Allow building without libelf, from Namhyung Kim.

 * Support DWARF CFI based unwind to have callchains when %bp
   based unwinding is not possible, from Jiri Olsa.

 * Symbol resolution fixes, while fixing support PPC64 files with an .opt ELF
   section was the end goal, several fixes for code that handles all
   architectures and cleanups are included, from Cody Schafer.

 * Add a description for the JIT interface, from Andi Kleen.

 * Assorted fixes for Documentation and build in 32 bit, from Robert Richter

 * Add support for non-tracepoint events in perf script python, from Feng Tang

 * Cache the libtraceevent event_format associated to each evsel early, so that we
   avoid relookups, i.e. calling pevent_find_event repeatedly when processing
   tracepoint events.

   [ This is to reduce the surface contact with libtraceevents and make clear what
     is that the perf tools needs from that lib: so far parsing the common and per
     event fields. ]

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 11 insertions, 5 deletions

diff --git a/fs/inode.c b/fs/inode.c
index c99163b1b31..ac8d904b3f1 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -182,7 +182,7 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
 	}
 	inode->i_private = NULL;
 	inode->i_mapping = mapping;
-	INIT_LIST_HEAD(&inode->i_dentry);	/* buggered by rcu freeing */
+	INIT_HLIST_HEAD(&inode->i_dentry);	/* buggered by rcu freeing */
 #ifdef CONFIG_FS_POSIX_ACL
 	inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
 #endif
@@ -1542,18 +1542,24 @@ void touch_atime(struct path *path)
 	if (timespec_equal(&inode->i_atime, &now))
 		return;
 
-	if (mnt_want_write(mnt))
+	if (!sb_start_write_trylock(inode->i_sb))
 		return;
 
+	if (__mnt_want_write(mnt))
+		goto skip_update;
 	/*
 	 * File systems can error out when updating inodes if they need to
 	 * allocate new space to modify an inode (such is the case for
 	 * Btrfs), but since we touch atime while walking down the path we
 	 * really don't care if we failed to update the atime of the file,
 	 * so just ignore the return value.
+	 * We may also fail on filesystems that have the ability to make parts
+	 * of the fs read only, e.g. subvolumes in Btrfs.
 	 */
 	update_time(inode, &now, S_ATIME);
-	mnt_drop_write(mnt);
+	__mnt_drop_write(mnt);
+skip_update:
+	sb_end_write(inode->i_sb);
 }
 EXPORT_SYMBOL(touch_atime);
 
@@ -1660,11 +1666,11 @@ int file_update_time(struct file *file)
 		return 0;
 
 	/* Finally allowed to write? Takes lock. */
-	if (mnt_want_write_file(file))
+	if (__mnt_want_write_file(file))
 		return 0;
 
 	ret = update_time(inode, &now, sync_it);
-	mnt_drop_write_file(file);
+	__mnt_drop_write_file(file);
 
 	return ret;
 }