lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

NFS: Fix a race when doing NFS write coalescing

Browse Source 
Currently we do write coalescing in a very inefficient manner: one pass in
generic_writepages() in order to lock the pages for writing, then one pass
in nfs_flush_mapping() and/or nfs_sync_mapping_wait() in order to gather
the locked pages for coalescing into RPC requests of size "wsize".

In fact, it turns out there is actually a deadlock possible here since we
only start I/O on the second pass. If the user signals the process while
we're in nfs_sync_mapping_wait(), for instance, then we may exit before
starting I/O on all the requests that have been queued up.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Trond Myklebust
2007-04-02 19:29:52 -04:00
parent 8b09bee308
commit c63c7b0513
4 changed files with 50 additions and 201 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
include/linux/nfs_page.h
View File

@@ -21,8 +21,7 @@
/*
* Valid flags for the radix tree
*/
#define NFS_PAGE_TAG_DIRTY 0
#define NFS_PAGE_TAG_WRITEBACK 1
#define NFS_PAGE_TAG_WRITEBACK 0
/*
* Valid flags for a dirty buffer
@@ -72,9 +71,6 @@ extern void nfs_clear_request(struct nfs_page *req);
extern void nfs_release_request(struct nfs_page *req);
extern long nfs_scan_dirty(struct address_space *mapping,
struct writeback_control *wbc,
struct list_head *dst);
extern int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *head, struct list_head *dst,
unsigned long idx_start, unsigned int npages);
extern void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
@@ -84,8 +80,6 @@ extern void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
int how);
extern int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
struct nfs_page *);
extern void nfs_pageio_add_list(struct nfs_pageio_descriptor *,
struct list_head *);
extern void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
extern int nfs_wait_on_request(struct nfs_page *);
extern void nfs_unlock_request(struct nfs_page *req);