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Message-ID: <20200905120427.GJ8670@sasha-vm>
Date: Sat, 5 Sep 2020 08:04:27 -0400
From: Sasha Levin <sashal@...nel.org>
To: Ilya Dryomov <idryomov@...il.com>
Cc: LKML <linux-kernel@...r.kernel.org>, stable@...r.kernel.org,
Jeff Layton <jlayton@...nel.org>,
Ulrich Weigand <Ulrich.Weigand@...ibm.com>,
Tuan Hoang1 <Tuan.Hoang1@....com>,
"Yan, Zheng" <zyan@...hat.com>,
Ceph Development <ceph-devel@...r.kernel.org>
Subject: Re: [PATCH AUTOSEL 5.8 25/42] ceph: fix inode number handling on
arches with 32-bit ino_t
On Mon, Aug 31, 2020 at 06:08:32PM +0200, Ilya Dryomov wrote:
>On Mon, Aug 31, 2020 at 5:30 PM Sasha Levin <sashal@...nel.org> wrote:
>>
>> From: Jeff Layton <jlayton@...nel.org>
>>
>> [ Upstream commit ebce3eb2f7ef9f6ef01a60874ebd232450107c9a ]
>>
>> Tuan and Ulrich mentioned that they were hitting a problem on s390x,
>> which has a 32-bit ino_t value, even though it's a 64-bit arch (for
>> historical reasons).
>>
>> I think the current handling of inode numbers in the ceph driver is
>> wrong. It tries to use 32-bit inode numbers on 32-bit arches, but that's
>> actually not a problem. 32-bit arches can deal with 64-bit inode numbers
>> just fine when userland code is compiled with LFS support (the common
>> case these days).
>>
>> What we really want to do is just use 64-bit numbers everywhere, unless
>> someone has mounted with the ino32 mount option. In that case, we want
>> to ensure that we hash the inode number down to something that will fit
>> in 32 bits before presenting the value to userland.
>>
>> Add new helper functions that do this, and only do the conversion before
>> presenting these values to userland in getattr and readdir.
>>
>> The inode table hashvalue is changed to just cast the inode number to
>> unsigned long, as low-order bits are the most likely to vary anyway.
>>
>> While it's not strictly required, we do want to put something in
>> inode->i_ino. Instead of basing it on BITS_PER_LONG, however, base it on
>> the size of the ino_t type.
>>
>> NOTE: This is a user-visible change on 32-bit arches:
>>
>> 1/ inode numbers will be seen to have changed between kernel versions.
>> 32-bit arches will see large inode numbers now instead of the hashed
>> ones they saw before.
>>
>> 2/ any really old software not built with LFS support may start failing
>> stat() calls with -EOVERFLOW on inode numbers >2^32. Nothing much we
>> can do about these, but hopefully the intersection of people running
>> such code on ceph will be very small.
>>
>> The workaround for both problems is to mount with "-o ino32".
>>
>> [ idryomov: changelog tweak ]
>>
>> URL: https://tracker.ceph.com/issues/46828
>> Reported-by: Ulrich Weigand <Ulrich.Weigand@...ibm.com>
>> Reported-and-Tested-by: Tuan Hoang1 <Tuan.Hoang1@....com>
>> Signed-off-by: Jeff Layton <jlayton@...nel.org>
>> Reviewed-by: "Yan, Zheng" <zyan@...hat.com>
>> Signed-off-by: Ilya Dryomov <idryomov@...il.com>
>> Signed-off-by: Sasha Levin <sashal@...nel.org>
>> ---
>> fs/ceph/caps.c | 14 ++++-----
>> fs/ceph/debugfs.c | 4 +--
>> fs/ceph/dir.c | 31 ++++++++-----------
>> fs/ceph/file.c | 4 +--
>> fs/ceph/inode.c | 19 ++++++------
>> fs/ceph/mds_client.h | 2 +-
>> fs/ceph/quota.c | 4 +--
>> fs/ceph/super.h | 73 +++++++++++++++++++++++---------------------
>> 8 files changed, 74 insertions(+), 77 deletions(-)
>>
>> diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
>> index 972c13aa42259..1206a481c5fc7 100644
>> --- a/fs/ceph/caps.c
>> +++ b/fs/ceph/caps.c
>> @@ -886,8 +886,8 @@ int __ceph_caps_issued_mask(struct ceph_inode_info *ci, int mask, int touch)
>> int have = ci->i_snap_caps;
>>
>> if ((have & mask) == mask) {
>> - dout("__ceph_caps_issued_mask ino 0x%lx snap issued %s"
>> - " (mask %s)\n", ci->vfs_inode.i_ino,
>> + dout("__ceph_caps_issued_mask ino 0x%llx snap issued %s"
>> + " (mask %s)\n", ceph_ino(&ci->vfs_inode),
>> ceph_cap_string(have),
>> ceph_cap_string(mask));
>> return 1;
>> @@ -898,8 +898,8 @@ int __ceph_caps_issued_mask(struct ceph_inode_info *ci, int mask, int touch)
>> if (!__cap_is_valid(cap))
>> continue;
>> if ((cap->issued & mask) == mask) {
>> - dout("__ceph_caps_issued_mask ino 0x%lx cap %p issued %s"
>> - " (mask %s)\n", ci->vfs_inode.i_ino, cap,
>> + dout("__ceph_caps_issued_mask ino 0x%llx cap %p issued %s"
>> + " (mask %s)\n", ceph_ino(&ci->vfs_inode), cap,
>> ceph_cap_string(cap->issued),
>> ceph_cap_string(mask));
>> if (touch)
>> @@ -910,8 +910,8 @@ int __ceph_caps_issued_mask(struct ceph_inode_info *ci, int mask, int touch)
>> /* does a combination of caps satisfy mask? */
>> have |= cap->issued;
>> if ((have & mask) == mask) {
>> - dout("__ceph_caps_issued_mask ino 0x%lx combo issued %s"
>> - " (mask %s)\n", ci->vfs_inode.i_ino,
>> + dout("__ceph_caps_issued_mask ino 0x%llx combo issued %s"
>> + " (mask %s)\n", ceph_ino(&ci->vfs_inode),
>> ceph_cap_string(cap->issued),
>> ceph_cap_string(mask));
>> if (touch) {
>> @@ -2870,7 +2870,7 @@ int ceph_get_caps(struct file *filp, int need, int want,
>> struct cap_wait cw;
>> DEFINE_WAIT_FUNC(wait, woken_wake_function);
>>
>> - cw.ino = inode->i_ino;
>> + cw.ino = ceph_ino(inode);
>> cw.tgid = current->tgid;
>> cw.need = need;
>> cw.want = want;
>> diff --git a/fs/ceph/debugfs.c b/fs/ceph/debugfs.c
>> index 070ed84813406..74747d8d48619 100644
>> --- a/fs/ceph/debugfs.c
>> +++ b/fs/ceph/debugfs.c
>> @@ -212,7 +212,7 @@ static int caps_show_cb(struct inode *inode, struct ceph_cap *cap, void *p)
>> {
>> struct seq_file *s = p;
>>
>> - seq_printf(s, "0x%-17lx%-17s%-17s\n", inode->i_ino,
>> + seq_printf(s, "0x%-17llx%-17s%-17s\n", ceph_ino(inode),
>> ceph_cap_string(cap->issued),
>> ceph_cap_string(cap->implemented));
>> return 0;
>> @@ -257,7 +257,7 @@ static int caps_show(struct seq_file *s, void *p)
>>
>> spin_lock(&mdsc->caps_list_lock);
>> list_for_each_entry(cw, &mdsc->cap_wait_list, list) {
>> - seq_printf(s, "%-13d0x%-17lx%-17s%-17s\n", cw->tgid, cw->ino,
>> + seq_printf(s, "%-13d0x%-17llx%-17s%-17s\n", cw->tgid, cw->ino,
>> ceph_cap_string(cw->need),
>> ceph_cap_string(cw->want));
>> }
>> diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
>> index 060bdcc5ce32c..040eaad9d0631 100644
>> --- a/fs/ceph/dir.c
>> +++ b/fs/ceph/dir.c
>> @@ -259,9 +259,7 @@ static int __dcache_readdir(struct file *file, struct dir_context *ctx,
>> dentry, dentry, d_inode(dentry));
>> ctx->pos = di->offset;
>> if (!dir_emit(ctx, dentry->d_name.name,
>> - dentry->d_name.len,
>> - ceph_translate_ino(dentry->d_sb,
>> - d_inode(dentry)->i_ino),
>> + dentry->d_name.len, ceph_present_inode(d_inode(dentry)),
>> d_inode(dentry)->i_mode >> 12)) {
>> dput(dentry);
>> err = 0;
>> @@ -324,18 +322,21 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
>> /* always start with . and .. */
>> if (ctx->pos == 0) {
>> dout("readdir off 0 -> '.'\n");
>> - if (!dir_emit(ctx, ".", 1,
>> - ceph_translate_ino(inode->i_sb, inode->i_ino),
>> + if (!dir_emit(ctx, ".", 1, ceph_present_inode(inode),
>> inode->i_mode >> 12))
>> return 0;
>> ctx->pos = 1;
>> }
>> if (ctx->pos == 1) {
>> - ino_t ino = parent_ino(file->f_path.dentry);
>> + u64 ino;
>> + struct dentry *dentry = file->f_path.dentry;
>> +
>> + spin_lock(&dentry->d_lock);
>> + ino = ceph_present_inode(dentry->d_parent->d_inode);
>> + spin_unlock(&dentry->d_lock);
>> +
>> dout("readdir off 1 -> '..'\n");
>> - if (!dir_emit(ctx, "..", 2,
>> - ceph_translate_ino(inode->i_sb, ino),
>> - inode->i_mode >> 12))
>> + if (!dir_emit(ctx, "..", 2, ino, inode->i_mode >> 12))
>> return 0;
>> ctx->pos = 2;
>> }
>> @@ -507,9 +508,6 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
>> }
>> for (; i < rinfo->dir_nr; i++) {
>> struct ceph_mds_reply_dir_entry *rde = rinfo->dir_entries + i;
>> - struct ceph_vino vino;
>> - ino_t ino;
>> - u32 ftype;
>>
>> BUG_ON(rde->offset < ctx->pos);
>>
>> @@ -519,13 +517,10 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
>> rde->name_len, rde->name, &rde->inode.in);
>>
>> BUG_ON(!rde->inode.in);
>> - ftype = le32_to_cpu(rde->inode.in->mode) >> 12;
>> - vino.ino = le64_to_cpu(rde->inode.in->ino);
>> - vino.snap = le64_to_cpu(rde->inode.in->snapid);
>> - ino = ceph_vino_to_ino(vino);
>>
>> if (!dir_emit(ctx, rde->name, rde->name_len,
>> - ceph_translate_ino(inode->i_sb, ino), ftype)) {
>> + ceph_present_ino(inode->i_sb, le64_to_cpu(rde->inode.in->ino)),
>> + le32_to_cpu(rde->inode.in->mode) >> 12)) {
>> dout("filldir stopping us...\n");
>> return 0;
>> }
>> @@ -1161,7 +1156,7 @@ static int ceph_unlink(struct inode *dir, struct dentry *dentry)
>>
>> if (try_async && op == CEPH_MDS_OP_UNLINK &&
>> (req->r_dir_caps = get_caps_for_async_unlink(dir, dentry))) {
>> - dout("async unlink on %lu/%.*s caps=%s", dir->i_ino,
>> + dout("async unlink on %llu/%.*s caps=%s", ceph_ino(dir),
>> dentry->d_name.len, dentry->d_name.name,
>> ceph_cap_string(req->r_dir_caps));
>> set_bit(CEPH_MDS_R_ASYNC, &req->r_req_flags);
>> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
>> index 160644ddaeed7..26172bb90a459 100644
>> --- a/fs/ceph/file.c
>> +++ b/fs/ceph/file.c
>> @@ -630,8 +630,8 @@ static int ceph_finish_async_create(struct inode *dir, struct dentry *dentry,
>> } else {
>> struct dentry *dn;
>>
>> - dout("%s d_adding new inode 0x%llx to 0x%lx/%s\n", __func__,
>> - vino.ino, dir->i_ino, dentry->d_name.name);
>> + dout("%s d_adding new inode 0x%llx to 0x%llx/%s\n", __func__,
>> + vino.ino, ceph_ino(dir), dentry->d_name.name);
>> ceph_dir_clear_ordered(dir);
>> ceph_init_inode_acls(inode, as_ctx);
>> if (inode->i_state & I_NEW) {
>> diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
>> index 357c937699d56..d163fa96cb401 100644
>> --- a/fs/ceph/inode.c
>> +++ b/fs/ceph/inode.c
>> @@ -41,8 +41,10 @@ static void ceph_inode_work(struct work_struct *work);
>> */
>> static int ceph_set_ino_cb(struct inode *inode, void *data)
>> {
>> - ceph_inode(inode)->i_vino = *(struct ceph_vino *)data;
>> - inode->i_ino = ceph_vino_to_ino(*(struct ceph_vino *)data);
>> + struct ceph_inode_info *ci = ceph_inode(inode);
>> +
>> + ci->i_vino = *(struct ceph_vino *)data;
>> + inode->i_ino = ceph_vino_to_ino_t(ci->i_vino);
>> inode_set_iversion_raw(inode, 0);
>> return 0;
>> }
>> @@ -50,17 +52,14 @@ static int ceph_set_ino_cb(struct inode *inode, void *data)
>> struct inode *ceph_get_inode(struct super_block *sb, struct ceph_vino vino)
>> {
>> struct inode *inode;
>> - ino_t t = ceph_vino_to_ino(vino);
>>
>> - inode = iget5_locked(sb, t, ceph_ino_compare, ceph_set_ino_cb, &vino);
>> + inode = iget5_locked(sb, (unsigned long)vino.ino, ceph_ino_compare,
>> + ceph_set_ino_cb, &vino);
>> if (!inode)
>> return ERR_PTR(-ENOMEM);
>> - if (inode->i_state & I_NEW)
>> - dout("get_inode created new inode %p %llx.%llx ino %llx\n",
>> - inode, ceph_vinop(inode), (u64)inode->i_ino);
>>
>> - dout("get_inode on %lu=%llx.%llx got %p\n", inode->i_ino, vino.ino,
>> - vino.snap, inode);
>> + dout("get_inode on %llu=%llx.%llx got %p new %d\n", ceph_present_inode(inode),
>> + ceph_vinop(inode), inode, !!(inode->i_state & I_NEW));
>> return inode;
>> }
>>
>> @@ -2378,7 +2377,7 @@ int ceph_getattr(const struct path *path, struct kstat *stat,
>> }
>>
>> generic_fillattr(inode, stat);
>> - stat->ino = ceph_translate_ino(inode->i_sb, inode->i_ino);
>> + stat->ino = ceph_present_inode(inode);
>>
>> /*
>> * btime on newly-allocated inodes is 0, so if this is still set to
>> diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
>> index 5e0c4073a6bea..63c9cd1c28d6c 100644
>> --- a/fs/ceph/mds_client.h
>> +++ b/fs/ceph/mds_client.h
>> @@ -369,7 +369,7 @@ struct ceph_quotarealm_inode {
>>
>> struct cap_wait {
>> struct list_head list;
>> - unsigned long ino;
>> + u64 ino;
>> pid_t tgid;
>> int need;
>> int want;
>> diff --git a/fs/ceph/quota.c b/fs/ceph/quota.c
>> index 198ddde5c1e6a..cc2c4d40b0222 100644
>> --- a/fs/ceph/quota.c
>> +++ b/fs/ceph/quota.c
>> @@ -23,12 +23,12 @@ static inline bool ceph_has_realms_with_quotas(struct inode *inode)
>> {
>> struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
>> struct super_block *sb = mdsc->fsc->sb;
>> + struct inode *root = d_inode(sb->s_root);
>>
>> if (atomic64_read(&mdsc->quotarealms_count) > 0)
>> return true;
>> /* if root is the real CephFS root, we don't have quota realms */
>> - if (sb->s_root->d_inode &&
>> - (sb->s_root->d_inode->i_ino == CEPH_INO_ROOT))
>> + if (root && ceph_ino(root) == CEPH_INO_ROOT)
>> return false;
>> /* otherwise, we can't know for sure */
>> return true;
>> diff --git a/fs/ceph/super.h b/fs/ceph/super.h
>> index 5a6cdd39bc103..2af3e06a6d0ce 100644
>> --- a/fs/ceph/super.h
>> +++ b/fs/ceph/super.h
>> @@ -457,15 +457,7 @@ ceph_vino(const struct inode *inode)
>> return ceph_inode(inode)->i_vino;
>> }
>>
>> -/*
>> - * ino_t is <64 bits on many architectures, blech.
>> - *
>> - * i_ino (kernel inode) st_ino (userspace)
>> - * i386 32 32
>> - * x86_64+ino32 64 32
>> - * x86_64 64 64
>> - */
>> -static inline u32 ceph_ino_to_ino32(__u64 vino)
>> +static inline u32 ceph_ino_to_ino32(u64 vino)
>> {
>> u32 ino = vino & 0xffffffff;
>> ino ^= vino >> 32;
>> @@ -475,34 +467,17 @@ static inline u32 ceph_ino_to_ino32(__u64 vino)
>> }
>>
>> /*
>> - * kernel i_ino value
>> + * Inode numbers in cephfs are 64 bits, but inode->i_ino is 32-bits on
>> + * some arches. We generally do not use this value inside the ceph driver, but
>> + * we do want to set it to something, so that generic vfs code has an
>> + * appropriate value for tracepoints and the like.
>> */
>> -static inline ino_t ceph_vino_to_ino(struct ceph_vino vino)
>> +static inline ino_t ceph_vino_to_ino_t(struct ceph_vino vino)
>> {
>> -#if BITS_PER_LONG == 32
>> - return ceph_ino_to_ino32(vino.ino);
>> -#else
>> + if (sizeof(ino_t) == sizeof(u32))
>> + return ceph_ino_to_ino32(vino.ino);
>> return (ino_t)vino.ino;
>> -#endif
>> -}
>> -
>> -/*
>> - * user-visible ino (stat, filldir)
>> - */
>> -#if BITS_PER_LONG == 32
>> -static inline ino_t ceph_translate_ino(struct super_block *sb, ino_t ino)
>> -{
>> - return ino;
>> -}
>> -#else
>> -static inline ino_t ceph_translate_ino(struct super_block *sb, ino_t ino)
>> -{
>> - if (ceph_test_mount_opt(ceph_sb_to_client(sb), INO32))
>> - ino = ceph_ino_to_ino32(ino);
>> - return ino;
>> }
>> -#endif
>> -
>>
>> /* for printf-style formatting */
>> #define ceph_vinop(i) ceph_inode(i)->i_vino.ino, ceph_inode(i)->i_vino.snap
>> @@ -511,11 +486,34 @@ static inline u64 ceph_ino(struct inode *inode)
>> {
>> return ceph_inode(inode)->i_vino.ino;
>> }
>> +
>> static inline u64 ceph_snap(struct inode *inode)
>> {
>> return ceph_inode(inode)->i_vino.snap;
>> }
>>
>> +/**
>> + * ceph_present_ino - format an inode number for presentation to userland
>> + * @sb: superblock where the inode lives
>> + * @ino: inode number to (possibly) convert
>> + *
>> + * If the user mounted with the ino32 option, then the 64-bit value needs
>> + * to be converted to something that can fit inside 32 bits. Note that
>> + * internal kernel code never uses this value, so this is entirely for
>> + * userland consumption.
>> + */
>> +static inline u64 ceph_present_ino(struct super_block *sb, u64 ino)
>> +{
>> + if (unlikely(ceph_test_mount_opt(ceph_sb_to_client(sb), INO32)))
>> + return ceph_ino_to_ino32(ino);
>> + return ino;
>> +}
>> +
>> +static inline u64 ceph_present_inode(struct inode *inode)
>> +{
>> + return ceph_present_ino(inode->i_sb, ceph_ino(inode));
>> +}
>> +
>> static inline int ceph_ino_compare(struct inode *inode, void *data)
>> {
>> struct ceph_vino *pvino = (struct ceph_vino *)data;
>> @@ -524,11 +522,16 @@ static inline int ceph_ino_compare(struct inode *inode, void *data)
>> ci->i_vino.snap == pvino->snap;
>> }
>>
>> +
>> static inline struct inode *ceph_find_inode(struct super_block *sb,
>> struct ceph_vino vino)
>> {
>> - ino_t t = ceph_vino_to_ino(vino);
>> - return ilookup5(sb, t, ceph_ino_compare, &vino);
>> + /*
>> + * NB: The hashval will be run through the fs/inode.c hash function
>> + * anyway, so there is no need to squash the inode number down to
>> + * 32-bits first. Just use low-order bits on arches with 32-bit long.
>> + */
>> + return ilookup5(sb, (unsigned long)vino.ino, ceph_ino_compare, &vino);
>> }
>>
>>
>> --
>> 2.25.1
>
>Hi Sasha,
>
>This is a user-visible change and wasn't marked for stable for that
>reason. Please drop it.
Dropped, thanks!
--
Thanks,
Sasha
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