tools/filetop: Add --recursive for directory filter

Signed-off-by: abushwang <[email protected]>

Author: abushwang

tools/filetop.py

@@ -20,18 +20,22 @@
 import argparse
 import os
 import stat
+import re
 from subprocess import call
 
+MAX_DENTRY_DEPTH_VAL = 32
+
 # arguments
-examples = """examples:
-    ./filetop                 # file I/O top, 1 second refresh
-    ./filetop -C              # don't clear the screen
-    ./filetop -p 181          # PID 181 only
-    ./filetop -d /home/user   # trace files in /home/user directory only
-    ./filetop 5               # 5 second summaries
-    ./filetop 5 10            # 5 second summaries, 10 times only
-    ./filetop 5 --read-only   # 5 second summaries, only read operations traced
-    ./filetop 5 --write-only  # 5 second summaries, only write operations traced
+examples = f"""examples:
+    ./filetop                    # file I/O top, 1 second refresh
+    ./filetop -C                 # don't clear the screen
+    ./filetop -p 181             # PID 181 only
+    ./filetop -d /home/user      # trace files in /home/user directory only
+    ./filetop -d /home/user -R   # trace files in /home/user and subdirectories (max depth {MAX_DENTRY_DEPTH_VAL})
+    ./filetop 5                  # 5 second summaries
+    ./filetop 5 10               # 5 second summaries, 10 times only
+    ./filetop 5 --read-only      # 5 second summaries, only read operations traced
+    ./filetop 5 --write-only     # 5 second summaries, only write operations traced
 """
 parser = argparse.ArgumentParser(
     description="File reads and writes by process",
@@ -60,6 +64,8 @@
     help=argparse.SUPPRESS)
 parser.add_argument("-d", "--directory", type=str,
     help="trace this directory only")
+parser.add_argument("-R", "--recursive", action="store_true",
+    help=f"when used with -d, also trace files in subdirectories (max depth {MAX_DENTRY_DEPTH_VAL})")
 
 args = parser.parse_args()
 interval = int(args.interval)
@@ -80,6 +86,28 @@
 #undef DNAME_INLINE_LEN
 #define DNAME_INLINE_LEN __BCC_DNAME_INLINE_LEN
 
+// Limit dentry parent walk depth to satisfy eBPF verifier loop
+#ifndef MAX_DENTRY_DEPTH
+#define MAX_DENTRY_DEPTH MAX_DENTRY_DEPTH_VALUE
+#endif
+
+static __always_inline int not_under_inode(struct dentry *de, unsigned long target_ino)
+{
+    struct dentry *pde = de;
+    int found = 0;
+    #pragma unroll
+    for (int i = 0; i < MAX_DENTRY_DEPTH; i++) {
+        if (!pde->d_parent)
+            break;
+        pde = pde->d_parent;
+        if (pde->d_inode && pde->d_inode->i_ino == target_ino) {
+            found = 1;
+            break;
+        }
+    }
+    return !found;
+}
+
 // the key for the output summary
 struct info_t {
     unsigned long inode;
@@ -169,6 +197,9 @@
 }
 
 """
+bpf_text = bpf_text.replace('MAX_DENTRY_DEPTH_VALUE', str(MAX_DENTRY_DEPTH_VAL))
+m = re.search(r'#define\s+MAX_DENTRY_DEPTH\s+(\d+)', bpf_text)
+MAX_DENTRY_DEPTH = int(m.group(1)) if m else 32
 if args.tgid:
     bpf_text = bpf_text.replace('TGID_FILTER', 'tgid != %d' % args.tgid)
 else:
@@ -180,12 +211,24 @@
 if args.directory:
     try:
         directory_inode = os.lstat(args.directory)[stat.ST_INO]
-        print(f'Tracing directory: {args.directory} (Inode: {directory_inode})')
-        bpf_text = bpf_text.replace('DIRECTORY_FILTER',  'file->f_path.dentry->d_parent->d_inode->i_ino != %d' % directory_inode)
+        if args.recursive:
+            print(
+                f'Tracing directory recursively: {args.directory} '
+                f'(Inode: {directory_inode}, max depth: {MAX_DENTRY_DEPTH_VAL})'
+            )
+            directory_filter = "not_under_inode(de, %d)" % directory_inode
+        else:
+            print(f'Tracing directory: {args.directory} (Inode: {directory_inode})')
+            directory_filter = "de->d_parent->d_inode->i_ino != %d" % directory_inode
+
+        bpf_text = bpf_text.replace('DIRECTORY_FILTER', directory_filter)
     except (FileNotFoundError, PermissionError) as e:
         print(f'Error accessing directory {args.directory}: {e}')
         exit(1)
 else:
+    if args.recursive:
+        print("Error: --recursive can only be used with -d/--directory option")
+        exit(1)
     bpf_text = bpf_text.replace('DIRECTORY_FILTER', '0')
 
 if debug or args.ebpf: