/* Also refresh inode by passing in file_info buf returned by SMBOpen
and calling get_inode_info with returned buf (at least
helps non-Unix server case */
+
+ /* BB we can not do this if this is the second open of a file
+ and the first handle has writebehind data, we might be
+ able to simply do a filemap_fdatawrite/filemap_fdatawait first */
buf = kmalloc(sizeof(FILE_ALL_INFO),GFP_KERNEL);
if(buf==0) {
if (full_path)
list_add(&pCifsFile->tlist,&pTcon->openFileList);
pCifsInode = CIFS_I(file->f_dentry->d_inode);
if(pCifsInode) {
- list_add(&pCifsFile->flist,&pCifsInode->openFileList);
+ /* want handles we can use to read with first */
+ /* in the list so we do not have to walk the */
+ /* list to search for one in prepare_write */
+ if ((file->f_flags & O_ACCMODE) == O_WRONLY) {
+ list_add_tail(&pCifsFile->flist,&pCifsInode->openFileList);
+ } else {
+ list_add(&pCifsFile->flist,&pCifsInode->openFileList);
+ }
write_unlock(&GlobalSMBSeslock);
write_unlock(&file->f_owner.lock);
if(pCifsInode->clientCanCacheRead) {
return rc;
}
-static int cifs_reopen_file(struct inode *inode, struct file *file)
+static int cifs_reopen_file(struct inode *inode, struct file *file, int can_flush)
{
int rc = -EACCES;
int xid, oplock;
int desiredAccess = 0x20197;
int disposition = FILE_OPEN;
__u16 netfid;
- FILE_ALL_INFO * buf = NULL;
if(inode == NULL)
return -EBADF;
else
oplock = FALSE;
- /* BB pass O_SYNC flag through on file attributes .. BB */
+
+ /* Can not refresh inode by passing in file_info buf to be returned
+ by SMBOpen and then calling get_inode_info with returned buf
+ since file might have write behind data that needs to be flushed
+ and server version of file size can be stale. If we
+ knew for sure that inode was not dirty locally we could do this */
- /* Also refresh inode by passing in file_info buf returned by SMBOpen
- and calling get_inode_info with returned buf (at least
- helps non-Unix server case */
- buf = kmalloc(sizeof(FILE_ALL_INFO),GFP_KERNEL);
+/* buf = kmalloc(sizeof(FILE_ALL_INFO),GFP_KERNEL);
if(buf==0) {
up(&pCifsFile->fh_sem);
if (full_path)
kfree(full_path);
FreeXid(xid);
return -ENOMEM;
- }
+ }*/
rc = CIFSSMBOpen(xid, pTcon, full_path, disposition, desiredAccess,
- CREATE_NOT_DIR, &netfid, &oplock, buf, cifs_sb->local_nls);
+ CREATE_NOT_DIR, &netfid, &oplock, NULL, cifs_sb->local_nls);
if (rc) {
up(&pCifsFile->fh_sem);
cFYI(1, ("cifs_open returned 0x%x ", rc));
up(&pCifsFile->fh_sem);
pCifsInode = CIFS_I(inode);
if(pCifsInode) {
- if (pTcon->ses->capabilities & CAP_UNIX)
- rc = cifs_get_inode_info_unix(&inode,
+ if(can_flush) {
+ filemap_fdatawrite(inode->i_mapping);
+ filemap_fdatawait(inode->i_mapping);
+ /* temporarily disable caching while we
+ go to server to get inode info */
+ pCifsInode->clientCanCacheAll = FALSE;
+ pCifsInode->clientCanCacheRead = FALSE;
+ if (pTcon->ses->capabilities & CAP_UNIX)
+ rc = cifs_get_inode_info_unix(&inode,
full_path, inode->i_sb);
- else
- rc = cifs_get_inode_info(&inode,
- full_path, buf, inode->i_sb);
-
+ else
+ rc = cifs_get_inode_info(&inode,
+ full_path, NULL, inode->i_sb);
+ } /* else we are writing out data to server already
+ and could deadlock if we tried to flush data, and
+ since we do not know if we have data that would
+ invalidate the current end of file on the server
+ we can not go to the server to get the new
+ inod info */
if((oplock & 0xF) == OPLOCK_EXCLUSIVE) {
pCifsInode->clientCanCacheAll = TRUE;
pCifsInode->clientCanCacheRead = TRUE;
}
}
- if (buf)
- kfree(buf);
if (full_path)
kfree(full_path);
FreeXid(xid);
FreeXid(xid);
return total_written;
}
- rc = cifs_reopen_file(file->f_dentry->d_inode,file);
+ /* we could deadlock if we called
+ filemap_fdatawait from here so tell
+ reopen_file not to flush data to server now */
+ rc = cifs_reopen_file(file->f_dentry->d_inode,
+ file,FALSE);
if(rc != 0)
break;
}
cifsInode = CIFS_I(mapping->host);
read_lock(&GlobalSMBSeslock);
+ /* BB we should start at the end */
list_for_each_safe(tmp, tmp1, &cifsInode->openFileList) {
open_file = list_entry(tmp,struct cifsFileInfo, flist);
if(open_file->closePend)
xid = GetXid();
/* BB add check for wbc flags */
page_cache_get(page);
+ if (!PageUptodate(page)) {
+ cFYI(1,("ppw - page not up to date"));
+ }
rc = cifs_partialpagewrite(page,0,PAGE_CACHE_SIZE);
SetPageUptodate(page); /* BB add check for error and Clearuptodate? */
int rc = 0;
struct inode *inode = page->mapping->host;
loff_t position = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
- /* struct cifsFileInfo *open_file;
- struct cifs_sb_info *cifs_sb; */
+ char * page_data;
xid = GetXid();
cFYI(1,("commit write for page %p up to position %lld for %d",page,position,to));
cFYI(1,(" SetEOF (commit write) rc = %d",rc));
}*/
}
- set_page_dirty(page);
+ if (!PageUptodate(page)) {
+ position = ((loff_t)page->index << PAGE_CACHE_SHIFT) + offset;
+ /* can not rely on (or let) writepage write this data */
+ if(to < offset) {
+ cFYI(1,("Illegal offsets, can not copy from %d to %d",
+ offset,to));
+ FreeXid(xid);
+ return rc;
+ }
+ /* this is probably better than directly calling
+ partialpage_write since in this function
+ the file handle is known which we might as well
+ leverage */
+ /* BB check if anything else missing out of ppw */
+ /* such as updating last write time */
+ page_data = kmap(page);
+ rc = cifs_write(file, page_data+offset,to-offset,
+ &position);
+ if(rc > 0)
+ rc = 0;
+ /* else if rc < 0 should we set writebehind rc? */
+ kunmap(page);
+ } else {
+ set_page_dirty(page);
+ }
FreeXid(xid);
return rc;
}
open_file = (struct cifsFileInfo *)file->private_data;
+ if((file->f_flags & O_ACCMODE) == O_WRONLY) {
+ cFYI(1,("attempting read on write only file instance"));
+ }
+
for (total_read = 0,current_offset=read_data; read_size > total_read;
total_read += bytes_read,current_offset+=bytes_read) {
current_read_size = min_t(const int,read_size - total_read,cifs_sb->rsize);
rc = -EAGAIN;
while(rc == -EAGAIN) {
if ((open_file->invalidHandle) && (!open_file->closePend)) {
- rc = cifs_reopen_file(file->f_dentry->d_inode,file);
+ rc = cifs_reopen_file(file->f_dentry->d_inode,
+ file,TRUE);
if(rc != 0)
break;
}
rc = -EAGAIN;
while(rc == -EAGAIN) {
if ((open_file->invalidHandle) && (!open_file->closePend)) {
- rc = cifs_reopen_file(file->f_dentry->d_inode,file);
+ rc = cifs_reopen_file(file->f_dentry->d_inode,
+ file, TRUE);
if(rc != 0)
break;
}
return rc;
}
-static int
-cifs_readpage(struct file *file, struct page *page)
+static int cifs_readpage_worker(struct file *file, struct page *page, loff_t * poffset)
{
- loff_t offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
char * read_data;
- int rc = -EACCES;
- int xid;
-
- xid = GetXid();
-
- if (file->private_data == NULL) {
- FreeXid(xid);
- return -EBADF;
- }
-
- cFYI(0,("readpage %p at offset %d 0x%x\n",page,(int)offset,(int)offset));
+ int rc;
page_cache_get(page);
read_data = kmap(page);
/* for reads over a certain size could initiate async read ahead */
-
- rc = cifs_read(file, read_data, PAGE_CACHE_SIZE, &offset);
-
+
+ rc = cifs_read(file, read_data, PAGE_CACHE_SIZE, poffset);
+
if (rc < 0)
goto io_error;
else {
cFYI(1,("Bytes read %d ",rc));
}
-
+
file->f_dentry->d_inode->i_atime = CURRENT_TIME;
-
+
if(PAGE_CACHE_SIZE > rc) {
memset(read_data+rc, 0, PAGE_CACHE_SIZE - rc);
}
flush_dcache_page(page);
SetPageUptodate(page);
rc = 0;
-
+
io_error:
- kunmap(page);
+ kunmap(page);
+ page_cache_release(page);
+ return rc;
+}
+
+static int
+cifs_readpage(struct file *file, struct page *page)
+{
+ loff_t offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
+ int rc = -EACCES;
+ int xid;
+
+ xid = GetXid();
+
+ if (file->private_data == NULL) {
+ FreeXid(xid);
+ return -EBADF;
+ }
+
+ cFYI(1,("readpage %p at offset %d 0x%x\n",page,(int)offset,(int)offset));
+
+ rc = cifs_readpage_worker(file,page,&offset);
+
unlock_page(page);
- page_cache_release(page);
FreeXid(xid);
return rc;
}
+/* We do not want to update the file size from server for inodes
+ open for write - to avoid races with writepage extending
+ the file - in the future we could consider allowing
+ refreshing the inode only on increases in the file size
+ but this is tricky to do without racing with writebehind
+ page caching in the current Linux kernel design */
+
+int is_size_safe_to_change(struct cifsInodeInfo * cifsInode)
+{
+ struct list_head *tmp;
+ struct list_head *tmp1;
+ struct cifsFileInfo *open_file = NULL;
+ int rc = TRUE;
+
+ if(cifsInode == NULL)
+ return rc;
+
+ read_lock(&GlobalSMBSeslock);
+ list_for_each_safe(tmp, tmp1, &cifsInode->openFileList) {
+ open_file = list_entry(tmp,struct cifsFileInfo, flist);
+ if(open_file == NULL)
+ break;
+ if(open_file->closePend)
+ continue;
+ /* We check if file is open for writing,
+ BB we could supplement this with a check to see if file size
+ changes have been flushed to server - ie inode metadata dirty */
+ if((open_file->pfile) &&
+ ((open_file->pfile->f_flags & O_RDWR) ||
+ (open_file->pfile->f_flags & O_WRONLY))) {
+ rc = FALSE;
+ break;
+ }
+ if(tmp->next == NULL) {
+ cFYI(1,("File instance %p removed",tmp));
+ break;
+ }
+ }
+ read_unlock(&GlobalSMBSeslock);
+ return rc;
+}
+
+
void
fill_in_inode(struct inode *tmp_inode,
FILE_DIRECTORY_INFO * pfindData, int *pobject_type)
atomic_set(&cifsInfo->inUse,1);
}
- i_size_write(tmp_inode,pfindData->EndOfFile);
- tmp_inode->i_blocks =
- (tmp_inode->i_blksize - 1 + pfindData->AllocationSize) >> tmp_inode->i_blkbits;
+ if(is_size_safe_to_change(cifsInfo)) {
+ /* can not safely change the file size here if the
+ client is writing to it due to potential races */
+ i_size_write(tmp_inode,pfindData->EndOfFile);
+
+ /* 512 bytes (2**9) is the fake blocksize that must be used */
+ /* for this calculation, even though the reported blocksize is larger */
+ tmp_inode->i_blocks = (512 - 1 + pfindData->AllocationSize) >> 9;
+ }
+
if (pfindData->AllocationSize < pfindData->EndOfFile)
cFYI(1, ("Possible sparse file: allocation size less than end of file "));
cFYI(1,
tmp_inode->i_nlink = le64_to_cpu(pfindData->Nlinks);
pfindData->NumOfBytes = le64_to_cpu(pfindData->NumOfBytes);
- pfindData->EndOfFile = le64_to_cpu(pfindData->EndOfFile);
- i_size_write(tmp_inode,pfindData->EndOfFile);
- tmp_inode->i_blocks =
- (tmp_inode->i_blksize - 1 + pfindData->NumOfBytes) >> tmp_inode->i_blkbits;
+
+ if(is_size_safe_to_change(cifsInfo)) {
+ /* can not safely change the file size here if the
+ client is writing to it due to potential races */
+ pfindData->EndOfFile = le64_to_cpu(pfindData->EndOfFile);
+ i_size_write(tmp_inode,pfindData->EndOfFile);
+
+ /* 512 bytes (2**9) is the fake blocksize that must be used */
+ /* for this calculation, not the real blocksize */
+ tmp_inode->i_blocks = (512 - 1 + pfindData->NumOfBytes) >> 9;
+ }
if (S_ISREG(tmp_inode->i_mode)) {
cFYI(1, ("File inode"));
/* BB overwrite the old name? i.e. tmp_dentry->d_name and tmp_dentry->d_name.len ?? */
if(*ptmp_inode == NULL) {
*ptmp_inode = new_inode(file->f_dentry->d_sb);
+ if(*ptmp_inode == NULL)
+ return;
d_instantiate(tmp_dentry, *ptmp_inode);
}
} else {
tmp_dentry = d_alloc(file->f_dentry, qstring);
if(tmp_dentry == NULL) {
cERROR(1,("Failed allocating dentry"));
+ *ptmp_inode = NULL;
return;
}
tmp_dentry->d_op = &cifs_dentry_ops;
cFYI(0, (" instantiate dentry 0x%p with inode 0x%p ",
tmp_dentry, *ptmp_inode));
+ if(*ptmp_inode == NULL)
+ return;
d_instantiate(tmp_dentry, *ptmp_inode);
d_rehash(tmp_dentry);
}
pqstring->len = pfindData->FileNameLength;
construct_dentry(pqstring, file, &tmp_inode, &tmp_dentry);
-
+ if((tmp_inode == NULL) || (tmp_dentry == NULL)) {
+ return -ENOMEM;
+ }
fill_in_inode(tmp_inode, pfindData, &object_type);
rc = filldir(direntry, pfindData->FileName, pqstring->len, file->f_pos,
tmp_inode->i_ino, object_type);
pqstring->len = strnlen(pUnixFindData->FileName, MAX_PATHCONF);
construct_dentry(pqstring, file, &tmp_inode, &tmp_dentry);
+ if((tmp_inode == NULL) || (tmp_dentry == NULL)) {
+ return -ENOMEM;
+ }
unix_fill_in_inode(tmp_inode, pUnixFindData, &object_type);
rc = filldir(direntry, pUnixFindData->FileName, pqstring->len,
int cifs_prepare_write(struct file *file, struct page *page,
unsigned from, unsigned to)
{
+ int rc = 0;
+ loff_t offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
cFYI(1,("prepare write for page %p from %d to %d",page,from,to));
if (!PageUptodate(page)) {
- if (to - from != PAGE_CACHE_SIZE) {
+ /* if (to - from != PAGE_CACHE_SIZE) {
void *kaddr = kmap_atomic(page, KM_USER0);
memset(kaddr, 0, from);
memset(kaddr + to, 0, PAGE_CACHE_SIZE - to);
flush_dcache_page(page);
kunmap_atomic(kaddr, KM_USER0);
+ } */
+ /* If we are writing a full page it will be up to date,
+ no need to read from the server */
+ if((to==PAGE_CACHE_SIZE) && (from == 0))
+ SetPageUptodate(page);
+
+ /* might as well read a page, it is fast enough */
+ if((file->f_flags & O_ACCMODE) != O_WRONLY) {
+ rc = cifs_readpage_worker(file,page,&offset);
+ } else {
+ /* should we try using another
+ file handle if there is one - how would we lock it
+ to prevent close of that handle racing with this read? */
+ /* In any case this will be written out by commit_write */
}
- SetPageUptodate(page);
}
+
+ /* BB should we pass any errors back? e.g. if we do not have read access to the file */
return 0;
}
.readpage = cifs_readpage,
.readpages = cifs_readpages,
.writepage = cifs_writepage,
- .prepare_write = simple_prepare_write, /* BB fixme BB */
-/* .prepare_write = cifs_prepare_write, */ /* BB removeme BB */
+ .prepare_write = cifs_prepare_write,
.commit_write = cifs_commit_write,
/* .sync_page = cifs_sync_page, */
/*.direct_IO = */
git://git.onelab.eu / linux-2.6.git / blobdiff