From 35d14f278e530ecb635ab00de984065ed90ee12f Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Tue, 12 Jan 2021 11:02:49 -0800 Subject: fs: clean up __mark_inode_dirty() a bit Improve some comments, and don't bother checking for the I_DIRTY_TIME flag in the case where we just cleared it. Also, warn if I_DIRTY_TIME and I_DIRTY_PAGES are passed to __mark_inode_dirty() at the same time, as this case isn't handled. Link: https://lore.kernel.org/r/20210112190253.64307-8-ebiggers@kernel.org Reviewed-by: Christoph Hellwig Reviewed-by: Jan Kara Signed-off-by: Eric Biggers Signed-off-by: Jan Kara --- fs/fs-writeback.c | 49 ++++++++++++++++++++++++++++++------------------- 1 file changed, 30 insertions(+), 19 deletions(-) (limited to 'fs/fs-writeback.c') diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 2e6064012f7d..80ee9816d9df 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -2219,23 +2219,24 @@ static noinline void block_dump___mark_inode_dirty(struct inode *inode) } /** - * __mark_inode_dirty - internal function + * __mark_inode_dirty - internal function to mark an inode dirty * * @inode: inode to mark - * @flags: what kind of dirty (i.e. I_DIRTY_SYNC) + * @flags: what kind of dirty, e.g. I_DIRTY_SYNC. This can be a combination of + * multiple I_DIRTY_* flags, except that I_DIRTY_TIME can't be combined + * with I_DIRTY_PAGES. * - * Mark an inode as dirty. Callers should use mark_inode_dirty or - * mark_inode_dirty_sync. + * Mark an inode as dirty. We notify the filesystem, then update the inode's + * dirty flags. Then, if needed we add the inode to the appropriate dirty list. * - * Put the inode on the super block's dirty list. + * Most callers should use mark_inode_dirty() or mark_inode_dirty_sync() + * instead of calling this directly. * - * CAREFUL! We mark it dirty unconditionally, but move it onto the - * dirty list only if it is hashed or if it refers to a blockdev. - * If it was not hashed, it will never be added to the dirty list - * even if it is later hashed, as it will have been marked dirty already. + * CAREFUL! We only add the inode to the dirty list if it is hashed or if it + * refers to a blockdev. Unhashed inodes will never be added to the dirty list + * even if they are later hashed, as they will have been marked dirty already. * - * In short, make sure you hash any inodes _before_ you start marking - * them dirty. + * In short, ensure you hash any inodes _before_ you start marking them dirty. * * Note that for blockdevs, inode->dirtied_when represents the dirtying time of * the block-special inode (/dev/hda1) itself. And the ->dirtied_when field of @@ -2247,25 +2248,34 @@ static noinline void block_dump___mark_inode_dirty(struct inode *inode) void __mark_inode_dirty(struct inode *inode, int flags) { struct super_block *sb = inode->i_sb; - int dirtytime; + int dirtytime = 0; trace_writeback_mark_inode_dirty(inode, flags); - /* - * Don't do this for I_DIRTY_PAGES - that doesn't actually - * dirty the inode itself - */ if (flags & I_DIRTY_INODE) { + /* + * Notify the filesystem about the inode being dirtied, so that + * (if needed) it can update on-disk fields and journal the + * inode. This is only needed when the inode itself is being + * dirtied now. I.e. it's only needed for I_DIRTY_INODE, not + * for just I_DIRTY_PAGES or I_DIRTY_TIME. + */ trace_writeback_dirty_inode_start(inode, flags); - if (sb->s_op->dirty_inode) sb->s_op->dirty_inode(inode, flags & I_DIRTY_INODE); - trace_writeback_dirty_inode(inode, flags); + /* I_DIRTY_INODE supersedes I_DIRTY_TIME. */ flags &= ~I_DIRTY_TIME; + } else { + /* + * Else it's either I_DIRTY_PAGES, I_DIRTY_TIME, or nothing. + * (We don't support setting both I_DIRTY_PAGES and I_DIRTY_TIME + * in one call to __mark_inode_dirty().) + */ + dirtytime = flags & I_DIRTY_TIME; + WARN_ON_ONCE(dirtytime && flags != I_DIRTY_TIME); } - dirtytime = flags & I_DIRTY_TIME; /* * Paired with smp_mb() in __writeback_single_inode() for the @@ -2288,6 +2298,7 @@ void __mark_inode_dirty(struct inode *inode, int flags) inode_attach_wb(inode, NULL); + /* I_DIRTY_INODE supersedes I_DIRTY_TIME. */ if (flags & I_DIRTY_INODE) inode->i_state &= ~I_DIRTY_TIME; inode->i_state |= flags; -- cgit 1.4.1