Commit 35d14f27 authored by Eric Biggers's avatar Eric Biggers Committed by Jan Kara
Browse files

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: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent a38ed483

fs/fs-writeback.c

+30 −19
Original line number Diff line number Diff line
@@ -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);



	if (flags & I_DIRTY_INODE) {

		/*

	 * Don't do this for I_DIRTY_PAGES - that doesn't actually

	 * dirty the inode itself

		 * 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.

		 */

	if (flags & I_DIRTY_INODE) {

		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);

	}



	/*

	 * 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;