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NFS: Fix an O_DIRECT Oops...
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We can't call nfs_readdata_release()/nfs_writedata_release() without
first initialising and referencing args.context. Doing so inside
nfs_direct_read_schedule_segment()/nfs_direct_write_schedule_segment()
causes an Oops.

We should rather be calling nfs_readdata_free()/nfs_writedata_free() in
those cases.

Looking at the O_DIRECT code, the "struct nfs_direct_req" is already
referencing the nfs_open_context for us. Since the readdata and writedata
structures carry a reference to that, we can simplify things by getting rid
of the extra nfs_open_context references, so that we can replace all
instances of nfs_readdata_release()/nfs_writedata_release().

Reported-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Tested-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Trond Myklebust authored and Linus Torvalds committed Aug 12, 2009
1 parent 7cb7beb commit 1ae88b2
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Showing 4 changed files with 16 additions and 21 deletions.
20 changes: 10 additions & 10 deletions fs/nfs/direct.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -255,7 +255,7 @@ static void nfs_direct_read_release(void *calldata)

if (put_dreq(dreq))
nfs_direct_complete(dreq);
nfs_readdata_release(calldata);
nfs_readdata_free(data);
}

static const struct rpc_call_ops nfs_read_direct_ops = {
Expand Down Expand Up @@ -314,14 +314,14 @@ static ssize_t nfs_direct_read_schedule_segment(struct nfs_direct_req *dreq,
data->npages, 1, 0, data->pagevec, NULL);
up_read(&current->mm->mmap_sem);
if (result < 0) {
nfs_readdata_release(data);
nfs_readdata_free(data);
break;
}
if ((unsigned)result < data->npages) {
bytes = result * PAGE_SIZE;
if (bytes <= pgbase) {
nfs_direct_release_pages(data->pagevec, result);
nfs_readdata_release(data);
nfs_readdata_free(data);
break;
}
bytes -= pgbase;
Expand All @@ -334,7 +334,7 @@ static ssize_t nfs_direct_read_schedule_segment(struct nfs_direct_req *dreq,
data->inode = inode;
data->cred = msg.rpc_cred;
data->args.fh = NFS_FH(inode);
data->args.context = get_nfs_open_context(ctx);
data->args.context = ctx;
data->args.offset = pos;
data->args.pgbase = pgbase;
data->args.pages = data->pagevec;
Expand Down Expand Up @@ -441,7 +441,7 @@ static void nfs_direct_free_writedata(struct nfs_direct_req *dreq)
struct nfs_write_data *data = list_entry(dreq->rewrite_list.next, struct nfs_write_data, pages);
list_del(&data->pages);
nfs_direct_release_pages(data->pagevec, data->npages);
nfs_writedata_release(data);
nfs_writedata_free(data);
}
}

Expand Down Expand Up @@ -534,7 +534,7 @@ static void nfs_direct_commit_release(void *calldata)

dprintk("NFS: %5u commit returned %d\n", data->task.tk_pid, status);
nfs_direct_write_complete(dreq, data->inode);
nfs_commitdata_release(calldata);
nfs_commit_free(data);
}

static const struct rpc_call_ops nfs_commit_direct_ops = {
Expand Down Expand Up @@ -570,7 +570,7 @@ static void nfs_direct_commit_schedule(struct nfs_direct_req *dreq)
data->args.fh = NFS_FH(data->inode);
data->args.offset = 0;
data->args.count = 0;
data->args.context = get_nfs_open_context(dreq->ctx);
data->args.context = dreq->ctx;
data->res.count = 0;
data->res.fattr = &data->fattr;
data->res.verf = &data->verf;
Expand Down Expand Up @@ -734,14 +734,14 @@ static ssize_t nfs_direct_write_schedule_segment(struct nfs_direct_req *dreq,
data->npages, 0, 0, data->pagevec, NULL);
up_read(&current->mm->mmap_sem);
if (result < 0) {
nfs_writedata_release(data);
nfs_writedata_free(data);
break;
}
if ((unsigned)result < data->npages) {
bytes = result * PAGE_SIZE;
if (bytes <= pgbase) {
nfs_direct_release_pages(data->pagevec, result);
nfs_writedata_release(data);
nfs_writedata_free(data);
break;
}
bytes -= pgbase;
Expand All @@ -756,7 +756,7 @@ static ssize_t nfs_direct_write_schedule_segment(struct nfs_direct_req *dreq,
data->inode = inode;
data->cred = msg.rpc_cred;
data->args.fh = NFS_FH(inode);
data->args.context = get_nfs_open_context(ctx);
data->args.context = ctx;
data->args.offset = pos;
data->args.pgbase = pgbase;
data->args.pages = data->pagevec;
Expand Down
6 changes: 2 additions & 4 deletions fs/nfs/read.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -60,17 +60,15 @@ struct nfs_read_data *nfs_readdata_alloc(unsigned int pagecount)
return p;
}

static void nfs_readdata_free(struct nfs_read_data *p)
void nfs_readdata_free(struct nfs_read_data *p)
{
if (p && (p->pagevec != &p->page_array[0]))
kfree(p->pagevec);
mempool_free(p, nfs_rdata_mempool);
}

void nfs_readdata_release(void *data)
static void nfs_readdata_release(struct nfs_read_data *rdata)
{
struct nfs_read_data *rdata = data;

put_nfs_open_context(rdata->args.context);
nfs_readdata_free(rdata);
}
Expand Down
6 changes: 2 additions & 4 deletions fs/nfs/write.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -87,17 +87,15 @@ struct nfs_write_data *nfs_writedata_alloc(unsigned int pagecount)
return p;
}

static void nfs_writedata_free(struct nfs_write_data *p)
void nfs_writedata_free(struct nfs_write_data *p)
{
if (p && (p->pagevec != &p->page_array[0]))
kfree(p->pagevec);
mempool_free(p, nfs_wdata_mempool);
}

void nfs_writedata_release(void *data)
static void nfs_writedata_release(struct nfs_write_data *wdata)
{
struct nfs_write_data *wdata = data;

put_nfs_open_context(wdata->args.context);
nfs_writedata_free(wdata);
}
Expand Down
5 changes: 2 additions & 3 deletions include/linux/nfs_fs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -473,7 +473,6 @@ extern int nfs_writepages(struct address_space *, struct writeback_control *);
extern int nfs_flush_incompatible(struct file *file, struct page *page);
extern int nfs_updatepage(struct file *, struct page *, unsigned int, unsigned int);
extern int nfs_writeback_done(struct rpc_task *, struct nfs_write_data *);
extern void nfs_writedata_release(void *);

/*
* Try to write back everything synchronously (but check the
Expand All @@ -488,7 +487,6 @@ extern int nfs_wb_page_cancel(struct inode *inode, struct page* page);
extern int nfs_commit_inode(struct inode *, int);
extern struct nfs_write_data *nfs_commitdata_alloc(void);
extern void nfs_commit_free(struct nfs_write_data *wdata);
extern void nfs_commitdata_release(void *wdata);
#else
static inline int
nfs_commit_inode(struct inode *inode, int how)
Expand All @@ -507,6 +505,7 @@ nfs_have_writebacks(struct inode *inode)
* Allocate nfs_write_data structures
*/
extern struct nfs_write_data *nfs_writedata_alloc(unsigned int npages);
extern void nfs_writedata_free(struct nfs_write_data *);

/*
* linux/fs/nfs/read.c
Expand All @@ -515,14 +514,14 @@ extern int nfs_readpage(struct file *, struct page *);
extern int nfs_readpages(struct file *, struct address_space *,
struct list_head *, unsigned);
extern int nfs_readpage_result(struct rpc_task *, struct nfs_read_data *);
extern void nfs_readdata_release(void *data);
extern int nfs_readpage_async(struct nfs_open_context *, struct inode *,
struct page *);

/*
* Allocate nfs_read_data structures
*/
extern struct nfs_read_data *nfs_readdata_alloc(unsigned int npages);
extern void nfs_readdata_free(struct nfs_read_data *);

/*
* linux/fs/nfs3proc.c
Expand Down

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