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 <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Eric Biggers 2021-01-12 11:02:49 -08:00 committed by Jan Kara
parent a38ed483a7
commit 35d14f278e

View file

@ -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;