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mount-util: EOVERFLOW might have other causes than buffer size issues

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When we get EOVERFLOW this might be caused by untriggered nfs4 mounts
(see discussion at
https://github.com/systemd/systemd/pull/7395#issuecomment-346164481 and
further down).

Handle this nicely by falling back to fdinfo-based mntid determination.

Fixes: #7082
This commit is contained in:
Lennart Poettering 2017-11-23 12:44:49 +01:00
parent 0d9bcb7c37
commit c83b20d73b
1 changed files with 5 additions and 4 deletions
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9
src/basic/mount-util.c
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@ -183,9 +183,10 @@ int fd_is_mount_point(int fd, const char *filename, int flags) {
* real mounts of their own. */
r = name_to_handle_at_loop(fd, filename, &h, &mount_id, flags);
if (IN_SET(r, -ENOSYS, -EACCES, -EPERM))
/* This kernel does not support name_to_handle_at() at all, or the syscall was blocked (maybe through
* seccomp, because we are running inside of a container?): fall back to simpler logic. */
if (IN_SET(r, -ENOSYS, -EACCES, -EPERM, -EOVERFLOW))
/* This kernel does not support name_to_handle_at() at all (ENOSYS), or the syscall was blocked
* (EACCES/EPERM; maybe through seccomp, because we are running inside of a container?), or the mount
* point is not triggered yet (EOVERFLOW, thinkg nfs4): fall back to simpler logic. */
goto fallback_fdinfo;
else if (r == -EOPNOTSUPP)
/* This kernel or file system does not support name_to_handle_at(), hence let's see if the upper fs
@ -307,7 +308,7 @@ int path_get_mnt_id(const char *path, int *ret) {
int r;
r = name_to_handle_at_loop(AT_FDCWD, path, NULL, ret, 0);
if (IN_SET(r, -EOPNOTSUPP, -ENOSYS, -EACCES, -EPERM)) /* kernel/fs don't support this, or seccomp blocks access */
if (IN_SET(r, -EOPNOTSUPP, -ENOSYS, -EACCES, -EPERM, -EOVERFLOW)) /* kernel/fs don't support this, or seccomp blocks access, or untriggered mount */
return fd_fdinfo_mnt_id(AT_FDCWD, path, 0, ret);
return r;