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linux-next/fs/ceph/snap.c

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ceph: factor out libceph from Ceph file system This factors out protocol and low-level storage parts of ceph into a separate libceph module living in net/ceph and include/linux/ceph. This is mostly a matter of moving files around. However, a few key pieces of the interface change as well: - ceph_client becomes ceph_fs_client and ceph_client, where the latter captures the mon and osd clients, and the fs_client gets the mds client and file system specific pieces. - Mount option parsing and debugfs setup is correspondingly broken into two pieces. - The mon client gets a generic handler callback for otherwise unknown messages (mds map, in this case). - The basic supported/required feature bits can be expanded (and are by ceph_fs_client). No functional change, aside from some subtle error handling cases that got cleaned up in the refactoring process. Signed-off-by: Sage Weil <sage@newdream.net>
2010-04-07 06:14:15 +08:00
#include <linux/ceph/ceph_debug.h>
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
#include <linux/sort.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 16:04:11 +08:00
#include <linux/slab.h>
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
#include "super.h"
ceph: factor out libceph from Ceph file system This factors out protocol and low-level storage parts of ceph into a separate libceph module living in net/ceph and include/linux/ceph. This is mostly a matter of moving files around. However, a few key pieces of the interface change as well: - ceph_client becomes ceph_fs_client and ceph_client, where the latter captures the mon and osd clients, and the fs_client gets the mds client and file system specific pieces. - Mount option parsing and debugfs setup is correspondingly broken into two pieces. - The mon client gets a generic handler callback for otherwise unknown messages (mds map, in this case). - The basic supported/required feature bits can be expanded (and are by ceph_fs_client). No functional change, aside from some subtle error handling cases that got cleaned up in the refactoring process. Signed-off-by: Sage Weil <sage@newdream.net>
2010-04-07 06:14:15 +08:00
#include "mds_client.h"
#include <linux/ceph/decode.h>
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
/*
* 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_read(&realm->nref) == 0) {
spin_lock(&mdsc->snap_empty_lock);
list_del_init(&realm->empty_item);
spin_unlock(&mdsc->snap_empty_lock);
}
atomic_inc(&realm->nref);
}
ceph: use rbtree for snap_realms Switch from radix tree to rbtree for snap realms. This is much more appropriate given that realm keys are few and far between. Signed-off-by: Sage Weil <sage@newdream.net>
2010-02-16 06:37:55 +08:00
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);
}
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
/*
* 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, 0); /* tree does not take a ref */
realm->ino = ino;
INIT_LIST_HEAD(&realm->children);
INIT_LIST_HEAD(&realm->child_item);
INIT_LIST_HEAD(&realm->empty_item);
ceph: fix cap_snap and realm split The cap_snap creation/queueing relies on both the current i_head_snapc _and_ the i_snap_realm pointers being correct, so that the new cap_snap can properly reference the old context and the new i_head_snapc can be updated to reference the new snaprealm's context. To fix this, we: - move inodes completely to the new (split) realm so that i_snap_realm is correct, and - generate the new snapc's _before_ queueing the cap_snaps in ceph_update_snap_trace(). Signed-off-by: Sage Weil <sage@newdream.net>
2010-09-17 07:26:51 +08:00
INIT_LIST_HEAD(&realm->dirty_item);
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
INIT_LIST_HEAD(&realm->inodes_with_caps);
spin_lock_init(&realm->inodes_with_caps_lock);
ceph: use rbtree for snap_realms Switch from radix tree to rbtree for snap realms. This is much more appropriate given that realm keys are few and far between. Signed-off-by: Sage Weil <sage@newdream.net>
2010-02-16 06:37:55 +08:00
__insert_snap_realm(&mdsc->snap_realms, realm);
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
dout("create_snap_realm %llx %p\n", realm->ino, realm);
return realm;
}
/*
ceph: use rbtree for snap_realms Switch from radix tree to rbtree for snap realms. This is much more appropriate given that realm keys are few and far between. Signed-off-by: Sage Weil <sage@newdream.net>
2010-02-16 06:37:55 +08:00
* lookup the realm rooted at @ino.
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
*
* caller must hold snap_rwsem for write.
*/
struct ceph_snap_realm *ceph_lookup_snap_realm(struct ceph_mds_client *mdsc,
u64 ino)
{
ceph: use rbtree for snap_realms Switch from radix tree to rbtree for snap realms. This is much more appropriate given that realm keys are few and far between. Signed-off-by: Sage Weil <sage@newdream.net>
2010-02-16 06:37:55 +08:00
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;
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
}
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);
ceph: use rbtree for snap_realms Switch from radix tree to rbtree for snap realms. This is much more appropriate given that realm keys are few and far between. Signed-off-by: Sage Weil <sage@newdream.net>
2010-02-16 06:37:55 +08:00
rb_erase(&realm->node, &mdsc->snap_realms);
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
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);
ceph: fix list_add in ceph_put_snap_realm Signed-off-by: Henry C Chang <henry.cy.chang@gmail.com> Signed-off-by: Sage Weil <sage@newdream.net>
2011-05-11 18:29:53 +08:00
list_add(&realm->empty_item, &mdsc->snap_empty);
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
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;
ceph_get_snap_realm(mdsc, 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 ceph_snap_realm *parent = realm->parent;
struct ceph_snap_context *snapc;
int err = 0;
int i;
int 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);
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 &&
ceph: fix snap rebuild condition We were rebuilding the snap context when it was not necessary (i.e. when the realm seq hadn't changed _and_ the parent seq was still older), which caused page snapc pointers to not match the realm's snapc pointer (even though the snap context itself was identical). This confused begin_write and put it into an endless loop. The correct logic is: rebuild snapc if _my_ realm seq changed, or if my parent realm's seq is newer than mine (and thus mine needs to be rebuilt too). Signed-off-by: Sage Weil <sage@newdream.net>
2010-03-20 04:24:39 +08:00
realm->cached_context->seq == realm->seq &&
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
(!parent ||
ceph: fix snap rebuild condition We were rebuilding the snap context when it was not necessary (i.e. when the realm seq hadn't changed _and_ the parent seq was still older), which caused page snapc pointers to not match the realm's snapc pointer (even though the snap context itself was identical). This confused begin_write and put it into an endless loop. The correct logic is: rebuild snapc if _my_ realm seq changed, or if my parent realm's seq is newer than mine (and thus mine needs to be rebuilt too). Signed-off-by: Sage Weil <sage@newdream.net>
2010-03-20 04:24:39 +08:00
realm->cached_context->seq >= parent->cached_context->seq)) {
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
dout("build_snap_context %llx %p: %p seq %lld (%d snaps)"
" (unchanged)\n",
realm->ino, realm, realm->cached_context,
realm->cached_context->seq,
realm->cached_context->num_snaps);
return 0;
}
/* alloc new snap context */
err = -ENOMEM;
if (num > ULONG_MAX / sizeof(u64) - sizeof(*snapc))
goto fail;
snapc = kzalloc(sizeof(*snapc) + num*sizeof(u64), GFP_NOFS);
if (!snapc)
goto fail;
atomic_set(&snapc->nref, 1);
/* build (reverse sorted) snap vector */
num = 0;
snapc->seq = realm->seq;
if (parent) {
Fix common misspellings Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2011-03-31 09:57:33 +08:00
/* include any of parent's snaps occurring _after_ my
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
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 (%d snaps)\n",
realm->ino, realm, snapc, snapc->seq, snapc->num_snaps);
if (realm->cached_context)
ceph_put_snap_context(realm->cached_context);
realm->cached_context = snapc;
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 ceph_snap_realm *child;
dout("rebuild_snap_realms %llx %p\n", realm->ino, realm);
build_snap_context(realm);
list_for_each_entry(child, &realm->children, child_item)
rebuild_snap_realms(child);
}
/*
* helper to allocate and decode an array of snapids. free prior
* instance, if any.
*/
static int dup_array(u64 **dst, __le64 *src, int num)
{
int 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;
}
/*
* 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).
*/
ceph: queue_cap_snap should always queue dirty context This simplifies the calling convention, and fixes a bug where we queue a capsnap with a context other than i_head_snapc (the one that matches the dirty pages). The result was a BUG at fs/ceph/caps.c:2178 on writeback completion when a capsnap matching the writeback snapc could not be found. Signed-off-by: Sage Weil <sage@newdream.net>
2010-04-14 02:41:22 +08:00
void ceph_queue_cap_snap(struct ceph_inode_info *ci)
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
{
struct inode *inode = &ci->vfs_inode;
struct ceph_cap_snap *capsnap;
ceph: include dirty xattrs state in snapped caps When we snapshot dirty metadata that needs to be written back to the MDS, include dirty xattr metadata. Make the capsnap reference the encoded xattr blob so that it will be written back in the FLUSHSNAP op. Also fix the capsnap creation guard to include dirty auth or file bits, not just tests specific to dirty file data or file writes in progress (this fixes auth metadata writeback). Signed-off-by: Sage Weil <sage@newdream.net>
2010-08-23 06:03:56 +08:00
int used, dirty;
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
capsnap = kzalloc(sizeof(*capsnap), GFP_NOFS);
if (!capsnap) {
pr_err("ENOMEM allocating ceph_cap_snap on %p\n", inode);
return;
}
spin_lock(&inode->i_lock);
used = __ceph_caps_used(ci);
ceph: include dirty xattrs state in snapped caps When we snapshot dirty metadata that needs to be written back to the MDS, include dirty xattr metadata. Make the capsnap reference the encoded xattr blob so that it will be written back in the FLUSHSNAP op. Also fix the capsnap creation guard to include dirty auth or file bits, not just tests specific to dirty file data or file writes in progress (this fixes auth metadata writeback). Signed-off-by: Sage Weil <sage@newdream.net>
2010-08-23 06:03:56 +08:00
dirty = __ceph_caps_dirty(ci);
ceph: fix snap writeback when racing with writes There are two problems that come up when we try to queue a capsnap while a write is in progress: - The FILE_WR cap is held, but not yet dirty, so we may queue a capsnap with dirty == 0. That will crash later in __ceph_flush_snaps(). Or on the FILE_WR cap if a write is in progress. - We may not have i_head_snapc set, which causes problems pretty quickly. Look to the snaprealm in this case. Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net> Signed-off-by: Sage Weil <sage@newdream.net>
2011-07-27 02:26:31 +08:00
/*
* 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;
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
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. */
ceph: queue_cap_snap should always queue dirty context This simplifies the calling convention, and fixes a bug where we queue a capsnap with a context other than i_head_snapc (the one that matches the dirty pages). The result was a BUG at fs/ceph/caps.c:2178 on writeback completion when a capsnap matching the writeback snapc could not be found. Signed-off-by: Sage Weil <sage@newdream.net>
2010-04-14 02:41:22 +08:00
dout("queue_cap_snap %p already pending\n", inode);
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
kfree(capsnap);
ceph: only queue capsnap if caps are dirty We used to go into this branch if i_wrbuffer_ref_head was non-zero. This was an ancient check from before we were careful about dealing with all kinds of caps (and not just dirty pages). It is cleaner to only queue a capsnap if there is an actual dirty cap. If we are racing with... something...we will end up here with ci->i_wrbuffer_refs but no dirty caps. Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net> Signed-off-by: Sage Weil <sage@newdream.net>
2011-07-27 02:26:41 +08:00
} else if (dirty & (CEPH_CAP_AUTH_EXCL|CEPH_CAP_XATTR_EXCL|
CEPH_CAP_FILE_EXCL|CEPH_CAP_FILE_WR)) {
ceph: queue_cap_snap should always queue dirty context This simplifies the calling convention, and fixes a bug where we queue a capsnap with a context other than i_head_snapc (the one that matches the dirty pages). The result was a BUG at fs/ceph/caps.c:2178 on writeback completion when a capsnap matching the writeback snapc could not be found. Signed-off-by: Sage Weil <sage@newdream.net>
2010-04-14 02:41:22 +08:00
struct ceph_snap_context *snapc = ci->i_head_snapc;
ceph: fix snap writeback when racing with writes There are two problems that come up when we try to queue a capsnap while a write is in progress: - The FILE_WR cap is held, but not yet dirty, so we may queue a capsnap with dirty == 0. That will crash later in __ceph_flush_snaps(). Or on the FILE_WR cap if a write is in progress. - We may not have i_head_snapc set, which causes problems pretty quickly. Look to the snaprealm in this case. Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net> Signed-off-by: Sage Weil <sage@newdream.net>
2011-07-27 02:26:31 +08:00
/*
* if we are a sync write, we may need to go to the snaprealm
* to get the current snapc.
*/
if (!snapc)
snapc = ci->i_snap_realm->cached_context;
dout("queue_cap_snap %p cap_snap %p queuing under %p %s\n",
inode, capsnap, snapc, ceph_cap_string(dirty));
fs: don't use igrab() while holding i_lock Fix the incorrect use of igrab() inside the i_lock in NFS and Ceph‥ If we are already holding the i_lock, we have a reference to the inode so we can safely use ihold() to gain an extra reference. This avoids hangs due to lock recursion on the i_lock now that the inode_lock is gone and igrab() uses the i_lock itself. Signed-off-by: Dave Chinner <dchinner@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Cc: Ryan Mallon <ryan@bluewatersys.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-29 15:08:50 +08:00
ihold(inode);
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
atomic_set(&capsnap->nref, 1);
capsnap->ci = ci;
INIT_LIST_HEAD(&capsnap->ci_item);
INIT_LIST_HEAD(&capsnap->flushing_item);
ceph: correctly set 'follows' in flushsnap messages The 'follows' should match the seq for the snap context for the given snap cap, which is the context under which we have been dirtying and writing data and metadata. The snapshot that _contains_ those updates thus _follows_ that context's seq #. Signed-off-by: Sage Weil <sage@newdream.net>
2010-09-15 06:45:44 +08:00
capsnap->follows = snapc->seq;
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
capsnap->issued = __ceph_caps_issued(ci, NULL);
ceph: include dirty xattrs state in snapped caps When we snapshot dirty metadata that needs to be written back to the MDS, include dirty xattr metadata. Make the capsnap reference the encoded xattr blob so that it will be written back in the FLUSHSNAP op. Also fix the capsnap creation guard to include dirty auth or file bits, not just tests specific to dirty file data or file writes in progress (this fixes auth metadata writeback). Signed-off-by: Sage Weil <sage@newdream.net>
2010-08-23 06:03:56 +08:00
capsnap->dirty = dirty;
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
capsnap->mode = inode->i_mode;
capsnap->uid = inode->i_uid;
capsnap->gid = inode->i_gid;
ceph: include dirty xattrs state in snapped caps When we snapshot dirty metadata that needs to be written back to the MDS, include dirty xattr metadata. Make the capsnap reference the encoded xattr blob so that it will be written back in the FLUSHSNAP op. Also fix the capsnap creation guard to include dirty auth or file bits, not just tests specific to dirty file data or file writes in progress (this fixes auth metadata writeback). Signed-off-by: Sage Weil <sage@newdream.net>
2010-08-23 06:03:56 +08:00
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;
}
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
/* 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;
ceph: queue_cap_snap should always queue dirty context This simplifies the calling convention, and fixes a bug where we queue a capsnap with a context other than i_head_snapc (the one that matches the dirty pages). The result was a BUG at fs/ceph/caps.c:2178 on writeback completion when a capsnap matching the writeback snapc could not be found. Signed-off-by: Sage Weil <sage@newdream.net>
2010-04-14 02:41:22 +08:00
capsnap->context = snapc;
ceph: maintain i_head_snapc when any caps are dirty, not just for data We used to use i_head_snapc to keep track of which snapc the current epoch of dirty data was dirtied under. It is used by queue_cap_snap to set up the cap_snap. However, since we queue cap snaps for any dirty caps, not just for dirty file data, we need to keep a valid i_head_snapc anytime we have dirty|flushing caps. This fixes a NULL pointer deref in queue_cap_snap when writing back dirty caps without data (e.g., snaptest-authwb.sh). Signed-off-by: Sage Weil <sage@newdream.net>
2010-08-24 23:44:16 +08:00
ci->i_head_snapc =
ceph_get_snap_context(ci->i_snap_realm->cached_context);
dout(" new snapc is %p\n", ci->i_head_snapc);
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
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, snapc, snapc->seq);
capsnap->writing = 1;
} else {
/* note mtime, size NOW. */
__ceph_finish_cap_snap(ci, capsnap);
}
} else {
dout("queue_cap_snap %p nothing dirty|writing\n", inode);
kfree(capsnap);
}
spin_unlock(&inode->i_lock);
}
/*
* 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_lock.
*/
int __ceph_finish_cap_snap(struct ceph_inode_info *ci,
struct ceph_cap_snap *capsnap)
{
struct inode *inode = &ci->vfs_inode;
ceph: factor out libceph from Ceph file system This factors out protocol and low-level storage parts of ceph into a separate libceph module living in net/ceph and include/linux/ceph. This is mostly a matter of moving files around. However, a few key pieces of the interface change as well: - ceph_client becomes ceph_fs_client and ceph_client, where the latter captures the mon and osd clients, and the fs_client gets the mds client and file system specific pieces. - Mount option parsing and debugfs setup is correspondingly broken into two pieces. - The mon client gets a generic handler callback for otherwise unknown messages (mds map, in this case). - The basic supported/required feature bits can be expanded (and are by ceph_fs_client). No functional change, aside from some subtle error handling cases that got cleaned up in the refactoring process. Signed-off-by: Sage Weil <sage@newdream.net>
2010-04-07 06:14:15 +08:00
struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
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;
if (capsnap->dirty_pages) {
ceph: fix leaked inode ref due to snap metadata writeback race We create a ceph_cap_snap if there is dirty cap metadata (for writeback to mds) OR dirty pages (for writeback to osd). It is thus possible that the metadata has been written back to the MDS but the OSD data has not when the cap_snap is created. This results in a cap_snap with dirty(caps) == 0. The problem is that cap writeback to the MDS isn't necessary, and a FLUSHSNAP cap op gets no ack from the MDS. This leaves the cap_snap attached to the inode along with its inode reference. Fix the problem by dropping the cap_snap if it becomes 'complete' (all pages written out) and dirty(caps) == 0 in ceph_put_wrbuffer_cap_refs(). Also, BUG() in __ceph_flush_snaps() if we encounter a cap_snap with dirty(caps) == 0. Signed-off-by: Sage Weil <sage@newdream.net>
2010-04-02 00:33:46 +08:00
dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu "
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
"still has %d dirty pages\n", inode, capsnap,
capsnap->context, capsnap->context->seq,
ceph: fix leaked inode ref due to snap metadata writeback race We create a ceph_cap_snap if there is dirty cap metadata (for writeback to mds) OR dirty pages (for writeback to osd). It is thus possible that the metadata has been written back to the MDS but the OSD data has not when the cap_snap is created. This results in a cap_snap with dirty(caps) == 0. The problem is that cap writeback to the MDS isn't necessary, and a FLUSHSNAP cap op gets no ack from the MDS. This leaves the cap_snap attached to the inode along with its inode reference. Fix the problem by dropping the cap_snap if it becomes 'complete' (all pages written out) and dirty(caps) == 0 in ceph_put_wrbuffer_cap_refs(). Also, BUG() in __ceph_flush_snaps() if we encounter a cap_snap with dirty(caps) == 0. Signed-off-by: Sage Weil <sage@newdream.net>
2010-04-02 00:33:46 +08:00
ceph_cap_string(capsnap->dirty), capsnap->size,
capsnap->dirty_pages);
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
return 0;
}
ceph: fix leaked inode ref due to snap metadata writeback race We create a ceph_cap_snap if there is dirty cap metadata (for writeback to mds) OR dirty pages (for writeback to osd). It is thus possible that the metadata has been written back to the MDS but the OSD data has not when the cap_snap is created. This results in a cap_snap with dirty(caps) == 0. The problem is that cap writeback to the MDS isn't necessary, and a FLUSHSNAP cap op gets no ack from the MDS. This leaves the cap_snap attached to the inode along with its inode reference. Fix the problem by dropping the cap_snap if it becomes 'complete' (all pages written out) and dirty(caps) == 0 in ceph_put_wrbuffer_cap_refs(). Also, BUG() in __ceph_flush_snaps() if we encounter a cap_snap with dirty(caps) == 0. Signed-off-by: Sage Weil <sage@newdream.net>
2010-04-02 00:33:46 +08:00
dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu\n",
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
inode, capsnap, capsnap->context,
ceph: fix leaked inode ref due to snap metadata writeback race We create a ceph_cap_snap if there is dirty cap metadata (for writeback to mds) OR dirty pages (for writeback to osd). It is thus possible that the metadata has been written back to the MDS but the OSD data has not when the cap_snap is created. This results in a cap_snap with dirty(caps) == 0. The problem is that cap writeback to the MDS isn't necessary, and a FLUSHSNAP cap op gets no ack from the MDS. This leaves the cap_snap attached to the inode along with its inode reference. Fix the problem by dropping the cap_snap if it becomes 'complete' (all pages written out) and dirty(caps) == 0 in ceph_put_wrbuffer_cap_refs(). Also, BUG() in __ceph_flush_snaps() if we encounter a cap_snap with dirty(caps) == 0. Signed-off-by: Sage Weil <sage@newdream.net>
2010-04-02 00:33:46 +08:00
capsnap->context->seq, ceph_cap_string(capsnap->dirty),
capsnap->size);
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
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 */
}
ceph: queue cap snap writeback for realm children on snap update When a realm is updated, we need to queue writeback on inodes in that realm _and_ its children. Otherwise, if the inode gets cowed on the server, we can get a hang later due to out-of-sync cap/snap state. Signed-off-by: Sage Weil <sage@newdream.net>
2010-08-17 04:37:31 +08:00
/*
* 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;
struct ceph_snap_realm *child;
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);
if (lastinode)
iput(lastinode);
lastinode = inode;
ceph_queue_cap_snap(ci);
spin_lock(&realm->inodes_with_caps_lock);
}
spin_unlock(&realm->inodes_with_caps_lock);
if (lastinode)
iput(lastinode);
ceph: queue cap_snaps once per realm We were forming a dirty list, and then queueing cap_snaps for each realm _and_ its children, regardless of whether the children were already in the dirty list. This meant we did it twice for some realms. Which in turn meant we corrupted mdsc->snap_flush_list when the cap_snap was re-added to the list it was already on, and could trigger an infinite loop. We were also using recursion to do reach all the children, a no-no when stack is limited. Instead, (re)queue any children on the dirty list, avoiding processing anything twice and avoiding any recursion. Signed-off-by: Sage Weil <sage@newdream.net>
2011-02-05 12:45:58 +08:00
list_for_each_entry(child, &realm->children, child_item) {
dout("queue_realm_cap_snaps %p %llx queue child %p %llx\n",
realm, realm->ino, child, child->ino);
list_del_init(&child->dirty_item);
list_add(&child->dirty_item, &realm->dirty_item);
}
ceph: queue cap snap writeback for realm children on snap update When a realm is updated, we need to queue writeback on inodes in that realm _and_ its children. Otherwise, if the inode gets cowed on the server, we can get a hang later due to out-of-sync cap/snap state. Signed-off-by: Sage Weil <sage@newdream.net>
2010-08-17 04:37:31 +08:00
ceph: queue cap_snaps once per realm We were forming a dirty list, and then queueing cap_snaps for each realm _and_ its children, regardless of whether the children were already in the dirty list. This meant we did it twice for some realms. Which in turn meant we corrupted mdsc->snap_flush_list when the cap_snap was re-added to the list it was already on, and could trigger an infinite loop. We were also using recursion to do reach all the children, a no-no when stack is limited. Instead, (re)queue any children on the dirty list, avoiding processing anything twice and avoiding any recursion. Signed-off-by: Sage Weil <sage@newdream.net>
2011-02-05 12:45:58 +08:00
list_del_init(&realm->dirty_item);
ceph: queue cap snap writeback for realm children on snap update When a realm is updated, we need to queue writeback on inodes in that realm _and_ its children. Otherwise, if the inode gets cowed on the server, we can get a hang later due to out-of-sync cap/snap state. Signed-off-by: Sage Weil <sage@newdream.net>
2010-08-17 04:37:31 +08:00
dout("queue_realm_cap_snaps %p %llx done\n", realm, realm->ino);
}
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
/*
* 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_mds_snap_realm *ri; /* encoded */
__le64 *snaps; /* encoded */
__le64 *prior_parent_snaps; /* encoded */
struct ceph_snap_realm *realm;
int invalidate = 0;
int err = -ENOMEM;
ceph: fix cap_snap and realm split The cap_snap creation/queueing relies on both the current i_head_snapc _and_ the i_snap_realm pointers being correct, so that the new cap_snap can properly reference the old context and the new i_head_snapc can be updated to reference the new snaprealm's context. To fix this, we: - move inodes completely to the new (split) realm so that i_snap_realm is correct, and - generate the new snapc's _before_ queueing the cap_snaps in ceph_update_snap_trace(). Signed-off-by: Sage Weil <sage@newdream.net>
2010-09-17 07:26:51 +08:00
LIST_HEAD(dirty_realms);
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
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) {
ceph: fix cap_snap and realm split The cap_snap creation/queueing relies on both the current i_head_snapc _and_ the i_snap_realm pointers being correct, so that the new cap_snap can properly reference the old context and the new i_head_snapc can be updated to reference the new snaprealm's context. To fix this, we: - move inodes completely to the new (split) realm so that i_snap_realm is correct, and - generate the new snapc's _before_ queueing the cap_snaps in ceph_update_snap_trace(). Signed-off-by: Sage Weil <sage@newdream.net>
2010-09-17 07:26:51 +08:00
dout("update_snap_trace updating %llx %p %lld -> %lld\n",
realm->ino, realm, realm->seq, le64_to_cpu(ri->seq));
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
/* 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;
ceph: fix cap_snap and realm split The cap_snap creation/queueing relies on both the current i_head_snapc _and_ the i_snap_realm pointers being correct, so that the new cap_snap can properly reference the old context and the new i_head_snapc can be updated to reference the new snaprealm's context. To fix this, we: - move inodes completely to the new (split) realm so that i_snap_realm is correct, and - generate the new snapc's _before_ queueing the cap_snaps in ceph_update_snap_trace(). Signed-off-by: Sage Weil <sage@newdream.net>
2010-09-17 07:26:51 +08:00
/* queue realm for cap_snap creation */
list_add(&realm->dirty_item, &dirty_realms);
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
invalidate = 1;
} else if (!realm->cached_context) {
ceph: fix cap_snap and realm split The cap_snap creation/queueing relies on both the current i_head_snapc _and_ the i_snap_realm pointers being correct, so that the new cap_snap can properly reference the old context and the new i_head_snapc can be updated to reference the new snaprealm's context. To fix this, we: - move inodes completely to the new (split) realm so that i_snap_realm is correct, and - generate the new snapc's _before_ queueing the cap_snaps in ceph_update_snap_trace(). Signed-off-by: Sage Weil <sage@newdream.net>
2010-09-17 07:26:51 +08:00
dout("update_snap_trace %llx %p seq %lld new\n",
realm->ino, realm, realm->seq);
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
invalidate = 1;
ceph: fix cap_snap and realm split The cap_snap creation/queueing relies on both the current i_head_snapc _and_ the i_snap_realm pointers being correct, so that the new cap_snap can properly reference the old context and the new i_head_snapc can be updated to reference the new snaprealm's context. To fix this, we: - move inodes completely to the new (split) realm so that i_snap_realm is correct, and - generate the new snapc's _before_ queueing the cap_snaps in ceph_update_snap_trace(). Signed-off-by: Sage Weil <sage@newdream.net>
2010-09-17 07:26:51 +08:00
} else {
dout("update_snap_trace %llx %p seq %lld unchanged\n",
realm->ino, realm, realm->seq);
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
}
dout("done with %llx %p, invalidated=%d, %p %p\n", realm->ino,
realm, invalidate, p, e);
if (p < e)
goto more;
/* invalidate when we reach the _end_ (root) of the trace */
if (invalidate)
rebuild_snap_realms(realm);
ceph: fix cap_snap and realm split The cap_snap creation/queueing relies on both the current i_head_snapc _and_ the i_snap_realm pointers being correct, so that the new cap_snap can properly reference the old context and the new i_head_snapc can be updated to reference the new snaprealm's context. To fix this, we: - move inodes completely to the new (split) realm so that i_snap_realm is correct, and - generate the new snapc's _before_ queueing the cap_snaps in ceph_update_snap_trace(). Signed-off-by: Sage Weil <sage@newdream.net>
2010-09-17 07:26:51 +08:00
/*
* queue cap snaps _after_ we've built the new snap contexts,
* so that i_head_snapc can be set appropriately.
*/
ceph: queue cap_snaps once per realm We were forming a dirty list, and then queueing cap_snaps for each realm _and_ its children, regardless of whether the children were already in the dirty list. This meant we did it twice for some realms. Which in turn meant we corrupted mdsc->snap_flush_list when the cap_snap was re-added to the list it was already on, and could trigger an infinite loop. We were also using recursion to do reach all the children, a no-no when stack is limited. Instead, (re)queue any children on the dirty list, avoiding processing anything twice and avoiding any recursion. Signed-off-by: Sage Weil <sage@newdream.net>
2011-02-05 12:45:58 +08:00
while (!list_empty(&dirty_realms)) {
realm = list_first_entry(&dirty_realms, struct ceph_snap_realm,
dirty_item);
ceph: fix cap_snap and realm split The cap_snap creation/queueing relies on both the current i_head_snapc _and_ the i_snap_realm pointers being correct, so that the new cap_snap can properly reference the old context and the new i_head_snapc can be updated to reference the new snaprealm's context. To fix this, we: - move inodes completely to the new (split) realm so that i_snap_realm is correct, and - generate the new snapc's _before_ queueing the cap_snaps in ceph_update_snap_trace(). Signed-off-by: Sage Weil <sage@newdream.net>
2010-09-17 07:26:51 +08:00
queue_realm_cap_snaps(realm);
}
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
__cleanup_empty_realms(mdsc);
return 0;
bad:
err = -EINVAL;
fail:
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;
ceph: use ihold when we already have an inode ref We should use ihold whenever we already have a stable inode ref, even when we aren't holding i_lock. This avoids adding new and unnecessary locking dependencies. Signed-off-by: Sage Weil <sage@newdream.net>
2011-05-28 00:24:26 +08:00
ihold(inode);
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
spin_unlock(&mdsc->snap_flush_lock);
spin_lock(&inode->i_lock);
ceph: only send one flushsnap per cap_snap per mds session Sending multiple flushsnap messages is problematic because we ignore the response if the tid doesn't match, and the server may only respond to each one once. It's also a waste. So, skip cap_snaps that are already on the flushing list, unless the caller tells us to resend (because we are reconnecting). Signed-off-by: Sage Weil <sage@newdream.net>
2010-09-17 23:03:08 +08:00
__ceph_flush_snaps(ci, &session, 0);
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
spin_unlock(&inode->i_lock);
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,
ceph: drop messages on unregistered mds sessions; cleanup Verify the mds session is currently registered before handling incoming messages. Clean up message handlers to pull mds out of session->s_mds instead of less trustworthy src field. Clean up con_{get,put} debug output. Signed-off-by: Sage Weil <sage@newdream.net>
2010-02-23 07:12:16 +08:00
struct ceph_mds_session *session,
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
struct ceph_msg *msg)
{
ceph: factor out libceph from Ceph file system This factors out protocol and low-level storage parts of ceph into a separate libceph module living in net/ceph and include/linux/ceph. This is mostly a matter of moving files around. However, a few key pieces of the interface change as well: - ceph_client becomes ceph_fs_client and ceph_client, where the latter captures the mon and osd clients, and the fs_client gets the mds client and file system specific pieces. - Mount option parsing and debugfs setup is correspondingly broken into two pieces. - The mon client gets a generic handler callback for otherwise unknown messages (mds map, in this case). - The basic supported/required feature bits can be expanded (and are by ceph_fs_client). No functional change, aside from some subtle error handling cases that got cleaned up in the refactoring process. Signed-off-by: Sage Weil <sage@newdream.net>
2010-04-07 06:14:15 +08:00
struct super_block *sb = mdsc->fsc->sb;
ceph: drop messages on unregistered mds sessions; cleanup Verify the mds session is currently registered before handling incoming messages. Clean up message handlers to pull mds out of session->s_mds instead of less trustworthy src field. Clean up con_{get,put} debug output. Signed-off-by: Sage Weil <sage@newdream.net>
2010-02-23 07:12:16 +08:00
int mds = session->s_mds;
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
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;
}
ceph_get_snap_realm(mdsc, realm);
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;
ceph: fix cap_snap and realm split The cap_snap creation/queueing relies on both the current i_head_snapc _and_ the i_snap_realm pointers being correct, so that the new cap_snap can properly reference the old context and the new i_head_snapc can be updated to reference the new snaprealm's context. To fix this, we: - move inodes completely to the new (split) realm so that i_snap_realm is correct, and - generate the new snapc's _before_ queueing the cap_snaps in ceph_update_snap_trace(). Signed-off-by: Sage Weil <sage@newdream.net>
2010-09-17 07:26:51 +08:00
struct ceph_snap_realm *oldrealm;
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
if (!inode)
continue;
ci = ceph_inode(inode);
spin_lock(&inode->i_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);
/*
ceph: fix cap_snap and realm split The cap_snap creation/queueing relies on both the current i_head_snapc _and_ the i_snap_realm pointers being correct, so that the new cap_snap can properly reference the old context and the new i_head_snapc can be updated to reference the new snaprealm's context. To fix this, we: - move inodes completely to the new (split) realm so that i_snap_realm is correct, and - generate the new snapc's _before_ queueing the cap_snaps in ceph_update_snap_trace(). Signed-off-by: Sage Weil <sage@newdream.net>
2010-09-17 07:26:51 +08:00
* Move the inode to the new realm
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
*/
ceph: add missing locking to protect i_snap_realm_item during split All ci->i_snap_realm_item/realm->inodes_with_caps manipulation should be protected by realm->inodes_with_caps_lock. This bug would have only bit us in a rare race with a realm split (during some snap creations). Signed-off-by: Sage Weil <sage@newdream.net>
2010-03-10 04:52:26 +08:00
spin_lock(&realm->inodes_with_caps_lock);
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
list_del_init(&ci->i_snap_realm_item);
ceph: fix cap_snap and realm split The cap_snap creation/queueing relies on both the current i_head_snapc _and_ the i_snap_realm pointers being correct, so that the new cap_snap can properly reference the old context and the new i_head_snapc can be updated to reference the new snaprealm's context. To fix this, we: - move inodes completely to the new (split) realm so that i_snap_realm is correct, and - generate the new snapc's _before_ queueing the cap_snaps in ceph_update_snap_trace(). Signed-off-by: Sage Weil <sage@newdream.net>
2010-09-17 07:26:51 +08:00
list_add(&ci->i_snap_realm_item,
&realm->inodes_with_caps);
oldrealm = ci->i_snap_realm;
ci->i_snap_realm = realm;
ceph: add missing locking to protect i_snap_realm_item during split All ci->i_snap_realm_item/realm->inodes_with_caps manipulation should be protected by realm->inodes_with_caps_lock. This bug would have only bit us in a rare race with a realm split (during some snap creations). Signed-off-by: Sage Weil <sage@newdream.net>
2010-03-10 04:52:26 +08:00
spin_unlock(&realm->inodes_with_caps_lock);
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
spin_unlock(&inode->i_lock);
ceph: fix cap_snap and realm split The cap_snap creation/queueing relies on both the current i_head_snapc _and_ the i_snap_realm pointers being correct, so that the new cap_snap can properly reference the old context and the new i_head_snapc can be updated to reference the new snaprealm's context. To fix this, we: - move inodes completely to the new (split) realm so that i_snap_realm is correct, and - generate the new snapc's _before_ queueing the cap_snaps in ceph_update_snap_trace(). Signed-off-by: Sage Weil <sage@newdream.net>
2010-09-17 07:26:51 +08:00
ceph_get_snap_realm(mdsc, realm);
ceph_put_snap_realm(mdsc, oldrealm);
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
iput(inode);
continue;
skip_inode:
spin_unlock(&inode->i_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 =
ceph_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);
ceph: fix cap_snap and realm split The cap_snap creation/queueing relies on both the current i_head_snapc _and_ the i_snap_realm pointers being correct, so that the new cap_snap can properly reference the old context and the new i_head_snapc can be updated to reference the new snaprealm's context. To fix this, we: - move inodes completely to the new (split) realm so that i_snap_realm is correct, and - generate the new snapc's _before_ queueing the cap_snaps in ceph_update_snap_trace(). Signed-off-by: Sage Weil <sage@newdream.net>
2010-09-17 07:26:51 +08:00
if (op == CEPH_SNAP_OP_SPLIT)
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
/* 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: hex dump corrupt server data to KERN_DEBUG Also, print fsid using standard format, NOT hex dump. Signed-off-by: Sage Weil <sage@newdream.net>
2009-12-15 07:13:47 +08:00
ceph_msg_dump(msg);
ceph: snapshot management Ceph snapshots rely on client cooperation in determining which operations apply to which snapshots, and appropriately flushing snapshotted data and metadata back to the OSD and MDS clusters. Because snapshots apply to subtrees of the file hierarchy and can be created at any time, there is a fair bit of bookkeeping required to make this work. Portions of the hierarchy that belong to the same set of snapshots are described by a single 'snap realm.' A 'snap context' describes the set of snapshots that exist for a given file or directory. Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 02:31:12 +08:00
out:
if (locked_rwsem)
up_write(&mdsc->snap_rwsem);
return;
}
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