Commit aea6ad0c authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Lachlan McIlroy

[XFS] fix unaligned access in readdir

This patch should fix the issue seen on Alpha with unaligned accesses in
the new readdir code. By aligning each dirent to sizeof(u64) we'll avoid
unaligned accesses. To make doubly sure we're not hitting problems also
rearrange struct hack_dirent to avoid holes.

SGI-PV: 975411
SGI-Modid: xfs-linux-melb:xfs-kern:30302a
Signed-off-by: default avatarChristoph Hellwig <hch@infradead.org>
Signed-off-by: default avatarLachlan McIlroy <lachlan@sgi.com>
parent fd0b45df
...@@ -261,9 +261,9 @@ xfs_file_readdir( ...@@ -261,9 +261,9 @@ xfs_file_readdir(
#else #else
struct hack_dirent { struct hack_dirent {
int namlen;
loff_t offset;
u64 ino; u64 ino;
loff_t offset;
int namlen;
unsigned int d_type; unsigned int d_type;
char name[]; char name[];
}; };
...@@ -285,8 +285,10 @@ xfs_hack_filldir( ...@@ -285,8 +285,10 @@ xfs_hack_filldir(
{ {
struct hack_callback *buf = __buf; struct hack_callback *buf = __buf;
struct hack_dirent *de = (struct hack_dirent *)(buf->dirent + buf->used); struct hack_dirent *de = (struct hack_dirent *)(buf->dirent + buf->used);
unsigned int reclen;
if (buf->used + sizeof(struct hack_dirent) + namlen > buf->len) reclen = ALIGN(sizeof(struct hack_dirent) + namlen, sizeof(u64));
if (buf->used + reclen > buf->len)
return -EINVAL; return -EINVAL;
de->namlen = namlen; de->namlen = namlen;
...@@ -294,7 +296,7 @@ xfs_hack_filldir( ...@@ -294,7 +296,7 @@ xfs_hack_filldir(
de->ino = ino; de->ino = ino;
de->d_type = d_type; de->d_type = d_type;
memcpy(de->name, name, namlen); memcpy(de->name, name, namlen);
buf->used += sizeof(struct hack_dirent) + namlen; buf->used += reclen;
return 0; return 0;
} }
...@@ -334,7 +336,8 @@ xfs_file_readdir( ...@@ -334,7 +336,8 @@ xfs_file_readdir(
offset = filp->f_pos; offset = filp->f_pos;
while (!eof) { while (!eof) {
int reclen; unsigned int reclen;
start_offset = offset; start_offset = offset;
buf.used = 0; buf.used = 0;
...@@ -355,7 +358,8 @@ xfs_file_readdir( ...@@ -355,7 +358,8 @@ xfs_file_readdir(
goto done; goto done;
} }
reclen = sizeof(struct hack_dirent) + de->namlen; reclen = ALIGN(sizeof(struct hack_dirent) + de->namlen,
sizeof(u64));
size -= reclen; size -= reclen;
de = (struct hack_dirent *)((char *)de + reclen); de = (struct hack_dirent *)((char *)de + reclen);
curr_offset = de->offset /* & 0x7fffffff */; curr_offset = de->offset /* & 0x7fffffff */;
......
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