ext4: fix mtime update in nodelalloc mode

Commits 5e8830dc85d0 and 41c4d25f78c0 introduced a regression into
v3.6-rc1 for ext4 in nodealloc mode, such that mtime updates would not
take place for files modified via mmap if the page was already in the
page cache.  This would also affect ext3 file systems mounted using
the ext4 file system driver.

The problem was that ext4_page_mkwrite() had a shortcut which would
avoid calling __block_page_mkwrite() under some circumstances, and the
above two commit transferred the responsibility of calling
file_update_time() to __block_page_mkwrite --- which woudln't get
called in some circumstances.

Since __block_page_mkwrite() only has three callers,
block_page_mkwrite(), ext4_page_mkwrite, and nilfs_page_mkwrite(), the
best way to solve this is to move the responsibility for calling
file_update_time() to its caller.

This problem was found via xfstests #215 with a file system mounted
with -o nodelalloc.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
Cc: stable@vger.kernel.org

diff --git a/fs/buffer.c b/fs/buffer.c
index 9f6d2e41281d69752f77d9c68772a46c855a8453..1fe3968357a955147ab891e5dba51f44b859b644 100644 (file)
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2318,12 +2318,6 @@ int __block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
        loff_t size;
        int ret;
 
-       /*
-        * Update file times before taking page lock. We may end up failing the
-        * fault so this update may be superfluous but who really cares...
-        */
-       file_update_time(vma->vm_file);
-
        lock_page(page);
        size = i_size_read(inode);
        if ((page->mapping != inode->i_mapping) ||
@@ -2361,6 +2355,13 @@ int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
        struct super_block *sb = vma->vm_file->f_path.dentry->d_inode->i_sb;
 
        sb_start_pagefault(sb);
+
+       /*
+        * Update file times before taking page lock. We may end up failing the
+        * fault so this update may be superfluous but who really cares...
+        */
+       file_update_time(vma->vm_file);
+
        ret = __block_page_mkwrite(vma, vmf, get_block);
        sb_end_pagefault(sb);
        return block_page_mkwrite_return(ret);

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 09308ad0f314a02f8e1d7f308422db6758fcedca..f18e786e87b0c92f7cb40381559298058463ab21 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4788,6 +4788,7 @@ int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
        int retries = 0;
 
        sb_start_pagefault(inode->i_sb);
+       file_update_time(vma->vm_file);
        /* Delalloc case is easy... */
        if (test_opt(inode->i_sb, DELALLOC) &&
            !ext4_should_journal_data(inode) &&

diff --git a/fs/nilfs2/file.c b/fs/nilfs2/file.c
index a4d56ac02e6cf075b81dfaee284175d86776219d..5b387a4c293e428d1f8a8eeb5241a23c18406157 100644 (file)
--- a/fs/nilfs2/file.c
+++ b/fs/nilfs2/file.c
@@ -116,6 +116,7 @@ static int nilfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
        if (unlikely(ret))
                goto out;
 
+       file_update_time(vma->vm_file);
        ret = __block_page_mkwrite(vma, vmf, nilfs_get_block);
        if (ret) {
                nilfs_transaction_abort(inode->i_sb);