diff options
| -rw-r--r-- | fs/fs-writeback.c | 142 |
1 files changed, 86 insertions, 56 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 3b87dc80fd30..5f2c68289610 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -364,6 +364,15 @@ static void requeue_inode(struct inode *inode, struct bdi_writeback *wb, (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)) inode->dirtied_when = jiffies; + if (wbc->pages_skipped) { + /* + * writeback is not making progress due to locked + * buffers. Skip this inode for now. + */ + redirty_tail(inode, wb); + return; + } + if (mapping_tagged(inode->i_mapping, PAGECACHE_TAG_DIRTY)) { /* * We didn't write back all the pages. nfs_writepages() @@ -396,46 +405,20 @@ static void requeue_inode(struct inode *inode, struct bdi_writeback *wb, } /* - * Write out an inode's dirty pages. Called under wb->list_lock and - * inode->i_lock. Either the caller has an active reference on the inode or - * the inode has I_WILL_FREE set. - * - * If `wait' is set, wait on the writeout. - * - * The whole writeout design is quite complex and fragile. We want to avoid - * starvation of particular inodes when others are being redirtied, prevent - * livelocks, etc. + * Write out an inode and its dirty pages. Do not update the writeback list + * linkage. That is left to the caller. The caller is also responsible for + * setting I_SYNC flag and calling inode_sync_complete() to clear it. */ static int -writeback_single_inode(struct inode *inode, struct bdi_writeback *wb, - struct writeback_control *wbc) +__writeback_single_inode(struct inode *inode, struct bdi_writeback *wb, + struct writeback_control *wbc) { struct address_space *mapping = inode->i_mapping; long nr_to_write = wbc->nr_to_write; unsigned dirty; int ret; - assert_spin_locked(&inode->i_lock); - - if (!atomic_read(&inode->i_count)) - WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING))); - else - WARN_ON(inode->i_state & I_WILL_FREE); - - if (inode->i_state & I_SYNC) { - if (wbc->sync_mode != WB_SYNC_ALL) - return 0; - /* - * It's a data-integrity sync. We must wait. - */ - inode_wait_for_writeback(inode); - } - - BUG_ON(inode->i_state & I_SYNC); - - /* Set I_SYNC, reset I_DIRTY_PAGES */ - inode->i_state |= I_SYNC; - spin_unlock(&inode->i_lock); + WARN_ON(!(inode->i_state & I_SYNC)); ret = do_writepages(mapping, wbc); @@ -468,12 +451,65 @@ writeback_single_inode(struct inode *inode, struct bdi_writeback *wb, if (ret == 0) ret = err; } + trace_writeback_single_inode(inode, wbc, nr_to_write); + return ret; +} + +/* + * Write out an inode's dirty pages. Either the caller has an active reference + * on the inode or the inode has I_WILL_FREE set. + * + * This function is designed to be called for writing back one inode which + * we go e.g. from filesystem. Flusher thread uses __writeback_single_inode() + * and does more profound writeback list handling in writeback_sb_inodes(). + */ +static int +writeback_single_inode(struct inode *inode, struct bdi_writeback *wb, + struct writeback_control *wbc) +{ + int ret = 0; + + spin_lock(&inode->i_lock); + if (!atomic_read(&inode->i_count)) + WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING))); + else + WARN_ON(inode->i_state & I_WILL_FREE); + + if (inode->i_state & I_SYNC) { + if (wbc->sync_mode != WB_SYNC_ALL) + goto out; + /* + * It's a data-integrity sync. We must wait. + */ + inode_wait_for_writeback(inode); + } + WARN_ON(inode->i_state & I_SYNC); + /* + * Skip inode if it is clean. We don't want to mess with writeback + * lists in this function since flusher thread may be doing for example + * sync in parallel and if we move the inode, it could get skipped. So + * here we make sure inode is on some writeback list and leave it there + * unless we have completely cleaned the inode. + */ + if (!(inode->i_state & I_DIRTY)) + goto out; + inode->i_state |= I_SYNC; + spin_unlock(&inode->i_lock); + + ret = __writeback_single_inode(inode, wb, wbc); spin_lock(&wb->list_lock); spin_lock(&inode->i_lock); - requeue_inode(inode, wb, wbc); + /* + * If inode is clean, remove it from writeback lists. Otherwise don't + * touch it. See comment above for explanation. + */ + if (!(inode->i_state & I_DIRTY)) + list_del_init(&inode->i_wb_list); + spin_unlock(&wb->list_lock); inode_sync_complete(inode); - trace_writeback_single_inode(inode, wbc, nr_to_write); +out: + spin_unlock(&inode->i_lock); return ret; } @@ -585,23 +621,29 @@ static long writeback_sb_inodes(struct super_block *sb, spin_unlock(&wb->list_lock); __iget(inode); + /* + * We already requeued the inode if it had I_SYNC set and we + * are doing WB_SYNC_NONE writeback. So this catches only the + * WB_SYNC_ALL case. + */ + if (inode->i_state & I_SYNC) + inode_wait_for_writeback(inode); + inode->i_state |= I_SYNC; + spin_unlock(&inode->i_lock); write_chunk = writeback_chunk_size(wb->bdi, work); wbc.nr_to_write = write_chunk; wbc.pages_skipped = 0; - writeback_single_inode(inode, wb, &wbc); + __writeback_single_inode(inode, wb, &wbc); work->nr_pages -= write_chunk - wbc.nr_to_write; wrote += write_chunk - wbc.nr_to_write; + spin_lock(&wb->list_lock); + spin_lock(&inode->i_lock); if (!(inode->i_state & I_DIRTY)) wrote++; - if (wbc.pages_skipped) { - /* - * writeback is not making progress due to locked - * buffers. Skip this inode for now. - */ - redirty_tail(inode, wb); - } + requeue_inode(inode, wb, &wbc); + inode_sync_complete(inode); spin_unlock(&inode->i_lock); spin_unlock(&wb->list_lock); iput(inode); @@ -1337,7 +1379,6 @@ EXPORT_SYMBOL(sync_inodes_sb); int write_inode_now(struct inode *inode, int sync) { struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; - int ret; struct writeback_control wbc = { .nr_to_write = LONG_MAX, .sync_mode = sync ? WB_SYNC_ALL : WB_SYNC_NONE, @@ -1349,11 +1390,7 @@ int write_inode_now(struct inode *inode, int sync) wbc.nr_to_write = 0; might_sleep(); - spin_lock(&inode->i_lock); - ret = writeback_single_inode(inode, wb, &wbc); - spin_unlock(&inode->i_lock); - spin_unlock(&wb->list_lock); - return ret; + return writeback_single_inode(inode, wb, &wbc); } EXPORT_SYMBOL(write_inode_now); @@ -1370,14 +1407,7 @@ EXPORT_SYMBOL(write_inode_now); */ int sync_inode(struct inode *inode, struct writeback_control *wbc) { - struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; - int ret; - - spin_lock(&inode->i_lock); - ret = writeback_single_inode(inode, wb, wbc); - spin_unlock(&inode->i_lock); - spin_unlock(&wb->list_lock); - return ret; + return writeback_single_inode(inode, &inode_to_bdi(inode)->wb, wbc); } EXPORT_SYMBOL(sync_inode); |