I created a single primary partition to my WD WD800BB-55JHA0 80GB HDD using MBR partitioning scheme. Into this partition I created an ext4 file-system with 200048640 inodes! Then I created loads of very small files with while true; do echo a > /media/$RANDOM$RANDOM$RANDOM; done command. At some point I was not able to add more files:

sh-4.2# strace echo a > /media/$RANDOM$RANDOM$RANDOM

The file is not created and there is no output to shell. It just hangs there forever.

Output of dumpe2fs /dev/sdb1 can be seen below:

Filesystem volume name:   <none>
Last mounted on:          /media
Filesystem UUID:          233d7f5b-51b0-4c3d-8f1d-5d8c34f08a8f
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal ext_attr resize_inode dir_index filetype needs_recovery extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize
Filesystem flags:         signed_directory_hash 
Default mount options:    user_xattr acl
Filesystem state:         clean with errors
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              200048640
Block count:              19536000
Reserved block count:     976871
Free blocks:              6665698
Free inodes:              199748660
First block:              0
Block size:               4096
Fragment size:            4096
Reserved GDT blocks:      1024
Blocks per group:         3200
Fragments per group:      3200
Inodes per group:         32768
Inode blocks per group:   2048
Flex block group size:    16
Filesystem created:       Thu Jan  5 11:20:15 2006
Last mount time:          Thu Jan  5 11:48:02 2006
Last write time:          Thu Jan  5 11:53:15 2006
Mount count:              1
Maximum mount count:      -1
Last checked:             Thu Jan  5 11:20:15 2006
Check interval:           0 (<none>)
Lifetime writes:          3540 MB
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
First inode:              11
Inode size:               256
Required extra isize:     28
Desired extra isize:      28
Journal inode:            8
First orphan inode:       280161
Default directory hash:   half_md4
Directory Hash Seed:      84caa27e-4e4c-4853-b222-e739c0fda1de
Journal backup:           inode blocks
FS Error count:           1
First error time:         Thu Jan  5 11:53:15 2006
First error function:     ext4_mb_generate_buddy
First error line #:       741
First error inode #:      0
First error block #:      0
Last error time:          Thu Jan  5 11:53:15 2006
Last error function:      ext4_mb_generate_buddy
Last error line #:        741
Last error inode #:       0
Last error block #:       0
Journal features:         (none)
Journal size:             128M
Journal length:           32768
Journal sequence:         0x000000c7
Journal start:            29840

I clearly did not run out of inodes and there is enough space left to create more files:

sh-4.2# df -i /dev/sdb1
Filesystem        Inodes  IUsed     IFree IUse% Mounted on
/dev/sdb1      200048640 299980 199748660    1% /media
sh-4.2# df /dev/sdb1
Filesystem     1K-blocks    Used Available Use% Mounted on
/dev/sdb1       28079472 1416684  22755304   6% /media

What might restricting new files? Is there a limit of files per directory?

  • 1
    strace echo a > file is wrong. The redirection takes place before strace is run. You need: strace -f bash -c 'echo a > /media/file' – Hauke Laging Jul 5 '13 at 12:38
  • 1
    Also, strace is probably not going to show you much more than a hanging write() syscall which you could have probably guessed. It's better to look at the log files like dmesg and messages to see if anything descriptive got printed there. – Bratchley Jul 5 '13 at 13:01
  • Just an FYI - You can also use the command tune2fs -l <dev> to get the superblock info. – slm Jul 5 '13 at 17:37

Per http://en.wikipedia.org/wiki/Ext4

There is a limit of 64,000 entries per directory. Your problem is that you have hit this limit.

Edited to fix the entries per directory.

  • 2
    Minor quibble: article actually says 32k is for ext3, ext4 has a 64k limit. – Bratchley Jul 5 '13 at 13:20

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