https://bugzilla.kernel.org/show_bug.cgi?id=196405 Bug ID: 196405 Summary: mkdir mishandles st_nlink in ext4 directory with 64997 subdirectories Product: File System Version: 2.5 Kernel Version: 4.13-rc1 Hardware: All OS: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: ext4 Assignee: fs_ext4@xxxxxxxxxxxxxxxxxxxx Reporter: eggert@xxxxxxxxxxx Regression: No See the following shell transcript, run in an ext4 directory, for an illustration of the bug. The first four commands set things up. The 5th command 'mkdir d/64998' calls 'mkdir("d/64998, 0777)' and succeeds. The 6th command shows that d's resulting st_nlink value is 1, which is incorrect; it should be 65000. I discovered this bug in Fedora 26, which runs Linux 4.11.10; from inspecting the source it appears the bug is still there in 4.13-rc1. $ LC_ALL=C $ export LC_ALL $ mkdir d d/{1..64997} $ strace -ve trace=%lstat ls -ld d lstat("d", {st_dev=makedev(8, 2), st_ino=41565723, st_mode=S_IFDIR|0755, st_nlink=64999, st_uid=1000, st_gid=1000, st_blksize=4096, st_blocks=2744, st_size=1404928, st_atime=1500319812 /* 2017-07-17T12:30:12.934815840-0700 */, st_atime_nsec=934815840, st_mtime=1500319822 /* 2017-07-17T12:30:22.896866173-0700 */, st_mtime_nsec=896866173, st_ctime=1500319822 /* 2017-07-17T12:30:22.896866173-0700 */, st_ctime_nsec=896866173}) = 0 drwxr-xr-x. 64999 eggert eggert 1404928 Jul 17 12:30 d +++ exited with 0 +++ $ mkdir d/64998 $ strace -ve trace=%lstat ls -ld d lstat("d", {st_dev=makedev(8, 2), st_ino=41565723, st_mode=S_IFDIR|0755, st_nlink=1, st_uid=1000, st_gid=1000, st_blksize=4096, st_blocks=2744, st_size=1404928, st_atime=1500319812 /* 2017-07-17T12:30:12.934815840-0700 */, st_atime_nsec=934815840, st_mtime=1500319845 /* 2017-07-17T12:30:45.104978381-0700 */, st_mtime_nsec=104978381, st_ctime=1500319845 /* 2017-07-17T12:30:45.104978381-0700 */, st_ctime_nsec=104978381}) = 0 drwxr-xr-x. 1 eggert eggert 1404928 Jul 17 12:30 d This bug report follows up on the following downstream bug reports: https://bugzilla.redhat.com/show_bug.cgi?id=1471967 https://debbugs.gnu.org/cgi/bugreport.cgi?bug=27739 -- You are receiving this mail because: You are watching the assignee of the bug.
