linux/fs/ceph/snap.c
Greg Kroah-Hartman b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00

982 lines
27 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/ceph/ceph_debug.h>
#include <linux/sort.h>
#include <linux/slab.h>
#include "super.h"
#include "mds_client.h"
#include <linux/ceph/decode.h>
/*
* Snapshots in ceph are driven in large part by cooperation from the
* client. In contrast to local file systems or file servers that
* implement snapshots at a single point in the system, ceph's
* distributed access to storage requires clients to help decide
* whether a write logically occurs before or after a recently created
* snapshot.
*
* This provides a perfect instantanous client-wide snapshot. Between
* clients, however, snapshots may appear to be applied at slightly
* different points in time, depending on delays in delivering the
* snapshot notification.
*
* Snapshots are _not_ file system-wide. Instead, each snapshot
* applies to the subdirectory nested beneath some directory. This
* effectively divides the hierarchy into multiple "realms," where all
* of the files contained by each realm share the same set of
* snapshots. An individual realm's snap set contains snapshots
* explicitly created on that realm, as well as any snaps in its
* parent's snap set _after_ the point at which the parent became it's
* parent (due to, say, a rename). Similarly, snaps from prior parents
* during the time intervals during which they were the parent are included.
*
* The client is spared most of this detail, fortunately... it must only
* maintains a hierarchy of realms reflecting the current parent/child
* realm relationship, and for each realm has an explicit list of snaps
* inherited from prior parents.
*
* A snap_realm struct is maintained for realms containing every inode
* with an open cap in the system. (The needed snap realm information is
* provided by the MDS whenever a cap is issued, i.e., on open.) A 'seq'
* version number is used to ensure that as realm parameters change (new
* snapshot, new parent, etc.) the client's realm hierarchy is updated.
*
* The realm hierarchy drives the generation of a 'snap context' for each
* realm, which simply lists the resulting set of snaps for the realm. This
* is attached to any writes sent to OSDs.
*/
/*
* Unfortunately error handling is a bit mixed here. If we get a snap
* update, but don't have enough memory to update our realm hierarchy,
* it's not clear what we can do about it (besides complaining to the
* console).
*/
/*
* increase ref count for the realm
*
* caller must hold snap_rwsem for write.
*/
void ceph_get_snap_realm(struct ceph_mds_client *mdsc,
struct ceph_snap_realm *realm)
{
dout("get_realm %p %d -> %d\n", realm,
atomic_read(&realm->nref), atomic_read(&realm->nref)+1);
/*
* since we _only_ increment realm refs or empty the empty
* list with snap_rwsem held, adjusting the empty list here is
* safe. we do need to protect against concurrent empty list
* additions, however.
*/
if (atomic_inc_return(&realm->nref) == 1) {
spin_lock(&mdsc->snap_empty_lock);
list_del_init(&realm->empty_item);
spin_unlock(&mdsc->snap_empty_lock);
}
}
static void __insert_snap_realm(struct rb_root *root,
struct ceph_snap_realm *new)
{
struct rb_node **p = &root->rb_node;
struct rb_node *parent = NULL;
struct ceph_snap_realm *r = NULL;
while (*p) {
parent = *p;
r = rb_entry(parent, struct ceph_snap_realm, node);
if (new->ino < r->ino)
p = &(*p)->rb_left;
else if (new->ino > r->ino)
p = &(*p)->rb_right;
else
BUG();
}
rb_link_node(&new->node, parent, p);
rb_insert_color(&new->node, root);
}
/*
* create and get the realm rooted at @ino and bump its ref count.
*
* caller must hold snap_rwsem for write.
*/
static struct ceph_snap_realm *ceph_create_snap_realm(
struct ceph_mds_client *mdsc,
u64 ino)
{
struct ceph_snap_realm *realm;
realm = kzalloc(sizeof(*realm), GFP_NOFS);
if (!realm)
return ERR_PTR(-ENOMEM);
atomic_set(&realm->nref, 1); /* for caller */
realm->ino = ino;
INIT_LIST_HEAD(&realm->children);
INIT_LIST_HEAD(&realm->child_item);
INIT_LIST_HEAD(&realm->empty_item);
INIT_LIST_HEAD(&realm->dirty_item);
INIT_LIST_HEAD(&realm->inodes_with_caps);
spin_lock_init(&realm->inodes_with_caps_lock);
__insert_snap_realm(&mdsc->snap_realms, realm);
dout("create_snap_realm %llx %p\n", realm->ino, realm);
return realm;
}
/*
* lookup the realm rooted at @ino.
*
* caller must hold snap_rwsem for write.
*/
static struct ceph_snap_realm *__lookup_snap_realm(struct ceph_mds_client *mdsc,
u64 ino)
{
struct rb_node *n = mdsc->snap_realms.rb_node;
struct ceph_snap_realm *r;
while (n) {
r = rb_entry(n, struct ceph_snap_realm, node);
if (ino < r->ino)
n = n->rb_left;
else if (ino > r->ino)
n = n->rb_right;
else {
dout("lookup_snap_realm %llx %p\n", r->ino, r);
return r;
}
}
return NULL;
}
struct ceph_snap_realm *ceph_lookup_snap_realm(struct ceph_mds_client *mdsc,
u64 ino)
{
struct ceph_snap_realm *r;
r = __lookup_snap_realm(mdsc, ino);
if (r)
ceph_get_snap_realm(mdsc, r);
return r;
}
static void __put_snap_realm(struct ceph_mds_client *mdsc,
struct ceph_snap_realm *realm);
/*
* called with snap_rwsem (write)
*/
static void __destroy_snap_realm(struct ceph_mds_client *mdsc,
struct ceph_snap_realm *realm)
{
dout("__destroy_snap_realm %p %llx\n", realm, realm->ino);
rb_erase(&realm->node, &mdsc->snap_realms);
if (realm->parent) {
list_del_init(&realm->child_item);
__put_snap_realm(mdsc, realm->parent);
}
kfree(realm->prior_parent_snaps);
kfree(realm->snaps);
ceph_put_snap_context(realm->cached_context);
kfree(realm);
}
/*
* caller holds snap_rwsem (write)
*/
static void __put_snap_realm(struct ceph_mds_client *mdsc,
struct ceph_snap_realm *realm)
{
dout("__put_snap_realm %llx %p %d -> %d\n", realm->ino, realm,
atomic_read(&realm->nref), atomic_read(&realm->nref)-1);
if (atomic_dec_and_test(&realm->nref))
__destroy_snap_realm(mdsc, realm);
}
/*
* caller needn't hold any locks
*/
void ceph_put_snap_realm(struct ceph_mds_client *mdsc,
struct ceph_snap_realm *realm)
{
dout("put_snap_realm %llx %p %d -> %d\n", realm->ino, realm,
atomic_read(&realm->nref), atomic_read(&realm->nref)-1);
if (!atomic_dec_and_test(&realm->nref))
return;
if (down_write_trylock(&mdsc->snap_rwsem)) {
__destroy_snap_realm(mdsc, realm);
up_write(&mdsc->snap_rwsem);
} else {
spin_lock(&mdsc->snap_empty_lock);
list_add(&realm->empty_item, &mdsc->snap_empty);
spin_unlock(&mdsc->snap_empty_lock);
}
}
/*
* Clean up any realms whose ref counts have dropped to zero. Note
* that this does not include realms who were created but not yet
* used.
*
* Called under snap_rwsem (write)
*/
static void __cleanup_empty_realms(struct ceph_mds_client *mdsc)
{
struct ceph_snap_realm *realm;
spin_lock(&mdsc->snap_empty_lock);
while (!list_empty(&mdsc->snap_empty)) {
realm = list_first_entry(&mdsc->snap_empty,
struct ceph_snap_realm, empty_item);
list_del(&realm->empty_item);
spin_unlock(&mdsc->snap_empty_lock);
__destroy_snap_realm(mdsc, realm);
spin_lock(&mdsc->snap_empty_lock);
}
spin_unlock(&mdsc->snap_empty_lock);
}
void ceph_cleanup_empty_realms(struct ceph_mds_client *mdsc)
{
down_write(&mdsc->snap_rwsem);
__cleanup_empty_realms(mdsc);
up_write(&mdsc->snap_rwsem);
}
/*
* adjust the parent realm of a given @realm. adjust child list, and parent
* pointers, and ref counts appropriately.
*
* return true if parent was changed, 0 if unchanged, <0 on error.
*
* caller must hold snap_rwsem for write.
*/
static int adjust_snap_realm_parent(struct ceph_mds_client *mdsc,
struct ceph_snap_realm *realm,
u64 parentino)
{
struct ceph_snap_realm *parent;
if (realm->parent_ino == parentino)
return 0;
parent = ceph_lookup_snap_realm(mdsc, parentino);
if (!parent) {
parent = ceph_create_snap_realm(mdsc, parentino);
if (IS_ERR(parent))
return PTR_ERR(parent);
}
dout("adjust_snap_realm_parent %llx %p: %llx %p -> %llx %p\n",
realm->ino, realm, realm->parent_ino, realm->parent,
parentino, parent);
if (realm->parent) {
list_del_init(&realm->child_item);
ceph_put_snap_realm(mdsc, realm->parent);
}
realm->parent_ino = parentino;
realm->parent = parent;
list_add(&realm->child_item, &parent->children);
return 1;
}
static int cmpu64_rev(const void *a, const void *b)
{
if (*(u64 *)a < *(u64 *)b)
return 1;
if (*(u64 *)a > *(u64 *)b)
return -1;
return 0;
}
/*
* build the snap context for a given realm.
*/
static int build_snap_context(struct ceph_snap_realm *realm,
struct list_head* dirty_realms)
{
struct ceph_snap_realm *parent = realm->parent;
struct ceph_snap_context *snapc;
int err = 0;
u32 num = realm->num_prior_parent_snaps + realm->num_snaps;
/*
* build parent context, if it hasn't been built.
* conservatively estimate that all parent snaps might be
* included by us.
*/
if (parent) {
if (!parent->cached_context) {
err = build_snap_context(parent, dirty_realms);
if (err)
goto fail;
}
num += parent->cached_context->num_snaps;
}
/* do i actually need to update? not if my context seq
matches realm seq, and my parents' does to. (this works
because we rebuild_snap_realms() works _downward_ in
hierarchy after each update.) */
if (realm->cached_context &&
realm->cached_context->seq == realm->seq &&
(!parent ||
realm->cached_context->seq >= parent->cached_context->seq)) {
dout("build_snap_context %llx %p: %p seq %lld (%u snaps)"
" (unchanged)\n",
realm->ino, realm, realm->cached_context,
realm->cached_context->seq,
(unsigned int)realm->cached_context->num_snaps);
return 0;
}
/* alloc new snap context */
err = -ENOMEM;
if (num > (SIZE_MAX - sizeof(*snapc)) / sizeof(u64))
goto fail;
snapc = ceph_create_snap_context(num, GFP_NOFS);
if (!snapc)
goto fail;
/* build (reverse sorted) snap vector */
num = 0;
snapc->seq = realm->seq;
if (parent) {
u32 i;
/* include any of parent's snaps occurring _after_ my
parent became my parent */
for (i = 0; i < parent->cached_context->num_snaps; i++)
if (parent->cached_context->snaps[i] >=
realm->parent_since)
snapc->snaps[num++] =
parent->cached_context->snaps[i];
if (parent->cached_context->seq > snapc->seq)
snapc->seq = parent->cached_context->seq;
}
memcpy(snapc->snaps + num, realm->snaps,
sizeof(u64)*realm->num_snaps);
num += realm->num_snaps;
memcpy(snapc->snaps + num, realm->prior_parent_snaps,
sizeof(u64)*realm->num_prior_parent_snaps);
num += realm->num_prior_parent_snaps;
sort(snapc->snaps, num, sizeof(u64), cmpu64_rev, NULL);
snapc->num_snaps = num;
dout("build_snap_context %llx %p: %p seq %lld (%u snaps)\n",
realm->ino, realm, snapc, snapc->seq,
(unsigned int) snapc->num_snaps);
ceph_put_snap_context(realm->cached_context);
realm->cached_context = snapc;
/* queue realm for cap_snap creation */
list_add_tail(&realm->dirty_item, dirty_realms);
return 0;
fail:
/*
* if we fail, clear old (incorrect) cached_context... hopefully
* we'll have better luck building it later
*/
if (realm->cached_context) {
ceph_put_snap_context(realm->cached_context);
realm->cached_context = NULL;
}
pr_err("build_snap_context %llx %p fail %d\n", realm->ino,
realm, err);
return err;
}
/*
* rebuild snap context for the given realm and all of its children.
*/
static void rebuild_snap_realms(struct ceph_snap_realm *realm,
struct list_head *dirty_realms)
{
struct ceph_snap_realm *child;
dout("rebuild_snap_realms %llx %p\n", realm->ino, realm);
build_snap_context(realm, dirty_realms);
list_for_each_entry(child, &realm->children, child_item)
rebuild_snap_realms(child, dirty_realms);
}
/*
* helper to allocate and decode an array of snapids. free prior
* instance, if any.
*/
static int dup_array(u64 **dst, __le64 *src, u32 num)
{
u32 i;
kfree(*dst);
if (num) {
*dst = kcalloc(num, sizeof(u64), GFP_NOFS);
if (!*dst)
return -ENOMEM;
for (i = 0; i < num; i++)
(*dst)[i] = get_unaligned_le64(src + i);
} else {
*dst = NULL;
}
return 0;
}
static bool has_new_snaps(struct ceph_snap_context *o,
struct ceph_snap_context *n)
{
if (n->num_snaps == 0)
return false;
/* snaps are in descending order */
return n->snaps[0] > o->seq;
}
/*
* When a snapshot is applied, the size/mtime inode metadata is queued
* in a ceph_cap_snap (one for each snapshot) until writeback
* completes and the metadata can be flushed back to the MDS.
*
* However, if a (sync) write is currently in-progress when we apply
* the snapshot, we have to wait until the write succeeds or fails
* (and a final size/mtime is known). In this case the
* cap_snap->writing = 1, and is said to be "pending." When the write
* finishes, we __ceph_finish_cap_snap().
*
* Caller must hold snap_rwsem for read (i.e., the realm topology won't
* change).
*/
void ceph_queue_cap_snap(struct ceph_inode_info *ci)
{
struct inode *inode = &ci->vfs_inode;
struct ceph_cap_snap *capsnap;
struct ceph_snap_context *old_snapc, *new_snapc;
int used, dirty;
capsnap = kzalloc(sizeof(*capsnap), GFP_NOFS);
if (!capsnap) {
pr_err("ENOMEM allocating ceph_cap_snap on %p\n", inode);
return;
}
spin_lock(&ci->i_ceph_lock);
used = __ceph_caps_used(ci);
dirty = __ceph_caps_dirty(ci);
old_snapc = ci->i_head_snapc;
new_snapc = ci->i_snap_realm->cached_context;
/*
* If there is a write in progress, treat that as a dirty Fw,
* even though it hasn't completed yet; by the time we finish
* up this capsnap it will be.
*/
if (used & CEPH_CAP_FILE_WR)
dirty |= CEPH_CAP_FILE_WR;
if (__ceph_have_pending_cap_snap(ci)) {
/* there is no point in queuing multiple "pending" cap_snaps,
as no new writes are allowed to start when pending, so any
writes in progress now were started before the previous
cap_snap. lucky us. */
dout("queue_cap_snap %p already pending\n", inode);
goto update_snapc;
}
if (ci->i_wrbuffer_ref_head == 0 &&
!(dirty & (CEPH_CAP_ANY_EXCL|CEPH_CAP_FILE_WR))) {
dout("queue_cap_snap %p nothing dirty|writing\n", inode);
goto update_snapc;
}
BUG_ON(!old_snapc);
/*
* There is no need to send FLUSHSNAP message to MDS if there is
* no new snapshot. But when there is dirty pages or on-going
* writes, we still need to create cap_snap. cap_snap is needed
* by the write path and page writeback path.
*
* also see ceph_try_drop_cap_snap()
*/
if (has_new_snaps(old_snapc, new_snapc)) {
if (dirty & (CEPH_CAP_ANY_EXCL|CEPH_CAP_FILE_WR))
capsnap->need_flush = true;
} else {
if (!(used & CEPH_CAP_FILE_WR) &&
ci->i_wrbuffer_ref_head == 0) {
dout("queue_cap_snap %p "
"no new_snap|dirty_page|writing\n", inode);
goto update_snapc;
}
}
dout("queue_cap_snap %p cap_snap %p queuing under %p %s %s\n",
inode, capsnap, old_snapc, ceph_cap_string(dirty),
capsnap->need_flush ? "" : "no_flush");
ihold(inode);
refcount_set(&capsnap->nref, 1);
INIT_LIST_HEAD(&capsnap->ci_item);
capsnap->follows = old_snapc->seq;
capsnap->issued = __ceph_caps_issued(ci, NULL);
capsnap->dirty = dirty;
capsnap->mode = inode->i_mode;
capsnap->uid = inode->i_uid;
capsnap->gid = inode->i_gid;
if (dirty & CEPH_CAP_XATTR_EXCL) {
__ceph_build_xattrs_blob(ci);
capsnap->xattr_blob =
ceph_buffer_get(ci->i_xattrs.blob);
capsnap->xattr_version = ci->i_xattrs.version;
} else {
capsnap->xattr_blob = NULL;
capsnap->xattr_version = 0;
}
capsnap->inline_data = ci->i_inline_version != CEPH_INLINE_NONE;
/* dirty page count moved from _head to this cap_snap;
all subsequent writes page dirties occur _after_ this
snapshot. */
capsnap->dirty_pages = ci->i_wrbuffer_ref_head;
ci->i_wrbuffer_ref_head = 0;
capsnap->context = old_snapc;
list_add_tail(&capsnap->ci_item, &ci->i_cap_snaps);
if (used & CEPH_CAP_FILE_WR) {
dout("queue_cap_snap %p cap_snap %p snapc %p"
" seq %llu used WR, now pending\n", inode,
capsnap, old_snapc, old_snapc->seq);
capsnap->writing = 1;
} else {
/* note mtime, size NOW. */
__ceph_finish_cap_snap(ci, capsnap);
}
capsnap = NULL;
old_snapc = NULL;
update_snapc:
if (ci->i_head_snapc) {
ci->i_head_snapc = ceph_get_snap_context(new_snapc);
dout(" new snapc is %p\n", new_snapc);
}
spin_unlock(&ci->i_ceph_lock);
kfree(capsnap);
ceph_put_snap_context(old_snapc);
}
/*
* Finalize the size, mtime for a cap_snap.. that is, settle on final values
* to be used for the snapshot, to be flushed back to the mds.
*
* If capsnap can now be flushed, add to snap_flush list, and return 1.
*
* Caller must hold i_ceph_lock.
*/
int __ceph_finish_cap_snap(struct ceph_inode_info *ci,
struct ceph_cap_snap *capsnap)
{
struct inode *inode = &ci->vfs_inode;
struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
BUG_ON(capsnap->writing);
capsnap->size = inode->i_size;
capsnap->mtime = inode->i_mtime;
capsnap->atime = inode->i_atime;
capsnap->ctime = inode->i_ctime;
capsnap->time_warp_seq = ci->i_time_warp_seq;
capsnap->truncate_size = ci->i_truncate_size;
capsnap->truncate_seq = ci->i_truncate_seq;
if (capsnap->dirty_pages) {
dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu "
"still has %d dirty pages\n", inode, capsnap,
capsnap->context, capsnap->context->seq,
ceph_cap_string(capsnap->dirty), capsnap->size,
capsnap->dirty_pages);
return 0;
}
ci->i_ceph_flags |= CEPH_I_FLUSH_SNAPS;
dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu\n",
inode, capsnap, capsnap->context,
capsnap->context->seq, ceph_cap_string(capsnap->dirty),
capsnap->size);
spin_lock(&mdsc->snap_flush_lock);
list_add_tail(&ci->i_snap_flush_item, &mdsc->snap_flush_list);
spin_unlock(&mdsc->snap_flush_lock);
return 1; /* caller may want to ceph_flush_snaps */
}
/*
* Queue cap_snaps for snap writeback for this realm and its children.
* Called under snap_rwsem, so realm topology won't change.
*/
static void queue_realm_cap_snaps(struct ceph_snap_realm *realm)
{
struct ceph_inode_info *ci;
struct inode *lastinode = NULL;
dout("queue_realm_cap_snaps %p %llx inodes\n", realm, realm->ino);
spin_lock(&realm->inodes_with_caps_lock);
list_for_each_entry(ci, &realm->inodes_with_caps, i_snap_realm_item) {
struct inode *inode = igrab(&ci->vfs_inode);
if (!inode)
continue;
spin_unlock(&realm->inodes_with_caps_lock);
iput(lastinode);
lastinode = inode;
ceph_queue_cap_snap(ci);
spin_lock(&realm->inodes_with_caps_lock);
}
spin_unlock(&realm->inodes_with_caps_lock);
iput(lastinode);
dout("queue_realm_cap_snaps %p %llx done\n", realm, realm->ino);
}
/*
* Parse and apply a snapblob "snap trace" from the MDS. This specifies
* the snap realm parameters from a given realm and all of its ancestors,
* up to the root.
*
* Caller must hold snap_rwsem for write.
*/
int ceph_update_snap_trace(struct ceph_mds_client *mdsc,
void *p, void *e, bool deletion,
struct ceph_snap_realm **realm_ret)
{
struct ceph_mds_snap_realm *ri; /* encoded */
__le64 *snaps; /* encoded */
__le64 *prior_parent_snaps; /* encoded */
struct ceph_snap_realm *realm = NULL;
struct ceph_snap_realm *first_realm = NULL;
int invalidate = 0;
int err = -ENOMEM;
LIST_HEAD(dirty_realms);
dout("update_snap_trace deletion=%d\n", deletion);
more:
ceph_decode_need(&p, e, sizeof(*ri), bad);
ri = p;
p += sizeof(*ri);
ceph_decode_need(&p, e, sizeof(u64)*(le32_to_cpu(ri->num_snaps) +
le32_to_cpu(ri->num_prior_parent_snaps)), bad);
snaps = p;
p += sizeof(u64) * le32_to_cpu(ri->num_snaps);
prior_parent_snaps = p;
p += sizeof(u64) * le32_to_cpu(ri->num_prior_parent_snaps);
realm = ceph_lookup_snap_realm(mdsc, le64_to_cpu(ri->ino));
if (!realm) {
realm = ceph_create_snap_realm(mdsc, le64_to_cpu(ri->ino));
if (IS_ERR(realm)) {
err = PTR_ERR(realm);
goto fail;
}
}
/* ensure the parent is correct */
err = adjust_snap_realm_parent(mdsc, realm, le64_to_cpu(ri->parent));
if (err < 0)
goto fail;
invalidate += err;
if (le64_to_cpu(ri->seq) > realm->seq) {
dout("update_snap_trace updating %llx %p %lld -> %lld\n",
realm->ino, realm, realm->seq, le64_to_cpu(ri->seq));
/* update realm parameters, snap lists */
realm->seq = le64_to_cpu(ri->seq);
realm->created = le64_to_cpu(ri->created);
realm->parent_since = le64_to_cpu(ri->parent_since);
realm->num_snaps = le32_to_cpu(ri->num_snaps);
err = dup_array(&realm->snaps, snaps, realm->num_snaps);
if (err < 0)
goto fail;
realm->num_prior_parent_snaps =
le32_to_cpu(ri->num_prior_parent_snaps);
err = dup_array(&realm->prior_parent_snaps, prior_parent_snaps,
realm->num_prior_parent_snaps);
if (err < 0)
goto fail;
if (realm->seq > mdsc->last_snap_seq)
mdsc->last_snap_seq = realm->seq;
invalidate = 1;
} else if (!realm->cached_context) {
dout("update_snap_trace %llx %p seq %lld new\n",
realm->ino, realm, realm->seq);
invalidate = 1;
} else {
dout("update_snap_trace %llx %p seq %lld unchanged\n",
realm->ino, realm, realm->seq);
}
dout("done with %llx %p, invalidated=%d, %p %p\n", realm->ino,
realm, invalidate, p, e);
/* invalidate when we reach the _end_ (root) of the trace */
if (invalidate && p >= e)
rebuild_snap_realms(realm, &dirty_realms);
if (!first_realm)
first_realm = realm;
else
ceph_put_snap_realm(mdsc, realm);
if (p < e)
goto more;
/*
* queue cap snaps _after_ we've built the new snap contexts,
* so that i_head_snapc can be set appropriately.
*/
while (!list_empty(&dirty_realms)) {
realm = list_first_entry(&dirty_realms, struct ceph_snap_realm,
dirty_item);
list_del_init(&realm->dirty_item);
queue_realm_cap_snaps(realm);
}
if (realm_ret)
*realm_ret = first_realm;
else
ceph_put_snap_realm(mdsc, first_realm);
__cleanup_empty_realms(mdsc);
return 0;
bad:
err = -EINVAL;
fail:
if (realm && !IS_ERR(realm))
ceph_put_snap_realm(mdsc, realm);
if (first_realm)
ceph_put_snap_realm(mdsc, first_realm);
pr_err("update_snap_trace error %d\n", err);
return err;
}
/*
* Send any cap_snaps that are queued for flush. Try to carry
* s_mutex across multiple snap flushes to avoid locking overhead.
*
* Caller holds no locks.
*/
static void flush_snaps(struct ceph_mds_client *mdsc)
{
struct ceph_inode_info *ci;
struct inode *inode;
struct ceph_mds_session *session = NULL;
dout("flush_snaps\n");
spin_lock(&mdsc->snap_flush_lock);
while (!list_empty(&mdsc->snap_flush_list)) {
ci = list_first_entry(&mdsc->snap_flush_list,
struct ceph_inode_info, i_snap_flush_item);
inode = &ci->vfs_inode;
ihold(inode);
spin_unlock(&mdsc->snap_flush_lock);
ceph_flush_snaps(ci, &session);
iput(inode);
spin_lock(&mdsc->snap_flush_lock);
}
spin_unlock(&mdsc->snap_flush_lock);
if (session) {
mutex_unlock(&session->s_mutex);
ceph_put_mds_session(session);
}
dout("flush_snaps done\n");
}
/*
* Handle a snap notification from the MDS.
*
* This can take two basic forms: the simplest is just a snap creation
* or deletion notification on an existing realm. This should update the
* realm and its children.
*
* The more difficult case is realm creation, due to snap creation at a
* new point in the file hierarchy, or due to a rename that moves a file or
* directory into another realm.
*/
void ceph_handle_snap(struct ceph_mds_client *mdsc,
struct ceph_mds_session *session,
struct ceph_msg *msg)
{
struct super_block *sb = mdsc->fsc->sb;
int mds = session->s_mds;
u64 split;
int op;
int trace_len;
struct ceph_snap_realm *realm = NULL;
void *p = msg->front.iov_base;
void *e = p + msg->front.iov_len;
struct ceph_mds_snap_head *h;
int num_split_inos, num_split_realms;
__le64 *split_inos = NULL, *split_realms = NULL;
int i;
int locked_rwsem = 0;
/* decode */
if (msg->front.iov_len < sizeof(*h))
goto bad;
h = p;
op = le32_to_cpu(h->op);
split = le64_to_cpu(h->split); /* non-zero if we are splitting an
* existing realm */
num_split_inos = le32_to_cpu(h->num_split_inos);
num_split_realms = le32_to_cpu(h->num_split_realms);
trace_len = le32_to_cpu(h->trace_len);
p += sizeof(*h);
dout("handle_snap from mds%d op %s split %llx tracelen %d\n", mds,
ceph_snap_op_name(op), split, trace_len);
mutex_lock(&session->s_mutex);
session->s_seq++;
mutex_unlock(&session->s_mutex);
down_write(&mdsc->snap_rwsem);
locked_rwsem = 1;
if (op == CEPH_SNAP_OP_SPLIT) {
struct ceph_mds_snap_realm *ri;
/*
* A "split" breaks part of an existing realm off into
* a new realm. The MDS provides a list of inodes
* (with caps) and child realms that belong to the new
* child.
*/
split_inos = p;
p += sizeof(u64) * num_split_inos;
split_realms = p;
p += sizeof(u64) * num_split_realms;
ceph_decode_need(&p, e, sizeof(*ri), bad);
/* we will peek at realm info here, but will _not_
* advance p, as the realm update will occur below in
* ceph_update_snap_trace. */
ri = p;
realm = ceph_lookup_snap_realm(mdsc, split);
if (!realm) {
realm = ceph_create_snap_realm(mdsc, split);
if (IS_ERR(realm))
goto out;
}
dout("splitting snap_realm %llx %p\n", realm->ino, realm);
for (i = 0; i < num_split_inos; i++) {
struct ceph_vino vino = {
.ino = le64_to_cpu(split_inos[i]),
.snap = CEPH_NOSNAP,
};
struct inode *inode = ceph_find_inode(sb, vino);
struct ceph_inode_info *ci;
struct ceph_snap_realm *oldrealm;
if (!inode)
continue;
ci = ceph_inode(inode);
spin_lock(&ci->i_ceph_lock);
if (!ci->i_snap_realm)
goto skip_inode;
/*
* If this inode belongs to a realm that was
* created after our new realm, we experienced
* a race (due to another split notifications
* arriving from a different MDS). So skip
* this inode.
*/
if (ci->i_snap_realm->created >
le64_to_cpu(ri->created)) {
dout(" leaving %p in newer realm %llx %p\n",
inode, ci->i_snap_realm->ino,
ci->i_snap_realm);
goto skip_inode;
}
dout(" will move %p to split realm %llx %p\n",
inode, realm->ino, realm);
/*
* Move the inode to the new realm
*/
spin_lock(&realm->inodes_with_caps_lock);
list_del_init(&ci->i_snap_realm_item);
list_add(&ci->i_snap_realm_item,
&realm->inodes_with_caps);
oldrealm = ci->i_snap_realm;
ci->i_snap_realm = realm;
spin_unlock(&realm->inodes_with_caps_lock);
spin_unlock(&ci->i_ceph_lock);
ceph_get_snap_realm(mdsc, realm);
ceph_put_snap_realm(mdsc, oldrealm);
iput(inode);
continue;
skip_inode:
spin_unlock(&ci->i_ceph_lock);
iput(inode);
}
/* we may have taken some of the old realm's children. */
for (i = 0; i < num_split_realms; i++) {
struct ceph_snap_realm *child =
__lookup_snap_realm(mdsc,
le64_to_cpu(split_realms[i]));
if (!child)
continue;
adjust_snap_realm_parent(mdsc, child, realm->ino);
}
}
/*
* update using the provided snap trace. if we are deleting a
* snap, we can avoid queueing cap_snaps.
*/
ceph_update_snap_trace(mdsc, p, e,
op == CEPH_SNAP_OP_DESTROY, NULL);
if (op == CEPH_SNAP_OP_SPLIT)
/* we took a reference when we created the realm, above */
ceph_put_snap_realm(mdsc, realm);
__cleanup_empty_realms(mdsc);
up_write(&mdsc->snap_rwsem);
flush_snaps(mdsc);
return;
bad:
pr_err("corrupt snap message from mds%d\n", mds);
ceph_msg_dump(msg);
out:
if (locked_rwsem)
up_write(&mdsc->snap_rwsem);
return;
}