Hi Hugo,

I was not able to reproduce your error with my repository: I pulled it
without problem.

However, enclosed you can find the patch (as attachment) with the Jan
suggestions about the spaces. You can pull the patch also from my repo (
same branch: fd-leaking). Moreover I inserted the patch as inlined.
Hoping that helps.

--------------------

commit b73abc9465d3a105b5f8f464f2867543a638e5e2
Author: Goffredo Baroncelli [off-list ref]
Date:   Tue Jun 5 19:11:06 2012 +0200

 scrub_fs_info( ) file handle leaking

 The function scrub_fs_info( ) closes and reopen a file handle
 passed as argument, when a caller uses the file handle even after the
 call.
 The function scrub_fs_info( ) is updated to remove the file handle
 argument, and instead uses a private own file handle.
 The callers are updated to not pass the argument.

diff --git a/cmds-scrub.c b/cmds-scrub.c
index c4503f4..6313e02 100644
--- a/cmds-scrub.c
+++ b/cmds-scrub.c

@@ -979,19 +979,26 @@ static int scrub_device_info(int fd, u64 devid,
        return ret ? -errno : 0;
 }

-static int scrub_fs_info(int fd, char *path,
+static int scrub_fs_info(char *path,
                                struct btrfs_ioctl_fs_info_args *fi_args,
                                struct btrfs_ioctl_dev_info_args **di_ret)
 {
        int ret = 0;
        int ndevs = 0;
        int i = 1;
+       int fd;
        struct btrfs_fs_devices *fs_devices_mnt = NULL;
        struct btrfs_ioctl_dev_info_args *di_args;
        char mp[BTRFS_PATH_NAME_MAX + 1];

        memset(fi_args, 0, sizeof(*fi_args));

+       fd  = open_file_or_dir(path);
+       if (fd < 0) {
+               fprintf(stderr, "ERROR: can't access to '%s'\n", path);
+               return -1;
+       }
+
        ret = ioctl(fd, BTRFS_IOC_FS_INFO, fi_args);
        if (ret && errno == EINVAL) {
                /* path is no mounted btrfs. try if it's a device */

@@ -1010,28 +1017,36 @@ static int scrub_fs_info(int fd, char *path,
                if (fd < 0)
                        return -errno;
        } else if (ret) {
+               close(fd);
                return -errno;
        }

-       if (!fi_args->num_devices)
+       if (!fi_args->num_devices) {
+               close(fd);
                return 0;
+       }

        di_args = *di_ret = malloc(fi_args->num_devices * sizeof(*di_args));
-       if (!di_args)
+       if (!di_args) {
+               close(fd);
                return -errno;
+       }

        for (; i <= fi_args->max_id; ++i) {
                BUG_ON(ndevs >= fi_args->num_devices);
                ret = scrub_device_info(fd, i, &di_args[ndevs]);
                if (ret == -ENODEV)
                        continue;
-               if (ret)
+               if (ret) {
+                       close(fd);
                        return ret;
+               }
                ++ndevs;
        }

        BUG_ON(ndevs == 0);

+       close(fd);
        return 0;
 }

@@ -1155,7 +1170,7 @@ static int scrub_start(int argc, char **argv, int

resume)
                return 12;
        }

-       ret = scrub_fs_info(fdmnt, path, &fi_args, &di_args);
+       ret = scrub_fs_info(path, &fi_args, &di_args);
        if (ret) {
                ERR(!do_quiet, "ERROR: getting dev info for scrub failed: "
                    "%s\n", strerror(-ret));

@@ -1586,7 +1601,6 @@ static int cmd_scrub_status(int argc, char **argv)
                .sun_family = AF_UNIX,
        };
        int ret;
-       int fdmnt;
        int i;
        int print_raw = 0;
        int do_stats_per_dev = 0;

@@ -1615,13 +1629,7 @@ static int cmd_scrub_status(int argc, char **argv)

        path = argv[optind];

-       fdmnt = open_file_or_dir(path);
-       if (fdmnt < 0) {
-               fprintf(stderr, "ERROR: can't access to '%s'\n", path);
-               return 12;
-       }
-
-       ret = scrub_fs_info(fdmnt, path, &fi_args, &di_args);
+       ret = scrub_fs_info(path, &fi_args, &di_args);
        if (ret) {
                fprintf(stderr, "ERROR: getting dev info for scrub failed: "
                                "%s\n", strerror(-ret));

@@ -1698,7 +1706,6 @@ static int cmd_scrub_status(int argc, char **argv)
 out:
        free_history(past_scrubs);
        free(di_args);
-       close(fdmnt);
        if (fdres > -1)
                close(fdres);

On 06/05/2012 01:01 PM, Hugo Mills wrote:

   Hi, Goffredo,

   I'm trying to do a new integration branch, and the patch inline in
the text is corrupt (plus it has a massively verbose commit message):

Applying: Leaking file handle in scrub_fs_info()
fatal: corrupt patch at line 74
Patch failed at 0001 Leaking file handle in scrub_fs_info()

   Normally, I'd use your git repo to get round the fact that every
single patch you send by mail is whitespace-damaged, but:

error: Unable to find 337bfb3250203a66b953ffcf7804418cb7c72052 under http://cassiopea.homelinux.net/git/btrfs-progs-unstable.git
Cannot obtain needed commit 337bfb3250203a66b953ffcf7804418cb7c72052
while processing commit ee3832b47a4b1d1dce8d1cacc802db32901b8c45.
error: Fetch failed.

   Plus Jan had some suggested tweaks regarding whitespace -- could
you re-roll the patch and maybe see what you can do to fix your git
repo? (Or at least use git-send-email to send the patch so it doesn't
get mangled).

   Thanks,
   Hugo.

On Tue, Apr 24, 2012 at 08:43:23PM +0200, Goffredo Baroncelli wrote:

quoted

I was giving a look to the function scrub_fs_info( ), and to me it seems
that could be a potential file handle leaking problem.


In fact:

static int scrub_fs_info(int fd, char *path,
                    struct btrfs_ioctl_fs_info_args *fi_args,
                    struct btrfs_ioctl_dev_info_args **di_ret)
{

[...]

        ret = ioctl(fd, BTRFS_IOC_FS_INFO, fi_args);
        if (ret && errno == EINVAL) {
                /* path is no mounted btrfs. try if it's a device */
[...]
                close(fd);			<--- Here the
						     file handle is
						     closed

                fd = open_file_or_dir(mp);	<--- then it is
						     re-opened
                if (fd < 0)
                        return -errno;
        } else if (ret) {
                return -errno;
        }
[...]

But in the rest of the function:
a) the file handle is not closed
b) the (new) file handle isn't returned

The function "scrub_fs_info()" is called from the functions
1) cmd_scrub_status(), which doesn't use the file handle after the call
to the cmd_scrub_status() [except for a close()]. So no problem at all.
2) scrub_start(), which uses the file handle after the call to the
cmd_scrub_status() functions.

My suggestions is to change scrub_fs_info() to accept only the path.
Then it open (and closes) its own (and private) the file descriptor.

Instead scrub_start(), opens a file descriptor after the call to the
scrub_fs_info() function.

What do you think ?

BR
G.Baroncelli

You can pull the patch below from

	http://cassiopea.homelinux.net/git/btrfs-progs-unstable.git

branch

	fd-leaking

-----

diff --git a/cmds-scrub.c b/cmds-scrub.c
index c4503f4..486768c 100644
--- a/cmds-scrub.c
+++ b/cmds-scrub.c

@@ -979,19 +979,26 @@ static int scrub_device_info(int fd, u64 devid,
 	return ret ? -errno : 0;
 }

-static int scrub_fs_info(int fd, char *path,
+static int scrub_fs_info( char *path,
 				struct btrfs_ioctl_fs_info_args *fi_args,
 				struct btrfs_ioctl_dev_info_args **di_ret)
 {
 	int ret = 0;
 	int ndevs = 0;
 	int i = 1;
+	int fd;
 	struct btrfs_fs_devices *fs_devices_mnt = NULL;
 	struct btrfs_ioctl_dev_info_args *di_args;
 	char mp[BTRFS_PATH_NAME_MAX + 1];

 	memset(fi_args, 0, sizeof(*fi_args));

+	fd  = open_file_or_dir(path);
+	if (fd < 0) {
+		fprintf(stderr, "ERROR: can't access to '%s'\n", path);
+		return -1;
+	}
+
 	ret = ioctl(fd, BTRFS_IOC_FS_INFO, fi_args);
 	if (ret && errno == EINVAL) {
 		/* path is no mounted btrfs. try if it's a device */

@@ -1010,28 +1017,36 @@ static int scrub_fs_info(int fd, char *path,
 		if (fd < 0)
 			return -errno;
 	} else if (ret) {
+		close(fd);
 		return -errno;
 	}

-	if (!fi_args->num_devices)
+	if (!fi_args->num_devices){
+		close(fd);
 		return 0;
+	}

 	di_args = *di_ret = malloc(fi_args->num_devices * sizeof(*di_args));
-	if (!di_args)
+	if (!di_args){
+		close(fd);
 		return -errno;
+	}

 	for (; i <= fi_args->max_id; ++i) {
 		BUG_ON(ndevs >= fi_args->num_devices);
 		ret = scrub_device_info(fd, i, &di_args[ndevs]);
 		if (ret == -ENODEV)
 			continue;
-		if (ret)
+		if (ret){
+			close(fd);
 			return ret;
+		}
 		++ndevs;
 	}

 	BUG_ON(ndevs == 0);

+	close(fd);
 	return 0;
 }

@@ -1155,7 +1170,7 @@ static int scrub_start(int argc, char **argv, int

resume)
 		return 12;
 	}

-	ret = scrub_fs_info(fdmnt, path, &fi_args, &di_args);
+	ret = scrub_fs_info(path, &fi_args, &di_args);
 	if (ret) {
 		ERR(!do_quiet, "ERROR: getting dev info for scrub failed: "
 		    "%s\n", strerror(-ret));

@@ -1586,7 +1601,6 @@ static int cmd_scrub_status(int argc, char **argv)
 		.sun_family = AF_UNIX,
 	};
 	int ret;
-	int fdmnt;
 	int i;
 	int print_raw = 0;
 	int do_stats_per_dev = 0;

@@ -1615,13 +1629,7 @@ static int cmd_scrub_status(int argc, char **argv)

 	path = argv[optind];

-	fdmnt = open_file_or_dir(path);
-	if (fdmnt < 0) {
-		fprintf(stderr, "ERROR: can't access to '%s'\n", path);
-		return 12;
-	}
-
-	ret = scrub_fs_info(fdmnt, path, &fi_args, &di_args);
+	ret = scrub_fs_info(path, &fi_args, &di_args);
 	if (ret) {
 		fprintf(stderr, "ERROR: getting dev info for scrub failed: "
 				"%s\n", strerror(-ret));

@@ -1698,7 +1706,6 @@ static int cmd_scrub_status(int argc, char **argv)
 out:
 	free_history(past_scrubs);
 	free(di_args);
-	close(fdmnt);
 	if (fdres > -1)
 		close(fdres);