ext4: add more tracepoints and use dev_t in the trace buffer

- Add more ext4 tracepoints.
- Change ext4 tracepoints to use dev_t field with MAJOR/MINOR macros
so that we can save 4 bytes in the ring buffer on some platforms.
- Add sync_mode to ext4_da_writepages, ext4_da_write_pages, and
ext4_da_writepages_result tracepoints. Also remove for_reclaim
field from ext4_da_writepages since it is usually not very useful.

Signed-off-by: Jiaying Zhang <jiayingz@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

6 files changed, 49 insertions, 9 deletions

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index adf96b822781..97b970e7dd13 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -21,6 +21,8 @@
 #include "ext4_jbd2.h"
 #include "mballoc.h"
 
+#include <trace/events/ext4.h>
+
 /*
  * balloc.c contains the blocks allocation and deallocation routines
  */
@@ -342,6 +344,7 @@ ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
          * We do it here so the bitmap uptodate bit
          * get set with buffer lock held.
          */
+        trace_ext4_read_block_bitmap_load(sb, block_group);
         set_bitmap_uptodate(bh);
         if (bh_submit_read(bh) < 0) {
                 put_bh(bh);
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 9ea1bc64ca6d..f46f6e3c02d7 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -44,6 +44,8 @@
 #include "ext4_jbd2.h"
 #include "ext4_extents.h"
 
+#include <trace/events/ext4.h>
+
 static int ext4_ext_truncate_extend_restart(handle_t *handle,
                                             struct inode *inode,
                                             int needed)
@@ -664,6 +666,8 @@ ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
                 if (unlikely(!bh))
                         goto err;
                 if (!bh_uptodate_or_lock(bh)) {
+                        trace_ext4_ext_load_extent(inode, block,
+                                                path[ppos].p_block);
                         if (bh_submit_read(bh) < 0) {
                                 put_bh(bh);
                                 goto err;
@@ -3297,7 +3301,7 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
         struct ext4_ext_path *path = NULL;
         struct ext4_extent_header *eh;
         struct ext4_extent newex, *ex;
-        ext4_fsblk_t newblock;
+        ext4_fsblk_t newblock = 0;
         int err = 0, depth, ret;
         unsigned int allocated = 0;
         struct ext4_allocation_request ar;
@@ -3305,6 +3309,7 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
 
         ext_debug("blocks %u/%u requested for inode %lu\n",
                   map->m_lblk, map->m_len, inode->i_ino);
+        trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
 
         /* check in cache */
         if (ext4_ext_in_cache(inode, map->m_lblk, &newex)) {
@@ -3525,6 +3530,8 @@ out2:
                 ext4_ext_drop_refs(path);
                 kfree(path);
         }
+        trace_ext4_ext_map_blocks_exit(inode, map->m_lblk,
+                newblock, map->m_len, err ? err : allocated);
         return err ? err : allocated;
 }
 
@@ -3658,6 +3665,7 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
                 return -EOPNOTSUPP;
 
+        trace_ext4_fallocate_enter(inode, offset, len, mode);
         map.m_lblk = offset >> blkbits;
         /*
          * We can't just convert len to max_blocks because
@@ -3673,6 +3681,7 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
         ret = inode_newsize_ok(inode, (len + offset));
         if (ret) {
                 mutex_unlock(&inode->i_mutex);
+                trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
                 return ret;
         }
 retry:
@@ -3717,6 +3726,8 @@ retry:
                 goto retry;
         }
         mutex_unlock(&inode->i_mutex);
+        trace_ext4_fallocate_exit(inode, offset, max_blocks,
+                                ret > 0 ? ret2 : ret);
         return ret > 0 ? ret2 : ret;
 }
 
diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c
index 7829b287822a..7f74019d6d77 100644
--- a/fs/ext4/fsync.c
+++ b/fs/ext4/fsync.c
@@ -164,20 +164,20 @@ int ext4_sync_file(struct file *file, int datasync)
 
         J_ASSERT(ext4_journal_current_handle() == NULL);
 
-        trace_ext4_sync_file(file, datasync);
+        trace_ext4_sync_file_enter(file, datasync);
 
         if (inode->i_sb->s_flags & MS_RDONLY)
                 return 0;
 
         ret = ext4_flush_completed_IO(inode);
         if (ret < 0)
-                return ret;
+                goto out;
 
         if (!journal) {
                 ret = generic_file_fsync(file, datasync);
                 if (!ret && !list_empty(&inode->i_dentry))
                         ext4_sync_parent(inode);
-                return ret;
+                goto out;
         }
 
         /*
@@ -194,8 +194,10 @@ int ext4_sync_file(struct file *file, int datasync)
          *  (they were dirtied by commit).  But that's OK - the blocks are
          *  safe in-journal, which is all fsync() needs to ensure.
          */
-        if (ext4_should_journal_data(inode))
-                return ext4_force_commit(inode->i_sb);
+        if (ext4_should_journal_data(inode)) {
+                ret = ext4_force_commit(inode->i_sb);
+                goto out;
+        }
 
         commit_tid = datasync ? ei->i_datasync_tid : ei->i_sync_tid;
         if (jbd2_log_start_commit(journal, commit_tid)) {
@@ -215,5 +217,7 @@ int ext4_sync_file(struct file *file, int datasync)
                 ret = jbd2_log_wait_commit(journal, commit_tid);
         } else if (journal->j_flags & JBD2_BARRIER)
                 blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
+ out:
+        trace_ext4_sync_file_exit(inode, ret);
         return ret;
 }
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index a679a482c986..254e6b98b5b4 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -152,6 +152,7 @@ ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
          * We do it here so the bitmap uptodate bit
          * get set with buffer lock held.
          */
+        trace_ext4_load_inode_bitmap(sb, block_group);
         set_bitmap_uptodate(bh);
         if (bh_submit_read(bh) < 0) {
                 put_bh(bh);
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index fc8c0ce84315..f44307a21136 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -973,6 +973,7 @@ static int ext4_ind_map_blocks(handle_t *handle, struct inode *inode,
         int count = 0;
         ext4_fsblk_t first_block = 0;
 
+        trace_ext4_ind_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
         J_ASSERT(!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)));
         J_ASSERT(handle != NULL || (flags & EXT4_GET_BLOCKS_CREATE) == 0);
         depth = ext4_block_to_path(inode, map->m_lblk, offsets,
@@ -1058,6 +1059,8 @@ cleanup:
                 partial--;
         }
 out:
+        trace_ext4_ind_map_blocks_exit(inode, map->m_lblk,
+                                map->m_pblk, map->m_len, err);
         return err;
 }
 
@@ -3379,6 +3382,7 @@ static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
 
 static int ext4_readpage(struct file *file, struct page *page)
 {
+        trace_ext4_readpage(page);
         return mpage_readpage(page, ext4_get_block);
 }
 
@@ -3413,6 +3417,8 @@ static void ext4_invalidatepage(struct page *page, unsigned long offset)
 {
         journal_t *journal = EXT4_JOURNAL(page->mapping->host);
 
+        trace_ext4_invalidatepage(page, offset);
+
         /*
          * free any io_end structure allocated for buffers to be discarded
          */
@@ -3434,6 +3440,8 @@ static int ext4_releasepage(struct page *page, gfp_t wait)
 {
         journal_t *journal = EXT4_JOURNAL(page->mapping->host);
 
+        trace_ext4_releasepage(page);
+
         WARN_ON(PageChecked(page));
         if (!page_has_buffers(page))
                 return 0;
@@ -3792,11 +3800,16 @@ static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
 {
         struct file *file = iocb->ki_filp;
         struct inode *inode = file->f_mapping->host;
+        ssize_t ret;
 
+        trace_ext4_direct_IO_enter(inode, offset, iov_length(iov, nr_segs), rw);
         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
-                return ext4_ext_direct_IO(rw, iocb, iov, offset, nr_segs);
-
-        return ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs);
+                ret = ext4_ext_direct_IO(rw, iocb, iov, offset, nr_segs);
+        else
+                ret = ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs);
+        trace_ext4_direct_IO_exit(inode, offset,
+                                iov_length(iov, nr_segs), rw, ret);
+        return ret;
 }
 
 /*
@@ -4425,6 +4438,8 @@ void ext4_truncate(struct inode *inode)
         ext4_lblk_t last_block;
         unsigned blocksize = inode->i_sb->s_blocksize;
 
+        trace_ext4_truncate_enter(inode);
+
         if (!ext4_can_truncate(inode))
                 return;
 
@@ -4435,6 +4450,7 @@ void ext4_truncate(struct inode *inode)
 
         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
                 ext4_ext_truncate(inode);
+                trace_ext4_truncate_exit(inode);
                 return;
         }
 
@@ -4564,6 +4580,7 @@ out_stop:
                 ext4_orphan_del(handle, inode);
 
         ext4_journal_stop(handle);
+        trace_ext4_truncate_exit(inode);
 }
 
 /*
@@ -4695,6 +4712,7 @@ make_io:
                  * has in-inode xattrs, or we don't have this inode in memory.
                  * Read the block from disk.
                  */
+                trace_ext4_load_inode(inode);
                 get_bh(bh);
                 bh->b_end_io = end_buffer_read_sync;
                 submit_bh(READ_META, bh);
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index ad87584aa8d2..f9f83878843a 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -40,6 +40,7 @@
 #include "xattr.h"
 #include "acl.h"
 
+#include <trace/events/ext4.h>
 /*
  * define how far ahead to read directories while searching them.
  */
@@ -2183,6 +2184,7 @@ static int ext4_unlink(struct inode *dir, struct dentry *dentry)
         struct ext4_dir_entry_2 *de;
         handle_t *handle;
 
+        trace_ext4_unlink_enter(dir, dentry);
         /* Initialize quotas before so that eventual writes go
          * in separate transaction */
         dquot_initialize(dir);
@@ -2228,6 +2230,7 @@ static int ext4_unlink(struct inode *dir, struct dentry *dentry)
 end_unlink:
         ext4_journal_stop(handle);
         brelse(bh);
+        trace_ext4_unlink_exit(dentry, retval);
         return retval;
 }