Hi! > Yeah, it's expected behavior for ext4. > Please this this url: > https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Storage_Administration_Guide/installconfig-fs.html > > Note: here the discussion is for directory. > > I checked the ext4 kernel source code in RHEL7.0RC: > > static void ext4_inc_count(handle_t *handle, struct inode *inode) > { > inc_nlink(inode); > if (is_dx(inode) && inode->i_nlink > 1) { > if (inode->i_nlink >= EXT4_LINK_MAX || inode->i_nlink == 2) { > set_nlink(inode, 1); > EXT4_SET_RO_COMPAT_FEATURE(inode->i_sb, > > EXT4_FEATURE_RO_COMPAT_DIR_NLINK); > } > } > } > > Here EXT4_LINK_MAX is 65000. From the above code, we can > see that if "is_dx(inode)" returns true and i_nlink count is greater than > 65000. > i_nlink will be reset to 1. Then if you stat parent directory, you will see > its link_count is 1. > > When we try to rmdir a directory, I also checked the ext4 kernel source code. > If a directory had nlink == 1, then the ext4 will still let it be 1. > > You can observe this by following steps: > [root@localhost ~]# mkdir ext4_test/ > [root@localhost ~]# cd ext4_test/; for((i=0; i <=65000;i++)) do mkdir $i; > done; > [root@localhost ext4_test]# stat . > File: '.' > Size: 1392640 Blocks: 2728 IO Block: 4096 directory > Device: 801h/2049d Inode: 3678747 Links: 1 > Access: (0755/drwxr-xr-x) Uid: ( 0/ root) Gid: ( 0/ root) > Access: 2014-05-20 19:36:24.541944536 +0800 > Modify: 2014-05-20 19:35:59.724942953 +0800 > Change: 2014-05-20 19:35:59.724942953 +0800 > Birth: - > > Now the links is 1. > If you delete some directory, the links will still be 1. > > So if we want to have a 65000 limit, we should "mkfs.ext4 -O ^dir_index > device", thanks.
Ok, thanks for the detailed explanation. > >> But EMLINK error value test need the directory have a valid LINK_MAX, > >> so for ext4, we use mkfs to clear "dir_index" filesystem feature, then > >> ext4 has a LINK_MAX:65000: mkfs.ext4 -O ^dir_index device > > So this is the same problem as with XFS. > > > > I still think that correct solution to this problem is to write a > > function that detects if there is a limit on number of links given a > > filesystem path. Then we can simply skip the EMLINK test if the number > > of links is unlimited. > > Agree, thanks. > For xfs, the number of links is unlimited. > For ext2/3, the number of links is 32000. > For ext4, it depends some options. > > So for xfs, I will skip EMLINK test for it. > For other files ystems, I will try to create as many as files, until the > EMLINK Is hit. > if EMLINK is not hit, there must be some other errors, such as ENOSPC, for > this > case, the EMLINK test should also be skipped. What about we create tst_get_max_links(const char *path) library function that would either return the actual limit or -1 if unlimited? Because this would be needed in more than one testcase, at least in the link() and linkat() ones. -- Cyril Hrubis chru...@suse.cz ------------------------------------------------------------------------------ "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE Instantly run your Selenium tests across 300+ browser/OS combos. Get unparalleled scalability from the best Selenium testing platform available Simple to use. Nothing to install. Get started now for free." http://p.sf.net/sfu/SauceLabs _______________________________________________ Ltp-list mailing list Ltp-list@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/ltp-list
