Messages in this thread Patch in this message | | | Date | Fri, 19 Oct 2007 15:11:05 +0200 | From | Christoph Hellwig <> | Subject | [PATCH] clean up vmtruncate |
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vmtruncate is a twisted maze of gotos, this patch cleans it up to have a proper if else for the two major cases of extending and truncating truncate and thus makes it a lot more readable while keeping exactly the same functinality.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Index: linux-2.6/mm/memory.c =================================================================== --- linux-2.6.orig/mm/memory.c 2007-09-14 13:51:55.000000000 +0200 +++ linux-2.6/mm/memory.c 2007-09-14 13:55:41.000000000 +0200 @@ -2003,50 +2003,49 @@ EXPORT_SYMBOL(unmap_mapping_range); */ int vmtruncate(struct inode * inode, loff_t offset) { - struct address_space *mapping = inode->i_mapping; - unsigned long limit; + if (inode->i_size < offset) { + unsigned long limit; - if (inode->i_size < offset) - goto do_expand; - /* - * truncation of in-use swapfiles is disallowed - it would cause - * subsequent swapout to scribble on the now-freed blocks. - */ - if (IS_SWAPFILE(inode)) - goto out_busy; - i_size_write(inode, offset); + limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; + if (limit != RLIM_INFINITY && offset > limit) + goto out_sig; + if (offset > inode->i_sb->s_maxbytes) + goto out_big; + i_size_write(inode, offset); + } else { + struct address_space *mapping = inode->i_mapping; - /* - * unmap_mapping_range is called twice, first simply for efficiency - * so that truncate_inode_pages does fewer single-page unmaps. However - * after this first call, and before truncate_inode_pages finishes, - * it is possible for private pages to be COWed, which remain after - * truncate_inode_pages finishes, hence the second unmap_mapping_range - * call must be made for correctness. - */ - unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); - truncate_inode_pages(mapping, offset); - unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); - goto out_truncate; - -do_expand: - limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; - if (limit != RLIM_INFINITY && offset > limit) - goto out_sig; - if (offset > inode->i_sb->s_maxbytes) - goto out_big; - i_size_write(inode, offset); + /* + * truncation of in-use swapfiles is disallowed - it would + * cause subsequent swapout to scribble on the now-freed + * blocks. + */ + if (IS_SWAPFILE(inode)) + return -ETXTBSY; + i_size_write(inode, offset); + + /* + * unmap_mapping_range is called twice, first simply for + * efficiency so that truncate_inode_pages does fewer + * single-page unmaps. However after this first call, and + * before truncate_inode_pages finishes, it is possible for + * private pages to be COWed, which remain after + * truncate_inode_pages finishes, hence the second + * unmap_mapping_range call must be made for correctness. + */ + unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); + truncate_inode_pages(mapping, offset); + unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); + } -out_truncate: if (inode->i_op && inode->i_op->truncate) inode->i_op->truncate(inode); return 0; + out_sig: send_sig(SIGXFSZ, current, 0); out_big: return -EFBIG; -out_busy: - return -ETXTBSY; } EXPORT_SYMBOL(vmtruncate); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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