2df485a774
When a nfs_page is freed, nfs_free_request is called which also calls nfs_clear_request to clean out the lock and open contexts and free the pagecache page. However, a couple of places in the nfs code call nfs_clear_request themselves. What happens here if the refcount on the request is still high? We'll be releasing contexts and freeing pointers while the request is possibly still in use. Remove those bare calls to nfs_clear_context. That should only be done when the request is being freed. Note that when doing this, we need to watch out for tests of req->wb_page. Previously, nfs_set_page_tag_locked() and nfs_clear_page_tag_locked() would check the value of req->wb_page to figure out if the page is mapped into the nfsi->nfs_page_tree. We now indicate the page is mapped using the new bit PG_MAPPED in req->wb_flags . Reported-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
140 lines
3.6 KiB
C
140 lines
3.6 KiB
C
/*
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* linux/include/linux/nfs_page.h
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*
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* Copyright (C) 2000 Trond Myklebust
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*
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* NFS page cache wrapper.
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*/
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#ifndef _LINUX_NFS_PAGE_H
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#define _LINUX_NFS_PAGE_H
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#include <linux/list.h>
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#include <linux/pagemap.h>
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#include <linux/wait.h>
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#include <linux/sunrpc/auth.h>
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#include <linux/nfs_xdr.h>
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#include <linux/kref.h>
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/*
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* Valid flags for the radix tree
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*/
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#define NFS_PAGE_TAG_LOCKED 0
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#define NFS_PAGE_TAG_COMMIT 1
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/*
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* Valid flags for a dirty buffer
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*/
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enum {
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PG_BUSY = 0,
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PG_MAPPED,
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PG_CLEAN,
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PG_NEED_COMMIT,
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PG_NEED_RESCHED,
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};
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struct nfs_inode;
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struct nfs_page {
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struct list_head wb_list; /* Defines state of page: */
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struct page *wb_page; /* page to read in/write out */
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struct nfs_open_context *wb_context; /* File state context info */
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struct nfs_lock_context *wb_lock_context; /* lock context info */
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atomic_t wb_complete; /* i/os we're waiting for */
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pgoff_t wb_index; /* Offset >> PAGE_CACHE_SHIFT */
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unsigned int wb_offset, /* Offset & ~PAGE_CACHE_MASK */
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wb_pgbase, /* Start of page data */
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wb_bytes; /* Length of request */
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struct kref wb_kref; /* reference count */
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unsigned long wb_flags;
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struct nfs_writeverf wb_verf; /* Commit cookie */
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};
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struct nfs_pageio_descriptor {
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struct list_head pg_list;
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unsigned long pg_bytes_written;
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size_t pg_count;
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size_t pg_bsize;
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unsigned int pg_base;
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struct inode *pg_inode;
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int (*pg_doio)(struct inode *, struct list_head *, unsigned int, size_t, int);
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int pg_ioflags;
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int pg_error;
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};
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#define NFS_WBACK_BUSY(req) (test_bit(PG_BUSY,&(req)->wb_flags))
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extern struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
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struct inode *inode,
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struct page *page,
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unsigned int offset,
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unsigned int count);
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extern void nfs_clear_request(struct nfs_page *req);
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extern void nfs_release_request(struct nfs_page *req);
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extern int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *dst,
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pgoff_t idx_start, unsigned int npages, int tag);
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extern void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
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struct inode *inode,
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int (*doio)(struct inode *, struct list_head *, unsigned int, size_t, int),
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size_t bsize,
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int how);
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extern int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
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struct nfs_page *);
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extern void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
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extern void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
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extern int nfs_wait_on_request(struct nfs_page *);
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extern void nfs_unlock_request(struct nfs_page *req);
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extern int nfs_set_page_tag_locked(struct nfs_page *req);
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extern void nfs_clear_page_tag_locked(struct nfs_page *req);
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/*
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* Lock the page of an asynchronous request without getting a new reference
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*/
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static inline int
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nfs_lock_request_dontget(struct nfs_page *req)
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{
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return !test_and_set_bit(PG_BUSY, &req->wb_flags);
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}
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/**
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* nfs_list_add_request - Insert a request into a list
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* @req: request
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* @head: head of list into which to insert the request.
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*/
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static inline void
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nfs_list_add_request(struct nfs_page *req, struct list_head *head)
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{
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list_add_tail(&req->wb_list, head);
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}
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/**
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* nfs_list_remove_request - Remove a request from its wb_list
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* @req: request
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*/
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static inline void
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nfs_list_remove_request(struct nfs_page *req)
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{
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if (list_empty(&req->wb_list))
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return;
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list_del_init(&req->wb_list);
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}
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static inline struct nfs_page *
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nfs_list_entry(struct list_head *head)
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{
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return list_entry(head, struct nfs_page, wb_list);
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}
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static inline
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loff_t req_offset(struct nfs_page *req)
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{
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return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
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}
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#endif /* _LINUX_NFS_PAGE_H */
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