ext4: Introduce FALLOC_FL_ZERO_RANGE flag for fallocate

Introduce new FALLOC_FL_ZERO_RANGE flag for fallocate. This has the same
functionality as xfs ioctl XFS_IOC_ZERO_RANGE.

It can be used to convert a range of file to zeros preferably without
issuing data IO. Blocks should be preallocated for the regions that span
holes in the file, and the entire range is preferable converted to
unwritten extents

This can be also used to preallocate blocks past EOF in the same way as
with fallocate. Flag FALLOC_FL_KEEP_SIZE which should cause the inode
size to remain the same.

Also add appropriate tracepoints.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 35 insertions, 33 deletions

diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h
index e9d7ee77d3a1..010ea89eeb0e 100644
--- a/include/trace/events/ext4.h
+++ b/include/trace/events/ext4.h
@@ -21,6 +21,10 @@ struct extent_status;
 #define FALLOC_FL_COLLAPSE_RANGE        0x08
 #endif
 
+#ifndef FALLOC_FL_ZERO_RANGE
+#define FALLOC_FL_ZERO_RANGE           0x10
+#endif
+
 #define EXT4_I(inode) (container_of(inode, struct ext4_inode_info, vfs_inode))
 
 #define show_mballoc_flags(flags) __print_flags(flags, "|",     \
@@ -77,7 +81,8 @@ struct extent_status;
         { FALLOC_FL_KEEP_SIZE,          "KEEP_SIZE"},           \
         { FALLOC_FL_PUNCH_HOLE,         "PUNCH_HOLE"},          \
         { FALLOC_FL_NO_HIDE_STALE,      "NO_HIDE_STALE"},       \
-        { FALLOC_FL_COLLAPSE_RANGE,     "COLLAPSE_RANGE"})
+        { FALLOC_FL_COLLAPSE_RANGE,     "COLLAPSE_RANGE"},      \
+        { FALLOC_FL_ZERO_RANGE,         "ZERO_RANGE"})
 
 
 TRACE_EVENT(ext4_free_inode,
@@ -1339,7 +1344,7 @@ TRACE_EVENT(ext4_direct_IO_exit,
                   __entry->rw, __entry->ret)
 );
 
-TRACE_EVENT(ext4_fallocate_enter,
+DECLARE_EVENT_CLASS(ext4__fallocate_mode,
         TP_PROTO(struct inode *inode, loff_t offset, loff_t len, int mode),
 
         TP_ARGS(inode, offset, len, mode),
@@ -1347,23 +1352,45 @@ TRACE_EVENT(ext4_fallocate_enter,
         TP_STRUCT__entry(
                 __field(        dev_t,  dev                     )
                 __field(        ino_t,  ino                     )
-                __field(        loff_t, pos                     )
-                __field(        loff_t, len                     )
+                __field(        loff_t, offset                  )
+                __field(        loff_t, len                     )
                 __field(        int,    mode                    )
         ),
 
         TP_fast_assign(
                 __entry->dev    = inode->i_sb->s_dev;
                 __entry->ino    = inode->i_ino;
-                __entry->pos    = offset;
+                __entry->offset = offset;
                 __entry->len    = len;
                 __entry->mode   = mode;
         ),
 
-        TP_printk("dev %d,%d ino %lu pos %lld len %lld mode %s",
+        TP_printk("dev %d,%d ino %lu offset %lld len %lld mode %s",
                   MAJOR(__entry->dev), MINOR(__entry->dev),
-                  (unsigned long) __entry->ino, __entry->pos,
-                  __entry->len, show_falloc_mode(__entry->mode))
+                  (unsigned long) __entry->ino,
+                  __entry->offset, __entry->len,
+                  show_falloc_mode(__entry->mode))
+);
+
+DEFINE_EVENT(ext4__fallocate_mode, ext4_fallocate_enter,
+
+        TP_PROTO(struct inode *inode, loff_t offset, loff_t len, int mode),
+
+        TP_ARGS(inode, offset, len, mode)
+);
+
+DEFINE_EVENT(ext4__fallocate_mode, ext4_punch_hole,
+
+        TP_PROTO(struct inode *inode, loff_t offset, loff_t len, int mode),
+
+        TP_ARGS(inode, offset, len, mode)
+);
+
+DEFINE_EVENT(ext4__fallocate_mode, ext4_zero_range,
+
+        TP_PROTO(struct inode *inode, loff_t offset, loff_t len, int mode),
+
+        TP_ARGS(inode, offset, len, mode)
 );
 
 TRACE_EVENT(ext4_fallocate_exit,
@@ -1395,31 +1422,6 @@ TRACE_EVENT(ext4_fallocate_exit,
                   __entry->ret)
 );
 
-TRACE_EVENT(ext4_punch_hole,
-        TP_PROTO(struct inode *inode, loff_t offset, loff_t len),
-
-        TP_ARGS(inode, offset, len),
-
-        TP_STRUCT__entry(
-                __field(        dev_t,  dev                     )
-                __field(        ino_t,  ino                     )
-                __field(        loff_t, offset                  )
-                __field(        loff_t, len                     )
-        ),
-
-        TP_fast_assign(
-                __entry->dev    = inode->i_sb->s_dev;
-                __entry->ino    = inode->i_ino;
-                __entry->offset = offset;
-                __entry->len    = len;
-        ),
-
-        TP_printk("dev %d,%d ino %lu offset %lld len %lld",
-                  MAJOR(__entry->dev), MINOR(__entry->dev),
-                  (unsigned long) __entry->ino,
-                  __entry->offset, __entry->len)
-);
-
 TRACE_EVENT(ext4_unlink_enter,
         TP_PROTO(struct inode *parent, struct dentry *dentry),