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jfs: fix readdir cookie incompatibility with NFSv4

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commit 44512449c0 upstream.

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>
[bwh: Backported to 3.2:
 - Adjust context
 - s/ctx->pos/filp->f_pos/]
Tested-by: Christian Kujau <lists@nerdbynature.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Dave Kleikamp 2013-08-15 15:36:49 -05:00 committed by Greg Kroah-Hartman
parent cc540ceece
commit 59fb9f6b1f
1 changed files with 23 additions and 8 deletions
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31
fs/jfs/jfs_dtree.c
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@ -3047,6 +3047,14 @@ int jfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
dir_index = (u32) filp->f_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 *filp, void *dirent, filldir_t filldir)
if (p->header.flag & BT_INTERNAL) {
jfs_err("jfs_readdir: bad index table");
DT_PUTPAGE(mp);
filp->f_pos = -1;
filp->f_pos = DIREND;
return 0;
}
} else {
@ -3094,7 +3102,7 @@ int jfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
/*
* self "."
*/
filp->f_pos = 0;
filp->f_pos = 1;
if (filldir(dirent, ".", 1, 0, ip->i_ino,
DT_DIR))
return 0;
@ -3102,7 +3110,7 @@ int jfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
/*
* parent ".."
*/
filp->f_pos = 1;
filp->f_pos = 2;
if (filldir(dirent, "..", 2, 1, PARENT(ip), DT_DIR))
return 0;
@ -3123,24 +3131,25 @@ int jfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
/*
* 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 = filp->f_pos;
if (dtpos == 0) {
if (dtpos < 2) {
/* build "." entry */
filp->f_pos = 1;
if (filldir(dirent, ".", 1, filp->f_pos, ip->i_ino,
DT_DIR))
return 0;
dtoffset->index = 1;
dtoffset->index = 2;
filp->f_pos = dtpos;
}
if (dtoffset->pn == 0) {
if (dtoffset->index == 1) {
if (dtoffset->index == 2) {
/* build ".." entry */
if (filldir(dirent, "..", 2, filp->f_pos,
@ -3233,6 +3242,12 @@ int jfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
}
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);