Messages in this thread | | | Subject | nobh_truncate_page question | From | Dmitriy Monakhov <> | Date | Thu, 08 Feb 2007 01:45:10 +0300 |
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Could some one please explain me what's happens with nobh_truncate_page?
int nobh_truncate_page(struct address_space *mapping, loff_t from) { ........ if ((offset & (blocksize - 1)) == 0) goto out;
ret = -ENOMEM; page = grab_cache_page(mapping, index); if (!page) goto out;
to = (offset + blocksize) & ~(blocksize - 1); ret = a_ops->prepare_write(NULL, page, offset, to); <<<<< This prepare_write() not balanced by appropriate commit_write() <<<<< Currently this not is fatal because this function used only <<<<< by ext2 and jfs witch unbalanced prepare/commit operations <<<<< not painful. if (ret == 0) { kaddr = kmap_atomic(page, KM_USER0); memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset); flush_dcache_page(page); kunmap_atomic(kaddr, KM_USER0); set_page_dirty(page); } unlock_page(page); page_cache_release(page); out: return ret; }
But we can't just call commit_write after all job done because this result in i_size increasing till block end. Where are two possible solutions: a) Call ->commit_write() and then restore i_size to old value. b) Leave code as it is now, but add warning comment about prepare/commit balance violation.
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