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samba-mirror/source3/modules/onefs_dir.c

622 lines
17 KiB
C

/*
* Unix SMB/CIFS implementation.
*
* Support for OneFS bulk directory enumeration API
*
* Copyright (C) Steven Danneman, 2009
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
#include "onefs.h"
#include "onefs_config.h"
#include <ifs/ifs_syscalls.h>
#include <isi_util/isi_dir.h>
/* The OneFS filesystem provides a readdirplus() syscall, equivalent to the
* NFSv3 PDU, which retrieves bulk directory listings with stat information
* in a single syscall.
*
* This file hides this bulk interface underneath Samba's very POSIX like
* opendir/readdir/telldir VFS interface. This is done to provide a
* significant performance improvement when listing the contents of large
* directories, which also require file meta information. ie a typical
* Windows Explorer request.
*/
#define RDP_RESUME_KEY_START 0x1
#define RDP_BATCH_SIZE 128
#define RDP_DIRENTRIES_SIZE ((size_t)(RDP_BATCH_SIZE * sizeof(struct dirent)))
static char *rdp_direntries = NULL;
static struct stat *rdp_stats = NULL;
static uint64_t *rdp_cookies = NULL;
struct rdp_dir_state {
struct rdp_dir_state *next, *prev;
SMB_STRUCT_DIR *dirp;
char *direntries_cursor; /* cursor to last returned direntry in cache */
size_t stat_count; /* number of entries stored in the cache */
size_t stat_cursor; /* cursor to last returned stat in the cache */
uint64_t resume_cookie; /* cookie from the last entry returned from the
cache */
};
static struct rdp_dir_state *dirstatelist = NULL;
SMB_STRUCT_DIR *rdp_last_dirp = NULL;
/**
* Given a DIR pointer, return our internal state.
*
* This function also tells us whether the given DIR is the same as we saw
* during the last call. Because we use a single globally allocated buffer
* for readdirplus entries we must check every call into this API to see if
* it's for the same directory listing, or a new one. If it's the same we can
* maintain our current cached entries, otherwise we must go to the kernel.
*
* @return 0 on success, 1 on failure
*/
static int
rdp_retrieve_dir_state(SMB_STRUCT_DIR *dirp, struct rdp_dir_state **dir_state,
bool *same_as_last)
{
struct rdp_dir_state *dsp;
/* Is this directory the same as the last call */
*same_as_last = (dirp == rdp_last_dirp);
for(dsp = dirstatelist; dsp; dsp = dsp->next)
if (dsp->dirp == dirp) {
*dir_state = dsp;
return 0;
}
/* Couldn't find existing dir_state for the given directory
* pointer. */
return 1;
}
/**
* Initialize the global readdirplus buffers.
*
* These same buffers are used for all calls into readdirplus.
*
* @return 0 on success, errno value on failure
*/
static int
rdp_init(struct rdp_dir_state *dsp)
{
/* Unfortunately, there is no good way to free these buffers. If we
* allocated and freed for every DIR handle performance would be
* adversely affected. For now these buffers will be leaked and only
* freed when the smbd process dies. */
if (!rdp_direntries) {
rdp_direntries = SMB_MALLOC(RDP_DIRENTRIES_SIZE);
if (!rdp_direntries)
return ENOMEM;
}
if (!rdp_stats) {
rdp_stats =
SMB_MALLOC(RDP_BATCH_SIZE * sizeof(struct stat));
if (!rdp_stats)
return ENOMEM;
}
if (!rdp_cookies) {
rdp_cookies = SMB_MALLOC(RDP_BATCH_SIZE * sizeof(uint64_t));
if (!rdp_cookies)
return ENOMEM;
}
dsp->direntries_cursor = rdp_direntries + RDP_DIRENTRIES_SIZE;
dsp->stat_count = RDP_BATCH_SIZE;
dsp->stat_cursor = RDP_BATCH_SIZE;
dsp->resume_cookie = RDP_RESUME_KEY_START;
return 0;
}
/**
* Call into readdirplus() to refill our global dirent cache.
*
* This function also resets all cursors back to the beginning of the cache.
* All stat buffers are retrieved by following symlinks.
*
* @return number of entries retrieved, -1 on error
*/
static int
rdp_fill_cache(struct rdp_dir_state *dsp)
{
int nread, dirfd;
dirfd = dirfd(dsp->dirp);
if (dirfd < 0) {
DEBUG(1, ("Could not retrieve fd for DIR\n"));
return -1;
}
/* Resize the stat_count to grab as many entries as possible */
dsp->stat_count = RDP_BATCH_SIZE;
DEBUG(9, ("Calling readdirplus() with DIR %p, dirfd: %d, "
"resume_cookie %#llx, size_to_read: %zu, "
"direntries_size: %zu, stat_count: %u\n",
dsp->dirp, dirfd, dsp->resume_cookie, RDP_BATCH_SIZE,
RDP_DIRENTRIES_SIZE, dsp->stat_count));
nread = readdirplus(dirfd,
RDP_FOLLOW,
&dsp->resume_cookie,
RDP_BATCH_SIZE,
rdp_direntries,
RDP_DIRENTRIES_SIZE,
&dsp->stat_count,
rdp_stats,
rdp_cookies);
if (nread < 0) {
DEBUG(1, ("Error calling readdirplus(): %s\n",
strerror(errno)));
return -1;
}
DEBUG(9, ("readdirplus() returned %u entries from DIR %p\n",
dsp->stat_count, dsp->dirp));
dsp->direntries_cursor = rdp_direntries;
dsp->stat_cursor = 0;
return nread;
}
/**
* Create a dir_state to track an open directory that we're enumerating.
*
* This utility function is globally accessible for use by other parts of the
* onefs.so module to initialize a dir_state when a directory is opened through
* a path other than the VFS layer.
*
* @return 0 on success and errno on failure
*
* @note: Callers of this function MUST cleanup the dir_state through a proper
* call to VFS_CLOSEDIR().
*/
int
onefs_rdp_add_dir_state(connection_struct *conn, SMB_STRUCT_DIR *dirp)
{
int ret = 0;
struct rdp_dir_state *dsp = NULL;
/* No-op if readdirplus is disabled */
if (!lp_parm_bool(SNUM(conn), PARM_ONEFS_TYPE,
PARM_USE_READDIRPLUS, PARM_USE_READDIRPLUS_DEFAULT))
{
return 0;
}
/* Create a struct dir_state */
dsp = SMB_MALLOC_P(struct rdp_dir_state);
if (!dsp) {
DEBUG(0, ("Error allocating struct rdp_dir_state.\n"));
return ENOMEM;
}
/* Initialize the dir_state structure and add it to the list */
ret = rdp_init(dsp);
if (ret) {
DEBUG(0, ("Error initializing readdirplus() buffers: %s\n",
strerror(ret)));
return ret;
}
/* Set the SMB_STRUCT_DIR in the dsp */
dsp->dirp = dirp;
DLIST_ADD(dirstatelist, dsp);
return 0;
}
/**
* Open a directory for enumeration.
*
* Create a state struct to track the state of this directory for the life
* of this open.
*
* @param[in] handle vfs handle given in most VFS calls
* @param[in] fname filename of the directory to open
* @param[in] mask unused
* @param[in] attr unused
*
* @return DIR pointer, NULL if directory does not exist, NULL on error
*/
SMB_STRUCT_DIR *
onefs_opendir(vfs_handle_struct *handle, const char *fname, const char *mask,
uint32 attr)
{
int ret = 0;
SMB_STRUCT_DIR *ret_dirp;
/* Fallback to default system routines if readdirplus is disabled */
if (!lp_parm_bool(SNUM(handle->conn), PARM_ONEFS_TYPE,
PARM_USE_READDIRPLUS, PARM_USE_READDIRPLUS_DEFAULT))
{
return SMB_VFS_NEXT_OPENDIR(handle, fname, mask, attr);
}
/* Open the directory */
ret_dirp = SMB_VFS_NEXT_OPENDIR(handle, fname, mask, attr);
if (!ret_dirp) {
DEBUG(3, ("Unable to open directory: %s\n", fname));
return NULL;
}
/* Create the dir_state struct and add it to the list */
ret = onefs_rdp_add_dir_state(handle->conn, ret_dirp);
if (ret) {
DEBUG(0, ("Error adding dir_state to the list\n"));
return NULL;
}
DEBUG(9, ("Opened handle on directory: \"%s\", DIR %p\n",
fname, ret_dirp));
return ret_dirp;
}
/**
* Retrieve one direntry and optional stat buffer from our readdir cache.
*
* Increment the internal resume cookie, and refresh the cache from the
* kernel if necessary.
*
* The cache cursor tracks the last entry which was successfully returned
* to a caller of onefs_readdir(). When a new entry is requested, this
* function first increments the cursor, then returns that entry.
*
* @param[in] handle vfs handle given in most VFS calls
* @param[in] dirp system DIR handle to retrieve direntries from
* @param[in/out] sbuf optional stat buffer to fill, this can be NULL
*
* @return dirent structure, NULL if at the end of the directory, NULL on error
*/
SMB_STRUCT_DIRENT *
onefs_readdir(vfs_handle_struct *handle, SMB_STRUCT_DIR *dirp,
SMB_STRUCT_STAT *sbuf)
{
struct rdp_dir_state *dsp = NULL;
SMB_STRUCT_DIRENT *ret_direntp;
bool same_as_last, filled_cache = false;
int ret = -1;
/* Set stat invalid in-case we error out */
if (sbuf)
SET_STAT_INVALID(*sbuf);
/* Fallback to default system routines if readdirplus is disabled */
if (!lp_parm_bool(SNUM(handle->conn), PARM_ONEFS_TYPE,
PARM_USE_READDIRPLUS, PARM_USE_READDIRPLUS_DEFAULT))
{
return sys_readdir(dirp);
}
/* Retrieve state based off DIR handle */
ret = rdp_retrieve_dir_state(dirp, &dsp, &same_as_last);
if (ret) {
DEBUG(1, ("Could not retrieve dir_state struct for "
"SMB_STRUCT_DIR pointer.\n"));
ret_direntp = NULL;
goto end;
}
/* DIR is the same, current buffer and cursors are valid.
* Check if there are any entries left in our current cache. */
if (same_as_last) {
if (dsp->stat_cursor == dsp->stat_count - 1) {
/* Cache is empty, refill from kernel */
ret = rdp_fill_cache(dsp);
if (ret <= 0) {
ret_direntp = NULL;
goto end;
}
filled_cache = true;
}
} else {
/* DIR is different from last call, reset all buffers and
* cursors, and refill the global cache from the new DIR */
ret = rdp_fill_cache(dsp);
if (ret <= 0) {
ret_direntp = NULL;
goto end;
}
filled_cache = true;
DEBUG(8, ("Switched global rdp cache to new DIR entry.\n"));
}
/* If we just filled the cache we treat that action as the cursor
* increment as the resume cookie used belonged to the previous
* directory entry. If the cache has not changed we first increment
* our cursor, then return the next entry */
if (!filled_cache) {
dsp->direntries_cursor +=
((SMB_STRUCT_DIRENT *)dsp->direntries_cursor)->d_reclen;
dsp->stat_cursor++;
}
/* The resume_cookie stored here purposely differs based on whether we
* just filled the cache. The resume cookie stored must always provide
* the next direntry, in case the cache is reloaded on every
* onefs_readdir() */
dsp->resume_cookie = rdp_cookies[dsp->stat_cursor];
/* Return an entry from cache */
ret_direntp = ((SMB_STRUCT_DIRENT *)dsp->direntries_cursor);
if (sbuf) {
struct stat onefs_sbuf;
onefs_sbuf = rdp_stats[dsp->stat_cursor];
init_stat_ex_from_onefs_stat(sbuf, &onefs_sbuf);
/* readdirplus() sets st_ino field to 0, if it was
* unable to retrieve stat information for that
* particular directory entry. */
if (sbuf->st_ex_ino == 0)
SET_STAT_INVALID(*sbuf);
}
DEBUG(9, ("Read from DIR %p, direntry: \"%s\", resume cookie: %#llx, "
"cache cursor: %zu, cache count: %zu\n",
dsp->dirp, ret_direntp->d_name, dsp->resume_cookie,
dsp->stat_cursor, dsp->stat_count));
/* FALLTHROUGH */
end:
/* Set rdp_last_dirp at the end of every VFS call where the cache was
* reloaded */
rdp_last_dirp = dirp;
return ret_direntp;
}
/**
* Set the location of the next direntry to be read via onefs_readdir().
*
* This function should only pass in locations retrieved from onefs_telldir().
*
* @param[in] handle vfs handle given in most VFS calls
* @param[in] dirp system DIR handle to set offset on
* @param[in] offset into the directory to resume reading from
*
* @return no return value
*/
void
onefs_seekdir(vfs_handle_struct *handle, SMB_STRUCT_DIR *dirp, long offset)
{
struct rdp_dir_state *dsp = NULL;
bool same_as_last;
uint64_t resume_cookie = 0;
int ret = -1;
/* Fallback to default system routines if readdirplus is disabled */
if (!lp_parm_bool(SNUM(handle->conn), PARM_ONEFS_TYPE,
PARM_USE_READDIRPLUS, PARM_USE_READDIRPLUS_DEFAULT))
{
return sys_seekdir(dirp, offset);
}
/* Validate inputs */
if (offset < 0) {
DEBUG(1, ("Invalid offset %ld passed.\n", offset));
return;
}
/* Retrieve state based off DIR handle */
ret = rdp_retrieve_dir_state(dirp, &dsp, &same_as_last);
if (ret) {
DEBUG(1, ("Could not retrieve dir_state struct for "
"SMB_STRUCT_DIR pointer.\n"));
/* XXX: we can't return an error, should we ABORT rather than
* return without actually seeking? */
return;
}
/* Convert offset to resume_cookie */
resume_cookie = rdp_offset31_to_cookie63(offset);
DEBUG(9, ("Seek DIR %p, offset: %ld, resume_cookie: %#llx\n",
dsp->dirp, offset, resume_cookie));
/* TODO: We could check if the resume_cookie is already in the cache
* through a linear search. This would allow us to avoid the cost of
* flushing the cache. Frequently, the seekdir offset will only be
* one entry before the current cache cursor. However, usually
* VFS_SEEKDIR() is only called at the end of a TRAND2_FIND read and
* we'll flush the cache at the beginning of the next PDU anyway. Some
* analysis should be done to see if this enhancement would provide
* better performance. */
/* Set the resume cookie and indicate that the cache should be reloaded
* on next read */
dsp->resume_cookie = resume_cookie;
rdp_last_dirp = NULL;
return;
}
/**
* Returns the location of the next direntry to be read via onefs_readdir().
*
* This value can be passed into onefs_seekdir().
*
* @param[in] handle vfs handle given in most VFS calls
* @param[in] dirp system DIR handle to set offset on
*
* @return offset into the directory to resume reading from
*/
long
onefs_telldir(vfs_handle_struct *handle, SMB_STRUCT_DIR *dirp)
{
struct rdp_dir_state *dsp = NULL;
bool same_as_last;
long offset;
int ret = -1;
/* Fallback to default system routines if readdirplus is disabled */
if (!lp_parm_bool(SNUM(handle->conn), PARM_ONEFS_TYPE,
PARM_USE_READDIRPLUS, PARM_USE_READDIRPLUS_DEFAULT))
{
return sys_telldir(dirp);
}
/* Retrieve state based off DIR handle */
ret = rdp_retrieve_dir_state(dirp, &dsp, &same_as_last);
if (ret) {
DEBUG(1, ("Could not retrieve dir_state struct for "
"SMB_STRUCT_DIR pointer.\n"));
return -1;
}
/* Convert resume_cookie to offset */
offset = rdp_cookie63_to_offset31(dsp->resume_cookie);
if (offset < 0) {
DEBUG(1, ("Unable to convert resume_cookie: %#llx to a "
"suitable 32-bit offset value. Error: %s\n",
dsp->resume_cookie, strerror(errno)));
return -1;
}
DEBUG(9, ("Seek DIR %p, offset: %ld, resume_cookie: %#llx\n",
dsp->dirp, offset, dsp->resume_cookie));
return offset;
}
/**
* Set the next direntry to be read via onefs_readdir() to the beginning of the
* directory.
*
* @param[in] handle vfs handle given in most VFS calls
* @param[in] dirp system DIR handle to set offset on
*
* @return no return value
*/
void
onefs_rewinddir(vfs_handle_struct *handle, SMB_STRUCT_DIR *dirp)
{
struct rdp_dir_state *dsp = NULL;
bool same_as_last;
int ret = -1;
/* Fallback to default system routines if readdirplus is disabled */
if (!lp_parm_bool(SNUM(handle->conn), PARM_ONEFS_TYPE,
PARM_USE_READDIRPLUS, PARM_USE_READDIRPLUS_DEFAULT))
{
return sys_rewinddir(dirp);
}
/* Retrieve state based off DIR handle */
ret = rdp_retrieve_dir_state(dirp, &dsp, &same_as_last);
if (ret) {
DEBUG(1, ("Could not retrieve dir_state struct for "
"SMB_STRUCT_DIR pointer.\n"));
return;
}
/* Reset location and resume key to beginning */
ret = rdp_init(dsp);
if (ret) {
DEBUG(0, ("Error re-initializing rdp cursors: %s\n",
strerror(ret)));
return;
}
DEBUG(9, ("Rewind DIR: %p, to resume_cookie: %#llx\n", dsp->dirp,
dsp->resume_cookie));
return;
}
/**
* Close DIR pointer and remove all state for that directory open.
*
* @param[in] handle vfs handle given in most VFS calls
* @param[in] dirp system DIR handle to set offset on
*
* @return -1 on failure, setting errno
*/
int
onefs_closedir(vfs_handle_struct *handle, SMB_STRUCT_DIR *dirp)
{
struct rdp_dir_state *dsp = NULL;
bool same_as_last;
int ret_val = -1;
int ret = -1;
/* Fallback to default system routines if readdirplus is disabled */
if (!lp_parm_bool(SNUM(handle->conn), PARM_ONEFS_TYPE,
PARM_USE_READDIRPLUS, PARM_USE_READDIRPLUS_DEFAULT))
{
return SMB_VFS_NEXT_CLOSEDIR(handle, dirp);
}
/* Retrieve state based off DIR handle */
ret = rdp_retrieve_dir_state(dirp, &dsp, &same_as_last);
if (ret) {
DEBUG(1, ("Could not retrieve dir_state struct for "
"SMB_STRUCT_DIR pointer.\n"));
errno = ENOENT;
return -1;
}
/* Close DIR pointer */
ret_val = SMB_VFS_NEXT_CLOSEDIR(handle, dsp->dirp);
DEBUG(9, ("Closed handle on DIR %p\n", dsp->dirp));
/* Tear down state struct */
DLIST_REMOVE(dirstatelist, dsp);
SAFE_FREE(dsp);
/* Set lastp to NULL, as cache is no longer valid */
rdp_last_dirp = NULL;
return ret_val;
}
/**
* Initialize cache data at the beginning of every SMB search operation
*
* Since filesystem operations, such as delete files or meta data
* updates can occur to files in the directory we're searching
* between FIND_FIRST and FIND_NEXT calls we must refresh the cache
* from the kernel on every new search SMB.
*
* @param[in] handle vfs handle given in most VFS calls
* @param[in] dirp system DIR handle for the current search
*
* @return nothing
*/
void
onefs_init_search_op(vfs_handle_struct *handle, SMB_STRUCT_DIR *dirp)
{
/* Setting the rdp_last_dirp to NULL will cause the next readdir
* operation to refill the cache. */
rdp_last_dirp = NULL;
return;
}