diff options
Diffstat (limited to 'fs/cifs/cached_dir.c')
| -rw-r--r-- | fs/cifs/cached_dir.c | 388 |
1 files changed, 388 insertions, 0 deletions
diff --git a/fs/cifs/cached_dir.c b/fs/cifs/cached_dir.c new file mode 100644 index 000000000000..b401339f6e73 --- /dev/null +++ b/fs/cifs/cached_dir.c @@ -0,0 +1,388 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Functions to handle the cached directory entries + * + * Copyright (c) 2022, Ronnie Sahlberg <lsahlber@redhat.com> + */ + +#include "cifsglob.h" +#include "cifsproto.h" +#include "cifs_debug.h" +#include "smb2proto.h" +#include "cached_dir.h" + +/* + * Open the and cache a directory handle. + * If error then *cfid is not initialized. + */ +int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon, + const char *path, + struct cifs_sb_info *cifs_sb, + bool lookup_only, struct cached_fid **ret_cfid) +{ + struct cifs_ses *ses; + struct TCP_Server_Info *server; + struct cifs_open_parms oparms; + struct smb2_create_rsp *o_rsp = NULL; + struct smb2_query_info_rsp *qi_rsp = NULL; + int resp_buftype[2]; + struct smb_rqst rqst[2]; + struct kvec rsp_iov[2]; + struct kvec open_iov[SMB2_CREATE_IOV_SIZE]; + struct kvec qi_iov[1]; + int rc, flags = 0; + __le16 utf16_path = 0; /* Null - since an open of top of share */ + u8 oplock = SMB2_OPLOCK_LEVEL_II; + struct cifs_fid *pfid; + struct dentry *dentry; + struct cached_fid *cfid; + + if (tcon == NULL || tcon->nohandlecache || + is_smb1_server(tcon->ses->server)) + return -EOPNOTSUPP; + + ses = tcon->ses; + server = ses->server; + + if (cifs_sb->root == NULL) + return -ENOENT; + + if (strlen(path)) + return -ENOENT; + + dentry = cifs_sb->root; + + cfid = tcon->cfid; + mutex_lock(&cfid->fid_mutex); + if (cfid->is_valid) { + cifs_dbg(FYI, "found a cached root file handle\n"); + *ret_cfid = cfid; + kref_get(&cfid->refcount); + mutex_unlock(&cfid->fid_mutex); + return 0; + } + + /* + * We do not hold the lock for the open because in case + * SMB2_open needs to reconnect, it will end up calling + * cifs_mark_open_files_invalid() which takes the lock again + * thus causing a deadlock + */ + mutex_unlock(&cfid->fid_mutex); + + if (lookup_only) + return -ENOENT; + + if (smb3_encryption_required(tcon)) + flags |= CIFS_TRANSFORM_REQ; + + if (!server->ops->new_lease_key) + return -EIO; + + pfid = &cfid->fid; + server->ops->new_lease_key(pfid); + + memset(rqst, 0, sizeof(rqst)); + resp_buftype[0] = resp_buftype[1] = CIFS_NO_BUFFER; + memset(rsp_iov, 0, sizeof(rsp_iov)); + + /* Open */ + memset(&open_iov, 0, sizeof(open_iov)); + rqst[0].rq_iov = open_iov; + rqst[0].rq_nvec = SMB2_CREATE_IOV_SIZE; + + oparms.tcon = tcon; + oparms.create_options = cifs_create_options(cifs_sb, CREATE_NOT_FILE); + oparms.desired_access = FILE_READ_ATTRIBUTES; + oparms.disposition = FILE_OPEN; + oparms.fid = pfid; + oparms.reconnect = false; + + rc = SMB2_open_init(tcon, server, + &rqst[0], &oplock, &oparms, &utf16_path); + if (rc) + goto oshr_free; + smb2_set_next_command(tcon, &rqst[0]); + + memset(&qi_iov, 0, sizeof(qi_iov)); + rqst[1].rq_iov = qi_iov; + rqst[1].rq_nvec = 1; + + rc = SMB2_query_info_init(tcon, server, + &rqst[1], COMPOUND_FID, + COMPOUND_FID, FILE_ALL_INFORMATION, + SMB2_O_INFO_FILE, 0, + sizeof(struct smb2_file_all_info) + + PATH_MAX * 2, 0, NULL); + if (rc) + goto oshr_free; + + smb2_set_related(&rqst[1]); + + rc = compound_send_recv(xid, ses, server, + flags, 2, rqst, + resp_buftype, rsp_iov); + mutex_lock(&cfid->fid_mutex); + + /* + * Now we need to check again as the cached root might have + * been successfully re-opened from a concurrent process + */ + + if (cfid->is_valid) { + /* work was already done */ + + /* stash fids for close() later */ + struct cifs_fid fid = { + .persistent_fid = pfid->persistent_fid, + .volatile_fid = pfid->volatile_fid, + }; + + /* + * caller expects this func to set the fid in cfid to valid + * cached root, so increment the refcount. + */ + kref_get(&cfid->refcount); + + mutex_unlock(&cfid->fid_mutex); + + if (rc == 0) { + /* close extra handle outside of crit sec */ + SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid); + } + rc = 0; + goto oshr_free; + } + + /* Cached root is still invalid, continue normaly */ + + if (rc) { + if (rc == -EREMCHG) { + tcon->need_reconnect = true; + pr_warn_once("server share %s deleted\n", + tcon->treeName); + } + goto oshr_exit; + } + + atomic_inc(&tcon->num_remote_opens); + + o_rsp = (struct smb2_create_rsp *)rsp_iov[0].iov_base; + oparms.fid->persistent_fid = o_rsp->PersistentFileId; + oparms.fid->volatile_fid = o_rsp->VolatileFileId; +#ifdef CONFIG_CIFS_DEBUG2 + oparms.fid->mid = le64_to_cpu(o_rsp->hdr.MessageId); +#endif /* CIFS_DEBUG2 */ + + cfid->tcon = tcon; + cfid->is_valid = true; + cfid->dentry = dentry; + dget(dentry); + kref_init(&cfid->refcount); + + /* BB TBD check to see if oplock level check can be removed below */ + if (o_rsp->OplockLevel == SMB2_OPLOCK_LEVEL_LEASE) { + /* + * See commit 2f94a3125b87. Increment the refcount when we + * get a lease for root, release it if lease break occurs + */ + kref_get(&cfid->refcount); + cfid->has_lease = true; + smb2_parse_contexts(server, o_rsp, + &oparms.fid->epoch, + oparms.fid->lease_key, &oplock, + NULL, NULL); + } else + goto oshr_exit; + + qi_rsp = (struct smb2_query_info_rsp *)rsp_iov[1].iov_base; + if (le32_to_cpu(qi_rsp->OutputBufferLength) < sizeof(struct smb2_file_all_info)) + goto oshr_exit; + if (!smb2_validate_and_copy_iov( + le16_to_cpu(qi_rsp->OutputBufferOffset), + sizeof(struct smb2_file_all_info), + &rsp_iov[1], sizeof(struct smb2_file_all_info), + (char *)&cfid->file_all_info)) + cfid->file_all_info_is_valid = true; + + cfid->time = jiffies; + +oshr_exit: + mutex_unlock(&cfid->fid_mutex); +oshr_free: + SMB2_open_free(&rqst[0]); + SMB2_query_info_free(&rqst[1]); + free_rsp_buf(resp_buftype[0], rsp_iov[0].iov_base); + free_rsp_buf(resp_buftype[1], rsp_iov[1].iov_base); + if (rc == 0) + *ret_cfid = cfid; + + return rc; +} + +int open_cached_dir_by_dentry(struct cifs_tcon *tcon, + struct dentry *dentry, + struct cached_fid **ret_cfid) +{ + struct cached_fid *cfid; + + cfid = tcon->cfid; + + mutex_lock(&cfid->fid_mutex); + if (cfid->dentry == dentry) { + cifs_dbg(FYI, "found a cached root file handle by dentry\n"); + *ret_cfid = cfid; + kref_get(&cfid->refcount); + mutex_unlock(&cfid->fid_mutex); + return 0; + } + mutex_unlock(&cfid->fid_mutex); + return -ENOENT; +} + +static void +smb2_close_cached_fid(struct kref *ref) +{ + struct cached_fid *cfid = container_of(ref, struct cached_fid, + refcount); + struct cached_dirent *dirent, *q; + + if (cfid->is_valid) { + cifs_dbg(FYI, "clear cached root file handle\n"); + SMB2_close(0, cfid->tcon, cfid->fid.persistent_fid, + cfid->fid.volatile_fid); + } + + /* + * We only check validity above to send SMB2_close, + * but we still need to invalidate these entries + * when this function is called + */ + cfid->is_valid = false; + cfid->file_all_info_is_valid = false; + cfid->has_lease = false; + if (cfid->dentry) { + dput(cfid->dentry); + cfid->dentry = NULL; + } + /* + * Delete all cached dirent names + */ + mutex_lock(&cfid->dirents.de_mutex); + list_for_each_entry_safe(dirent, q, &cfid->dirents.entries, entry) { + list_del(&dirent->entry); + kfree(dirent->name); + kfree(dirent); + } + cfid->dirents.is_valid = 0; + cfid->dirents.is_failed = 0; + cfid->dirents.ctx = NULL; + cfid->dirents.pos = 0; + mutex_unlock(&cfid->dirents.de_mutex); + +} + +void close_cached_dir(struct cached_fid *cfid) +{ + mutex_lock(&cfid->fid_mutex); + kref_put(&cfid->refcount, smb2_close_cached_fid); + mutex_unlock(&cfid->fid_mutex); +} + +void close_cached_dir_lease_locked(struct cached_fid *cfid) +{ + if (cfid->has_lease) { + cfid->has_lease = false; + kref_put(&cfid->refcount, smb2_close_cached_fid); + } +} + +void close_cached_dir_lease(struct cached_fid *cfid) +{ + mutex_lock(&cfid->fid_mutex); + close_cached_dir_lease_locked(cfid); + mutex_unlock(&cfid->fid_mutex); +} + +/* + * Called from cifs_kill_sb when we unmount a share + */ +void close_all_cached_dirs(struct cifs_sb_info *cifs_sb) +{ + struct rb_root *root = &cifs_sb->tlink_tree; + struct rb_node *node; + struct cached_fid *cfid; + struct cifs_tcon *tcon; + struct tcon_link *tlink; + + for (node = rb_first(root); node; node = rb_next(node)) { + tlink = rb_entry(node, struct tcon_link, tl_rbnode); + tcon = tlink_tcon(tlink); + if (IS_ERR(tcon)) + continue; + cfid = tcon->cfid; + mutex_lock(&cfid->fid_mutex); + if (cfid->dentry) { + dput(cfid->dentry); + cfid->dentry = NULL; + } + mutex_unlock(&cfid->fid_mutex); + } +} + +/* + * Invalidate and close all cached dirs when a TCON has been reset + * due to a session loss. + */ +void invalidate_all_cached_dirs(struct cifs_tcon *tcon) +{ + mutex_lock(&tcon->cfid->fid_mutex); + tcon->cfid->is_valid = false; + /* cached handle is not valid, so SMB2_CLOSE won't be sent below */ + close_cached_dir_lease_locked(tcon->cfid); + memset(&tcon->cfid->fid, 0, sizeof(struct cifs_fid)); + mutex_unlock(&tcon->cfid->fid_mutex); +} + +static void +smb2_cached_lease_break(struct work_struct *work) +{ + struct cached_fid *cfid = container_of(work, + struct cached_fid, lease_break); + + close_cached_dir_lease(cfid); +} + +int cached_dir_lease_break(struct cifs_tcon *tcon, __u8 lease_key[16]) +{ + if (tcon->cfid->is_valid && + !memcmp(lease_key, + tcon->cfid->fid.lease_key, + SMB2_LEASE_KEY_SIZE)) { + tcon->cfid->time = 0; + INIT_WORK(&tcon->cfid->lease_break, + smb2_cached_lease_break); + queue_work(cifsiod_wq, + &tcon->cfid->lease_break); + return true; + } + return false; +} + +struct cached_fid *init_cached_dir(void) +{ + struct cached_fid *cfid; + + cfid = kzalloc(sizeof(*cfid), GFP_KERNEL); + if (!cfid) + return NULL; + INIT_LIST_HEAD(&cfid->dirents.entries); + mutex_init(&cfid->dirents.de_mutex); + mutex_init(&cfid->fid_mutex); + return cfid; +} + +void free_cached_dir(struct cifs_tcon *tcon) +{ + kfree(tcon->cfid); +} |