diff options
Diffstat (limited to 'fs/ext4/inode.c')
| -rw-r--r-- | fs/ext4/inode.c | 111 |
1 files changed, 68 insertions, 43 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 5042c8773ad..2fa18bb0bf3 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -875,32 +875,40 @@ static int ext4_write_begin(struct file *file, struct address_space *mapping, ret = ext4_try_to_write_inline_data(mapping, inode, pos, len, flags, pagep); if (ret < 0) - goto out; - if (ret == 1) { - ret = 0; - goto out; - } + return ret; + if (ret == 1) + return 0; } -retry: + /* + * grab_cache_page_write_begin() can take a long time if the + * system is thrashing due to memory pressure, or if the page + * is being written back. So grab it first before we start + * the transaction handle. This also allows us to allocate + * the page (if needed) without using GFP_NOFS. + */ +retry_grab: + page = grab_cache_page_write_begin(mapping, index, flags); + if (!page) + return -ENOMEM; + unlock_page(page); + +retry_journal: handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, needed_blocks); if (IS_ERR(handle)) { - ret = PTR_ERR(handle); - goto out; + page_cache_release(page); + return PTR_ERR(handle); } - /* We cannot recurse into the filesystem as the transaction is already - * started */ - flags |= AOP_FLAG_NOFS; - - page = grab_cache_page_write_begin(mapping, index, flags); - if (!page) { + lock_page(page); + if (page->mapping != mapping) { + /* The page got truncated from under us */ + unlock_page(page); + page_cache_release(page); ext4_journal_stop(handle); - ret = -ENOMEM; - goto out; + goto retry_grab; } - - *pagep = page; + wait_on_page_writeback(page); if (ext4_should_dioread_nolock(inode)) ret = __block_write_begin(page, pos, len, ext4_get_block_write); @@ -915,7 +923,6 @@ retry: if (ret) { unlock_page(page); - page_cache_release(page); /* * __block_write_begin may have instantiated a few blocks * outside i_size. Trim these off again. Don't need @@ -939,11 +946,14 @@ retry: if (inode->i_nlink) ext4_orphan_del(NULL, inode); } - } - if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) - goto retry; -out: + if (ret == -ENOSPC && + ext4_should_retry_alloc(inode->i_sb, &retries)) + goto retry_journal; + page_cache_release(page); + return ret; + } + *pagep = page; return ret; } @@ -2458,42 +2468,52 @@ static int ext4_da_write_begin(struct file *file, struct address_space *mapping, pos, len, flags, pagep, fsdata); if (ret < 0) - goto out; - if (ret == 1) { - ret = 0; - goto out; - } + return ret; + if (ret == 1) + return 0; } -retry: + /* + * grab_cache_page_write_begin() can take a long time if the + * system is thrashing due to memory pressure, or if the page + * is being written back. So grab it first before we start + * the transaction handle. This also allows us to allocate + * the page (if needed) without using GFP_NOFS. + */ +retry_grab: + page = grab_cache_page_write_begin(mapping, index, flags); + if (!page) + return -ENOMEM; + unlock_page(page); + /* * With delayed allocation, we don't log the i_disksize update * if there is delayed block allocation. But we still need * to journalling the i_disksize update if writes to the end * of file which has an already mapped buffer. */ +retry_journal: handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, 1); if (IS_ERR(handle)) { - ret = PTR_ERR(handle); - goto out; + page_cache_release(page); + return PTR_ERR(handle); } - /* We cannot recurse into the filesystem as the transaction is already - * started */ - flags |= AOP_FLAG_NOFS; - page = grab_cache_page_write_begin(mapping, index, flags); - if (!page) { + lock_page(page); + if (page->mapping != mapping) { + /* The page got truncated from under us */ + unlock_page(page); + page_cache_release(page); ext4_journal_stop(handle); - ret = -ENOMEM; - goto out; + goto retry_grab; } - *pagep = page; + /* In case writeback began while the page was unlocked */ + wait_on_page_writeback(page); ret = __block_write_begin(page, pos, len, ext4_da_get_block_prep); if (ret < 0) { unlock_page(page); ext4_journal_stop(handle); - page_cache_release(page); /* * block_write_begin may have instantiated a few blocks * outside i_size. Trim these off again. Don't need @@ -2501,11 +2521,16 @@ retry: */ if (pos + len > inode->i_size) ext4_truncate_failed_write(inode); + + if (ret == -ENOSPC && + ext4_should_retry_alloc(inode->i_sb, &retries)) + goto retry_journal; + + page_cache_release(page); + return ret; } - if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) - goto retry; -out: + *pagep = page; return ret; } |