[PATCH 08/21] ceph: file operations

Sage Weil
2009-09-22T17:45:50Z

File open and close operations, and read and write methods that ensure
we have obtained the proper capabilities from the MDS cluster before
performing IO on a file. We take references on held capabilities for
the duration of the read/write to avoid prematurely releasing them
back to the MDS.

We implement two main paths for read and write: one that is buffered
(and uses generic_aio_{read,write}), and one that is fully synchronous
and blocking (operating either on a __user pointer or, if O_DIRECT,
directly on user pages).

Signed-off-by: Sage Weil <sage@newdream.net>
---
fs/ceph/file.c | 902 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 902 insertions(+), 0 deletions(-)
create mode 100644 fs/ceph/file.c

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
new file mode 100644
index 0000000..23bca66
--- /dev/null
+++ b/fs/ceph/file.c
@@ -0,0 +1,902 @@
+
+#include <linux/sched.h>
+#include <linux/file.h>
+#include <linux/namei.h>
+#include <linux/writeback.h>
+
+#include "ceph_debug.h"
+#include "super.h"
+#include "mds_client.h"
+
+/*
+ * Ceph file operations
+ *
+ * Implement basic open/close functionality, and implement
+ * read/write.
+ *
+ * We implement three modes of file I/O:
+ * - buffered uses the generic_file_aio_{read,write} helpers
+ *
+ * - synchronous is used when there is multi-client read/write
+ * sharing, avoids the page cache, and synchronously waits for an
+ * ack from the OSD.
+ *
+ * - direct io takes the variant of the sync path that references
+ * user pages directly.
+ *
+ * fsync() flushes and waits on dirty pages, but just queues metadata
+ * for writeback: since the MDS can recover size and mtime there is no
+ * need to wait for MDS acknowledgement.
+ */
+
+
+/*
+ * Prepare an open request. Preallocate ceph_cap to avoid an
+ * inopportune ENOMEM later.
+ */
+static struct ceph_mds_request *
+prepare_open_request(struct super_block *sb, int flags, int create_mode)
+{
+ struct ceph_client *client = ceph_sb_to_client(sb);
+ struct ceph_mds_client *mdsc = &client->mdsc;
+ struct ceph_mds_request *req;
+ int want_auth = USE_ANY_MDS;
+ int op = (flags & O_CREAT) ? CEPH_MDS_OP_CREATE : CEPH_MDS_OP_OPEN;
+
+ if (flags & (O_WRONLY|O_RDWR|O_CREAT|O_TRUNC))
+ want_auth = USE_AUTH_MDS;
+
+ req = ceph_mdsc_create_request(mdsc, op, want_auth);
+ if (IS_ERR(req))
+ goto out;
+ req->r_fmode = ceph_flags_to_mode(flags);
+ req->r_args.open.flags = cpu_to_le32(flags);
+ req->r_args.open.mode = cpu_to_le32(create_mode);
+out:
+ return req;
+}
+
+/*
+ * initialize private struct file data.
+ * if we fail, clean up by dropping fmode reference on the ceph_inode
+ */
+static int ceph_init_file(struct inode *inode, struct file *file, int fmode)
+{
+ struct ceph_file_info *cf;
+ int ret = 0;
+
+ switch (inode->i_mode & S_IFMT) {
+ case S_IFREG:
+ case S_IFDIR:
+ dout("init_file %p %p 0%o (regular)\n", inode, file,
+ inode->i_mode);
+ cf = kmem_cache_alloc(ceph_file_cachep, GFP_NOFS | __GFP_ZERO);
+ if (cf == NULL) {
+ ceph_put_fmode(ceph_inode(inode), fmode); /* clean up */
+ return -ENOMEM;
+ }
+ cf->fmode = fmode;
+ cf->next_offset = 2;
+ file->private_data = cf;
+ BUG_ON(inode->i_fop->release != ceph_release);
+ break;
+
+ case S_IFLNK:
+ dout("init_file %p %p 0%o (symlink)\n", inode, file,
+ inode->i_mode);
+ ceph_put_fmode(ceph_inode(inode), fmode); /* clean up */
+ break;
+
+ default:
+ dout("init_file %p %p 0%o (special)\n", inode, file,
+ inode->i_mode);
+ /*
+ * we need to drop the open ref now, since we don't
+ * have .release set to ceph_release.
+ */
+ ceph_put_fmode(ceph_inode(inode), fmode); /* clean up */
+ BUG_ON(inode->i_fop->release == ceph_release);
+
+ /* call the proper open fop */
+ ret = inode->i_fop->open(inode, file);
+ }
+ return ret;
+}
+
+/*
+ * If the filp already has private_data, that means the file was
+ * already opened by intent during lookup, and we do nothing.
+ *
+ * If we already have the requisite capabilities, we can satisfy
+ * the open request locally (no need to request new caps from the
+ * MDS). We do, however, need to inform the MDS (asynchronously)
+ * if our wanted caps set expands.
+ */
+int ceph_open(struct inode *inode, struct file *file)
+{
+ struct ceph_inode_info *ci = ceph_inode(inode);
+ struct ceph_client *client = ceph_sb_to_client(inode->i_sb);
+ struct ceph_mds_client *mdsc = &client->mdsc;
+ struct ceph_mds_request *req;
+ struct ceph_file_info *cf = file->private_data;
+ struct inode *parent_inode = file->f_dentry->d_parent->d_inode;
+ int err;
+ int flags, fmode, wanted;
+
+ if (cf) {
+ dout("open file %p is already opened\n", file);
+ return 0;
+ }
+
+ /* filter out O_CREAT|O_EXCL; vfs did that already. yuck. */
+ flags = file->f_flags & ~(O_CREAT|O_EXCL);
+ if (S_ISDIR(inode->i_mode))
+ flags = O_DIRECTORY; /* mds likes to know */
+
+ dout("open inode %p ino %llx.%llx file %p flags %d (%d)\n", inode,
+ ceph_vinop(inode), file, flags, file->f_flags);
+ fmode = ceph_flags_to_mode(flags);
+ wanted = ceph_caps_for_mode(fmode);
+
+ /* snapped files are read-only */
+ if (ceph_snap(inode) != CEPH_NOSNAP && (file->f_mode & FMODE_WRITE))
+ return -EROFS;
+
+ /* trivially open snapdir */
+ if (ceph_snap(inode) == CEPH_SNAPDIR) {
+ spin_lock(&inode->i_lock);
+ __ceph_get_fmode(ci, fmode);
+ spin_unlock(&inode->i_lock);
+ return ceph_init_file(inode, file, fmode);
+ }
+
+ /*
+ * No need to block if we have any caps. Update wanted set
+ * asynchronously.
+ */
+ spin_lock(&inode->i_lock);
+ if (__ceph_is_any_real_caps(ci)) {
+ int mds_wanted = __ceph_caps_mds_wanted(ci);
+ int issued = __ceph_caps_issued(ci, NULL);
+
+ dout("open %p fmode %d want %s issued %s using existing\n",
+ inode, fmode, ceph_cap_string(wanted),
+ ceph_cap_string(issued));
+ __ceph_get_fmode(ci, fmode);
+ spin_unlock(&inode->i_lock);
+
+ /* adjust wanted? */
+ if ((issued & wanted) != wanted &&
+ (mds_wanted & wanted) != wanted &&
+ ceph_snap(inode) != CEPH_SNAPDIR)
+ ceph_check_caps(ci, 0, NULL);
+
+ return ceph_init_file(inode, file, fmode);
+ } else if (ceph_snap(inode) != CEPH_NOSNAP &&
+ (ci->i_snap_caps & wanted) == wanted) {
+ __ceph_get_fmode(ci, fmode);
+ spin_unlock(&inode->i_lock);
+ return ceph_init_file(inode, file, fmode);
+ }
+ spin_unlock(&inode->i_lock);
+
+ dout("open fmode %d wants %s\n", fmode, ceph_cap_string(wanted));
+ req = prepare_open_request(inode->i_sb, flags, 0);
+ if (IS_ERR(req)) {
+ err = PTR_ERR(req);
+ goto out;
+ }
+ req->r_inode = igrab(inode);
+ req->r_num_caps = 1;
+ err = ceph_mdsc_do_request(mdsc, parent_inode, req);
+ if (!err)
+ err = ceph_init_file(inode, file, req->r_fmode);
+ ceph_mdsc_put_request(req);
+ dout("open result=%d on %llx.%llx\n", err, ceph_vinop(inode));
+out:
+ return err;
+}
+
+
+/*
+ * Do a lookup + open with a single request.
+ *
+ * If this succeeds, but some subsequent check in the vfs
+ * may_open() fails, the struct *file gets cleaned up (i.e.
+ * ceph_release gets called). So fear not!
+ */
+/*
+ * flags
+ * path_lookup_open -> LOOKUP_OPEN
+ * path_lookup_create -> LOOKUP_OPEN|LOOKUP_CREATE
+ */
+struct dentry *ceph_lookup_open(struct inode *dir, struct dentry *dentry,
+ struct nameidata *nd, int mode,
+ int locked_dir)
+{
+ struct ceph_client *client = ceph_sb_to_client(dir->i_sb);
+ struct ceph_mds_client *mdsc = &client->mdsc;
+ struct file *file = nd->intent.open.file;
+ struct inode *parent_inode = get_dentry_parent_inode(file->f_dentry);
+ struct ceph_mds_request *req;
+ int err;
+ int flags = nd->intent.open.flags - 1; /* silly vfs! */
+
+ dout("ceph_lookup_open dentry %p '%.*s' flags %d mode 0%o\n",
+ dentry, dentry->d_name.len, dentry->d_name.name, flags, mode);
+
+ /* do the open */
+ req = prepare_open_request(dir->i_sb, flags, mode);
+ if (IS_ERR(req))
+ return ERR_PTR(PTR_ERR(req));
+ req->r_dentry = dget(dentry);
+ req->r_num_caps = 2;
+ if (flags & O_CREAT) {
+ req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
+ req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
+ }
+ req->r_locked_dir = dir; /* caller holds dir->i_mutex */
+ err = ceph_mdsc_do_request(mdsc, parent_inode, req);
+ dentry = ceph_finish_lookup(req, dentry, err);
+ if (!err && (flags & O_CREAT) && !req->r_reply_info.head->is_dentry)
+ err = ceph_handle_notrace_create(dir, dentry);
+ if (!err)
+ err = ceph_init_file(req->r_dentry->d_inode, file,
+ req->r_fmode);
+ ceph_mdsc_put_request(req);
+ dout("ceph_lookup_open result=%p\n", dentry);
+ return dentry;
+}
+
+int ceph_release(struct inode *inode, struct file *file)
+{
+ struct ceph_inode_info *ci = ceph_inode(inode);
+ struct ceph_file_info *cf = file->private_data;
+
+ dout("release inode %p file %p\n", inode, file);
+ ceph_put_fmode(ci, cf->fmode);
+ if (cf->last_readdir)
+ ceph_mdsc_put_request(cf->last_readdir);
+ kfree(cf->last_name);
+ kfree(cf->dir_info);
+ dput(cf->dentry);
+ kmem_cache_free(ceph_file_cachep, cf);
+ return 0;
+}
+
+/*
+ * build a vector of user pages
+ */
+static struct page **get_direct_page_vector(const char __user *data,
+ int num_pages,
+ loff_t off, size_t len)
+{
+ struct page **pages;
+ int rc;
+
+ pages = kmalloc(sizeof(*pages) * num_pages, GFP_NOFS);
+ if (!pages)
+ return ERR_PTR(-ENOMEM);
+
+ down_read(&current->mm->mmap_sem);
+ rc = get_user_pages(current, current->mm, (unsigned long)data,
+ num_pages, 0, 0, pages, NULL);
+ up_read(&current->mm->mmap_sem);
+ if (rc < 0)
+ goto fail;
+ return pages;
+
+fail:
+ kfree(pages);
+ return ERR_PTR(rc);
+}
+
+static void put_page_vector(struct page **pages, int num_pages)
+{
+ int i;
+
+ for (i = 0; i < num_pages; i++)
+ put_page(pages[i]);
+ kfree(pages);
+}
+
+void ceph_release_page_vector(struct page **pages, int num_pages)
+{
+ int i;
+
+ for (i = 0; i < num_pages; i++)
+ __free_pages(pages[i], 0);
+ kfree(pages);
+}
+
+/*
+ * allocate a vector new pages
+ */
+static struct page **alloc_page_vector(int num_pages)
+{
+ struct page **pages;
+ int i;
+
+ pages = kmalloc(sizeof(*pages) * num_pages, GFP_NOFS);
+ if (!pages)
+ return ERR_PTR(-ENOMEM);
+ for (i = 0; i < num_pages; i++) {
+ pages[i] = alloc_page(GFP_NOFS);
+ if (pages[i] == NULL) {
+ ceph_release_page_vector(pages, i);
+ return ERR_PTR(-ENOMEM);
+ }
+ }
+ return pages;
+}
+
+/*
+ * copy user data into a page vector
+ */
+static int copy_user_to_page_vector(struct page **pages,
+ const char __user *data,
+ loff_t off, size_t len)
+{
+ int i = 0;
+ int po = off & ~PAGE_CACHE_MASK;
+ int left = len;
+ int l, bad;
+
+ while (left > 0) {
+ l = min_t(int, PAGE_CACHE_SIZE-po, left);
+ bad = copy_from_user(page_address(pages[i]) + po, data, l);
+ if (bad == l)
+ return -EFAULT;
+ data += l - bad;
+ left -= l - bad;
+ if (po) {
+ po += l - bad;
+ if (po == PAGE_CACHE_SIZE)
+ po = 0;
+ }
+ }
+ return len;
+}
+
+/*
+ * copy user data from a page vector into a user pointer
+ */
+static int copy_page_vector_to_user(struct page **pages, char __user *data,
+ loff_t off, size_t len)
+{
+ int i = 0;
+ int po = off & ~PAGE_CACHE_MASK;
+ int left = len;
+ int l, bad;
+
+ while (left > 0) {
+ l = min_t(int, left, PAGE_CACHE_SIZE-po);
+ bad = copy_to_user(data, page_address(pages[i]) + po, l);
+ if (bad == l)
+ return -EFAULT;
+ data += l - bad;
+ left -= l - bad;
+ if (po) {
+ po += l - bad;
+ if (po == PAGE_CACHE_SIZE)
+ po = 0;
+ }
+ i++;
+ }
+ return len;
+}
+
+/*
+ * Zero an extent within a page vector. Offset is relative to the
+ * start of the first page.
+ */
+static void zero_page_vector_range(int off, int len, struct page **pages)
+{
+ int i = off >> PAGE_CACHE_SHIFT;
+
+ dout("zero_page_vector_page %u~%u\n", off, len);
+ BUG_ON(len < PAGE_CACHE_SIZE);
+
+ /* leading partial page? */
+ if (off & ~PAGE_CACHE_MASK) {
+ dout("zeroing %d %p head from %d\n", i, pages[i],
+ (int)(off & ~PAGE_CACHE_MASK));
+ zero_user_segment(pages[i], off & ~PAGE_CACHE_MASK,
+ PAGE_CACHE_SIZE);
+ off += PAGE_CACHE_SIZE;
+ off &= PAGE_CACHE_MASK;
+ i++;
+ }
+ while (len >= PAGE_CACHE_SIZE) {
+ dout("zeroing %d %p\n", i, pages[i]);
+ zero_user_segment(pages[i], 0, PAGE_CACHE_SIZE);
+ off += PAGE_CACHE_SIZE;
+ len -= PAGE_CACHE_SIZE;
+ i++;
+ }
+ /* trailing partial page? */
+ if (len) {
+ dout("zeroing %d %p tail to %d\n", i, pages[i], (int)len);
+ zero_user_segment(pages[i], 0, len);
+ }
+}
+
+
+/*
+ * Read a range of bytes striped over one or more objects. Iterate over
+ * objects we stripe over. (That's not atomic, but good enough for now.)
+ *
+ * If we get a short result from the OSD, check against i_size; we need to
+ * only return a short read to the caller if we hit EOF.
+ */
+static int striped_read(struct inode *inode,
+ u64 off, u64 len,
+ struct page **pages, int num_pages)
+{
+ struct ceph_client *client = ceph_inode_to_client(inode);
+ struct ceph_inode_info *ci = ceph_inode(inode);
+ u64 pos, this_len;
+ int page_off = off & ~PAGE_CACHE_SIZE; /* first byte's offset in page */
+ int left, pages_left;
+ int read;
+ struct page **page_pos;
+ int ret;
+ bool hit_stripe, was_short;
+
+ /*
+ * we may need to do multiple reads. not atomic, unfortunately.
+ */
+ pos = off;
+ left = len;
+ page_pos = pages;
+ pages_left = num_pages;
+ read = 0;
+
+more:
+ this_len = left;
+ ret = ceph_osdc_readpages(&client->osdc, ceph_vino(inode),
+ &ci->i_layout, pos, &this_len,
+ ci->i_truncate_seq,
+ ci->i_truncate_size,
+ page_pos, pages_left);
+ hit_stripe = this_len < left;
+ was_short = ret >= 0 && ret < this_len;
+ if (ret == -ENOENT)
+ ret = 0;
+ dout("striped_read %llu~%u (read %u) got %d%s%s\n", pos, left, read,
+ ret, hit_stripe ? " HITSTRIPE" : "", was_short ? " SHORT" : "");
+
+ if (ret > 0) {
+ int didpages =
+ ((pos & ~PAGE_CACHE_MASK) + ret) >> PAGE_CACHE_SHIFT;
+
+ if (read < pos - off) {
+ dout(" zero gap %llu to %llu\n", off + read, pos);
+ zero_page_vector_range(page_off + read,
+ pos - off - read, pages);
+ }
+ pos += ret;
+ read = pos - off;
+ left -= ret;
+ page_pos += didpages;
+ pages_left -= didpages;
+
+ /* hit stripe? */
+ if (left && hit_stripe)
+ goto more;
+ }
+
+ if (was_short) {
+ /* was original extent fully inside i_size? */
+ if (pos + left <= inode->i_size) {
+ dout("zero tail\n");
+ zero_page_vector_range(page_off + read, len - read,
+ pages);
+ goto out;
+ }
+
+ /* check i_size */
+ ret = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE);
+ if (ret < 0)
+ goto out;
+
+ /* hit EOF? */
+ if (pos >= inode->i_size)
+ goto out;
+
+ goto more;
+ }
+
+out:
+ if (ret >= 0)
+ ret = read;
+ dout("striped_read returns %d\n", ret);
+ return ret;
+}
+
+/*
+ * Completely synchronous read and write methods. Direct from __user
+ * buffer to osd, or directly to user pages (if O_DIRECT).
+ *
+ * If the read spans object boundary, just do multiple reads.
+ */
+static ssize_t ceph_sync_read(struct file *file, char __user *data,
+ unsigned len, loff_t *poff)
+{
+ struct inode *inode = file->f_dentry->d_inode;
+ struct page **pages;
+ u64 off = *poff;
+ int num_pages = calc_pages_for(off, len);
+ int ret;
+
+ dout("sync_read on file %p %llu~%u %s\n", file, off, len,
+ (file->f_flags & O_DIRECT) ? "O_DIRECT" : "");
+
+ if (file->f_flags & O_DIRECT) {
+ pages = get_direct_page_vector(data, num_pages, off, len);
+
+ /*
+ * flush any page cache pages in this range. this
+ * will make concurrent normal and O_DIRECT io slow,
+ * but it will at least behave sensibly when they are
+ * in sequence.
+ */
+ filemap_write_and_wait(inode->i_mapping);
+ } else {
+ pages = alloc_page_vector(num_pages);
+ }
+ if (IS_ERR(pages))
+ return PTR_ERR(pages);
+
+ ret = striped_read(inode, off, len, pages, num_pages);
+
+ if (ret >= 0 && (file->f_flags & O_DIRECT) == 0)
+ ret = copy_page_vector_to_user(pages, data, off, ret);
+ if (ret >= 0)
+ *poff = off + ret;
+
+ if (file->f_flags & O_DIRECT)
+ put_page_vector(pages, num_pages);
+ else
+ ceph_release_page_vector(pages, num_pages);
+ dout("sync_read result %d\n", ret);
+ return ret;
+}
+
+/*
+ * Write commit callback, called if we requested both an ACK and
+ * ONDISK commit reply from the OSD.
+ */
+static void sync_write_commit(struct ceph_osd_request *req,
+ struct ceph_msg *msg)
+{
+ struct ceph_inode_info *ci = ceph_inode(req->r_inode);
+
+ dout("sync_write_commit %p tid %llu\n", req, req->r_tid);
+ spin_lock(&ci->i_unsafe_lock);
+ list_del_init(&req->r_unsafe_item);
+ spin_unlock(&ci->i_unsafe_lock);
+ ceph_put_cap_refs(ci, CEPH_CAP_FILE_WR);
+}
+
+/*
+ * Synchronous write, straight from __user pointer or user pages (if
+ * O_DIRECT).
+ *
+ * If write spans object boundary, just do multiple writes. (For a
+ * correct atomic write, we should e.g. take write locks on all
+ * objects, rollback on failure, etc.)
+ */
+static ssize_t ceph_sync_write(struct file *file, const char __user *data,
+ size_t left, loff_t *offset)
+{
+ struct inode *inode = file->f_dentry->d_inode;
+ struct ceph_inode_info *ci = ceph_inode(inode);
+ struct ceph_client *client = ceph_inode_to_client(inode);
+ struct ceph_osd_request *req;
+ struct page **pages;
+ int num_pages;
+ long long unsigned pos;
+ u64 len;
+ int written = 0;
+ int flags;
+ int do_sync = 0;
+ int check_caps = 0;
+ int ret;
+ struct timespec mtime = CURRENT_TIME;
+
+ if (ceph_snap(file->f_dentry->d_inode) != CEPH_NOSNAP)
+ return -EROFS;
+
+ dout("sync_write on file %p %lld~%u %s\n", file, *offset,
+ (unsigned)left, (file->f_flags & O_DIRECT) ? "O_DIRECT" : "");
+
+ if (file->f_flags & O_APPEND)
+ pos = i_size_read(inode);
+ else
+ pos = *offset;
+
+ flags = CEPH_OSD_FLAG_ORDERSNAP |
+ CEPH_OSD_FLAG_ONDISK |
+ CEPH_OSD_FLAG_WRITE;
+ if ((file->f_flags & (O_SYNC|O_DIRECT)) == 0)
+ flags |= CEPH_OSD_FLAG_ACK;
+ else
+ do_sync = 1;
+
+ /*
+ * we may need to do multiple writes here if we span an object
+ * boundary. this isn't atomic, unfortunately. :(
+ */
+more:
+ len = left;
+ req = ceph_osdc_new_request(&client->osdc, &ci->i_layout,
+ ceph_vino(inode), pos, &len,
+ CEPH_OSD_OP_WRITE, flags,
+ ci->i_snap_realm->cached_context,
+ do_sync,
+ ci->i_truncate_seq, ci->i_truncate_size,
+ &mtime, false, 2);
+ if (IS_ERR(req))
+ return PTR_ERR(req);
+
+ num_pages = calc_pages_for(pos, len);
+
+ if (file->f_flags & O_DIRECT) {
+ pages = get_direct_page_vector(data, num_pages, pos, len);
+ if (IS_ERR(pages)) {
+ ret = PTR_ERR(pages);
+ goto out;
+ }
+
+ /*
+ * throw out any page cache pages in this range. this
+ * may block.
+ */
+ truncate_inode_pages_range(inode->i_mapping, pos, pos+len);
+ } else {
+ pages = alloc_page_vector(num_pages);
+ if (IS_ERR(pages)) {
+ ret = PTR_ERR(pages);
+ goto out;
+ }
+ ret = copy_user_to_page_vector(pages, data, pos, len);
+ if (ret < 0) {
+ ceph_release_page_vector(pages, num_pages);
+ goto out;
+ }
+
+ if ((file->f_flags & O_SYNC) == 0) {
+ /* get a second commit callback */
+ req->r_safe_callback = sync_write_commit;
+ req->r_own_pages = 1;
+ }
+ }
+ req->r_pages = pages;
+ req->r_num_pages = num_pages;
+ req->r_inode = inode;
+
+ ret = ceph_osdc_start_request(&client->osdc, req, false);
+ if (!ret) {
+ if (req->r_safe_callback) {
+ /*
+ * Add to inode unsafe list only after we
+ * start_request so that a tid has been assigned.
+ */
+ spin_lock(&ci->i_unsafe_lock);
+ list_add(&ci->i_unsafe_writes, &req->r_unsafe_item);
+ spin_unlock(&ci->i_unsafe_lock);
+ ceph_get_cap_refs(ci, CEPH_CAP_FILE_WR);
+ }
+ ret = ceph_osdc_wait_request(&client->osdc, req);
+ }
+
+ if (file->f_flags & O_DIRECT)
+ put_page_vector(pages, num_pages);
+ else if (file->f_flags & O_SYNC)
+ ceph_release_page_vector(pages, num_pages);
+
+out:
+ ceph_osdc_put_request(req);
+ if (ret == 0) {
+ pos += len;
+ written += len;
+ left -= len;
+ if (left)
+ goto more;
+
+ ret = written;
+ *offset = pos;
+ if (pos > i_size_read(inode))
+ check_caps = ceph_inode_set_size(inode, pos);
+ if (check_caps)
+ ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY,
+ NULL);
+ }
+ return ret;
+}
+
+/*
+ * Wrap generic_file_aio_read with checks for cap bits on the inode.
+ * Atomically grab references, so that those bits are not released
+ * back to the MDS mid-read.
+ *
+ * Hmm, the sync read case isn't actually async... should it be?
+ */
+static ssize_t ceph_aio_read(struct kiocb *iocb, const struct iovec *iov,
+ unsigned long nr_segs, loff_t pos)
+{
+ struct file *filp = iocb->ki_filp;
+ loff_t *ppos = &iocb->ki_pos;
+ size_t len = iov->iov_len;
+ struct inode *inode = filp->f_dentry->d_inode;
+ struct ceph_inode_info *ci = ceph_inode(inode);
+ ssize_t ret;
+ int got = 0;
+
+ dout("aio_read %p %llx.%llx %llu~%u trying to get caps on %p\n",
+ inode, ceph_vinop(inode), pos, (unsigned)len, inode);
+ __ceph_do_pending_vmtruncate(inode);
+ ret = ceph_get_caps(ci, CEPH_CAP_FILE_RD, CEPH_CAP_FILE_CACHE,
+ &got, -1);
+ if (ret < 0)
+ goto out;
+ dout("aio_read %p %llx.%llx %llu~%u got cap refs on %s\n",
+ inode, ceph_vinop(inode), pos, (unsigned)len,
+ ceph_cap_string(got));
+
+ if ((got & CEPH_CAP_FILE_CACHE) == 0 ||
+ (iocb->ki_filp->f_flags & O_DIRECT) ||
+ (inode->i_sb->s_flags & MS_SYNCHRONOUS))
+ /* hmm, this isn't really async... */
+ ret = ceph_sync_read(filp, iov->iov_base, len, ppos);
+ else
+ ret = generic_file_aio_read(iocb, iov, nr_segs, pos);
+
+out:
+ dout("aio_read %p %llx.%llx dropping cap refs on %s = %d\n",
+ inode, ceph_vinop(inode), ceph_cap_string(got), (int)ret);
+ ceph_put_cap_refs(ci, got);
+ return ret;
+}
+
+/*
+ * Take cap references to avoid releasing caps to MDS mid-write.
+ *
+ * If we are synchronous, and write with an old snap context, the OSD
+ * may return EOLDSNAPC. In that case, retry the write.. _after_
+ * dropping our cap refs and allowing the pending snap to logically
+ * complete _before_ this write occurs.
+ *
+ * If we are near ENOSPC, write synchronously.
+ */
+static ssize_t ceph_aio_write(struct kiocb *iocb, const struct iovec *iov,
+ unsigned long nr_segs, loff_t pos)
+{
+ struct file *file = iocb->ki_filp;
+ struct address_space *mapping = file->f_mapping;
+ struct inode *inode = file->f_dentry->d_inode;
+ struct ceph_inode_info *ci = ceph_inode(inode);
+ struct ceph_osd_client *osdc = &ceph_client(inode->i_sb)->osdc;
+ loff_t endoff = pos + iov->iov_len;
+ int got = 0;
+ int ret;
+
+ if (ceph_snap(inode) != CEPH_NOSNAP)
+ return -EROFS;
+
+retry_snap:
+ if (ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_FULL))
+ return -ENOSPC;
+ __ceph_do_pending_vmtruncate(inode);
+ dout("aio_write %p %llx.%llx %llu~%u getting caps. i_size %llu\n",
+ inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
+ inode->i_size);
+ ret = ceph_get_caps(ci, CEPH_CAP_FILE_WR, CEPH_CAP_FILE_BUFFER,
+ &got, endoff);
+ if (ret < 0)
+ goto out;
+
+ dout("aio_write %p %llx.%llx %llu~%u got cap refs on %s\n",
+ inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
+ ceph_cap_string(got));
+
+ if ((got & CEPH_CAP_FILE_BUFFER) == 0 ||
+ (iocb->ki_filp->f_flags & O_DIRECT) ||
+ (inode->i_sb->s_flags & MS_SYNCHRONOUS)) {
+ ret = ceph_sync_write(file, iov->iov_base, iov->iov_len,
+ &iocb->ki_pos);
+ } else {
+ ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
+
+ if (ret >= 0 &&
+ ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_NEARFULL))
+ ret = sync_page_range(inode, mapping, pos, ret);
+ }
+ if (ret >= 0) {
+ spin_lock(&inode->i_lock);
+ __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR);
+ spin_unlock(&inode->i_lock);
+ }
+
+out:
+ dout("aio_write %p %llx.%llx %llu~%u dropping cap refs on %s\n",
+ inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
+ ceph_cap_string(got));
+ ceph_put_cap_refs(ci, got);
+
+ if (ret == -EOLDSNAPC) {
+ dout("aio_write %p %llx.%llx %llu~%u got EOLDSNAPC, retrying\n",
+ inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len);
+ goto retry_snap;
+ }
+
+ return ret;
+}
+
+/*
+ * llseek. be sure to verify file size on SEEK_END.
+ */
+static loff_t ceph_llseek(struct file *file, loff_t offset, int origin)
+{
+ struct inode *inode = file->f_mapping->host;
+ int ret;
+
+ mutex_lock(&inode->i_mutex);
+ __ceph_do_pending_vmtruncate(inode);
+ switch (origin) {
+ case SEEK_END:
+ ret = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE);
+ if (ret < 0) {
+ offset = ret;
+ goto out;
+ }
+ offset += inode->i_size;
+ break;
+ case SEEK_CUR:
+ /*
+ * Here we special-case the lseek(fd, 0, SEEK_CUR)
+ * position-querying operation. Avoid rewriting the "same"
+ * f_pos value back to the file because a concurrent read(),
+ * write() or lseek() might have altered it
+ */
+ if (offset == 0) {
+ offset = file->f_pos;
+ goto out;
+ }
+ offset += file->f_pos;
+ break;
+ }
+
+ if (offset < 0 || offset > inode->i_sb->s_maxbytes) {
+ offset = -EINVAL;
+ goto out;
+ }
+
+ /* Special lock needed here? */
+ if (offset != file->f_pos) {
+ file->f_pos = offset;
+ file->f_version = 0;
+ }
+
+out:
+ mutex_unlock(&inode->i_mutex);
+ return offset;
+}
+
+const struct file_operations ceph_file_fops = {
+ .open = ceph_open,
+ .release = ceph_release,
+ .llseek = ceph_llseek,
+ .read = do_sync_read,
+ .write = do_sync_write,
+ .aio_read = ceph_aio_read,
+ .aio_write = ceph_aio_write,
+ .mmap = ceph_mmap,
+ .fsync = ceph_fsync,
+ .splice_read = generic_file_splice_read,
+ .splice_write = generic_file_splice_write,
+ .unlocked_ioctl = ceph_ioctl,
+ .compat_ioctl = ceph_ioctl,
+};
+
--
1.5.6.5