[PATCH 41/61] sysfs: sysfs_add_one WARNs with full path to duplicate filename

Greg Kroah-Hartman
2009-03-25T00:44:54Z

From: Alex Chiang <achiang@hp.com>

sysfs: sysfs_add_one WARNs with full path to duplicate filename

As a debugging aid, it can be useful to know the full path to a
duplicate file being created in sysfs.

We now will display warnings such as:

sysfs: cannot create duplicate filename '/foo'

when attempting to create multiple files named 'foo' in the sysfs
root, or:

sysfs: cannot create duplicate filename '/bus/pci/slots/5/foo'

when attempting to create multiple files named 'foo' under a
given directory in sysfs.

The path displayed is always a relative path to sysfs_root. The
leading '/' in the path name refers to the sysfs_root mount
point, and should not be confused with the "real" '/'.

Thanks to Alex Williamson for essentially writing sysfs_pathname.

Cc: Alex Williamson <alex.williamson@hp.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
fs/sysfs/dir.c | 32 ++++++++++++++++++++++++++++++--
1 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 82d3b79..f13d852 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -434,6 +434,26 @@ int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
}

/**
+ * sysfs_pathname - return full path to sysfs dirent
+ * @sd: sysfs_dirent whose path we want
+ * @path: caller allocated buffer
+ *
+ * Gives the name "/" to the sysfs_root entry; any path returned
+ * is relative to wherever sysfs is mounted.
+ *
+ * XXX: does no error checking on @path size
+ */
+static char *sysfs_pathname(struct sysfs_dirent *sd, char *path)
+{
+ if (sd->s_parent) {
+ sysfs_pathname(sd->s_parent, path);
+ strcat(path, "/");
+ }
+ strcat(path, sd->s_name);
+ return path;
+}
+
+/**
* sysfs_add_one - add sysfs_dirent to parent
* @acxt: addrm context to use
* @sd: sysfs_dirent to be added
@@ -458,8 +478,16 @@ int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
int ret;

ret = __sysfs_add_one(acxt, sd);
- WARN(ret == -EEXIST, KERN_WARNING "sysfs: duplicate filename '%s' "
- "can not be created\n", sd->s_name);
+ if (ret == -EEXIST) {
+ char *path = kzalloc(PATH_MAX, GFP_KERNEL);
+ WARN(1, KERN_WARNING
+ "sysfs: cannot create duplicate filename '%s'\n",
+ (path == NULL) ? sd->s_name :
+ strcat(strcat(sysfs_pathname(acxt->parent_sd, path), "/"),
+ sd->s_name));
+ kfree(path);
+ }
+
return ret;
}

--
1.6.2