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[PATCH] NFS: large non-page-aligned direct I/O clobbers memory

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The logic in nfs_direct_read_schedule and nfs_direct_write_schedule can
allow data->npages to be one larger than rpages.  This causes a page
pointer to be written beyond the end of the pagevec in nfs_read_data (or
nfs_write_data).

Fix this by making nfs_(read|write)_alloc() calculate the size of the
pagevec array, and initialise data->npages.

Also get rid of the redundant argument to nfs_commit_alloc().

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Trond Myklebust
2006-09-08 09:48:54 -07:00
committed by Linus Torvalds
parent 016eb4a0ed
commit e9f7bee1df
5 changed files with 47 additions and 74 deletions
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50
fs/nfs/direct.c
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@@ -100,25 +100,6 @@ static inline int put_dreq(struct nfs_direct_req *dreq)
return atomic_dec_and_test(&dreq->io_count);
}
/*
* "size" is never larger than rsize or wsize.
*/
static inline int nfs_direct_count_pages(unsigned long user_addr, size_t size)
{
int page_count;
page_count = (user_addr + size + PAGE_SIZE - 1) >> PAGE_SHIFT;
page_count -= user_addr >> PAGE_SHIFT;
BUG_ON(page_count < 0);
return page_count;
}
static inline unsigned int nfs_max_pages(unsigned int size)
{
return (size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
}
/**
* nfs_direct_IO - NFS address space operation for direct I/O
* @rw: direction (read or write)
@@ -276,28 +257,24 @@ static ssize_t nfs_direct_read_schedule(struct nfs_direct_req *dreq, unsigned lo
struct nfs_open_context *ctx = dreq->ctx;
struct inode *inode = ctx->dentry->d_inode;
size_t rsize = NFS_SERVER(inode)->rsize;
unsigned int rpages = nfs_max_pages(rsize);
unsigned int pgbase;
int result;
ssize_t started = 0;
get_dreq(dreq);
pgbase = user_addr & ~PAGE_MASK;
do {
struct nfs_read_data *data;
size_t bytes;
pgbase = user_addr & ~PAGE_MASK;
bytes = min(rsize,count);
result = -ENOMEM;
data = nfs_readdata_alloc(rpages);
data = nfs_readdata_alloc(pgbase + bytes);
if (unlikely(!data))
break;
bytes = rsize;
if (count < rsize)
bytes = count;
data->npages = nfs_direct_count_pages(user_addr, bytes);
down_read(&current->mm->mmap_sem);
result = get_user_pages(current, current->mm, user_addr,
data->npages, 1, 0, data->pagevec, NULL);
@@ -344,8 +321,10 @@ static ssize_t nfs_direct_read_schedule(struct nfs_direct_req *dreq, unsigned lo
started += bytes;
user_addr += bytes;
pos += bytes;
/* FIXME: Remove this unnecessary math from final patch */
pgbase += bytes;
pgbase &= ~PAGE_MASK;
BUG_ON(pgbase != (user_addr & ~PAGE_MASK));
count -= bytes;
} while (count != 0);
@@ -524,7 +503,7 @@ static void nfs_direct_write_complete(struct nfs_direct_req *dreq, struct inode
static void nfs_alloc_commit_data(struct nfs_direct_req *dreq)
{
dreq->commit_data = nfs_commit_alloc(0);
dreq->commit_data = nfs_commit_alloc();
if (dreq->commit_data != NULL)
dreq->commit_data->req = (struct nfs_page *) dreq;
}
@@ -605,28 +584,24 @@ static ssize_t nfs_direct_write_schedule(struct nfs_direct_req *dreq, unsigned l
struct nfs_open_context *ctx = dreq->ctx;
struct inode *inode = ctx->dentry->d_inode;
size_t wsize = NFS_SERVER(inode)->wsize;
unsigned int wpages = nfs_max_pages(wsize);
unsigned int pgbase;
int result;
ssize_t started = 0;
get_dreq(dreq);
pgbase = user_addr & ~PAGE_MASK;
do {
struct nfs_write_data *data;
size_t bytes;
pgbase = user_addr & ~PAGE_MASK;
bytes = min(wsize,count);
result = -ENOMEM;
data = nfs_writedata_alloc(wpages);
data = nfs_writedata_alloc(pgbase + bytes);
if (unlikely(!data))
break;
bytes = wsize;
if (count < wsize)
bytes = count;
data->npages = nfs_direct_count_pages(user_addr, bytes);
down_read(&current->mm->mmap_sem);
result = get_user_pages(current, current->mm, user_addr,
data->npages, 0, 0, data->pagevec, NULL);
@@ -676,8 +651,11 @@ static ssize_t nfs_direct_write_schedule(struct nfs_direct_req *dreq, unsigned l
started += bytes;
user_addr += bytes;
pos += bytes;
/* FIXME: Remove this useless math from the final patch */
pgbase += bytes;
pgbase &= ~PAGE_MASK;
BUG_ON(pgbase != (user_addr & ~PAGE_MASK));
count -= bytes;
} while (count != 0);