On Tue, Nov 08, 2022 at 08:25:22AM -0800, Darrick J. Wong wrote:
> On Tue, Nov 08, 2022 at 02:30:09PM +0100, Lukas Czerner wrote:
> > Implement user and group quota support for tmpfs using system quota file
> > in vfsv0 quota format. Because everything in tmpfs is temporary and as a
> > result is lost on umount, the quota files are initialized on every
> > mount. This also goes for quota limits, that needs to be set up after
> > every mount.
> >
> > The quota support in tmpfs is well separated from the rest of the
> > filesystem and is only enabled using mount option -o quota (and
> > usrquota and grpquota for compatibility reasons). Only quota accounting
> > is enabled this way, enforcement needs to be enable by regular quota
> > tools (using Q_QUOTAON ioctl).
> >
> > Signed-off-by: Lukas Czerner <lczerner@xxxxxxxxxx>
> > ---
> > Documentation/filesystems/tmpfs.rst | 12 +
> > include/linux/shmem_fs.h | 3 +
> > mm/shmem.c | 361 ++++++++++++++++++++++++++--
> > 3 files changed, 353 insertions(+), 23 deletions(-)
> >
> > diff --git a/Documentation/filesystems/tmpfs.rst b/Documentation/filesystems/tmpfs.rst
> > index 0408c245785e..9c4f228ef4f3 100644
> > --- a/Documentation/filesystems/tmpfs.rst
> > +++ b/Documentation/filesystems/tmpfs.rst
> > @@ -86,6 +86,18 @@ use up all the memory on the machine; but enhances the scalability of
> > that instance in a system with many CPUs making intensive use of it.
> >
> >
> > +tmpfs also supports quota with the following mount options
> > +
> > +======== =============================================================
> > +quota Quota accounting is enabled on the mount. Tmpfs is using
> > + hidden system quota files that are initialized on mount.
> > + Quota limits can quota enforcement can be enabled using
> > + standard quota tools.
> > +usrquota Same as quota option. Exists for compatibility reasons.
> > +grpquota Same as quota option. Exists for compatibility reasons.
>
> I guess this is following ext* where group and user quota cannot be
> enabled individually, nor is there a 'noenforce' mode?
It's not exactly the same as in ext* as Jan pointed out and the idea was
not to bother with enabling user and group quota separately. And there
is no 'noenforce' mode. With these options only accounting is enabled.
Enforcement can be enabled with ioctl, or using the quota limit options
introduced in the second patch.
Jan seems to think that it should be possible to enable user and group
quotas separately and I have no problem with that.
>
> Not complaining here, since it /does/ cut down on the number of mount
> options. :)
>
> > +======== =============================================================
> > +
> > +
> > tmpfs has a mount option to set the NUMA memory allocation policy for
> > all files in that instance (if CONFIG_NUMA is enabled) - which can be
> > adjusted on the fly via 'mount -o remount ...'
> > diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
> > index d500ea967dc7..02a328c98d3a 100644
> > --- a/include/linux/shmem_fs.h
> > +++ b/include/linux/shmem_fs.h
> > @@ -26,6 +26,9 @@ struct shmem_inode_info {
> > atomic_t stop_eviction; /* hold when working on inode */
> > struct timespec64 i_crtime; /* file creation time */
> > unsigned int fsflags; /* flags for FS_IOC_[SG]ETFLAGS */
> > +#ifdef CONFIG_QUOTA
> > + struct dquot *i_dquot[MAXQUOTAS];
> > +#endif
> > struct inode vfs_inode;
> > };
> >
> > diff --git a/mm/shmem.c b/mm/shmem.c
> > index c1d8b8a1aa3b..ec16659c2255 100644
> > --- a/mm/shmem.c
> > +++ b/mm/shmem.c
> > @@ -79,6 +79,12 @@ static struct vfsmount *shm_mnt;
> > #include <linux/userfaultfd_k.h>
> > #include <linux/rmap.h>
> > #include <linux/uuid.h>
> > +#include <linux/quotaops.h>
> > +/*
> > + * Required for structures definitions and macros for quote file
> > + * initialization.
> > + */
> > +#include <../fs/quota/quotaio_v2.h>
> >
> > #include <linux/uaccess.h>
> >
> > @@ -120,8 +126,13 @@ struct shmem_options {
> > #define SHMEM_SEEN_INODES 2
> > #define SHMEM_SEEN_HUGE 4
> > #define SHMEM_SEEN_INUMS 8
> > +#define SHMEM_SEEN_QUOTA 16
> > };
> >
> > +static void shmem_set_inode_flags(struct inode *, unsigned int);
> > +static struct inode *shmem_get_inode_noquota(struct super_block *,
> > + struct inode *, umode_t, dev_t, unsigned long);
> > +
> > #ifdef CONFIG_TMPFS
> > static unsigned long shmem_default_max_blocks(void)
> > {
> > @@ -136,6 +147,10 @@ static unsigned long shmem_default_max_inodes(void)
> > }
> > #endif
> >
> > +#if defined(CONFIG_TMPFS) && defined(CONFIG_QUOTA)
> > +#define SHMEM_QUOTA_TMPFS
> > +#endif
> > +
> > static int shmem_swapin_folio(struct inode *inode, pgoff_t index,
> > struct folio **foliop, enum sgp_type sgp,
> > gfp_t gfp, struct vm_area_struct *vma,
> > @@ -198,26 +213,34 @@ static inline void shmem_unacct_blocks(unsigned long flags, long pages)
> > vm_unacct_memory(pages * VM_ACCT(PAGE_SIZE));
> > }
> >
> > -static inline bool shmem_inode_acct_block(struct inode *inode, long pages)
> > +static inline int shmem_inode_acct_block(struct inode *inode, long pages)
> > {
> > struct shmem_inode_info *info = SHMEM_I(inode);
> > struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
> > + int err = -ENOSPC;
> >
> > if (shmem_acct_block(info->flags, pages))
> > - return false;
> > + return err;
> >
> > if (sbinfo->max_blocks) {
> > if (percpu_counter_compare(&sbinfo->used_blocks,
> > sbinfo->max_blocks - pages) > 0)
> > goto unacct;
> > + if (dquot_alloc_block_nodirty(inode, pages)) {
> > + err = -EDQUOT;
> > + goto unacct;
> > + }
> > percpu_counter_add(&sbinfo->used_blocks, pages);
> > + } else if (dquot_alloc_block_nodirty(inode, pages)) {
> > + err = -EDQUOT;
> > + goto unacct;
> > }
> >
> > - return true;
> > + return 0;
> >
> > unacct:
> > shmem_unacct_blocks(info->flags, pages);
> > - return false;
> > + return err;
> > }
> >
> > static inline void shmem_inode_unacct_blocks(struct inode *inode, long pages)
> > @@ -225,6 +248,8 @@ static inline void shmem_inode_unacct_blocks(struct inode *inode, long pages)
> > struct shmem_inode_info *info = SHMEM_I(inode);
> > struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
> >
> > + dquot_free_block_nodirty(inode, pages);
> > +
> > if (sbinfo->max_blocks)
> > percpu_counter_sub(&sbinfo->used_blocks, pages);
> > shmem_unacct_blocks(info->flags, pages);
> > @@ -247,6 +272,218 @@ bool vma_is_shmem(struct vm_area_struct *vma)
> > static LIST_HEAD(shmem_swaplist);
> > static DEFINE_MUTEX(shmem_swaplist_mutex);
> >
> > +#ifdef SHMEM_QUOTA_TMPFS
> > +
> > +#define SHMEM_MAXQUOTAS 2
> > +
> > +/*
> > + * Define macros needed for quota file initialization.
> > + */
> > +#define MAX_IQ_TIME 604800 /* (7*24*60*60) 1 week */
> > +#define MAX_DQ_TIME 604800 /* (7*24*60*60) 1 week */
> > +#define QT_TREEOFF 1 /* Offset of tree in file in blocks */
> > +#define QUOTABLOCK_BITS 10
> > +#define QUOTABLOCK_SIZE (1 << QUOTABLOCK_BITS)
> > +
> > +static ssize_t shmem_quota_write_inode(struct inode *inode, int type,
> > + const char *data, size_t len, loff_t off)
> > +{
> > + loff_t i_size = i_size_read(inode);
> > + struct page *page = NULL;
> > + unsigned long offset;
> > + struct folio *folio;
> > + int err = 0;
> > + pgoff_t index;
> > +
> > + index = off >> PAGE_SHIFT;
> > + offset = off & ~PAGE_MASK;
> > +
> > + /*
> > + * We expect the write to fit into a single page
> > + */
> > + if (PAGE_SIZE - offset < len) {
> > + pr_warn("tmpfs: quota write (off=%llu, len=%llu) doesn't fit into a single page\n",
> > + (unsigned long long)off, (unsigned long long)len);
> > + return -EIO;
> > + }
> > +
> > + err = shmem_get_folio(inode, index, &folio, SGP_WRITE);
> > + if (err)
> > + return err;
> > +
> > + page = folio_file_page(folio, index);
> > + if (PageHWPoison(page)) {
> > + folio_unlock(folio);
> > + folio_put(folio);
> > + return -EIO;
> > + }
> > +
> > + /* Write data, or zeroout the portion of the page */
> > + if (data)
> > + memcpy(page_address(page) + offset, data, len);
> > + else
> > + memset(page_address(page) + offset, 0, len);
> > +
> > + SetPageUptodate(page);
>
> Don't we need to mark the /folio/ uptodate here? Or at least the head
> page if the quota file got a THP?
>
> Hm. shmem_write_end will SetPageUptodate on the head page if it's a
> compound page, but it'll set_page_dirty to mark the whole folio dirty.
> Now I'm confused completely. :(
>
> OTOH I guess these are quota files, perhaps they simply don't need THP
> anyway?
Honestly the folio bussiness is still a bit confusing for me in this
regard so I'd have to think some more about what it means and what the
right action here is.
>
> > + flush_dcache_folio(folio);
> > + folio_mark_dirty(folio);
> > + folio_unlock(folio);
> > + folio_put(folio);
> > +
> > + if (i_size < off + len)
> > + i_size_write(inode, off + len);
> > + return err ? err : len;
> > +}
> > +
> > +static ssize_t shmem_quota_write(struct super_block *sb, int type,
> > + const char *data, size_t len, loff_t off)
> > +{
> > + struct inode *inode = sb_dqopt(sb)->files[type];
> > +
> > + return shmem_quota_write_inode(inode, type, data, len, off);
> > +}
> > +
> > +static int shmem_enable_quotas(struct super_block *sb)
> > +{
> > + int type, err = 0;
> > + struct inode *inode;
> > + struct v2_disk_dqheader qheader;
> > + struct v2_disk_dqinfo qinfo;
> > + static const uint quota_magics[] = V2_INITQMAGICS;
> > + static const uint quota_versions[] = V2_INITQVERSIONS;
> > +
> > + sb_dqopt(sb)->flags |= DQUOT_QUOTA_SYS_FILE | DQUOT_NOLIST_DIRTY;
> > + for (type = 0; type < SHMEM_MAXQUOTAS; type++) {
> > + inode = shmem_get_inode_noquota(sb, NULL, S_IFREG | 0777, 0,
> > + VM_NORESERVE);
> > + if (IS_ERR_OR_NULL(inode)) {
> > + err = PTR_ERR(inode);
> > + goto out_err;
> > + }
> > + inode->i_flags |= S_NOQUOTA;
> > +
> > + /* Initialize generic quota file header */
> > + qheader.dqh_magic = cpu_to_le32(quota_magics[type]);
> > + qheader.dqh_version = cpu_to_le32(quota_versions[type]);
> > +
> > + /* Initialize the quota file info structure */
> > + qinfo.dqi_bgrace = cpu_to_le32(MAX_DQ_TIME);
> > + qinfo.dqi_igrace = cpu_to_le32(MAX_IQ_TIME);
> > + qinfo.dqi_flags = cpu_to_le32(0);
> > + qinfo.dqi_blocks = cpu_to_le32(QT_TREEOFF + 1);
> > + qinfo.dqi_free_blk = cpu_to_le32(0);
> > + qinfo.dqi_free_entry = cpu_to_le32(0);
> > +
> > + /*
> > + * Write out generic quota header, quota info structure and
> > + * zeroout first tree block.
> > + */
> > + shmem_quota_write_inode(inode, type, (const char *)&qheader,
> > + sizeof(qheader), 0);
>
> Why is it not important to check error returns here?
Because dquot_load_quota_inode() would fail if there is something wrong.
But it won't hurt to check the return either.
>
> > + shmem_quota_write_inode(inode, type, (const char *)&qinfo,
> > + sizeof(qinfo), sizeof(qheader));
> > + shmem_quota_write_inode(inode, type, 0,
> > + QT_TREEOFF * QUOTABLOCK_SIZE,
> > + QUOTABLOCK_SIZE);
> > +
> > + shmem_set_inode_flags(inode, FS_NOATIME_FL | FS_IMMUTABLE_FL);
> > +
> > + err = dquot_load_quota_inode(inode, type, QFMT_VFS_V1,
>
> I wonder, what's the difference between quota v1 and v2? Wouldn't we
> want the newer version?
As Jan already explained in his reply the QFMT_VFS_V1 is the newest
format and yes the versioning is a bit confusing ;)
>
> > + DQUOT_USAGE_ENABLED);
> > + iput(inode);
> > + if (err)
> > + goto out_err;
> > + }
> > + return 0;
> > +
> > +out_err:
> > + pr_warn("tmpfs: failed to enable quota tracking (type=%d, err=%d)\n",
> > + type, err);
> > + for (type--; type >= 0; type--) {
> > + inode = sb_dqopt(sb)->files[type];
> > + if (inode)
> > + inode = igrab(inode);
> > + dquot_quota_off(sb, type);
> > + if (inode)
> > + iput(inode);
> > + }
> > + return err;
> > +}
> > +
> > +static void shmem_disable_quotas(struct super_block *sb)
> > +{
> > + struct inode *inode = NULL;
> > + int type;
> > +
> > + for (type = 0; type < SHMEM_MAXQUOTAS; type++) {
> > + inode = sb_dqopt(sb)->files[type];
> > + if (inode)
> > + inode = igrab(inode);
> > + dquot_quota_off(sb, type);
> > + if (inode)
> > + iput(inode);
> > + }
> > +}
> > +
> > +static ssize_t shmem_quota_read(struct super_block *sb, int type, char *data,
> > + size_t len, loff_t off)
> > +{
> > + struct inode *inode = sb_dqopt(sb)->files[type];
> > + loff_t i_size = i_size_read(inode);
> > + struct folio *folio = NULL;
> > + struct page *page = NULL;
> > + unsigned long offset;
> > + int tocopy, err = 0;
> > + pgoff_t index;
> > + size_t toread;
> > +
> > + index = off >> PAGE_SHIFT;
> > + offset = off & ~PAGE_MASK;
> > +
> > + if (off > i_size)
> > + return 0;
> > + if (off+len > i_size)
> > + len = i_size - off;
> > + toread = len;
> > + while (toread > 0) {
> > + tocopy = PAGE_SIZE - offset < toread ?
> > + PAGE_SIZE - offset : toread;
> > +
> > + err = shmem_get_folio(inode, index, &folio, SGP_READ);
> > + if (err) {
> > + if (err == -EINVAL)
> > + err = 0;
> > + return err;
> > + }
> > +
> > + if (folio) {
>
> folio && folio_test_uptodate() ?
>
> > + folio_unlock(folio);
> > + page = folio_file_page(folio, index);
> > + if (PageHWPoison(page)) {
> > + folio_put(folio);
> > + return -EIO;
> > + }
> > + memcpy(data, page_address(page) + offset, tocopy);
> > + folio_put(folio);
>
> Also, I'm a little surprised that it's safe to read the contents of a
> folio after unlocking it.
That's how shmem_file_read_iter() seems to be doing it. Anyway as Jan
pointed out we can get rid of the quota_read/write business and just
hold the information in memory.
My approach worked well as PoC but Jan is right that it's not exactly
an efficient way of doing this on memory based fs.
>
> > + } else { /* A hole */
> > + memset(data, 0, tocopy);
> > + }
> > +
> > + offset = 0;
> > + toread -= tocopy;
> > + data += tocopy;
> > + index++;
> > + cond_resched();
> > + }
> > + return len;
> > +}
> > +
> > +static struct dquot **shmem_get_dquots(struct inode *inode)
> > +{
> > + return SHMEM_I(inode)->i_dquot;
> > +}
> > +#endif /* SHMEM_QUOTA_TMPFS */
> > +
> > /*
> > * shmem_reserve_inode() performs bookkeeping to reserve a shmem inode, and
> > * produces a novel ino for the newly allocated inode.
> > @@ -353,7 +590,6 @@ static void shmem_recalc_inode(struct inode *inode)
> > freed = info->alloced - info->swapped - inode->i_mapping->nrpages;
> > if (freed > 0) {
> > info->alloced -= freed;
> > - inode->i_blocks -= freed * BLOCKS_PER_PAGE;
>
> I guess the quotaops helpers take care of the i_blocks updates now?
Yes exactly.
Thanks!
-Lukas
>
> --D
>
> > shmem_inode_unacct_blocks(inode, freed);
> > }
> > }
> > @@ -363,7 +599,7 @@ bool shmem_charge(struct inode *inode, long pages)
> > struct shmem_inode_info *info = SHMEM_I(inode);
> > unsigned long flags;
> >
> > - if (!shmem_inode_acct_block(inode, pages))
> > + if (shmem_inode_acct_block(inode, pages))
> > return false;
> >
> > /* nrpages adjustment first, then shmem_recalc_inode() when balanced */
> > @@ -371,7 +607,6 @@ bool shmem_charge(struct inode *inode, long pages)
> >
> > spin_lock_irqsave(&info->lock, flags);
> > info->alloced += pages;
> > - inode->i_blocks += pages * BLOCKS_PER_PAGE;
> > shmem_recalc_inode(inode);
> > spin_unlock_irqrestore(&info->lock, flags);
> >
> > @@ -387,7 +622,6 @@ void shmem_uncharge(struct inode *inode, long pages)
> >
> > spin_lock_irqsave(&info->lock, flags);
> > info->alloced -= pages;
> > - inode->i_blocks -= pages * BLOCKS_PER_PAGE;
> > shmem_recalc_inode(inode);
> > spin_unlock_irqrestore(&info->lock, flags);
> >
> > @@ -1119,6 +1353,13 @@ static int shmem_setattr(struct user_namespace *mnt_userns,
> > }
> > }
> >
> > + /* Transfer quota accounting */
> > + if (i_uid_needs_update(mnt_userns, attr, inode) ||
> > + i_gid_needs_update(mnt_userns, attr, inode))
> > + error = dquot_transfer(mnt_userns, inode, attr);
> > + if (error)
> > + return error;
> > +
> > setattr_copy(&init_user_ns, inode, attr);
> > if (attr->ia_valid & ATTR_MODE)
> > error = posix_acl_chmod(&init_user_ns, inode, inode->i_mode);
> > @@ -1164,7 +1405,9 @@ static void shmem_evict_inode(struct inode *inode)
> > simple_xattrs_free(&info->xattrs);
> > WARN_ON(inode->i_blocks);
> > shmem_free_inode(inode->i_sb);
> > + dquot_free_inode(inode);
> > clear_inode(inode);
> > + dquot_drop(inode);
> > }
> >
> > static int shmem_find_swap_entries(struct address_space *mapping,
> > @@ -1569,14 +1812,14 @@ static struct folio *shmem_alloc_and_acct_folio(gfp_t gfp, struct inode *inode,
> > {
> > struct shmem_inode_info *info = SHMEM_I(inode);
> > struct folio *folio;
> > - int nr;
> > - int err = -ENOSPC;
> > + int nr, err;
> >
> > if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
> > huge = false;
> > nr = huge ? HPAGE_PMD_NR : 1;
> >
> > - if (!shmem_inode_acct_block(inode, nr))
> > + err = shmem_inode_acct_block(inode, nr);
> > + if (err)
> > goto failed;
> >
> > if (huge)
> > @@ -1949,7 +2192,6 @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index,
> >
> > spin_lock_irq(&info->lock);
> > info->alloced += folio_nr_pages(folio);
> > - inode->i_blocks += (blkcnt_t)BLOCKS_PER_PAGE << folio_order(folio);
> > shmem_recalc_inode(inode);
> > spin_unlock_irq(&info->lock);
> > alloced = true;
> > @@ -2315,8 +2557,10 @@ static void shmem_set_inode_flags(struct inode *inode, unsigned int fsflags)
> > #define shmem_initxattrs NULL
> > #endif
> >
> > -static struct inode *shmem_get_inode(struct super_block *sb, struct inode *dir,
> > - umode_t mode, dev_t dev, unsigned long flags)
> > +static struct inode *shmem_get_inode_noquota(struct super_block *sb,
> > + struct inode *dir,
> > + umode_t mode, dev_t dev,
> > + unsigned long flags)
> > {
> > struct inode *inode;
> > struct shmem_inode_info *info;
> > @@ -2384,6 +2628,35 @@ static struct inode *shmem_get_inode(struct super_block *sb, struct inode *dir,
> > return inode;
> > }
> >
> > +static struct inode *shmem_get_inode(struct super_block *sb, struct inode *dir,
> > + umode_t mode, dev_t dev, unsigned long flags)
> > +{
> > + int err;
> > + struct inode *inode;
> > +
> > + inode = shmem_get_inode_noquota(sb, dir, mode, dev, flags);
> > + if (inode) {
> > + err = dquot_initialize(inode);
> > + if (err)
> > + goto errout;
> > +
> > + err = dquot_alloc_inode(inode);
> > + if (err) {
> > + dquot_drop(inode);
> > + goto errout;
> > + }
> > + }
> > + return inode;
> > +
> > +errout:
> > + inode->i_flags |= S_NOQUOTA;
> > + iput(inode);
> > + shmem_free_inode(sb);
> > + if (err)
> > + return ERR_PTR(err);
> > + return NULL;
> > +}
> > +
> > #ifdef CONFIG_USERFAULTFD
> > int shmem_mfill_atomic_pte(struct mm_struct *dst_mm,
> > pmd_t *dst_pmd,
> > @@ -2403,7 +2676,7 @@ int shmem_mfill_atomic_pte(struct mm_struct *dst_mm,
> > int ret;
> > pgoff_t max_off;
> >
> > - if (!shmem_inode_acct_block(inode, 1)) {
> > + if (shmem_inode_acct_block(inode, 1)) {
> > /*
> > * We may have got a page, returned -ENOENT triggering a retry,
> > * and now we find ourselves with -ENOMEM. Release the page, to
> > @@ -2487,7 +2760,6 @@ int shmem_mfill_atomic_pte(struct mm_struct *dst_mm,
> >
> > spin_lock_irq(&info->lock);
> > info->alloced++;
> > - inode->i_blocks += BLOCKS_PER_PAGE;
> > shmem_recalc_inode(inode);
> > spin_unlock_irq(&info->lock);
> >
> > @@ -2908,7 +3180,7 @@ shmem_mknod(struct user_namespace *mnt_userns, struct inode *dir,
> > int error = -ENOSPC;
> >
> > inode = shmem_get_inode(dir->i_sb, dir, mode, dev, VM_NORESERVE);
> > - if (inode) {
> > + if (!IS_ERR_OR_NULL(inode)) {
> > error = simple_acl_create(dir, inode);
> > if (error)
> > goto out_iput;
> > @@ -2924,7 +3196,8 @@ shmem_mknod(struct user_namespace *mnt_userns, struct inode *dir,
> > inode_inc_iversion(dir);
> > d_instantiate(dentry, inode);
> > dget(dentry); /* Extra count - pin the dentry in core */
> > - }
> > + } else if (IS_ERR(inode))
> > + error = PTR_ERR(inode);
> > return error;
> > out_iput:
> > iput(inode);
> > @@ -2939,7 +3212,7 @@ shmem_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
> > int error = -ENOSPC;
> >
> > inode = shmem_get_inode(dir->i_sb, dir, mode, 0, VM_NORESERVE);
> > - if (inode) {
> > + if (!IS_ERR_OR_NULL(inode)) {
> > error = security_inode_init_security(inode, dir,
> > NULL,
> > shmem_initxattrs, NULL);
> > @@ -2949,7 +3222,8 @@ shmem_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
> > if (error)
> > goto out_iput;
> > d_tmpfile(file, inode);
> > - }
> > + } else if (IS_ERR(inode))
> > + error = PTR_ERR(inode);
> > return finish_open_simple(file, error);
> > out_iput:
> > iput(inode);
> > @@ -3126,6 +3400,8 @@ static int shmem_symlink(struct user_namespace *mnt_userns, struct inode *dir,
> > VM_NORESERVE);
> > if (!inode)
> > return -ENOSPC;
> > + else if (IS_ERR(inode))
> > + return PTR_ERR(inode);
> >
> > error = security_inode_init_security(inode, dir, &dentry->d_name,
> > shmem_initxattrs, NULL);
> > @@ -3443,6 +3719,7 @@ enum shmem_param {
> > Opt_uid,
> > Opt_inode32,
> > Opt_inode64,
> > + Opt_quota,
> > };
> >
> > static const struct constant_table shmem_param_enums_huge[] = {
> > @@ -3464,6 +3741,9 @@ const struct fs_parameter_spec shmem_fs_parameters[] = {
> > fsparam_u32 ("uid", Opt_uid),
> > fsparam_flag ("inode32", Opt_inode32),
> > fsparam_flag ("inode64", Opt_inode64),
> > + fsparam_flag ("quota", Opt_quota),
> > + fsparam_flag ("usrquota", Opt_quota),
> > + fsparam_flag ("grpquota", Opt_quota),
> > {}
> > };
> >
> > @@ -3547,6 +3827,13 @@ static int shmem_parse_one(struct fs_context *fc, struct fs_parameter *param)
> > ctx->full_inums = true;
> > ctx->seen |= SHMEM_SEEN_INUMS;
> > break;
> > + case Opt_quota:
> > +#ifdef CONFIG_QUOTA
> > + ctx->seen |= SHMEM_SEEN_QUOTA;
> > +#else
> > + goto unsupported_parameter;
> > +#endif
> > + break;
> > }
> > return 0;
> >
> > @@ -3646,6 +3933,12 @@ static int shmem_reconfigure(struct fs_context *fc)
> > goto out;
> > }
> >
> > + if (ctx->seen & SHMEM_SEEN_QUOTA &&
> > + !sb_any_quota_loaded(fc->root->d_sb)) {
> > + err = "Cannot enable quota on remount";
> > + goto out;
> > + }
> > +
> > if (ctx->seen & SHMEM_SEEN_HUGE)
> > sbinfo->huge = ctx->huge;
> > if (ctx->seen & SHMEM_SEEN_INUMS)
> > @@ -3728,6 +4021,9 @@ static void shmem_put_super(struct super_block *sb)
> > {
> > struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
> >
> > +#ifdef SHMEM_QUOTA_TMPFS
> > + shmem_disable_quotas(sb);
> > +#endif
> > free_percpu(sbinfo->ino_batch);
> > percpu_counter_destroy(&sbinfo->used_blocks);
> > mpol_put(sbinfo->mpol);
> > @@ -3805,14 +4101,26 @@ static int shmem_fill_super(struct super_block *sb, struct fs_context *fc)
> > #endif
> > uuid_gen(&sb->s_uuid);
> >
> > +#ifdef SHMEM_QUOTA_TMPFS
> > + if (ctx->seen & SHMEM_SEEN_QUOTA) {
> > + sb->dq_op = &dquot_operations;
> > + sb->s_qcop = &dquot_quotactl_sysfile_ops;
> > + sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP;
> > +
> > + if (shmem_enable_quotas(sb))
> > + goto failed;
> > + }
> > +#endif /* SHMEM_QUOTA_TMPFS */
> > +
> > inode = shmem_get_inode(sb, NULL, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE);
> > - if (!inode)
> > + if (IS_ERR_OR_NULL(inode))
> > goto failed;
> > inode->i_uid = sbinfo->uid;
> > inode->i_gid = sbinfo->gid;
> > sb->s_root = d_make_root(inode);
> > if (!sb->s_root)
> > goto failed;
> > +
> > return 0;
> >
> > failed:
> > @@ -3976,7 +4284,12 @@ static const struct super_operations shmem_ops = {
> > #ifdef CONFIG_TMPFS
> > .statfs = shmem_statfs,
> > .show_options = shmem_show_options,
> > -#endif
> > +#ifdef CONFIG_QUOTA
> > + .quota_read = shmem_quota_read,
> > + .quota_write = shmem_quota_write,
> > + .get_dquots = shmem_get_dquots,
> > +#endif /* CONFIG_QUOTA */
> > +#endif /* CONFIG_TMPFS */
> > .evict_inode = shmem_evict_inode,
> > .drop_inode = generic_delete_inode,
> > .put_super = shmem_put_super,
> > @@ -4196,8 +4509,10 @@ static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *name, l
> >
> > inode = shmem_get_inode(mnt->mnt_sb, NULL, S_IFREG | S_IRWXUGO, 0,
> > flags);
> > - if (unlikely(!inode)) {
> > + if (IS_ERR_OR_NULL(inode)) {
> > shmem_unacct_size(flags, size);
> > + if (IS_ERR(inode))
> > + return (struct file *)inode;
> > return ERR_PTR(-ENOSPC);
> > }
> > inode->i_flags |= i_flags;
> > --
> > 2.38.1
> >
>
