Commit 59e356a9 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Use the 64-bit server readdir cookies when possible 



When we're running as a 64-bit architecture and are not running in
32-bit compatibility mode, it is better to use the 64-bit readdir
cookies that supplied by the server. Doing so improves the accuracy
of telldir()/seekdir(), particularly when the directory is changing,
for instance, when doing 'rm -rf'.

We still fall back to using the 32-bit offsets on 32-bit architectures
and when in compatibility mode.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
parent fb33c651

fs/nfs/dir.c

+44 −17
Original line number Diff line number Diff line
@@ -144,7 +144,6 @@ struct nfs_cache_array { 
	struct nfs_cache_array_entry array[0];

};



typedef int (*decode_dirent_t)(struct xdr_stream *, struct nfs_entry *, bool);

typedef struct {

	struct file	*file;

	struct page	*page;
@@ -153,7 +152,7 @@ typedef struct { 
	u64		*dir_cookie;

	u64		last_cookie;

	loff_t		current_index;

	decode_dirent_t	decode;

	loff_t		prev_index;



	unsigned long	dir_verifier;

	unsigned long	timestamp;
@@ -240,6 +239,25 @@ out: 
	return ret;

}



static inline

int is_32bit_api(void)

{

#ifdef CONFIG_COMPAT

	return in_compat_syscall();

#else

	return (BITS_PER_LONG == 32);

#endif

}



static

bool nfs_readdir_use_cookie(const struct file *filp)

{

	if ((filp->f_mode & FMODE_32BITHASH) ||

	    (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))

		return false;

	return true;

}



static

int nfs_readdir_search_for_pos(struct nfs_cache_array *array, nfs_readdir_descriptor_t *desc)

{
@@ -289,7 +307,7 @@ int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, nfs_readdir_des 
			    !nfs_readdir_inode_mapping_valid(nfsi)) {

				ctx->duped = 0;

				ctx->attr_gencount = nfsi->attr_gencount;

			} else if (new_pos < desc->ctx->pos) {

			} else if (new_pos < desc->prev_index) {

				if (ctx->duped > 0

				    && ctx->dup_cookie == *desc->dir_cookie) {

					if (printk_ratelimit()) {
@@ -305,7 +323,11 @@ int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, nfs_readdir_des 
				ctx->dup_cookie = *desc->dir_cookie;

				ctx->duped = -1;

			}

			if (nfs_readdir_use_cookie(desc->file))

				desc->ctx->pos = *desc->dir_cookie;

			else

				desc->ctx->pos = new_pos;

			desc->prev_index = new_pos;

			desc->cache_entry_index = i;

			return 0;

		}
@@ -376,9 +398,10 @@ error: 
static int xdr_decode(nfs_readdir_descriptor_t *desc,

		      struct nfs_entry *entry, struct xdr_stream *xdr)

{

	struct inode *inode = file_inode(desc->file);

	int error;



	error = desc->decode(xdr, entry, desc->plus);

	error = NFS_PROTO(inode)->decode_dirent(xdr, entry, desc->plus);

	if (error)

		return error;

	entry->fattr->time_start = desc->timestamp;
@@ -756,6 +779,7 @@ int readdir_search_pagecache(nfs_readdir_descriptor_t *desc) 


	if (desc->page_index == 0) {

		desc->current_index = 0;

		desc->prev_index = 0;

		desc->last_cookie = 0;

	}

	do {
@@ -786,11 +810,14 @@ int nfs_do_filldir(nfs_readdir_descriptor_t *desc) 
			desc->eof = true;

			break;

		}

		desc->ctx->pos++;

		if (i < (array->size-1))

			*desc->dir_cookie = array->array[i+1].cookie;

		else

			*desc->dir_cookie = array->last_cookie;

		if (nfs_readdir_use_cookie(file))

			desc->ctx->pos = *desc->dir_cookie;

		else

			desc->ctx->pos++;

		if (ctx->duped != 0)

			ctx->duped = 1;

	}
@@ -860,9 +887,14 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx) 
{

	struct dentry	*dentry = file_dentry(file);

	struct inode	*inode = d_inode(dentry);

	nfs_readdir_descriptor_t my_desc,

			*desc = &my_desc;

	struct nfs_open_dir_context *dir_ctx = file->private_data;

	nfs_readdir_descriptor_t my_desc = {

		.file = file,

		.ctx = ctx,

		.dir_cookie = &dir_ctx->dir_cookie,

		.plus = nfs_use_readdirplus(inode, ctx),

	},

			*desc = &my_desc;

	int res = 0;



	dfprintk(FILE, "NFS: readdir(%pD2) starting at cookie %llu\n",
@@ -875,14 +907,6 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx) 
	 * to either find the entry with the appropriate number or

	 * revalidate the cookie.

	 */

	memset(desc, 0, sizeof(*desc));



	desc->file = file;

	desc->ctx = ctx;

	desc->dir_cookie = &dir_ctx->dir_cookie;

	desc->decode = NFS_PROTO(inode)->decode_dirent;

	desc->plus = nfs_use_readdirplus(inode, ctx);



	if (ctx->pos == 0 || nfs_attribute_cache_expired(inode))

		res = nfs_revalidate_mapping(inode, file->f_mapping);

	if (res < 0)
@@ -954,6 +978,9 @@ static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int whence) 
	}

	if (offset != filp->f_pos) {

		filp->f_pos = offset;

		if (nfs_readdir_use_cookie(filp))

			dir_ctx->dir_cookie = offset;

		else

			dir_ctx->dir_cookie = 0;

		dir_ctx->duped = 0;

	}

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