On Fri, 13 Jul 2007 16:00:48 +0530 Kalpak Shah <kalpak@xxxxxxxxxxxxx> wrote: > > > > > > - if (inode->i_nlink >= EXT4_LINK_MAX) > > > + if (EXT4_DIR_LINK_MAX(inode)) > > > return -EMLINK; > > > > argh. WHY_IS_EXT4_FULL_OF_UPPER_CASE_MACROS_WHICH_COULD_BE_IMPLEMENTED > > as_lower_case_inlines? Sigh. It's all the old-timers, I guess. > > > > EXT4_DIR_LINK_MAX() is buggy: it evaluates its arg twice. > > #define EXT4_DIR_LINK_MAX(dir) (!is_dx(dir) && (dir)->i_nlink >= EXT4_LINK_MAX) > > This just checks if directory has hash indexing in which case we need not worry about EXT4_LINK_MAX subdir limit. If directory is not hash indexed then we will need to enforce a max subdir limit. > > Sorry, I didn't understand what is the problem with this macro? Macros should never evaluate their argument more than once, because if they do they will misbehave when someone passes them an expression-with-side-effects: struct inode *p = q; EXT4_DIR_LINK_MAX(p++); one expects `p' to have the value q+1 here. But it might be q+2. and EXT4_DIR_LINK_MAX(some_function()); might cause some_function() to be called twice. This is one of the many problems which gets fixed when we write code in C rather than in cpp. - To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
