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NFS: Ensure contents of struct nfs_open_dir_context are consistent
Ensure that the contents of struct nfs_open_dir_context are consistent by setting them under the file->f_lock from a private copy (that is known to be consistent). Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Dave Wysochanski <dwysocha@redhat.com>
This commit is contained in:
Trond Myklebust
parent
05ad917561
commit
2e7a464179
72
fs/nfs/dir.c
72
fs/nfs/dir.c
@ -144,20 +144,23 @@ struct nfs_cache_array {
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struct nfs_cache_array_entry array[];
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};
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typedef struct {
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typedef struct nfs_readdir_descriptor {
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struct file *file;
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struct page *page;
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struct dir_context *ctx;
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unsigned long page_index;
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u64 *dir_cookie;
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u64 dir_cookie;
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u64 last_cookie;
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u64 dup_cookie;
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loff_t current_index;
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loff_t prev_index;
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unsigned long dir_verifier;
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unsigned long timestamp;
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unsigned long gencount;
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unsigned long attr_gencount;
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unsigned int cache_entry_index;
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signed char duped;
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bool plus;
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bool eof;
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} nfs_readdir_descriptor_t;
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@ -273,7 +276,7 @@ int nfs_readdir_search_for_pos(struct nfs_cache_array *array, nfs_readdir_descri
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}
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index = (unsigned int)diff;
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*desc->dir_cookie = array->array[index].cookie;
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desc->dir_cookie = array->array[index].cookie;
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desc->cache_entry_index = index;
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return 0;
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out_eof:
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@ -298,33 +301,32 @@ int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, nfs_readdir_des
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int status = -EAGAIN;
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for (i = 0; i < array->size; i++) {
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if (array->array[i].cookie == *desc->dir_cookie) {
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if (array->array[i].cookie == desc->dir_cookie) {
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struct nfs_inode *nfsi = NFS_I(file_inode(desc->file));
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struct nfs_open_dir_context *ctx = desc->file->private_data;
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new_pos = desc->current_index + i;
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if (ctx->attr_gencount != nfsi->attr_gencount ||
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if (desc->attr_gencount != nfsi->attr_gencount ||
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!nfs_readdir_inode_mapping_valid(nfsi)) {
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ctx->duped = 0;
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ctx->attr_gencount = nfsi->attr_gencount;
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desc->duped = 0;
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desc->attr_gencount = nfsi->attr_gencount;
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} else if (new_pos < desc->prev_index) {
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if (ctx->duped > 0
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&& ctx->dup_cookie == *desc->dir_cookie) {
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if (desc->duped > 0
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&& desc->dup_cookie == desc->dir_cookie) {
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if (printk_ratelimit()) {
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pr_notice("NFS: directory %pD2 contains a readdir loop."
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"Please contact your server vendor. "
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"The file: %.*s has duplicate cookie %llu\n",
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desc->file, array->array[i].string.len,
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array->array[i].string.name, *desc->dir_cookie);
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array->array[i].string.name, desc->dir_cookie);
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}
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status = -ELOOP;
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goto out;
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}
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ctx->dup_cookie = *desc->dir_cookie;
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ctx->duped = -1;
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desc->dup_cookie = desc->dir_cookie;
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desc->duped = -1;
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}
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if (nfs_readdir_use_cookie(desc->file))
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desc->ctx->pos = *desc->dir_cookie;
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desc->ctx->pos = desc->dir_cookie;
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else
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desc->ctx->pos = new_pos;
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desc->prev_index = new_pos;
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@ -334,7 +336,7 @@ int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, nfs_readdir_des
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}
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if (array->eof_index >= 0) {
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status = -EBADCOOKIE;
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if (*desc->dir_cookie == array->last_cookie)
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if (desc->dir_cookie == array->last_cookie)
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desc->eof = true;
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}
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out:
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@ -349,7 +351,7 @@ int nfs_readdir_search_array(nfs_readdir_descriptor_t *desc)
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array = kmap(desc->page);
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if (*desc->dir_cookie == 0)
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if (desc->dir_cookie == 0)
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status = nfs_readdir_search_for_pos(array, desc);
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else
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status = nfs_readdir_search_for_cookie(array, desc);
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@ -801,7 +803,6 @@ int nfs_do_filldir(nfs_readdir_descriptor_t *desc)
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int i = 0;
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int res = 0;
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struct nfs_cache_array *array = NULL;
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struct nfs_open_dir_context *ctx = file->private_data;
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array = kmap(desc->page);
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for (i = desc->cache_entry_index; i < array->size; i++) {
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@ -814,22 +815,22 @@ int nfs_do_filldir(nfs_readdir_descriptor_t *desc)
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break;
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}
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if (i < (array->size-1))
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*desc->dir_cookie = array->array[i+1].cookie;
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desc->dir_cookie = array->array[i+1].cookie;
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else
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*desc->dir_cookie = array->last_cookie;
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desc->dir_cookie = array->last_cookie;
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if (nfs_readdir_use_cookie(file))
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desc->ctx->pos = *desc->dir_cookie;
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desc->ctx->pos = desc->dir_cookie;
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else
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desc->ctx->pos++;
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if (ctx->duped != 0)
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ctx->duped = 1;
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if (desc->duped != 0)
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desc->duped = 1;
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}
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if (array->eof_index >= 0)
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desc->eof = true;
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kunmap(desc->page);
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dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling ended @ cookie %Lu; returning = %d\n",
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(unsigned long long)*desc->dir_cookie, res);
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(unsigned long long)desc->dir_cookie, res);
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return res;
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}
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@ -851,10 +852,9 @@ int uncached_readdir(nfs_readdir_descriptor_t *desc)
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struct page *page = NULL;
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int status;
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struct inode *inode = file_inode(desc->file);
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struct nfs_open_dir_context *ctx = desc->file->private_data;
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dfprintk(DIRCACHE, "NFS: uncached_readdir() searching for cookie %Lu\n",
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(unsigned long long)*desc->dir_cookie);
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(unsigned long long)desc->dir_cookie);
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page = alloc_page(GFP_HIGHUSER);
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if (!page) {
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@ -863,9 +863,9 @@ int uncached_readdir(nfs_readdir_descriptor_t *desc)
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}
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desc->page_index = 0;
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desc->last_cookie = *desc->dir_cookie;
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desc->last_cookie = desc->dir_cookie;
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desc->page = page;
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ctx->duped = 0;
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desc->duped = 0;
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status = nfs_readdir_xdr_to_array(desc, page, inode);
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if (status < 0)
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@ -894,7 +894,6 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx)
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nfs_readdir_descriptor_t my_desc = {
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.file = file,
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.ctx = ctx,
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.dir_cookie = &dir_ctx->dir_cookie,
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.plus = nfs_use_readdirplus(inode, ctx),
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},
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*desc = &my_desc;
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@ -915,13 +914,20 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx)
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if (res < 0)
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goto out;
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spin_lock(&file->f_lock);
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desc->dir_cookie = dir_ctx->dir_cookie;
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desc->dup_cookie = dir_ctx->dup_cookie;
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desc->duped = dir_ctx->duped;
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desc->attr_gencount = dir_ctx->attr_gencount;
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spin_unlock(&file->f_lock);
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do {
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res = readdir_search_pagecache(desc);
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if (res == -EBADCOOKIE) {
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res = 0;
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/* This means either end of directory */
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if (*desc->dir_cookie && !desc->eof) {
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if (desc->dir_cookie && !desc->eof) {
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/* Or that the server has 'lost' a cookie */
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res = uncached_readdir(desc);
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if (res == 0)
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@ -946,6 +952,14 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx)
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if (res < 0)
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break;
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} while (!desc->eof);
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spin_lock(&file->f_lock);
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dir_ctx->dir_cookie = desc->dir_cookie;
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dir_ctx->dup_cookie = desc->dup_cookie;
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dir_ctx->duped = desc->duped;
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dir_ctx->attr_gencount = desc->attr_gencount;
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spin_unlock(&file->f_lock);
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out:
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if (res > 0)
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res = 0;
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