From: Mel Gorman Date: Thu, 27 Jun 2013 23:52:09 +0000 (+1000) Subject: documentation: document the is_dirty_writeback aops callback X-Git-Tag: next-20130628~3^2~434 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=59094e4d65f2d35d56f28cab327410b1509f7e1f;p=karo-tx-linux.git documentation: document the is_dirty_writeback aops callback Signed-off-by: Mel Gorman Signed-off-by: Andrew Morton --- diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index 49254eb5efd1..4493f414a831 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -577,6 +577,7 @@ struct address_space_operations { int (*launder_page) (struct page *); int (*is_partially_uptodate) (struct page *, read_descriptor_t *, unsigned long); + void (*is_dirty_writeback) (struct page *, bool *, bool *); int (*error_remove_page) (struct mapping *mapping, struct page *page); int (*swap_activate)(struct file *); int (*swap_deactivate)(struct file *); @@ -741,6 +742,15 @@ struct address_space_operations { block is up to date then the read can complete without needing the IO to bring the whole page up to date. + is_dirty_writeback: Called by the VM when attempting to reclaim a page. + The VM uses dirty and writeback information to determine if it needs + to stall to allow flushers a chance to complete some IO. Ordinarily + it can use PageDirty and PageWriteback but some filesystems have + more complex state (unstable pages in NFS prevent reclaim) or + do not set those flags due to locking problems (jbd). This callback + allows a filesystem to indicate to the VM if a page should be + treated as dirty or writeback for the purposes of stalling. + error_remove_page: normally set to generic_error_remove_page if truncation is ok for this address space. Used for memory failure handling. Setting this implies you deal with pages going away under you,