Bug#714974: [PATCH] jfs: fix readdir cookie incompatibility with NFSv4
This patch replaces the one I posted yesterday. I like this better since
it doesn't require fixing existing on-disk cookies or skipping a
position in the in-inode index table.
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: Dave Kleikamp <dave.kleikamp@oracle.com>
---
fs/jfs/jfs_dtree.c | 31 +++++++++++++++++++++++--------
1 file changed, 23 insertions(+), 8 deletions(-)
diff --git a/fs/jfs/jfs_dtree.c b/fs/jfs/jfs_dtree.c
index 8743ba9..0ec767e 100644
--- a/fs/jfs/jfs_dtree.c
+++ b/fs/jfs/jfs_dtree.c
@@ -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 we add
+ * 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);
--
1.8.3.4
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