diff options
author | Paul Mackerras <paulus@samba.org> | 2007-05-08 07:37:51 +0400 |
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committer | Paul Mackerras <paulus@samba.org> | 2007-05-08 07:37:51 +0400 |
commit | 02bbc0f09c90cefdb2837605c96a66c5ce4ba2e1 (patch) | |
tree | 04ef573cd4de095c500c9fc3477f4278c0b36300 /fs/nfs/pagelist.c | |
parent | 7487a2245b8841c77ba9db406cf99a483b9334e9 (diff) | |
parent | 5b94f675f57e4ff16c8fda09088d7480a84dcd91 (diff) | |
download | linux-02bbc0f09c90cefdb2837605c96a66c5ce4ba2e1.tar.xz |
Merge branch 'linux-2.6'
Diffstat (limited to 'fs/nfs/pagelist.c')
-rw-r--r-- | fs/nfs/pagelist.c | 242 |
1 files changed, 132 insertions, 110 deletions
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index ca4b1d4ff42b..388950118f59 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -17,7 +17,8 @@ #include <linux/nfs_page.h> #include <linux/nfs_fs.h> #include <linux/nfs_mount.h> -#include <linux/writeback.h> + +#include "internal.h" #define NFS_PARANOIA 1 @@ -50,9 +51,7 @@ nfs_page_free(struct nfs_page *p) * @count: number of bytes to read/write * * The page must be locked by the caller. This makes sure we never - * create two different requests for the same page, and avoids - * a possible deadlock when we reach the hard limit on the number - * of dirty pages. + * create two different requests for the same page. * User should ensure it is safe to sleep in this function. */ struct nfs_page * @@ -63,16 +62,12 @@ nfs_create_request(struct nfs_open_context *ctx, struct inode *inode, struct nfs_server *server = NFS_SERVER(inode); struct nfs_page *req; - /* Deal with hard limits. */ for (;;) { /* try to allocate the request struct */ req = nfs_page_alloc(); if (req != NULL) break; - /* Try to free up at least one request in order to stay - * below the hard limit - */ if (signalled() && (server->flags & NFS_MOUNT_INTR)) return ERR_PTR(-ERESTARTSYS); yield(); @@ -223,124 +218,151 @@ out: } /** - * nfs_coalesce_requests - Split coalesced requests out from a list. - * @head: source list - * @dst: destination list - * @nmax: maximum number of requests to coalesce - * - * Moves a maximum of 'nmax' elements from one list to another. - * The elements are checked to ensure that they form a contiguous set - * of pages, and that the RPC credentials are the same. + * nfs_pageio_init - initialise a page io descriptor + * @desc: pointer to descriptor + * @inode: pointer to inode + * @doio: pointer to io function + * @bsize: io block size + * @io_flags: extra parameters for the io function */ -int -nfs_coalesce_requests(struct list_head *head, struct list_head *dst, - unsigned int nmax) +void nfs_pageio_init(struct nfs_pageio_descriptor *desc, + struct inode *inode, + int (*doio)(struct inode *, struct list_head *, unsigned int, size_t, int), + size_t bsize, + int io_flags) { - struct nfs_page *req = NULL; - unsigned int npages = 0; - - while (!list_empty(head)) { - struct nfs_page *prev = req; - - req = nfs_list_entry(head->next); - if (prev) { - if (req->wb_context->cred != prev->wb_context->cred) - break; - if (req->wb_context->lockowner != prev->wb_context->lockowner) - break; - if (req->wb_context->state != prev->wb_context->state) - break; - if (req->wb_index != (prev->wb_index + 1)) - break; - - if (req->wb_pgbase != 0) - break; - } - nfs_list_remove_request(req); - nfs_list_add_request(req, dst); - npages++; - if (req->wb_pgbase + req->wb_bytes != PAGE_CACHE_SIZE) - break; - if (npages >= nmax) - break; - } - return npages; + INIT_LIST_HEAD(&desc->pg_list); + desc->pg_bytes_written = 0; + desc->pg_count = 0; + desc->pg_bsize = bsize; + desc->pg_base = 0; + desc->pg_inode = inode; + desc->pg_doio = doio; + desc->pg_ioflags = io_flags; + desc->pg_error = 0; } -#define NFS_SCAN_MAXENTRIES 16 /** - * nfs_scan_dirty - Scan the radix tree for dirty requests - * @mapping: pointer to address space - * @wbc: writeback_control structure - * @dst: Destination list + * nfs_can_coalesce_requests - test two requests for compatibility + * @prev: pointer to nfs_page + * @req: pointer to nfs_page * - * Moves elements from one of the inode request lists. - * If the number of requests is set to 0, the entire address_space - * starting at index idx_start, is scanned. - * The requests are *not* checked to ensure that they form a contiguous set. - * You must be holding the inode's req_lock when calling this function + * The nfs_page structures 'prev' and 'req' are compared to ensure that the + * page data area they describe is contiguous, and that their RPC + * credentials, NFSv4 open state, and lockowners are the same. + * + * Return 'true' if this is the case, else return 'false'. */ -long nfs_scan_dirty(struct address_space *mapping, - struct writeback_control *wbc, - struct list_head *dst) +static int nfs_can_coalesce_requests(struct nfs_page *prev, + struct nfs_page *req) { - struct nfs_inode *nfsi = NFS_I(mapping->host); - struct nfs_page *pgvec[NFS_SCAN_MAXENTRIES]; - struct nfs_page *req; - pgoff_t idx_start, idx_end; - long res = 0; - int found, i; - - if (nfsi->ndirty == 0) + if (req->wb_context->cred != prev->wb_context->cred) return 0; - if (wbc->range_cyclic) { - idx_start = 0; - idx_end = ULONG_MAX; - } else if (wbc->range_end == 0) { - idx_start = wbc->range_start >> PAGE_CACHE_SHIFT; - idx_end = ULONG_MAX; - } else { - idx_start = wbc->range_start >> PAGE_CACHE_SHIFT; - idx_end = wbc->range_end >> PAGE_CACHE_SHIFT; - } + if (req->wb_context->lockowner != prev->wb_context->lockowner) + return 0; + if (req->wb_context->state != prev->wb_context->state) + return 0; + if (req->wb_index != (prev->wb_index + 1)) + return 0; + if (req->wb_pgbase != 0) + return 0; + if (prev->wb_pgbase + prev->wb_bytes != PAGE_CACHE_SIZE) + return 0; + return 1; +} - for (;;) { - unsigned int toscan = NFS_SCAN_MAXENTRIES; +/** + * nfs_pageio_do_add_request - Attempt to coalesce a request into a page list. + * @desc: destination io descriptor + * @req: request + * + * Returns true if the request 'req' was successfully coalesced into the + * existing list of pages 'desc'. + */ +static int nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc, + struct nfs_page *req) +{ + size_t newlen = req->wb_bytes; - found = radix_tree_gang_lookup_tag(&nfsi->nfs_page_tree, - (void **)&pgvec[0], idx_start, toscan, - NFS_PAGE_TAG_DIRTY); + if (desc->pg_count != 0) { + struct nfs_page *prev; - /* Did we make progress? */ - if (found <= 0) - break; + /* + * FIXME: ideally we should be able to coalesce all requests + * that are not block boundary aligned, but currently this + * is problematic for the case of bsize < PAGE_CACHE_SIZE, + * since nfs_flush_multi and nfs_pagein_multi assume you + * can have only one struct nfs_page. + */ + if (desc->pg_bsize < PAGE_SIZE) + return 0; + newlen += desc->pg_count; + if (newlen > desc->pg_bsize) + return 0; + prev = nfs_list_entry(desc->pg_list.prev); + if (!nfs_can_coalesce_requests(prev, req)) + return 0; + } else + desc->pg_base = req->wb_pgbase; + nfs_list_remove_request(req); + nfs_list_add_request(req, &desc->pg_list); + desc->pg_count = newlen; + return 1; +} - for (i = 0; i < found; i++) { - req = pgvec[i]; - if (!wbc->range_cyclic && req->wb_index > idx_end) - goto out; +/* + * Helper for nfs_pageio_add_request and nfs_pageio_complete + */ +static void nfs_pageio_doio(struct nfs_pageio_descriptor *desc) +{ + if (!list_empty(&desc->pg_list)) { + int error = desc->pg_doio(desc->pg_inode, + &desc->pg_list, + nfs_page_array_len(desc->pg_base, + desc->pg_count), + desc->pg_count, + desc->pg_ioflags); + if (error < 0) + desc->pg_error = error; + else + desc->pg_bytes_written += desc->pg_count; + } + if (list_empty(&desc->pg_list)) { + desc->pg_count = 0; + desc->pg_base = 0; + } +} - /* Try to lock request and mark it for writeback */ - if (!nfs_set_page_writeback_locked(req)) - goto next; - radix_tree_tag_clear(&nfsi->nfs_page_tree, - req->wb_index, NFS_PAGE_TAG_DIRTY); - nfsi->ndirty--; - nfs_list_remove_request(req); - nfs_list_add_request(req, dst); - res++; - if (res == LONG_MAX) - goto out; -next: - idx_start = req->wb_index + 1; - } +/** + * nfs_pageio_add_request - Attempt to coalesce a request into a page list. + * @desc: destination io descriptor + * @req: request + * + * Returns true if the request 'req' was successfully coalesced into the + * existing list of pages 'desc'. + */ +int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc, + struct nfs_page *req) +{ + while (!nfs_pageio_do_add_request(desc, req)) { + nfs_pageio_doio(desc); + if (desc->pg_error < 0) + return 0; } -out: - WARN_ON ((nfsi->ndirty == 0) != list_empty(&nfsi->dirty)); - return res; + return 1; } /** + * nfs_pageio_complete - Complete I/O on an nfs_pageio_descriptor + * @desc: pointer to io descriptor + */ +void nfs_pageio_complete(struct nfs_pageio_descriptor *desc) +{ + nfs_pageio_doio(desc); +} + +#define NFS_SCAN_MAXENTRIES 16 +/** * nfs_scan_list - Scan a list for matching requests * @nfsi: NFS inode * @head: One of the NFS inode request lists @@ -355,12 +377,12 @@ out: * You must be holding the inode's req_lock when calling this function */ int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *head, - struct list_head *dst, unsigned long idx_start, + struct list_head *dst, pgoff_t idx_start, unsigned int npages) { struct nfs_page *pgvec[NFS_SCAN_MAXENTRIES]; struct nfs_page *req; - unsigned long idx_end; + pgoff_t idx_end; int found, i; int res; |