Hi,
I got the following BUG in nfs_inode_add_request() when I was using
eCryptfs on NFS. (Don't ask me why I was doing that)
------------[ cut here ]------------
kernel BUG at fs/nfs/write.c:387!
invalid opcode: 0000 [#1]
PREEMPT SMP
Modules linked in: cbc md5 aes ecb blkcipher cryptomgr crypto_algapi ecryptfs
nfs iscsi_tcp libiscsi scsi_transport_iscsi nfsd exportfs lockd nfs_acl sunrpc
nbd md_mod dm_snapshot dm_mirror dm_mod video output
CPU: 5
EIP: 0060:[<f90113e2>] Not tainted VLI
EFLAGS: 00010246 (2.6.23-rc3 #5)
EIP is at nfs_writepage_setup+0xc8/0x305 [nfs]
eax: ffffffef ebx: ffffffef ecx: 00000000 edx: f776a6c8
esi: f776a700 edi: f3392680 ebp: f6489c04 esp: f6489bc4
ds: 007b es: 007b fs: 00d8 gs: 0033 ss: 0068
Process dd (pid: 4260, ti=f6488000 task=f5719500 task.ti=f6488000)
Stack: 00000000 00001000 dd751a4f 730e4905 00000000 c404e0c0 f5a86a80 f33927e4
f3392774 00000000 f6489bf4 c029e298 00000000 f6812780 00000000 c404e0c0
f6489c44 f9011b8c 00001000 00001000 00000010 fff2b000 f6489d08 00000246
Call Trace:
[<c01082d6>] show_trace_log_lvl+0x1a/0x2f
[<c0108388>] show_stack_log_lvl+0x9d/0xa5
[<c0108581>] show_registers+0x1f1/0x332
[<c01087dd>] die+0x11b/0x250
[<c0480cd0>] do_trap+0x8a/0xa3
[<c0108bd1>] do_invalid_op+0x88/0x92
[<c0480a9a>] error_code+0x72/0x78
[<f9011b8c>] nfs_updatepage+0x14d/0x1b3 [nfs]
[<f9008f93>] nfs_commit_write+0x29/0x39 [nfs]
[<f8fe0ae5>] ecryptfs_commit_lower_page+0x26/0x6b [ecryptfs]
[<f8fe2675>] ecryptfs_write_out_page+0x28/0x73 [ecryptfs]
[<f8fe32ac>] ecryptfs_encrypt_page+0x3a4/0x419 [ecryptfs]
[<f8fe12e0>] ecryptfs_commit_write+0x1ba/0x31f [ecryptfs]
[<c015c1ab>] generic_file_buffered_write+0x3a6/0x54e
[<c015c793>] __generic_file_aio_write_nolock+0x440/0x493
[<c015c83c>] generic_file_aio_write+0x56/0xb4
[<c0178a7c>] do_sync_write+0xc5/0x102
[<c017923e>] vfs_write+0xaf/0x138
[<c0179806>] sys_write+0x3d/0x61
[<c010719a>] syscall_call+0x7/0xb
=======================
Code: 00 00 00 f0 0f ba 6e 28 00 19 c0 8b 7d e0 81 ef f4 00 00 00 8b 56
14 8b 45 e0 83 e8 1c 89 f1 e8 50 db 29 c7 89 c3 83 f8 ef 75 04 <0f> 0b
eb fe 85 c0 75 4e 83 bf e8 00 00 00 00 75 10 8b 45 e0 e8
EIP: [<f90113e2>] nfs_writepage_setup+0xc8/0x305 [nfs] SS:ESP 0068:f6489bc4
As you may have guessed, the BUG shows a collision of nfs_page in a nfs
page tree. That is, there is a case that nfs_page remains even if
the requested page is removed from page cache.
static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
{
struct nfs_inode *nfsi = NFS_I(inode);
int error;
error = radix_tree_insert(&nfsi->nfs_page_tree, req->wb_index, req);
BUG_ON(error == -EEXIST);
...
}
By some tests, it turned out to be a discordance between
nfs_invalidate_page() and truncate_inode_pages() in recent kernels.
In kernel 2.6.20, truncate_complete_page() was changed to clear dirty flag
from the removing page just before calling a_ops->invalidatepage().
As a result, nfs_wb_page_priority(), which is called from nfs_invalidate_page(),
get to skip nfs_writepage_locked() that starts to write dirty pages.
int nfs_wb_page_priority(struct inode *inode, struct page *page, int how)
{
...
if (clear_page_dirty_for_io(page)) {
ret = nfs_writepage_locked(page, &wbc);
if (ret < 0)
goto out;
}
if (!PagePrivate(page))
return 0;
ret = nfs_sync_mapping_wait(page->mapping, &wbc, how);
...
}
Since nfs_sync_mapping_wait() does not care for non-dirty, unwritten,
and uncommitted pages, their nfs_page get into orphans.
It seems to need some sort of change to handle unwritten non-dirty
pages.
For reference, I will show the way to reproduce the BUG using
eCryptfs below. I tried other way, but I couldn't find simpler
way not requiring eCryptfs so far.
# mount -t nfs server:/pub /nfs
# mount -t ecryptfs -o cipher=aes,ecryptfs_key_bytes=16 /nfs /secret
# dd if=/dev/zero of=/secret/aaa bs=4096 count=1
# dd if=/dev/zero of=/secret/aaa bs=4096 count=1
These procedures do truncate an unwritten NFS page.
Note that overwritting without use of eCryptfs doesn't reproduce
the problem because it calls nfs_setattr() and forces the pages
to be written back.
Cheers,
Ryusuke Konishi
It looks as if ecryptfs is dropping the page lock between the calls to
prepare_write() and commit_write(). That would be a bug.
Cheers
Trond
On Fri, 2007-08-24 at 16:43 +0900, Ryusuke Konishi wrote:
> Hi,
>
> I got the following BUG in nfs_inode_add_request() when I was using
> eCryptfs on NFS. (Don't ask me why I was doing that)
>
> ------------[ cut here ]------------
> kernel BUG at fs/nfs/write.c:387!
> invalid opcode: 0000 [#1]
> PREEMPT SMP
> Modules linked in: cbc md5 aes ecb blkcipher cryptomgr crypto_algapi ecryptfs
> nfs iscsi_tcp libiscsi scsi_transport_iscsi nfsd exportfs lockd nfs_acl sunrpc
> nbd md_mod dm_snapshot dm_mirror dm_mod video output
> CPU: 5
> EIP: 0060:[<f90113e2>] Not tainted VLI
> EFLAGS: 00010246 (2.6.23-rc3 #5)
> EIP is at nfs_writepage_setup+0xc8/0x305 [nfs]
> eax: ffffffef ebx: ffffffef ecx: 00000000 edx: f776a6c8
> esi: f776a700 edi: f3392680 ebp: f6489c04 esp: f6489bc4
> ds: 007b es: 007b fs: 00d8 gs: 0033 ss: 0068
> Process dd (pid: 4260, ti=f6488000 task=f5719500 task.ti=f6488000)
> Stack: 00000000 00001000 dd751a4f 730e4905 00000000 c404e0c0 f5a86a80 f33927e4
> f3392774 00000000 f6489bf4 c029e298 00000000 f6812780 00000000 c404e0c0
> f6489c44 f9011b8c 00001000 00001000 00000010 fff2b000 f6489d08 00000246
> Call Trace:
> [<c01082d6>] show_trace_log_lvl+0x1a/0x2f
> [<c0108388>] show_stack_log_lvl+0x9d/0xa5
> [<c0108581>] show_registers+0x1f1/0x332
> [<c01087dd>] die+0x11b/0x250
> [<c0480cd0>] do_trap+0x8a/0xa3
> [<c0108bd1>] do_invalid_op+0x88/0x92
> [<c0480a9a>] error_code+0x72/0x78
> [<f9011b8c>] nfs_updatepage+0x14d/0x1b3 [nfs]
> [<f9008f93>] nfs_commit_write+0x29/0x39 [nfs]
> [<f8fe0ae5>] ecryptfs_commit_lower_page+0x26/0x6b [ecryptfs]
> [<f8fe2675>] ecryptfs_write_out_page+0x28/0x73 [ecryptfs]
> [<f8fe32ac>] ecryptfs_encrypt_page+0x3a4/0x419 [ecryptfs]
> [<f8fe12e0>] ecryptfs_commit_write+0x1ba/0x31f [ecryptfs]
> [<c015c1ab>] generic_file_buffered_write+0x3a6/0x54e
> [<c015c793>] __generic_file_aio_write_nolock+0x440/0x493
> [<c015c83c>] generic_file_aio_write+0x56/0xb4
> [<c0178a7c>] do_sync_write+0xc5/0x102
> [<c017923e>] vfs_write+0xaf/0x138
> [<c0179806>] sys_write+0x3d/0x61
> [<c010719a>] syscall_call+0x7/0xb
> =======================
> Code: 00 00 00 f0 0f ba 6e 28 00 19 c0 8b 7d e0 81 ef f4 00 00 00 8b 56
> 14 8b 45 e0 83 e8 1c 89 f1 e8 50 db 29 c7 89 c3 83 f8 ef 75 04 <0f> 0b
> eb fe 85 c0 75 4e 83 bf e8 00 00 00 00 75 10 8b 45 e0 e8
> EIP: [<f90113e2>] nfs_writepage_setup+0xc8/0x305 [nfs] SS:ESP 0068:f6489bc4
>
> As you may have guessed, the BUG shows a collision of nfs_page in a nfs
> page tree. That is, there is a case that nfs_page remains even if
> the requested page is removed from page cache.
>
> static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
> {
> struct nfs_inode *nfsi = NFS_I(inode);
> int error;
>
> error = radix_tree_insert(&nfsi->nfs_page_tree, req->wb_index, req);
> BUG_ON(error == -EEXIST);
> ...
> }
>
> By some tests, it turned out to be a discordance between
> nfs_invalidate_page() and truncate_inode_pages() in recent kernels.
>
> In kernel 2.6.20, truncate_complete_page() was changed to clear dirty flag
> from the removing page just before calling a_ops->invalidatepage().
> As a result, nfs_wb_page_priority(), which is called from nfs_invalidate_page(),
> get to skip nfs_writepage_locked() that starts to write dirty pages.
>
> int nfs_wb_page_priority(struct inode *inode, struct page *page, int how)
> {
> ...
> if (clear_page_dirty_for_io(page)) {
> ret = nfs_writepage_locked(page, &wbc);
> if (ret < 0)
> goto out;
> }
> if (!PagePrivate(page))
> return 0;
> ret = nfs_sync_mapping_wait(page->mapping, &wbc, how);
> ...
> }
>
> Since nfs_sync_mapping_wait() does not care for non-dirty, unwritten,
> and uncommitted pages, their nfs_page get into orphans.
> It seems to need some sort of change to handle unwritten non-dirty
> pages.
>
> For reference, I will show the way to reproduce the BUG using
> eCryptfs below. I tried other way, but I couldn't find simpler
> way not requiring eCryptfs so far.
>
> # mount -t nfs server:/pub /nfs
> # mount -t ecryptfs -o cipher=aes,ecryptfs_key_bytes=16 /nfs /secret
> # dd if=/dev/zero of=/secret/aaa bs=4096 count=1
> # dd if=/dev/zero of=/secret/aaa bs=4096 count=1
>
> These procedures do truncate an unwritten NFS page.
> Note that overwritting without use of eCryptfs doesn't reproduce
> the problem because it calls nfs_setattr() and forces the pages
> to be written back.
>
> Cheers,
> Ryusuke Konishi
On Mon, 27 Aug 2007 09:30:12 -0400, Trond Myklebust wrote:
>It looks as if ecryptfs is dropping the page lock between the calls to
>prepare_write() and commit_write(). That would be a bug.
No, ecryptfs is holding the page lock between the calls to
nfs_prepare_write() and nfs_commit_write().
This is a regression since kernel 2.6.20; kernel 2.6.19 does not
yield the BUG.
Please look at truncate_complete_page() and nfs_wb_page_priority()
which is called from nfs_invalidate_page().
The recent truncate_complete_page() clears the dirty flag from a page
before calling a_ops->invalidatepage(),
^^^^^^
static void
truncate_complete_page(struct address_space *mapping, struct page *page)
{
...
cancel_dirty_page(page, PAGE_CACHE_SIZE); <--- Inserted here at kernel 2.6.20
if (PagePrivate(page))
do_invalidatepage(page, 0); ---> will call a_ops->invalidatepage()
...
}
and this is disturbing nfs_wb_page_priority() from calling
nfs_writepage_locked() that is expected to handle the pending
request (=nfs_page) associated with the page.
int nfs_wb_page_priority(struct inode *inode, struct page *page, int how)
{
...
if (clear_page_dirty_for_io(page)) {
ret = nfs_writepage_locked(page, &wbc);
if (ret < 0)
goto out;
}
...
}
Since truncate_complete_page() will get rid of the page after
a_ops->invalidatepage() returns, the request (=nfs_page) associated
with the page becomes a garbage in nfs_inode->nfs_page_tree.
This causes the collision of nfs_page and yields the BUG.
Cheers,
Ryusuke Konishi
>
>On Fri, 2007-08-24 at 16:43 +0900, Ryusuke Konishi wrote:
>> Hi,
>>
>> I got the following BUG in nfs_inode_add_request() when I was using
>> eCryptfs on NFS. (Don't ask me why I was doing that)
>>
>> ------------[ cut here ]------------
>> kernel BUG at fs/nfs/write.c:387!
>> invalid opcode: 0000 [#1]
>> PREEMPT SMP
>> Modules linked in: cbc md5 aes ecb blkcipher cryptomgr crypto_algapi ecryptfs
>> nfs iscsi_tcp libiscsi scsi_transport_iscsi nfsd exportfs lockd nfs_acl sunrpc
>> nbd md_mod dm_snapshot dm_mirror dm_mod video output
>> CPU: 5
>> EIP: 0060:[<f90113e2>] Not tainted VLI
>> EFLAGS: 00010246 (2.6.23-rc3 #5)
>> EIP is at nfs_writepage_setup+0xc8/0x305 [nfs]
>> eax: ffffffef ebx: ffffffef ecx: 00000000 edx: f776a6c8
>> esi: f776a700 edi: f3392680 ebp: f6489c04 esp: f6489bc4
>> ds: 007b es: 007b fs: 00d8 gs: 0033 ss: 0068
>> Process dd (pid: 4260, ti=f6488000 task=f5719500 task.ti=f6488000)
>> Stack: 00000000 00001000 dd751a4f 730e4905 00000000 c404e0c0 f5a86a80 f33927e4
>> f3392774 00000000 f6489bf4 c029e298 00000000 f6812780 00000000 c404e0c0
>> f6489c44 f9011b8c 00001000 00001000 00000010 fff2b000 f6489d08 00000246
>> Call Trace:
>> [<c01082d6>] show_trace_log_lvl+0x1a/0x2f
>> [<c0108388>] show_stack_log_lvl+0x9d/0xa5
>> [<c0108581>] show_registers+0x1f1/0x332
>> [<c01087dd>] die+0x11b/0x250
>> [<c0480cd0>] do_trap+0x8a/0xa3
>> [<c0108bd1>] do_invalid_op+0x88/0x92
>> [<c0480a9a>] error_code+0x72/0x78
>> [<f9011b8c>] nfs_updatepage+0x14d/0x1b3 [nfs]
>> [<f9008f93>] nfs_commit_write+0x29/0x39 [nfs]
>> [<f8fe0ae5>] ecryptfs_commit_lower_page+0x26/0x6b [ecryptfs]
>> [<f8fe2675>] ecryptfs_write_out_page+0x28/0x73 [ecryptfs]
>> [<f8fe32ac>] ecryptfs_encrypt_page+0x3a4/0x419 [ecryptfs]
>> [<f8fe12e0>] ecryptfs_commit_write+0x1ba/0x31f [ecryptfs]
>> [<c015c1ab>] generic_file_buffered_write+0x3a6/0x54e
>> [<c015c793>] __generic_file_aio_write_nolock+0x440/0x493
>> [<c015c83c>] generic_file_aio_write+0x56/0xb4
>> [<c0178a7c>] do_sync_write+0xc5/0x102
>> [<c017923e>] vfs_write+0xaf/0x138
>> [<c0179806>] sys_write+0x3d/0x61
>> [<c010719a>] syscall_call+0x7/0xb
>> =======================
>> Code: 00 00 00 f0 0f ba 6e 28 00 19 c0 8b 7d e0 81 ef f4 00 00 00 8b 56
>> 14 8b 45 e0 83 e8 1c 89 f1 e8 50 db 29 c7 89 c3 83 f8 ef 75 04 <0f> 0b
>> eb fe 85 c0 75 4e 83 bf e8 00 00 00 00 75 10 8b 45 e0 e8
>> EIP: [<f90113e2>] nfs_writepage_setup+0xc8/0x305 [nfs] SS:ESP 0068:f6489bc4
>>
>> As you may have guessed, the BUG shows a collision of nfs_page in a nfs
>> page tree. That is, there is a case that nfs_page remains even if
>> the requested page is removed from page cache.
>>
>> static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
>> {
>> struct nfs_inode *nfsi = NFS_I(inode);
>> int error;
>>
>> error = radix_tree_insert(&nfsi->nfs_page_tree, req->wb_index, req);
>> BUG_ON(error == -EEXIST);
>> ...
>> }
>>
>> By some tests, it turned out to be a discordance between
>> nfs_invalidate_page() and truncate_inode_pages() in recent kernels.
>>
>> In kernel 2.6.20, truncate_complete_page() was changed to clear dirty flag
>> from the removing page just before calling a_ops->invalidatepage().
>> As a result, nfs_wb_page_priority(), which is called from nfs_invalidate_page(),
>> get to skip nfs_writepage_locked() that starts to write dirty pages.
>>
>> int nfs_wb_page_priority(struct inode *inode, struct page *page, int how)
>> {
>> ...
>> if (clear_page_dirty_for_io(page)) {
>> ret = nfs_writepage_locked(page, &wbc);
>> if (ret < 0)
>> goto out;
>> }
>> if (!PagePrivate(page))
>> return 0;
>> ret = nfs_sync_mapping_wait(page->mapping, &wbc, how);
>> ...
>> }
>>
>> Since nfs_sync_mapping_wait() does not care for non-dirty, unwritten,
>> and uncommitted pages, their nfs_page get into orphans.
>> It seems to need some sort of change to handle unwritten non-dirty
>> pages.
>>
>> For reference, I will show the way to reproduce the BUG using
>> eCryptfs below. I tried other way, but I couldn't find simpler
>> way not requiring eCryptfs so far.
>>
>> # mount -t nfs server:/pub /nfs
>> # mount -t ecryptfs -o cipher=aes,ecryptfs_key_bytes=16 /nfs /secret
>> # dd if=/dev/zero of=/secret/aaa bs=4096 count=1
>> # dd if=/dev/zero of=/secret/aaa bs=4096 count=1
>>
>> These procedures do truncate an unwritten NFS page.
>> Note that overwritting without use of eCryptfs doesn't reproduce
>> the problem because it calls nfs_setattr() and forces the pages
>> to be written back.
>>
>> Cheers,
>> Ryusuke Konishi
>
>
On Tue, 2007-08-28 at 17:32 +0900, Ryusuke Konishi wrote:
> On Mon, 27 Aug 2007 09:30:12 -0400, Trond Myklebust wrote:
> >It looks as if ecryptfs is dropping the page lock between the calls to
> >prepare_write() and commit_write(). That would be a bug.
>
> No, ecryptfs is holding the page lock between the calls to
> nfs_prepare_write() and nfs_commit_write().
> This is a regression since kernel 2.6.20; kernel 2.6.19 does not
> yield the BUG.
>
> Please look at truncate_complete_page() and nfs_wb_page_priority()
> which is called from nfs_invalidate_page().
>
> The recent truncate_complete_page() clears the dirty flag from a page
> before calling a_ops->invalidatepage(),
> ^^^^^^
> static void
> truncate_complete_page(struct address_space *mapping, struct page *page)
> {
> ...
> cancel_dirty_page(page, PAGE_CACHE_SIZE); <--- Inserted here at kernel 2.6.20
>
> if (PagePrivate(page))
> do_invalidatepage(page, 0); ---> will call a_ops->invalidatepage()
> ...
> }
>
> and this is disturbing nfs_wb_page_priority() from calling
> nfs_writepage_locked() that is expected to handle the pending
> request (=nfs_page) associated with the page.
>
> int nfs_wb_page_priority(struct inode *inode, struct page *page, int how)
> {
> ...
> if (clear_page_dirty_for_io(page)) {
> ret = nfs_writepage_locked(page, &wbc);
> if (ret < 0)
> goto out;
> }
> ...
> }
>
> Since truncate_complete_page() will get rid of the page after
> a_ops->invalidatepage() returns, the request (=nfs_page) associated
> with the page becomes a garbage in nfs_inode->nfs_page_tree.
>
> This causes the collision of nfs_page and yields the BUG.
>
>
> Cheers,
> Ryusuke Konishi
OK. I see your point... Basically, you are saying that the new
->invalidatepage() semantics do not allow us to rely on the dirty status
of the page in order to figure out if we need to clean up.
Andrew, that was a fairly significant change in semantics...
Anyhow, well done debugging it! Does the following patch fix the Oops?
Trond
On Wed, 29 Aug 2007 11:49:22 -0400, Trond Myklebust wrote:
>OK. I see your point... Basically, you are saying that the new
>->invalidatepage() semantics do not allow us to rely on the dirty status
>of the page in order to figure out if we need to clean up.
Exactly.
>Andrew, that was a fairly significant change in semantics...
>
>Anyhow, well done debugging it! Does the following patch fix the Oops?
>
>Trond
Yes, the patch did fix the Oops crash.
I've tested it in serveral ways, and it's working well enough so far.
Thanks!
Ryusuke Konishi
>On Tue, 2007-08-28 at 17:32 +0900, Ryusuke Konishi wrote:
>> On Mon, 27 Aug 2007 09:30:12 -0400, Trond Myklebust wrote:
>> >It looks as if ecryptfs is dropping the page lock between the calls to
>> >prepare_write() and commit_write(). That would be a bug.
>>
>> No, ecryptfs is holding the page lock between the calls to
>> nfs_prepare_write() and nfs_commit_write().
>> This is a regression since kernel 2.6.20; kernel 2.6.19 does not
>> yield the BUG.
>>
>> Please look at truncate_complete_page() and nfs_wb_page_priority()
>> which is called from nfs_invalidate_page().
>>
>> The recent truncate_complete_page() clears the dirty flag from a page
>> before calling a_ops->invalidatepage(),
>> ^^^^^^
>> static void
>> truncate_complete_page(struct address_space *mapping, struct page *page)
>> {
>> ...
>> cancel_dirty_page(page, PAGE_CACHE_SIZE); <--- Inserted here at kernel 2.6.20
>>
>> if (PagePrivate(page))
>> do_invalidatepage(page, 0); ---> will call a_ops->invalidatepage()
>> ...
>> }
>>
>> and this is disturbing nfs_wb_page_priority() from calling
>> nfs_writepage_locked() that is expected to handle the pending
>> request (=nfs_page) associated with the page.
>>
>> int nfs_wb_page_priority(struct inode *inode, struct page *page, int how)
>> {
>> ...
>> if (clear_page_dirty_for_io(page)) {
>> ret = nfs_writepage_locked(page, &wbc);
>> if (ret < 0)
>> goto out;
>> }
>> ...
>> }
>>
>> Since truncate_complete_page() will get rid of the page after
>> a_ops->invalidatepage() returns, the request (=nfs_page) associated
>> with the page becomes a garbage in nfs_inode->nfs_page_tree.
>>
>> This causes the collision of nfs_page and yields the BUG.
>>
>>
>> Cheers,
>> Ryusuke Konishi
>
>OK. I see your point... Basically, you are saying that the new
>->invalidatepage() semantics do not allow us to rely on the dirty status
>of the page in order to figure out if we need to clean up.
>
>Andrew, that was a fairly significant change in semantics...
>
>Anyhow, well done debugging it! Does the following patch fix the Oops?
>
>Trond
>
>______________________________________________________________________
>From: Trond Myklebust <[email protected]>
>Date: Tue, 28 Aug 2007 10:29:36 -0400
>NFS: Fix a write request leak in nfs_invalidate_page()
>Subject: No Subject
>Message-Id: <[email protected]>
>Mime-Version: 1.0
>Content-Transfer-Encoding: 7bit
>
>Ryusuke Konishi says:
>
>The recent truncate_complete_page() clears the dirty flag from a page
>before calling a_ops->invalidatepage(),
>^^^^^^
>static void
>truncate_complete_page(struct address_space *mapping, struct page *page)
>{
> ...
> cancel_dirty_page(page, PAGE_CACHE_SIZE); <--- Inserted here at
>kernel 2.6.20
>
> if (PagePrivate(page))
> do_invalidatepage(page, 0); ---> will call
>a_ops->invalidatepage()
> ...
>}
>
>and this is disturbing nfs_wb_page_priority() from calling
>nfs_writepage_locked() that is expected to handle the pending
>request (=nfs_page) associated with the page.
>
>int nfs_wb_page_priority(struct inode *inode, struct page *page, int how)
>{
> ...
> if (clear_page_dirty_for_io(page)) {
> ret = nfs_writepage_locked(page, &wbc);
> if (ret < 0)
> goto out;
> }
> ...
>}
>
>Since truncate_complete_page() will get rid of the page after
>a_ops->invalidatepage() returns, the request (=nfs_page) associated
>with the page becomes a garbage in nfs_inode->nfs_page_tree.
>------------------------
>
>Fix this by ensuring that nfs_wb_page_priority() recognises that it may
>also need to clear out non-dirty pages that have an nfs_page associated
>with them.
>
>Signed-off-by: Trond Myklebust <[email protected]>
>---
>
> fs/nfs/file.c | 2 +-
> fs/nfs/write.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
> include/linux/nfs_fs.h | 1 +
> 3 files changed, 46 insertions(+), 1 deletions(-)
>
>diff --git a/fs/nfs/file.c b/fs/nfs/file.c
>index c87dc71..579cf8a 100644
>--- a/fs/nfs/file.c
>+++ b/fs/nfs/file.c
>@@ -316,7 +316,7 @@ static void nfs_invalidate_page(struct page *page, unsigned long offset)
> if (offset != 0)
> return;
> /* Cancel any unstarted writes on this page */
>- nfs_wb_page_priority(page->mapping->host, page, FLUSH_INVALIDATE);
>+ nfs_wb_page_cancel(page->mapping->host, page);
> }
>
> static int nfs_release_page(struct page *page, gfp_t gfp)
>diff --git a/fs/nfs/write.c b/fs/nfs/write.c
>index ef97e0c..0d7a77c 100644
>--- a/fs/nfs/write.c
>+++ b/fs/nfs/write.c
>@@ -1396,6 +1396,50 @@ out:
> return ret;
> }
>
>+int nfs_wb_page_cancel(struct inode *inode, struct page *page)
>+{
>+ struct nfs_page *req;
>+ loff_t range_start = page_offset(page);
>+ loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1);
>+ struct writeback_control wbc = {
>+ .bdi = page->mapping->backing_dev_info,
>+ .sync_mode = WB_SYNC_ALL,
>+ .nr_to_write = LONG_MAX,
>+ .range_start = range_start,
>+ .range_end = range_end,
>+ };
>+ int ret = 0;
>+
>+ BUG_ON(!PageLocked(page));
>+ for (;;) {
>+ req = nfs_page_find_request(page);
>+ if (req == NULL)
>+ goto out;
>+ if (test_bit(PG_NEED_COMMIT, &req->wb_flags)) {
>+ nfs_release_request(req);
>+ break;
>+ }
>+ if (nfs_lock_request_dontget(req)) {
>+ nfs_inode_remove_request(req);
>+ /*
>+ * In case nfs_inode_remove_request has marked the
>+ * page as being dirty
>+ */
>+ cancel_dirty_page(page, PAGE_CACHE_SIZE);
>+ nfs_unlock_request(req);
>+ break;
>+ }
>+ ret = nfs_wait_on_request(req);
>+ if (ret < 0)
>+ goto out;
>+ }
>+ if (!PagePrivate(page))
>+ return 0;
>+ ret = nfs_sync_mapping_wait(page->mapping, &wbc, FLUSH_INVALIDATE);
>+out:
>+ return ret;
>+}
>+
> int nfs_wb_page_priority(struct inode *inode, struct page *page, int how)
> {
> loff_t range_start = page_offset(page);
>diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
>index 157dcb0..7250eea 100644
>--- a/include/linux/nfs_fs.h
>+++ b/include/linux/nfs_fs.h
>@@ -431,6 +431,7 @@ extern int nfs_sync_mapping_range(struct address_space *, loff_t, loff_t, int);
> extern int nfs_wb_all(struct inode *inode);
> extern int nfs_wb_page(struct inode *inode, struct page* page);
> extern int nfs_wb_page_priority(struct inode *inode, struct page* page, int how);
>+extern int nfs_wb_page_cancel(struct inode *inode, struct page* page);
> #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
> extern int nfs_commit_inode(struct inode *, int);
> extern struct nfs_write_data *nfs_commit_alloc(void);