There is a particular directory (/var/www), that when I run ls (with or without some options), the command hangs and never completes. There is only about 10-15 files and directories in /var/www. Mostly just text files. Here is some investigative info:

[me@server www]$ df .
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/vg_dev-lv_root
                       50G   19G   29G  40% /

[me@server www]$ df -i .
Filesystem            Inodes   IUsed   IFree IUse% Mounted on
/dev/mapper/vg_dev-lv_root
                        3.2M    435K    2.8M   14% /

find works fine. Also I can type in cd /var/www/ and press TAB before pressing enter and it will successfully tab-completion list of all files/directories in there:

[me@server www]$ cd /var/www/
cgi-bin/         create_vhost.sh  html/            manual/          phpMyAdmin/      scripts/         usage/
conf/            error/           icons/           mediawiki/       rackspace        sqlbuddy/        vhosts/
[me@server www]$ cd /var/www/

I have had to kill my terminal sessions several times because of the ls hanging:

[me@server ~]$ ps | grep ls
gdm       6215  0.0  0.0 488152  2488 ?        S<sl Jan18   0:00 /usr/bin/pulseaudio --start --log-target=syslog
root     23269  0.0  0.0 117724  1088 ?        D    18:24   0:00 ls -Fh --color=always -l
root     23477  0.0  0.0 117724  1088 ?        D    18:34   0:00 ls -Fh --color=always -l
root     23579  0.0  0.0 115592   820 ?        D    18:36   0:00 ls -Fh --color=always
root     23634  0.0  0.0 115592   816 ?        D    18:38   0:00 ls -Fh --color=always
root     23740  0.0  0.0 117724  1088 ?        D    18:40   0:00 ls -Fh --color=always -l
me       23770  0.0  0.0 103156   816 pts/6    S+   18:41   0:00 grep ls

kill doesn't seem to have any affect on the processes, even as sudo.

What else should I do to investigate this problem? It just randomly started happening today.

UPDATE

dmesg is a big list of things, mostly related to an external USB HDD that I've mounted too many times and the max mount count has been reached, but that is an un-related problem I think. Near the bottom of dmesg I'm seeing this:

INFO: task ls:23579 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
ls            D ffff88041fc230c0     0 23579  23505 0x00000080
 ffff8801688a1bb8 0000000000000086 0000000000000000 ffffffff8119d279
 ffff880406d0ea20 ffff88007e2c2268 ffff880071fe80c8 00000003ae82967a
 ffff880407169ad8 ffff8801688a1fd8 0000000000010518 ffff880407169ad8
Call Trace:
 [<ffffffff8119d279>] ? __find_get_block+0xa9/0x200
 [<ffffffff814c97ae>] __mutex_lock_slowpath+0x13e/0x180
 [<ffffffff814c964b>] mutex_lock+0x2b/0x50
 [<ffffffff8117a4d3>] do_lookup+0xd3/0x220
 [<ffffffff8117b145>] __link_path_walk+0x6f5/0x1040
 [<ffffffff8117a47d>] ? do_lookup+0x7d/0x220
 [<ffffffff8117bd1a>] path_walk+0x6a/0xe0
 [<ffffffff8117beeb>] do_path_lookup+0x5b/0xa0
 [<ffffffff8117cb57>] user_path_at+0x57/0xa0
 [<ffffffff81178986>] ? generic_readlink+0x76/0xc0
 [<ffffffff8117cb62>] ? user_path_at+0x62/0xa0
 [<ffffffff81171d3c>] vfs_fstatat+0x3c/0x80
 [<ffffffff81258ae5>] ? _atomic_dec_and_lock+0x55/0x80
 [<ffffffff81171eab>] vfs_stat+0x1b/0x20
 [<ffffffff81171ed4>] sys_newstat+0x24/0x50
 [<ffffffff810d40a2>] ? audit_syscall_entry+0x272/0x2a0
 [<ffffffff81013172>] system_call_fastpath+0x16/0x1b

And also, strace ls /var/www/ spits out a whole BUNCH of information. I don't know what is useful here... The last handful of lines:

ioctl(1, SNDCTL_TMR_TIMEBASE or TCGETS, {B38400 opost isig icanon echo ...}) = 0
ioctl(1, TIOCGWINSZ, {ws_row=68, ws_col=145, ws_xpixel=0, ws_ypixel=0}) = 0
stat("/var/www/", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
open("/var/www/", O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC) = 3
fcntl(3, F_GETFD)                       = 0x1 (flags FD_CLOEXEC)
getdents(3, /* 16 entries */, 32768)    = 488
getdents(3, /* 0 entries */, 32768)     = 0
close(3)                                = 0
fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 9), ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f3093b18000
write(1, "cgi-bin  conf  create_vhost.sh\te"..., 125cgi-bin  conf  create_vhost.sh      error  html  icons  manual  mediawiki  phpMyAdmin  rackspace  scripts  sqlbuddy  usage   vhosts
) = 125
close(1)                                = 0
munmap(0x7f3093b18000, 4096)            = 0
close(2)                                = 0
exit_group(0)                           = ?