static int gfs2_readpage(struct file *file, struct page *page)
{
struct address_space *mapping = page->mapping;
struct gfs2_inode *ip = GFS2_I(mapping->host);
struct gfs2_holder gh;
int error;
unlock_page(page);
gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh);
error = gfs2_glock_nq_atime(&gh);
if (unlikely(error))
goto out;
error = AOP_TRUNCATED_PAGE;
lock_page(page);
if (page->mapping == mapping && !PageUptodate(page))
error = __gfs2_readpage(file, page);
else
unlock_page(page);
gfs2_glock_dq(&gh);
out:
gfs2_holder_uninit(&gh);
if (error && error != AOP_TRUNCATED_PAGE)
lock_page(page);
return error;
}
static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
const struct iovec *iov, loff_t offset,
unsigned long nr_segs)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_holder gh;
int rv;
/*
* Deferred lock, even if its a write, since we do no allocation
* on this path. All we need change is atime, and this lock mode
* ensures that other nodes have flushed their buffered read caches
* (i.e. their page cache entries for this inode). We do not,
* unfortunately have the option of only flushing a range like
* the VFS does.
*/
gfs2_holder_init(ip->i_gl, LM_ST_DEFERRED, GL_ATIME, &gh);
rv = gfs2_glock_nq_atime(&gh);
if (rv)
return rv;
rv = gfs2_ok_for_dio(ip, rw, offset);
if (rv != 1)
goto out; /* dio not valid, fall back to buffered i/o */
rv = blockdev_direct_IO_no_locking(rw, iocb, inode, inode->i_sb->s_bdev,
iov, offset, nr_segs,
gfs2_get_block_direct, NULL);
out:
gfs2_glock_dq_m(1, &gh);
gfs2_holder_uninit(&gh);
return rv;
}
static int gfs2_mmap(struct file *file, struct vm_area_struct *vma)
{
struct gfs2_inode *ip = GFS2_I(file->f_mapping->host);
struct gfs2_holder i_gh;
int error;
gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &i_gh);
error = gfs2_glock_nq_atime(&i_gh);
if (error) {
gfs2_holder_uninit(&i_gh);
return error;
}
/* This is VM_MAYWRITE instead of VM_WRITE because a call
to mprotect() can turn on VM_WRITE later. */
if ((vma->vm_flags & (VM_MAYSHARE | VM_MAYWRITE)) ==
(VM_MAYSHARE | VM_MAYWRITE))
vma->vm_ops = &gfs2_vm_ops_sharewrite;
else
vma->vm_ops = &gfs2_vm_ops_private;
gfs2_glock_dq_uninit(&i_gh);
return error;
}
static int gfs2_readpage(struct file *file, struct page *page)
{
struct gfs2_inode *ip = GFS2_I(page->mapping->host);
struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
struct gfs2_file *gf = NULL;
struct gfs2_holder gh;
int error;
int do_unlock = 0;
if (likely(file != &gfs2_internal_file_sentinel)) {
if (file) {
gf = file->private_data;
if (test_bit(GFF_EXLOCK, &gf->f_flags))
/* gfs2_sharewrite_nopage has grabbed the ip->i_gl already */
goto skip_lock;
}
gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME|LM_FLAG_TRY_1CB, &gh);
do_unlock = 1;
error = gfs2_glock_nq_atime(&gh);
if (unlikely(error))
goto out_unlock;
}
skip_lock:
if (gfs2_is_stuffed(ip)) {
error = stuffed_readpage(ip, page);
unlock_page(page);
} else
error = mpage_readpage(page, gfs2_get_block);
if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
error = -EIO;
if (do_unlock) {
gfs2_glock_dq_m(1, &gh);
gfs2_holder_uninit(&gh);
}
out:
return error;
out_unlock:
unlock_page(page);
if (error == GLR_TRYFAILED) {
error = AOP_TRUNCATED_PAGE;
yield();
}
if (do_unlock)
gfs2_holder_uninit(&gh);
goto out;
}
/**
* gfs2_readpages - Read a bunch of pages at once
*
* Some notes:
* 1. This is only for readahead, so we can simply ignore any things
* which are slightly inconvenient (such as locking conflicts between
* the page lock and the glock) and return having done no I/O. Its
* obviously not something we'd want to do on too regular a basis.
* Any I/O we ignore at this time will be done via readpage later.
* 2. We don't handle stuffed files here we let readpage do the honours.
* 3. mpage_readpages() does most of the heavy lifting in the common case.
* 4. gfs2_get_block() is relied upon to set BH_Boundary in the right places.
* 5. We use LM_FLAG_TRY_1CB here, effectively we then have lock-ahead as
* well as read-ahead.
*/
static int gfs2_readpages(struct file *file, struct address_space *mapping,
struct list_head *pages, unsigned nr_pages)
{
struct inode *inode = mapping->host;
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_sbd *sdp = GFS2_SB(inode);
struct gfs2_holder gh;
int ret = 0;
int do_unlock = 0;
if (likely(file != &gfs2_internal_file_sentinel)) {
if (file) {
struct gfs2_file *gf = file->private_data;
if (test_bit(GFF_EXLOCK, &gf->f_flags))
goto skip_lock;
}
gfs2_holder_init(ip->i_gl, LM_ST_SHARED,
LM_FLAG_TRY_1CB|GL_ATIME, &gh);
do_unlock = 1;
ret = gfs2_glock_nq_atime(&gh);
if (ret == GLR_TRYFAILED)
goto out_noerror;
if (unlikely(ret))
goto out_unlock;
}
skip_lock:
if (!gfs2_is_stuffed(ip))
ret = mpage_readpages(mapping, pages, nr_pages, gfs2_get_block);
if (do_unlock) {
gfs2_glock_dq_m(1, &gh);
gfs2_holder_uninit(&gh);
}
out:
if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
ret = -EIO;
return ret;
out_noerror:
ret = 0;
out_unlock:
if (do_unlock)
gfs2_holder_uninit(&gh);
goto out;
}
static int gfs2_get_flags(struct file *filp, u32 __user *ptr)
{
struct inode *inode = filp->f_path.dentry->d_inode;
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_holder gh;
int error;
u32 fsflags;
gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh);
error = gfs2_glock_nq_atime(&gh);
if (error)
return error;
fsflags = fsflags_cvt(gfs2_to_fsflags, ip->i_di.di_flags);
if (put_user(fsflags, ptr))
error = -EFAULT;
gfs2_glock_dq_m(1, &gh);
gfs2_holder_uninit(&gh);
return error;
}
static int gfs2_readpages(struct file *file, struct address_space *mapping,
struct list_head *pages, unsigned nr_pages)
{
struct inode *inode = mapping->host;
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_sbd *sdp = GFS2_SB(inode);
struct gfs2_holder gh;
int ret;
gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh);
ret = gfs2_glock_nq_atime(&gh);
if (unlikely(ret))
goto out_uninit;
if (!gfs2_is_stuffed(ip))
ret = mpage_readpages(mapping, pages, nr_pages, gfs2_block_map);
gfs2_glock_dq(&gh);
out_uninit:
gfs2_holder_uninit(&gh);
if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
ret = -EIO;
return ret;
}
static int gfs2_readpage(struct file *file, struct page *page)
{
struct gfs2_inode *ip = GFS2_I(page->mapping->host);
struct gfs2_holder gh;
int error;
gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME|LM_FLAG_TRY_1CB, &gh);
error = gfs2_glock_nq_atime(&gh);
if (unlikely(error)) {
unlock_page(page);
goto out;
}
error = __gfs2_readpage(file, page);
gfs2_glock_dq(&gh);
out:
gfs2_holder_uninit(&gh);
if (error == GLR_TRYFAILED) {
yield();
return AOP_TRUNCATED_PAGE;
}
return error;
}
static int gfs2_readdir(struct file *file, void *dirent, filldir_t filldir)
{
struct inode *dir = file->f_mapping->host;
struct gfs2_inode *dip = GFS2_I(dir);
struct gfs2_holder d_gh;
u64 offset = file->f_pos;
int error;
gfs2_holder_init(dip->i_gl, LM_ST_SHARED, GL_ATIME, &d_gh);
error = gfs2_glock_nq_atime(&d_gh);
if (error) {
gfs2_holder_uninit(&d_gh);
return error;
}
error = gfs2_dir_read(dir, &offset, dirent, filldir);
gfs2_glock_dq_uninit(&d_gh);
file->f_pos = offset;
return error;
}
static int gfs2_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
struct gfs2_inode *ip = GFS2_I(mapping->host);
struct gfs2_sbd *sdp = GFS2_SB(mapping->host);
unsigned int data_blocks, ind_blocks, rblocks;
int alloc_required;
int error = 0;
struct gfs2_alloc *al;
pgoff_t index = pos >> PAGE_CACHE_SHIFT;
unsigned from = pos & (PAGE_CACHE_SIZE - 1);
unsigned to = from + len;
struct page *page;
gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_ATIME, &ip->i_gh);
error = gfs2_glock_nq_atime(&ip->i_gh);
if (unlikely(error))
goto out_uninit;
gfs2_write_calc_reserv(ip, len, &data_blocks, &ind_blocks);
error = gfs2_write_alloc_required(ip, pos, len, &alloc_required);
if (error)
goto out_unlock;
if (alloc_required) {
al = gfs2_alloc_get(ip);
if (!al) {
error = -ENOMEM;
goto out_unlock;
}
error = gfs2_quota_lock_check(ip);
if (error)
goto out_alloc_put;
al->al_requested = data_blocks + ind_blocks;
error = gfs2_inplace_reserve(ip);
if (error)
goto out_qunlock;
}
rblocks = RES_DINODE + ind_blocks;
if (gfs2_is_jdata(ip))
rblocks += data_blocks ? data_blocks : 1;
if (ind_blocks || data_blocks)
rblocks += RES_STATFS + RES_QUOTA;
error = gfs2_trans_begin(sdp, rblocks,
PAGE_CACHE_SIZE/sdp->sd_sb.sb_bsize);
if (error)
goto out_trans_fail;
error = -ENOMEM;
page = grab_cache_page_write_begin(mapping, index, flags);
*pagep = page;
if (unlikely(!page))
goto out_endtrans;
if (gfs2_is_stuffed(ip)) {
error = 0;
if (pos + len > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
error = gfs2_unstuff_dinode(ip, page);
if (error == 0)
goto prepare_write;
} else if (!PageUptodate(page)) {
error = stuffed_readpage(ip, page);
}
goto out;
}
prepare_write:
error = block_prepare_write(page, from, to, gfs2_block_map);
out:
if (error == 0)
return 0;
page_cache_release(page);
if (pos + len > ip->i_inode.i_size)
vmtruncate(&ip->i_inode, ip->i_inode.i_size);
out_endtrans:
gfs2_trans_end(sdp);
out_trans_fail:
if (alloc_required) {
gfs2_inplace_release(ip);
out_qunlock:
gfs2_quota_unlock(ip);
out_alloc_put:
gfs2_alloc_put(ip);
}
out_unlock:
gfs2_glock_dq(&ip->i_gh);
out_uninit:
gfs2_holder_uninit(&ip->i_gh);
return error;
}
static int gfs2_prepare_write(struct file *file, struct page *page,
unsigned from, unsigned to)
{
struct gfs2_inode *ip = GFS2_I(page->mapping->host);
struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
unsigned int data_blocks, ind_blocks, rblocks;
int alloc_required;
int error = 0;
loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + from;
loff_t end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
struct gfs2_alloc *al;
unsigned int write_len = to - from;
gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_ATIME|LM_FLAG_TRY_1CB, &ip->i_gh);
error = gfs2_glock_nq_atime(&ip->i_gh);
if (unlikely(error)) {
if (error == GLR_TRYFAILED) {
unlock_page(page);
error = AOP_TRUNCATED_PAGE;
yield();
}
goto out_uninit;
}
gfs2_write_calc_reserv(ip, write_len, &data_blocks, &ind_blocks);
error = gfs2_write_alloc_required(ip, pos, write_len, &alloc_required);
if (error)
goto out_unlock;
ip->i_alloc.al_requested = 0;
if (alloc_required) {
al = gfs2_alloc_get(ip);
error = gfs2_quota_lock(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
if (error)
goto out_alloc_put;
error = gfs2_quota_check(ip, ip->i_inode.i_uid, ip->i_inode.i_gid);
if (error)
goto out_qunlock;
al->al_requested = data_blocks + ind_blocks;
error = gfs2_inplace_reserve(ip);
if (error)
goto out_qunlock;
}
rblocks = RES_DINODE + ind_blocks;
if (gfs2_is_jdata(ip))
rblocks += data_blocks ? data_blocks : 1;
if (ind_blocks || data_blocks)
rblocks += RES_STATFS + RES_QUOTA;
error = gfs2_trans_begin(sdp, rblocks, 0);
if (error)
goto out;
if (gfs2_is_stuffed(ip)) {
if (end > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
error = gfs2_unstuff_dinode(ip, page);
if (error == 0)
goto prepare_write;
} else if (!PageUptodate(page))
error = stuffed_readpage(ip, page);
goto out;
}
prepare_write:
error = block_prepare_write(page, from, to, gfs2_get_block);
out:
if (error) {
gfs2_trans_end(sdp);
if (alloc_required) {
gfs2_inplace_release(ip);
out_qunlock:
gfs2_quota_unlock(ip);
out_alloc_put:
gfs2_alloc_put(ip);
}
out_unlock:
gfs2_glock_dq_m(1, &ip->i_gh);
out_uninit:
gfs2_holder_uninit(&ip->i_gh);
}
return error;
}