afs: introduce get_dcache_readahead

[openafs.git] / src / afs / LINUX / osi_vnodeops.c

diff --git a/src/afs/LINUX/osi_vnodeops.c b/src/afs/LINUX/osi_vnodeops.c
index b4b1016..6bf0019 100644 (file)
--- a/src/afs/LINUX/osi_vnodeops.c
+++ b/src/afs/LINUX/osi_vnodeops.c
@@ -2734,6 +2734,81 @@ afs_linux_readpage(struct file *fp, struct page *pp)
     return code;
 }
 
+/*
+ * Updates the adc and acacheFp parameters
+ * Returns:
+ *    0 - success
+ *   -1 - problem getting inode or no mapping function
+ */
+static int
+get_dcache_readahead(struct dcache **adc, struct file **acacheFp,
+                    struct vcache *avc, loff_t offset)
+{
+    struct dcache *tdc = *adc;
+    struct file *cacheFp = *acacheFp;
+    int code;
+
+    if (tdc != NULL && tdc->f.chunk != AFS_CHUNK(offset)) {
+       AFS_GLOCK();
+       ReleaseReadLock(&tdc->lock);
+       afs_PutDCache(tdc);
+       AFS_GUNLOCK();
+       tdc = NULL;
+       if (cacheFp != NULL) {
+           filp_close(cacheFp, NULL);
+           cacheFp = NULL;
+       }
+    }
+
+    if (tdc == NULL) {
+       AFS_GLOCK();
+       tdc = afs_FindDCache(avc, offset);
+       if (tdc != NULL) {
+           ObtainReadLock(&tdc->lock);
+           if (!afs_IsDCacheFresh(tdc, avc) ||
+               (tdc->dflags & DFFetching) != 0) {
+               ReleaseReadLock(&tdc->lock);
+               afs_PutDCache(tdc);
+               tdc = NULL;
+           }
+       }
+       AFS_GUNLOCK();
+       if (tdc != NULL) {
+           cacheFp = afs_linux_raw_open(&tdc->f.inode);
+           if (cacheFp == NULL) {
+               /* Problem getting the inode */
+               code = -1;
+               goto out;
+           }
+           if (cacheFp->f_dentry->d_inode->i_mapping->a_ops->readpage == NULL) {
+               cachefs_noreadpage = 1;
+               /* No mapping function */
+               code = -1;
+               goto out;
+           }
+       }
+    }
+    code = 0;
+
+ out:
+    if (code != 0) {
+       if (cacheFp != NULL) {
+           filp_close(cacheFp, NULL);
+           cacheFp = NULL;
+       }
+       if (tdc != NULL) {
+           AFS_GLOCK();
+           ReleaseReadLock(&tdc->lock);
+           afs_PutDCache(tdc);
+           AFS_GUNLOCK();
+           tdc = NULL;
+       }
+    }
+    *adc = tdc;
+    *acacheFp = cacheFp;
+    return code;
+}
+
 /* Readpages reads a number of pages for a particular file. We use
  * this to optimise the reading, by limiting the number of times upon which
  * we have to lookup, lock and open vcaches and dcaches
@@ -2783,42 +2858,9 @@ afs_linux_readpages(struct file *fp, struct address_space *mapping,
        list_del(&page->lru);
        offset = page_offset(page);
 
-       if (tdc && tdc->f.chunk != AFS_CHUNK(offset)) {
-           AFS_GLOCK();
-           ReleaseReadLock(&tdc->lock);
-           afs_PutDCache(tdc);
-           AFS_GUNLOCK();
-           tdc = NULL;
-           if (cacheFp) {
-               filp_close(cacheFp, NULL);
-               cacheFp = NULL;
-           }
-       }
-
-       if (!tdc) {
-           AFS_GLOCK();
-           if ((tdc = afs_FindDCache(avc, offset))) {
-               ObtainReadLock(&tdc->lock);
-               if (!afs_IsDCacheFresh(tdc, avc) ||
-                   (tdc->dflags & DFFetching)) {
-                   ReleaseReadLock(&tdc->lock);
-                   afs_PutDCache(tdc);
-                   tdc = NULL;
-               }
-           }
-           AFS_GUNLOCK();
-           if (tdc) {
-               cacheFp = afs_linux_raw_open(&tdc->f.inode);
-               if (cacheFp == NULL) {
-                   /* Problem getting the inode */
-                   goto out;
-               }
-               if (!cacheFp->f_dentry->d_inode->i_mapping->a_ops->readpage) {
-                   cachefs_noreadpage = 1;
-                   goto out;
-               }
-           }
-       }
+       code = get_dcache_readahead(&tdc, &cacheFp, avc, offset);
+       if (code != 0)
+           goto out;
 
        if (tdc && !add_to_page_cache(page, mapping, page->index,
                                      GFP_KERNEL)) {