[PATCH 6/6] xfs: increase number of ACL entries for V5 superblocks

Dave Chinner
2013-06-03T05:29:25Z

From: Dave Chinner <dchinner@redhat.com>

The limit of 25 ACL entries is arbitrary, but baked into the on-disk
format. For version 5 superblocks, increase it to the maximum nuber
of ACLs that can fit into a single xattr.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
---
fs/xfs/xfs_acl.c | 31 ++++++++++++++++++-------------
fs/xfs/xfs_acl.h | 30 +++++++++++++++++++++++-------
2 files changed, 41 insertions(+), 20 deletions(-)

diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c
index 1d32f1d..58b6da3 100644
--- a/fs/xfs/xfs_acl.c
+++ b/fs/xfs/xfs_acl.c
@@ -21,6 +21,8 @@
#include "xfs_bmap_btree.h"
#include "xfs_inode.h"
#include "xfs_vnodeops.h"
+#include "xfs_sb.h"
+#include "xfs_mount.h"
#include "xfs_trace.h"
#include <linux/slab.h>
#include <linux/xattr.h>
@@ -34,7 +36,9 @@
*/

STATIC struct posix_acl *
-xfs_acl_from_disk(struct xfs_acl *aclp)
+xfs_acl_from_disk(
+ struct xfs_acl *aclp,
+ int max_entries)
{
struct posix_acl_entry *acl_e;
struct posix_acl *acl;
@@ -42,7 +46,7 @@ xfs_acl_from_disk(struct xfs_acl *aclp)
unsigned int count, i;

count = be32_to_cpu(aclp->acl_cnt);
- if (count > XFS_ACL_MAX_ENTRIES)
+ if (count > max_entries)
return ERR_PTR(-EFSCORRUPTED);

acl = posix_acl_alloc(count, GFP_KERNEL);
@@ -108,9 +112,9 @@ xfs_get_acl(struct inode *inode, int type)
struct xfs_inode *ip = XFS_I(inode);
struct posix_acl *acl;
struct xfs_acl *xfs_acl;
- int len = sizeof(struct xfs_acl);
unsigned char *ea_name;
int error;
+ int len;

acl = get_cached_acl(inode, type);
if (acl != ACL_NOT_CACHED)
@@ -133,8 +137,8 @@ xfs_get_acl(struct inode *inode, int type)
* If we have a cached ACLs value just return it, not need to
* go out to the disk.
*/
-
- xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL);
+ len = XFS_ACL_SIZE(ip->i_mount);
+ xfs_acl = kzalloc(len, GFP_KERNEL);
if (!xfs_acl)
return ERR_PTR(-ENOMEM);

@@ -153,7 +157,7 @@ xfs_get_acl(struct inode *inode, int type)
goto out;
}

- acl = xfs_acl_from_disk(xfs_acl);
+ acl = xfs_acl_from_disk(xfs_acl, XFS_ACL_MAX_ENTRIES(ip->i_mount));
if (IS_ERR(acl))
goto out;

@@ -189,16 +193,17 @@ xfs_set_acl(struct inode *inode, int type, struct posix_acl *acl)

if (acl) {
struct xfs_acl *xfs_acl;
- int len;
+ int len = XFS_ACL_SIZE(ip->i_mount);

- xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL);
+ xfs_acl = kzalloc(len, GFP_KERNEL);
if (!xfs_acl)
return -ENOMEM;

xfs_acl_to_disk(xfs_acl, acl);
- len = sizeof(struct xfs_acl) -
- (sizeof(struct xfs_acl_entry) *
- (XFS_ACL_MAX_ENTRIES - acl->a_count));
+
+ /* subtract away the unused acl entries */
+ len -= sizeof(struct xfs_acl_entry) *
+ (XFS_ACL_MAX_ENTRIES(ip->i_mount) - acl->a_count);

error = -xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl,
len, ATTR_ROOT);
@@ -243,7 +248,7 @@ xfs_set_mode(struct inode *inode, umode_t mode)
static int
xfs_acl_exists(struct inode *inode, unsigned char *name)
{
- int len = sizeof(struct xfs_acl);
+ int len = XFS_ACL_SIZE(XFS_M(inode->i_sb));

return (xfs_attr_get(XFS_I(inode), name, NULL, &len,
ATTR_ROOT|ATTR_KERNOVAL) == 0);
@@ -379,7 +384,7 @@ xfs_xattr_acl_set(struct dentry *dentry, const char *name,
goto out_release;

error = -EINVAL;
- if (acl->a_count > XFS_ACL_MAX_ENTRIES)
+ if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb)))
goto out_release;

if (type == ACL_TYPE_ACCESS) {
diff --git a/fs/xfs/xfs_acl.h b/fs/xfs/xfs_acl.h
index 39632d9..0da8725 100644
--- a/fs/xfs/xfs_acl.h
+++ b/fs/xfs/xfs_acl.h
@@ -22,19 +22,35 @@ struct inode;
struct posix_acl;
struct xfs_inode;

-#define XFS_ACL_MAX_ENTRIES 25
#define XFS_ACL_NOT_PRESENT (-1)

/* On-disk XFS access control list structure */
+struct xfs_acl_entry {
+ __be32 ae_tag;
+ __be32 ae_id;
+ __be16 ae_perm;
+ __be16 ae_pad; /* fill the implicit hole in the structure */
+};
+
struct xfs_acl {
- __be32 acl_cnt;
- struct xfs_acl_entry {
- __be32 ae_tag;
- __be32 ae_id;
- __be16 ae_perm;
- } acl_entry[XFS_ACL_MAX_ENTRIES];
+ __be32 acl_cnt;
+ struct xfs_acl_entry acl_entry[0];
};

+/*
+ * The number of ACL entries allowed is defined by the on-disk format.
+ * For v4 superblocks, that is limited to 25 entries. For v5 superblocks, it is
+ * limited only by the maximum size of the xattr that stores the information.
+ */
+#define XFS_ACL_MAX_ENTRIES(mp) \
+ (xfs_sb_version_hascrc(&mp->m_sb) \
+ ? (XATTR_SIZE_MAX - sizeof(__be32)) / sizeof(struct xfs_acl_entry) \
+ : 25)
+
+#define XFS_ACL_SIZE(mp) \
+ (sizeof(struct xfs_acl) + \
+ sizeof(struct xfs_acl_entry) * XFS_ACL_MAX_ENTRIES((mp)))
+
/* On-disk XFS extended attribute names */
#define SGI_ACL_FILE (unsigned char *)"SGI_ACL_FILE"
#define SGI_ACL_DEFAULT (unsigned char *)"SGI_ACL_DEFAULT"
--
1.7.10.4