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    Subject[PATCH 09/24] ceph: file operations
    Date
    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 | 904 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
    1 files changed, 904 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..fc8aff4
    --- /dev/null
    +++ b/fs/ceph/file.c
    @@ -0,0 +1,904 @@
    +#include "ceph_debug.h"
    +
    +#include <linux/sched.h>
    +#include <linux/file.h>
    +#include <linux/namei.h>
    +#include <linux/writeback.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);
    + req->r_args.open.preferred = cpu_to_le32(-1);
    +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 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 || ret == -EIOCBQUEUED) &&
    + ((file->f_flags & O_SYNC) || IS_SYNC(file->f_mapping->host)
    + || ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_NEARFULL)))
    + ret = vfs_fsync_range(file, file->f_path.dentry,
    + pos, pos + ret - 1, 1);
    + }
    + 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,
    +};
    +
    --
    1.6.5


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      Last update: 2009-12-04 00:45    [W:0.072 / U:208.296 seconds]
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