diff options
Diffstat (limited to 'fs/ceph/file.c')
| -rw-r--r-- | fs/ceph/file.c | 937 |
1 files changed, 937 insertions, 0 deletions
diff --git a/fs/ceph/file.c b/fs/ceph/file.c new file mode 100644 index 0000000..5d2af84 --- /dev/null +++ b/fs/ceph/file.c @@ -0,0 +1,937 @@ +#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); + + /* wake up anyone waiting for caps on this inode */ + wake_up(&ci->i_cap_wq); + 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(¤t->mm->mmap_sem); + rc = get_user_pages(current, current->mm, (unsigned long)data, + num_pages, 0, 0, pages, NULL); + up_read(¤t->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; + po += l - bad; + if (po == PAGE_CACHE_SIZE) { + po = 0; + i++; + } + } + 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; + + off &= ~PAGE_CACHE_MASK; + + dout("zero_page_vector_page %u~%u\n", off, len); + + /* leading partial page? */ + if (off) { + int end = min((int)PAGE_CACHE_SIZE, off + len); + dout("zeroing %d %p head from %d\n", i, pages[i], + (int)off); + zero_user_segment(pages[i], off, end); + len -= (end - off); + i++; + } + while (len >= PAGE_CACHE_SIZE) { + dout("zeroing %d %p len=%d\n", i, pages[i], len); + zero_user_segment(pages[i], 0, 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, + int *checkeof) +{ + 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_MASK; /* 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); + read = len; + goto out; + } + + /* check i_size */ + *checkeof = 1; + } + +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, int *checkeof) +{ + 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. + */ + } else { + pages = alloc_page_vector(num_pages); + } + if (IS_ERR(pages)) + return PTR_ERR(pages); + + ret = filemap_write_and_wait(inode->i_mapping); + if (ret < 0) + goto done; + + ret = striped_read(inode, off, len, pages, num_pages, checkeof); + + 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; + +done: + 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; + + ret = filemap_write_and_wait_range(inode->i_mapping, pos, pos + left); + if (ret < 0) + return ret; + + ret = invalidate_inode_pages2_range(inode->i_mapping, + pos >> PAGE_CACHE_SHIFT, + (pos + left) >> PAGE_CACHE_SHIFT); + if (ret < 0) + dout("invalidate_inode_pages2_range returned %d\n", ret); + + 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); + void *base = iov->iov_base; + ssize_t ret; + int got = 0; + int checkeof = 0, read = 0; + + dout("aio_read %p %llx.%llx %llu~%u trying to get caps on %p\n", + inode, ceph_vinop(inode), pos, (unsigned)len, inode); +again: + __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, base, len, ppos, &checkeof); + 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); + + if (checkeof && ret >= 0) { + int statret = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE); + + /* hit EOF or hole? */ + if (statret == 0 && *ppos < inode->i_size) { + dout("aio_read sync_read hit hole, reading more\n"); + read += ret; + base += ret; + len -= ret; + checkeof = 0; + goto again; + } + } + if (ret >= 0) + ret += read; + + 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, err; + + 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))) { + err = vfs_fsync_range(file, file->f_path.dentry, + pos, pos + ret - 1, 1); + if (err < 0) + ret = err; + } + } + 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, +}; + |
