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author | Al Viro <viro@zeniv.linux.org.uk> | 2021-03-06 03:53:48 +0100 |
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committer | Steve French <stfrench@microsoft.com> | 2021-04-25 23:28:23 +0200 |
commit | 991e72eb0e99764219865b9a3a07328695148e14 (patch) | |
tree | 824a82b7a321f1a1b88de01222f87f6a77b721e3 /fs/cifs | |
parent | cifs: allocate buffer in the caller of build_path_from_dentry() (diff) | |
download | linux-991e72eb0e99764219865b9a3a07328695148e14.tar.xz linux-991e72eb0e99764219865b9a3a07328695148e14.zip |
cifs: switch build_path_from_dentry() to using dentry_path_raw()
The cost is that we might need to flip '/' to '\\' in more than
just the prefix. Needs profiling, but I suspect that we won't
get slowdown on that.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Steve French <stfrench@microsoft.com>
Diffstat (limited to 'fs/cifs')
-rw-r--r-- | fs/cifs/dir.c | 85 |
1 files changed, 23 insertions, 62 deletions
diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c index 6e855f004f50..03afad8b24af 100644 --- a/fs/cifs/dir.c +++ b/fs/cifs/dir.c @@ -93,20 +93,16 @@ char * build_path_from_dentry_optional_prefix(struct dentry *direntry, void *page, bool prefix) { - struct dentry *temp; - int namelen; int dfsplen; int pplen = 0; - char *full_path = page; - char dirsep; struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb); struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb); - unsigned seq; + char dirsep = CIFS_DIR_SEP(cifs_sb); + char *s; if (unlikely(!page)) return ERR_PTR(-ENOMEM); - dirsep = CIFS_DIR_SEP(cifs_sb); if (prefix) dfsplen = strnlen(tcon->treeName, MAX_TREE_SIZE + 1); else @@ -115,74 +111,39 @@ build_path_from_dentry_optional_prefix(struct dentry *direntry, void *page, if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) pplen = cifs_sb->prepath ? strlen(cifs_sb->prepath) + 1 : 0; -cifs_bp_rename_retry: - namelen = dfsplen + pplen; - seq = read_seqbegin(&rename_lock); - rcu_read_lock(); - for (temp = direntry; !IS_ROOT(temp);) { - namelen += (1 + temp->d_name.len); - temp = temp->d_parent; - } - rcu_read_unlock(); - - if (namelen >= PAGE_SIZE) + s = dentry_path_raw(direntry, page, PAGE_SIZE); + if (IS_ERR(s)) + return s; + if (!s[1]) // for root we want "", not "/" + s++; + if (s < (char *)page + pplen + dfsplen) return ERR_PTR(-ENAMETOOLONG); - - full_path[namelen] = 0; /* trailing null */ - rcu_read_lock(); - for (temp = direntry; !IS_ROOT(temp);) { - spin_lock(&temp->d_lock); - namelen -= 1 + temp->d_name.len; - if (namelen < 0) { - spin_unlock(&temp->d_lock); - break; - } else { - full_path[namelen] = dirsep; - strncpy(full_path + namelen + 1, temp->d_name.name, - temp->d_name.len); - cifs_dbg(FYI, "name: %s\n", full_path + namelen); - } - spin_unlock(&temp->d_lock); - temp = temp->d_parent; - } - rcu_read_unlock(); - if (namelen != dfsplen + pplen || read_seqretry(&rename_lock, seq)) { - cifs_dbg(FYI, "did not end path lookup where expected. namelen=%ddfsplen=%d\n", - namelen, dfsplen); - /* presumably this is only possible if racing with a rename - of one of the parent directories (we can not lock the dentries - above us to prevent this, but retrying should be harmless) */ - goto cifs_bp_rename_retry; - } - /* DIR_SEP already set for byte 0 / vs \ but not for - subsequent slashes in prepath which currently must - be entered the right way - not sure if there is an alternative - since the '\' is a valid posix character so we can not switch - those safely to '/' if any are found in the middle of the prepath */ - /* BB test paths to Windows with '/' in the midst of prepath */ - if (pplen) { - int i; - cifs_dbg(FYI, "using cifs_sb prepath <%s>\n", cifs_sb->prepath); - memcpy(full_path+dfsplen+1, cifs_sb->prepath, pplen-1); - full_path[dfsplen] = dirsep; - for (i = 0; i < pplen-1; i++) - if (full_path[dfsplen+1+i] == '/') - full_path[dfsplen+1+i] = CIFS_DIR_SEP(cifs_sb); + s -= pplen; + memcpy(s + 1, cifs_sb->prepath, pplen - 1); + *s = '/'; } + if (dirsep != '/') { + /* BB test paths to Windows with '/' in the midst of prepath */ + char *p; + for (p = s; *p; p++) + if (*p == '/') + *p = dirsep; + } if (dfsplen) { - strncpy(full_path, tcon->treeName, dfsplen); + s -= dfsplen; + memcpy(s, tcon->treeName, dfsplen); if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS) { int i; for (i = 0; i < dfsplen; i++) { - if (full_path[i] == '\\') - full_path[i] = '/'; + if (s[i] == '\\') + s[i] = '/'; } } } - return full_path; + return s; } /* |