From 0c0308066ca53fdf1423895f3a42838b67b3a5a8 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Sat, 30 Jul 2011 12:45:35 -0400 Subject: [PATCH] NFS: Fix spurious readdir cookie loop messages If the directory contents change, then we have to accept that the file->f_pos value may shrink if we do a 'search-by-cookie'. In that case, we should turn off the loop detection and let the NFS client try to recover. The patch also fixes a second loop detection bug by ensuring that after turning on the ctx->duped flag, we read at least one new cookie into ctx->dir_cookie before attempting to match with ctx->dup_cookie. Reported-by: Petr Vandrovec Cc: stable@kernel.org [2.6.39+] Signed-off-by: Trond Myklebust --- fs/nfs/dir.c | 56 +++++++++++++++++++++++++----------------- include/linux/nfs_fs.h | 3 ++- 2 files changed, 35 insertions(+), 24 deletions(-) diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 57f578e2560a..d23108b1e338 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -134,18 +134,19 @@ const struct inode_operations nfs4_dir_inode_operations = { #endif /* CONFIG_NFS_V4 */ -static struct nfs_open_dir_context *alloc_nfs_open_dir_context(struct rpc_cred *cred) +static struct nfs_open_dir_context *alloc_nfs_open_dir_context(struct inode *dir, struct rpc_cred *cred) { struct nfs_open_dir_context *ctx; ctx = kmalloc(sizeof(*ctx), GFP_KERNEL); if (ctx != NULL) { ctx->duped = 0; + ctx->attr_gencount = NFS_I(dir)->attr_gencount; ctx->dir_cookie = 0; ctx->dup_cookie = 0; ctx->cred = get_rpccred(cred); - } else - ctx = ERR_PTR(-ENOMEM); - return ctx; + return ctx; + } + return ERR_PTR(-ENOMEM); } static void put_nfs_open_dir_context(struct nfs_open_dir_context *ctx) @@ -173,7 +174,7 @@ nfs_opendir(struct inode *inode, struct file *filp) cred = rpc_lookup_cred(); if (IS_ERR(cred)) return PTR_ERR(cred); - ctx = alloc_nfs_open_dir_context(cred); + ctx = alloc_nfs_open_dir_context(inode, cred); if (IS_ERR(ctx)) { res = PTR_ERR(ctx); goto out; @@ -323,7 +324,6 @@ int nfs_readdir_search_for_pos(struct nfs_cache_array *array, nfs_readdir_descri { loff_t diff = desc->file->f_pos - desc->current_index; unsigned int index; - struct nfs_open_dir_context *ctx = desc->file->private_data; if (diff < 0) goto out_eof; @@ -336,7 +336,6 @@ int nfs_readdir_search_for_pos(struct nfs_cache_array *array, nfs_readdir_descri index = (unsigned int)diff; *desc->dir_cookie = array->array[index].cookie; desc->cache_entry_index = index; - ctx->duped = 0; return 0; out_eof: desc->eof = 1; @@ -349,14 +348,33 @@ int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, nfs_readdir_des int i; loff_t new_pos; int status = -EAGAIN; - struct nfs_open_dir_context *ctx = desc->file->private_data; for (i = 0; i < array->size; i++) { if (array->array[i].cookie == *desc->dir_cookie) { + struct nfs_inode *nfsi = NFS_I(desc->file->f_path.dentry->d_inode); + struct nfs_open_dir_context *ctx = desc->file->private_data; + new_pos = desc->current_index + i; - if (new_pos < desc->file->f_pos) { + if (ctx->attr_gencount != nfsi->attr_gencount + || (nfsi->cache_validity & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA))) { + ctx->duped = 0; + ctx->attr_gencount = nfsi->attr_gencount; + } else if (new_pos < desc->file->f_pos) { + if (ctx->duped > 0 + && ctx->dup_cookie == *desc->dir_cookie) { + if (printk_ratelimit()) { + pr_notice("NFS: directory %s/%s contains a readdir loop." + "Please contact your server vendor. " + "Offending cookie: %llu\n", + desc->file->f_dentry->d_parent->d_name.name, + desc->file->f_dentry->d_name.name, + *desc->dir_cookie); + } + status = -ELOOP; + goto out; + } ctx->dup_cookie = *desc->dir_cookie; - ctx->duped = 1; + ctx->duped = -1; } desc->file->f_pos = new_pos; desc->cache_entry_index = i; @@ -368,6 +386,7 @@ int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, nfs_readdir_des if (*desc->dir_cookie == array->last_cookie) desc->eof = 1; } +out: return status; } @@ -740,19 +759,6 @@ int nfs_do_filldir(nfs_readdir_descriptor_t *desc, void *dirent, struct nfs_cache_array *array = NULL; struct nfs_open_dir_context *ctx = file->private_data; - if (ctx->duped != 0 && ctx->dup_cookie == *desc->dir_cookie) { - if (printk_ratelimit()) { - pr_notice("NFS: directory %s/%s contains a readdir loop. " - "Please contact your server vendor. " - "Offending cookie: %llu\n", - file->f_dentry->d_parent->d_name.name, - file->f_dentry->d_name.name, - *desc->dir_cookie); - } - res = -ELOOP; - goto out; - } - array = nfs_readdir_get_array(desc->page); if (IS_ERR(array)) { res = PTR_ERR(array); @@ -774,6 +780,8 @@ int nfs_do_filldir(nfs_readdir_descriptor_t *desc, void *dirent, *desc->dir_cookie = array->array[i+1].cookie; else *desc->dir_cookie = array->last_cookie; + if (ctx->duped != 0) + ctx->duped = 1; } if (array->eof_index >= 0) desc->eof = 1; @@ -805,6 +813,7 @@ int uncached_readdir(nfs_readdir_descriptor_t *desc, void *dirent, struct page *page = NULL; int status; struct inode *inode = desc->file->f_path.dentry->d_inode; + struct nfs_open_dir_context *ctx = desc->file->private_data; dfprintk(DIRCACHE, "NFS: uncached_readdir() searching for cookie %Lu\n", (unsigned long long)*desc->dir_cookie); @@ -818,6 +827,7 @@ int uncached_readdir(nfs_readdir_descriptor_t *desc, void *dirent, desc->page_index = 0; desc->last_cookie = *desc->dir_cookie; desc->page = page; + ctx->duped = 0; status = nfs_readdir_xdr_to_array(desc, page, inode); if (status < 0) diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h index 8b579beb6358..b96fb99072ff 100644 --- a/include/linux/nfs_fs.h +++ b/include/linux/nfs_fs.h @@ -99,9 +99,10 @@ struct nfs_open_context { struct nfs_open_dir_context { struct rpc_cred *cred; + unsigned long attr_gencount; __u64 dir_cookie; __u64 dup_cookie; - int duped; + signed char duped; }; /* -- 2.20.1