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Fixed a possible deadlock (the requests benaphore is now unlocked before

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waiting on the write semaphore).
The write functions didn't change the buffer address on a partial write
which could lead to corruption in the pipe data.


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@9111 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Axel Dörfler 2004-09-29 14:30:53 +00:00
parent a83d9efacf
commit 8b41e11557
1 changed files with 47 additions and 24 deletions
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71
src/kernel/core/fs/pipefs.cpp
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@ -26,9 +26,8 @@
// ToDo: handles file names suboptimally - it has all file names
// in a singly linked list, no hash lookups or whatever.
#define PIPEFS_TRACE 0
#if PIPEFS_TRACE
#define TRACE_PIPEFS
#ifdef TRACE_PIPEFS
# define TRACE(x) dprintf x
#else
# define TRACE(x)
@ -140,12 +139,12 @@ class Inode {
benaphore *RequestLock() { return &fRequestLock; }
DoublyLinked::List<ReadRequest> &Requests() { return fRequests; }
status_t WriteBufferToChain(const void *buffer, size_t *_bufferSize, bool nonBlocking);
status_t WriteBufferToChain(const void **_buffer, size_t *_bytesLeft, bool nonBlocking);
// status_t ReadBufferFromChain(void *buffer, size_t *_bufferSize);
size_t BytesInChain() const { return cbuf_get_length(fBufferChain); }
void MayReleaseWriter();
void FillPendingRequests(const void *buffer, size_t *_bytesLeft);
void FillPendingRequests(const void **_buffer, size_t *_bytesLeft);
void FillPendingRequests();
status_t AddRequest(ReadRequest &request);
status_t RemoveRequest(ReadRequest &request);
@ -493,12 +492,24 @@ Inode::InitCheck()
*/
status_t
Inode::WriteBufferToChain(const void *buffer, size_t *_bufferSize, bool nonBlocking)
Inode::WriteBufferToChain(const void **_buffer, size_t *_bytesLeft, bool nonBlocking)
{
size_t bufferSize = *_bufferSize;
const void *buffer = *_buffer;
size_t bufferSize = *_bytesLeft;
// if this is a blocking call, we need to make sure that data can
// still come in and we don't block the whole inode data transfer
// to prevent deadlocks from happening
if (!nonBlocking)
benaphore_unlock(&fRequestLock);
status_t status = acquire_sem_etc(fWriteLock, 1, (nonBlocking ? B_TIMEOUT : 0)
| B_CAN_INTERRUPT, 0);
if (!nonBlocking)
benaphore_lock(&fRequestLock);
status_t status = acquire_sem_etc(fWriteLock, 1,
( nonBlocking ? B_TIMEOUT : 0 ) | B_CAN_INTERRUPT, 0);
if (status != B_OK)
return status;
@ -528,7 +539,8 @@ Inode::WriteBufferToChain(const void *buffer, size_t *_bufferSize, bool nonBlock
chain = cbuf_merge_chains(fBufferChain, chain);
fBufferChain = chain;
*_bufferSize = bufferSize;
*_buffer = (const void *)((addr_t)buffer + bufferSize);
*_bytesLeft -= bufferSize;
MayReleaseWriter();
@ -544,6 +556,12 @@ Inode::MayReleaseWriter()
}
/** This functions fills pending requests out of the buffer chain.
* It either stops when there are no more requests to satisfy, or
* the buffer chain is empty, whatever comes first.
* You must hold the request lock when calling this function.
*/
void
Inode::FillPendingRequests()
{
@ -562,8 +580,13 @@ Inode::FillPendingRequests()
}
/** This function feeds the pending read requests using the provided
* buffer.
* You must hold the request lock when calling this function.
*/
void
Inode::FillPendingRequests(const void *buffer, size_t *_bytesLeft)
Inode::FillPendingRequests(const void **_buffer, size_t *_bytesLeft)
{
team_id team = team_get_current_team_id();
@ -574,7 +597,7 @@ Inode::FillPendingRequests(const void *buffer, size_t *_bytesLeft)
size_t bytesRead;
if (request->PutBufferChain(fBufferChain, &bytesRead, false) != B_OK)
continue;
MayReleaseWriter();
if (request->SpaceLeft() > 0
@ -585,7 +608,7 @@ Inode::FillPendingRequests(const void *buffer, size_t *_bytesLeft)
// remapping copy on write or a direct copy.
// place our data into that buffer
request->PutBuffer(&buffer, _bytesLeft);
request->PutBuffer(_buffer, _bytesLeft);
}
}
}
@ -641,7 +664,7 @@ int32
Inode::HashNextOffset()
{
Inode *inode;
return (addr)&inode->fHashNext - (addr)inode;
return (addr_t)&inode->fHashNext - (addr_t)inode;
}
@ -695,7 +718,7 @@ status_t
ReadRequest::Wait(bool nonBlocking)
{
TRACE(("pipefs: request@%p waits for data (%sblocking), thread 0x%lx\n", this, nonBlocking ? "non" : "", find_thread(NULL)));
return acquire_sem_etc(fLock, 1, ( nonBlocking ? B_TIMEOUT : 0 ) | B_CAN_INTERRUPT, 0);
return acquire_sem_etc(fLock, 1, (nonBlocking ? B_TIMEOUT : 0) | B_CAN_INTERRUPT, 0);
}
@ -751,11 +774,11 @@ ReadRequest::PutBufferChain(cbuf *bufferChain, size_t *_bytesRead, bool releaseP
*/
status_t
ReadRequest::PutBuffer(const void **_buffer, size_t *_bufferSize)
ReadRequest::PutBuffer(const void **_buffer, size_t *_bytesLeft)
{
TRACE(("pipefs: ReadRequest::PutBuffer(buffer = %p, size = %lu)\n", *_buffer, *_bufferSize));
TRACE(("pipefs: ReadRequest::PutBuffer(buffer = %p, size = %lu)\n", *_buffer, *_bytesLeft));
size_t bytes = *_bufferSize;
size_t bytes = *_bytesLeft;
if (bytes > SpaceLeft())
bytes = SpaceLeft();
@ -768,9 +791,9 @@ ReadRequest::PutBuffer(const void **_buffer, size_t *_bufferSize)
fBytesRead += bytes;
*_buffer = (void *)(source + bytes);
*_bufferSize -= bytes;
release_sem(fLock);
*_bytesLeft -= bytes;
release_sem(fLock);
return B_OK;
}
@ -896,7 +919,7 @@ pipefs_get_vnode(fs_volume _volume, vnode_id id, fs_vnode *_inode, bool reenter)
static status_t
pipefs_put_vnode(fs_volume _volume, fs_vnode _node, bool reenter)
{
#if TRACE_PIPEFS
#ifdef TRACE_PIPEFS
Inode *inode = (Inode *)_node;
TRACE(("pipefs_putvnode: entry on vnode 0x%Lx, r %d\n", inode->ID(), reenter));
#endif
@ -940,7 +963,7 @@ pipefs_create(fs_volume _volume, fs_vnode _dir, const char *name, int openMode,
Volume *volume = (Volume *)_volume;
TRACE(("pipefs_create(): dir = %p, name = '%s', perms = %d, &id = %p\n",
_dir, name, perms, _newVnodeID));
_dir, name, mode, _newVnodeID));
file_cookie *cookie = (file_cookie *)malloc(sizeof(file_cookie));
if (cookie == NULL)
@ -1075,7 +1098,7 @@ pipefs_write(fs_volume _volume, fs_vnode _node, fs_cookie _cookie, off_t /*pos*/
benaphore_lock(inode->RequestLock());
size_t bytesLeft = *_length;
inode->FillPendingRequests(buffer, &bytesLeft);
inode->FillPendingRequests(&buffer, &bytesLeft);
status_t status;
@ -1083,7 +1106,7 @@ pipefs_write(fs_volume _volume, fs_vnode _node, fs_cookie _cookie, off_t /*pos*/
// we could not place all our data in pending requests, so
// have to put them into a temporary buffer
status = inode->WriteBufferToChain(buffer, &bytesLeft, (cookie->open_mode & O_NONBLOCK) != 0);
status = inode->WriteBufferToChain(&buffer, &bytesLeft, (cookie->open_mode & O_NONBLOCK) != 0);
if (status == B_OK) {
inode->FillPendingRequests();
*_length -= bytesLeft;