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Commit 44512449 authored by Dave Kleikamp's avatar Dave Kleikamp
Browse files

jfs: fix readdir cookie incompatibility with NFSv4 



NFSv4 reserves readdir cookie values 0-2 for special entries (. and ..),
but jfs allows a value of 2 for a non-special entry. This incompatibility
can result in the nfs client reporting a readdir loop.

This patch doesn't change the value stored internally, but adds one to
the value exposed to the iterate method.

Signed-off-by: default avatarDave Kleikamp <dave.kleikamp@oracle.com>
Tested-by: default avatarChristian Kujau <lists@nerdbynature.de>
parent f1d6e17f

fs/jfs/jfs_dtree.c

+23 −8
Original line number Diff line number Diff line
@@ -3047,6 +3047,14 @@ int jfs_readdir(struct file *file, struct dir_context *ctx) 


		dir_index = (u32) ctx->pos;



		/*

		 * NFSv4 reserves cookies 1 and 2 for . and .. so the value

		 * we return to the vfs is one greater than the one we use

		 * internally.

		 */

		if (dir_index)

			dir_index--;



		if (dir_index > 1) {

			struct dir_table_slot dirtab_slot;
@@ -3086,7 +3094,7 @@ int jfs_readdir(struct file *file, struct dir_context *ctx) 
			if (p->header.flag & BT_INTERNAL) {

				jfs_err("jfs_readdir: bad index table");

				DT_PUTPAGE(mp);

				ctx->pos = -1;

				ctx->pos = DIREND;

				return 0;

			}

		} else {
@@ -3094,14 +3102,14 @@ int jfs_readdir(struct file *file, struct dir_context *ctx) 
				/*

				 * self "."

				 */

				ctx->pos = 0;

				ctx->pos = 1;

				if (!dir_emit(ctx, ".", 1, ip->i_ino, DT_DIR))

					return 0;

			}

			/*

			 * parent ".."

			 */

			ctx->pos = 1;

			ctx->pos = 2;

			if (!dir_emit(ctx, "..", 2, PARENT(ip), DT_DIR))

				return 0;
@@ -3122,22 +3130,23 @@ int jfs_readdir(struct file *file, struct dir_context *ctx) 
		/*

		 * Legacy filesystem - OS/2 & Linux JFS < 0.3.6

		 *

		 * pn = index = 0:	First entry "."

		 * pn = 0; index = 1:	Second entry ".."

		 * pn = 0; index = 1:	First entry "."

		 * pn = 0; index = 2:	Second entry ".."

		 * pn > 0:		Real entries, pn=1 -> leftmost page

		 * pn = index = -1:	No more entries

		 */

		dtpos = ctx->pos;

		if (dtpos == 0) {

		if (dtpos < 2) {

			/* build "." entry */

			ctx->pos = 1;

			if (!dir_emit(ctx, ".", 1, ip->i_ino, DT_DIR))

				return 0;

			dtoffset->index = 1;

			dtoffset->index = 2;

			ctx->pos = dtpos;

		}



		if (dtoffset->pn == 0) {

			if (dtoffset->index == 1) {

			if (dtoffset->index == 2) {

				/* build ".." entry */

				if (!dir_emit(ctx, "..", 2, PARENT(ip), DT_DIR))

					return 0;
@@ -3228,6 +3237,12 @@ int jfs_readdir(struct file *file, struct dir_context *ctx) 
					}

					jfs_dirent->position = unique_pos++;

				}

				/*

				 * We add 1 to the index because we may

				 * use a value of 2 internally, and NFSv4

				 * doesn't like that.

				 */

				jfs_dirent->position++;

			} else {

				jfs_dirent->position = dtpos;

				len = min(d_namleft, DTLHDRDATALEN_LEGACY);