| Message ID | 4fe1739-d9e7-8dfd-5bce-12e7339711da@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | tmpfs: user xattrs and direct IO | expand |
On Tue 08-08-23 21:32:21, Hugh Dickins wrote: > In preparation for assigning some inode space to extended attributes, > keep track of free_ispace instead of number of free_inodes: as if one > tmpfs inode (and accompanying dentry) occupies very approximately 1KiB. > > Unsigned long is large enough for free_ispace, on 64-bit and on 32-bit: > but take care to enforce the maximum. And fix the nr_blocks maximum on > 32-bit: S64_MAX would be too big for it there, so say LONG_MAX instead. > > Delete the incorrect limited<->unlimited blocks/inodes comment above > shmem_reconfigure(): leave it to the error messages below to describe. > > Signed-off-by: Hugh Dickins <hughd@google.com> Looks good to me. Feel free to add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > include/linux/shmem_fs.h | 2 +- > mm/shmem.c | 33 +++++++++++++++++---------------- > 2 files changed, 18 insertions(+), 17 deletions(-) > > diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h > index 9b2d2faff1d0..6b0c626620f5 100644 > --- a/include/linux/shmem_fs.h > +++ b/include/linux/shmem_fs.h > @@ -54,7 +54,7 @@ struct shmem_sb_info { > unsigned long max_blocks; /* How many blocks are allowed */ > struct percpu_counter used_blocks; /* How many are allocated */ > unsigned long max_inodes; /* How many inodes are allowed */ > - unsigned long free_inodes; /* How many are left for allocation */ > + unsigned long free_ispace; /* How much ispace left for allocation */ > raw_spinlock_t stat_lock; /* Serialize shmem_sb_info changes */ > umode_t mode; /* Mount mode for root directory */ > unsigned char huge; /* Whether to try for hugepages */ > diff --git a/mm/shmem.c b/mm/shmem.c > index df3cabf54206..c39471384168 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -90,6 +90,9 @@ static struct vfsmount *shm_mnt; > /* Pretend that each entry is of this size in directory's i_size */ > #define BOGO_DIRENT_SIZE 20 > > +/* Pretend that one inode + its dentry occupy this much memory */ > +#define BOGO_INODE_SIZE 1024 > + > /* Symlink up to this size is kmalloc'ed instead of using a swappable page */ > #define SHORT_SYMLINK_LEN 128 > > @@ -137,7 +140,8 @@ static unsigned long shmem_default_max_inodes(void) > { > unsigned long nr_pages = totalram_pages(); > > - return min(nr_pages - totalhigh_pages(), nr_pages / 2); > + return min3(nr_pages - totalhigh_pages(), nr_pages / 2, > + ULONG_MAX / BOGO_INODE_SIZE); > } > #endif > > @@ -331,11 +335,11 @@ static int shmem_reserve_inode(struct super_block *sb, ino_t *inop) > if (!(sb->s_flags & SB_KERNMOUNT)) { > raw_spin_lock(&sbinfo->stat_lock); > if (sbinfo->max_inodes) { > - if (!sbinfo->free_inodes) { > + if (sbinfo->free_ispace < BOGO_INODE_SIZE) { > raw_spin_unlock(&sbinfo->stat_lock); > return -ENOSPC; > } > - sbinfo->free_inodes--; > + sbinfo->free_ispace -= BOGO_INODE_SIZE; > } > if (inop) { > ino = sbinfo->next_ino++; > @@ -394,7 +398,7 @@ static void shmem_free_inode(struct super_block *sb) > struct shmem_sb_info *sbinfo = SHMEM_SB(sb); > if (sbinfo->max_inodes) { > raw_spin_lock(&sbinfo->stat_lock); > - sbinfo->free_inodes++; > + sbinfo->free_ispace += BOGO_INODE_SIZE; > raw_spin_unlock(&sbinfo->stat_lock); > } > } > @@ -3155,7 +3159,7 @@ static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) > } > if (sbinfo->max_inodes) { > buf->f_files = sbinfo->max_inodes; > - buf->f_ffree = sbinfo->free_inodes; > + buf->f_ffree = sbinfo->free_ispace / BOGO_INODE_SIZE; > } > /* else leave those fields 0 like simple_statfs */ > > @@ -3815,13 +3819,13 @@ static int shmem_parse_one(struct fs_context *fc, struct fs_parameter *param) > break; > case Opt_nr_blocks: > ctx->blocks = memparse(param->string, &rest); > - if (*rest || ctx->blocks > S64_MAX) > + if (*rest || ctx->blocks > LONG_MAX) > goto bad_value; > ctx->seen |= SHMEM_SEEN_BLOCKS; > break; > case Opt_nr_inodes: > ctx->inodes = memparse(param->string, &rest); > - if (*rest) > + if (*rest || ctx->inodes > ULONG_MAX / BOGO_INODE_SIZE) > goto bad_value; > ctx->seen |= SHMEM_SEEN_INODES; > break; > @@ -4002,21 +4006,17 @@ static int shmem_parse_options(struct fs_context *fc, void *data) > > /* > * Reconfigure a shmem filesystem. > - * > - * Note that we disallow change from limited->unlimited blocks/inodes while any > - * are in use; but we must separately disallow unlimited->limited, because in > - * that case we have no record of how much is already in use. > */ > static int shmem_reconfigure(struct fs_context *fc) > { > struct shmem_options *ctx = fc->fs_private; > struct shmem_sb_info *sbinfo = SHMEM_SB(fc->root->d_sb); > - unsigned long inodes; > + unsigned long used_isp; > struct mempolicy *mpol = NULL; > const char *err; > > raw_spin_lock(&sbinfo->stat_lock); > - inodes = sbinfo->max_inodes - sbinfo->free_inodes; > + used_isp = sbinfo->max_inodes * BOGO_INODE_SIZE - sbinfo->free_ispace; > > if ((ctx->seen & SHMEM_SEEN_BLOCKS) && ctx->blocks) { > if (!sbinfo->max_blocks) { > @@ -4034,7 +4034,7 @@ static int shmem_reconfigure(struct fs_context *fc) > err = "Cannot retroactively limit inodes"; > goto out; > } > - if (ctx->inodes < inodes) { > + if (ctx->inodes * BOGO_INODE_SIZE < used_isp) { > err = "Too few inodes for current use"; > goto out; > } > @@ -4080,7 +4080,7 @@ static int shmem_reconfigure(struct fs_context *fc) > sbinfo->max_blocks = ctx->blocks; > if (ctx->seen & SHMEM_SEEN_INODES) { > sbinfo->max_inodes = ctx->inodes; > - sbinfo->free_inodes = ctx->inodes - inodes; > + sbinfo->free_ispace = ctx->inodes * BOGO_INODE_SIZE - used_isp; > } > > /* > @@ -4211,7 +4211,8 @@ static int shmem_fill_super(struct super_block *sb, struct fs_context *fc) > sb->s_flags |= SB_NOUSER; > #endif > sbinfo->max_blocks = ctx->blocks; > - sbinfo->free_inodes = sbinfo->max_inodes = ctx->inodes; > + sbinfo->max_inodes = ctx->inodes; > + sbinfo->free_ispace = sbinfo->max_inodes * BOGO_INODE_SIZE; > if (sb->s_flags & SB_KERNMOUNT) { > sbinfo->ino_batch = alloc_percpu(ino_t); > if (!sbinfo->ino_batch) > -- > 2.35.3 >
On Tue, Aug 08, 2023 at 09:32:21PM -0700, Hugh Dickins wrote: > In preparation for assigning some inode space to extended attributes, > keep track of free_ispace instead of number of free_inodes: as if one > tmpfs inode (and accompanying dentry) occupies very approximately 1KiB. > > Unsigned long is large enough for free_ispace, on 64-bit and on 32-bit: > but take care to enforce the maximum. And fix the nr_blocks maximum on > 32-bit: S64_MAX would be too big for it there, so say LONG_MAX instead. > > Delete the incorrect limited<->unlimited blocks/inodes comment above > shmem_reconfigure(): leave it to the error messages below to describe. > > Signed-off-by: Hugh Dickins <hughd@google.com> Looks fine, feel free to add: Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> > --- > include/linux/shmem_fs.h | 2 +- > mm/shmem.c | 33 +++++++++++++++++---------------- > 2 files changed, 18 insertions(+), 17 deletions(-) > > diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h > index 9b2d2faff1d0..6b0c626620f5 100644 > --- a/include/linux/shmem_fs.h > +++ b/include/linux/shmem_fs.h > @@ -54,7 +54,7 @@ struct shmem_sb_info { > unsigned long max_blocks; /* How many blocks are allowed */ > struct percpu_counter used_blocks; /* How many are allocated */ > unsigned long max_inodes; /* How many inodes are allowed */ > - unsigned long free_inodes; /* How many are left for allocation */ > + unsigned long free_ispace; /* How much ispace left for allocation */ > raw_spinlock_t stat_lock; /* Serialize shmem_sb_info changes */ > umode_t mode; /* Mount mode for root directory */ > unsigned char huge; /* Whether to try for hugepages */ > diff --git a/mm/shmem.c b/mm/shmem.c > index df3cabf54206..c39471384168 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -90,6 +90,9 @@ static struct vfsmount *shm_mnt; > /* Pretend that each entry is of this size in directory's i_size */ > #define BOGO_DIRENT_SIZE 20 > > +/* Pretend that one inode + its dentry occupy this much memory */ > +#define BOGO_INODE_SIZE 1024 > + > /* Symlink up to this size is kmalloc'ed instead of using a swappable page */ > #define SHORT_SYMLINK_LEN 128 > > @@ -137,7 +140,8 @@ static unsigned long shmem_default_max_inodes(void) > { > unsigned long nr_pages = totalram_pages(); > > - return min(nr_pages - totalhigh_pages(), nr_pages / 2); > + return min3(nr_pages - totalhigh_pages(), nr_pages / 2, > + ULONG_MAX / BOGO_INODE_SIZE); > } > #endif > > @@ -331,11 +335,11 @@ static int shmem_reserve_inode(struct super_block *sb, ino_t *inop) > if (!(sb->s_flags & SB_KERNMOUNT)) { > raw_spin_lock(&sbinfo->stat_lock); > if (sbinfo->max_inodes) { > - if (!sbinfo->free_inodes) { > + if (sbinfo->free_ispace < BOGO_INODE_SIZE) { > raw_spin_unlock(&sbinfo->stat_lock); > return -ENOSPC; > } > - sbinfo->free_inodes--; > + sbinfo->free_ispace -= BOGO_INODE_SIZE; > } > if (inop) { > ino = sbinfo->next_ino++; > @@ -394,7 +398,7 @@ static void shmem_free_inode(struct super_block *sb) > struct shmem_sb_info *sbinfo = SHMEM_SB(sb); > if (sbinfo->max_inodes) { > raw_spin_lock(&sbinfo->stat_lock); > - sbinfo->free_inodes++; > + sbinfo->free_ispace += BOGO_INODE_SIZE; > raw_spin_unlock(&sbinfo->stat_lock); > } > } > @@ -3155,7 +3159,7 @@ static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) > } > if (sbinfo->max_inodes) { > buf->f_files = sbinfo->max_inodes; > - buf->f_ffree = sbinfo->free_inodes; > + buf->f_ffree = sbinfo->free_ispace / BOGO_INODE_SIZE; > } > /* else leave those fields 0 like simple_statfs */ > > @@ -3815,13 +3819,13 @@ static int shmem_parse_one(struct fs_context *fc, struct fs_parameter *param) > break; > case Opt_nr_blocks: > ctx->blocks = memparse(param->string, &rest); > - if (*rest || ctx->blocks > S64_MAX) > + if (*rest || ctx->blocks > LONG_MAX) > goto bad_value; > ctx->seen |= SHMEM_SEEN_BLOCKS; > break; > case Opt_nr_inodes: > ctx->inodes = memparse(param->string, &rest); > - if (*rest) > + if (*rest || ctx->inodes > ULONG_MAX / BOGO_INODE_SIZE) > goto bad_value; > ctx->seen |= SHMEM_SEEN_INODES; > break; > @@ -4002,21 +4006,17 @@ static int shmem_parse_options(struct fs_context *fc, void *data) > > /* > * Reconfigure a shmem filesystem. > - * > - * Note that we disallow change from limited->unlimited blocks/inodes while any > - * are in use; but we must separately disallow unlimited->limited, because in > - * that case we have no record of how much is already in use. > */ > static int shmem_reconfigure(struct fs_context *fc) > { > struct shmem_options *ctx = fc->fs_private; > struct shmem_sb_info *sbinfo = SHMEM_SB(fc->root->d_sb); > - unsigned long inodes; > + unsigned long used_isp; > struct mempolicy *mpol = NULL; > const char *err; > > raw_spin_lock(&sbinfo->stat_lock); > - inodes = sbinfo->max_inodes - sbinfo->free_inodes; > + used_isp = sbinfo->max_inodes * BOGO_INODE_SIZE - sbinfo->free_ispace; > > if ((ctx->seen & SHMEM_SEEN_BLOCKS) && ctx->blocks) { > if (!sbinfo->max_blocks) { > @@ -4034,7 +4034,7 @@ static int shmem_reconfigure(struct fs_context *fc) > err = "Cannot retroactively limit inodes"; > goto out; > } > - if (ctx->inodes < inodes) { > + if (ctx->inodes * BOGO_INODE_SIZE < used_isp) { > err = "Too few inodes for current use"; > goto out; > } > @@ -4080,7 +4080,7 @@ static int shmem_reconfigure(struct fs_context *fc) > sbinfo->max_blocks = ctx->blocks; > if (ctx->seen & SHMEM_SEEN_INODES) { > sbinfo->max_inodes = ctx->inodes; > - sbinfo->free_inodes = ctx->inodes - inodes; > + sbinfo->free_ispace = ctx->inodes * BOGO_INODE_SIZE - used_isp; > } > > /* > @@ -4211,7 +4211,8 @@ static int shmem_fill_super(struct super_block *sb, struct fs_context *fc) > sb->s_flags |= SB_NOUSER; > #endif > sbinfo->max_blocks = ctx->blocks; > - sbinfo->free_inodes = sbinfo->max_inodes = ctx->inodes; > + sbinfo->max_inodes = ctx->inodes; > + sbinfo->free_ispace = sbinfo->max_inodes * BOGO_INODE_SIZE; > if (sb->s_flags & SB_KERNMOUNT) { > sbinfo->ino_batch = alloc_percpu(ino_t); > if (!sbinfo->ino_batch) > -- > 2.35.3 >
diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index 9b2d2faff1d0..6b0c626620f5 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -54,7 +54,7 @@ struct shmem_sb_info { unsigned long max_blocks; /* How many blocks are allowed */ struct percpu_counter used_blocks; /* How many are allocated */ unsigned long max_inodes; /* How many inodes are allowed */ - unsigned long free_inodes; /* How many are left for allocation */ + unsigned long free_ispace; /* How much ispace left for allocation */ raw_spinlock_t stat_lock; /* Serialize shmem_sb_info changes */ umode_t mode; /* Mount mode for root directory */ unsigned char huge; /* Whether to try for hugepages */ diff --git a/mm/shmem.c b/mm/shmem.c index df3cabf54206..c39471384168 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -90,6 +90,9 @@ static struct vfsmount *shm_mnt; /* Pretend that each entry is of this size in directory's i_size */ #define BOGO_DIRENT_SIZE 20 +/* Pretend that one inode + its dentry occupy this much memory */ +#define BOGO_INODE_SIZE 1024 + /* Symlink up to this size is kmalloc'ed instead of using a swappable page */ #define SHORT_SYMLINK_LEN 128 @@ -137,7 +140,8 @@ static unsigned long shmem_default_max_inodes(void) { unsigned long nr_pages = totalram_pages(); - return min(nr_pages - totalhigh_pages(), nr_pages / 2); + return min3(nr_pages - totalhigh_pages(), nr_pages / 2, + ULONG_MAX / BOGO_INODE_SIZE); } #endif @@ -331,11 +335,11 @@ static int shmem_reserve_inode(struct super_block *sb, ino_t *inop) if (!(sb->s_flags & SB_KERNMOUNT)) { raw_spin_lock(&sbinfo->stat_lock); if (sbinfo->max_inodes) { - if (!sbinfo->free_inodes) { + if (sbinfo->free_ispace < BOGO_INODE_SIZE) { raw_spin_unlock(&sbinfo->stat_lock); return -ENOSPC; } - sbinfo->free_inodes--; + sbinfo->free_ispace -= BOGO_INODE_SIZE; } if (inop) { ino = sbinfo->next_ino++; @@ -394,7 +398,7 @@ static void shmem_free_inode(struct super_block *sb) struct shmem_sb_info *sbinfo = SHMEM_SB(sb); if (sbinfo->max_inodes) { raw_spin_lock(&sbinfo->stat_lock); - sbinfo->free_inodes++; + sbinfo->free_ispace += BOGO_INODE_SIZE; raw_spin_unlock(&sbinfo->stat_lock); } } @@ -3155,7 +3159,7 @@ static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) } if (sbinfo->max_inodes) { buf->f_files = sbinfo->max_inodes; - buf->f_ffree = sbinfo->free_inodes; + buf->f_ffree = sbinfo->free_ispace / BOGO_INODE_SIZE; } /* else leave those fields 0 like simple_statfs */ @@ -3815,13 +3819,13 @@ static int shmem_parse_one(struct fs_context *fc, struct fs_parameter *param) break; case Opt_nr_blocks: ctx->blocks = memparse(param->string, &rest); - if (*rest || ctx->blocks > S64_MAX) + if (*rest || ctx->blocks > LONG_MAX) goto bad_value; ctx->seen |= SHMEM_SEEN_BLOCKS; break; case Opt_nr_inodes: ctx->inodes = memparse(param->string, &rest); - if (*rest) + if (*rest || ctx->inodes > ULONG_MAX / BOGO_INODE_SIZE) goto bad_value; ctx->seen |= SHMEM_SEEN_INODES; break; @@ -4002,21 +4006,17 @@ static int shmem_parse_options(struct fs_context *fc, void *data) /* * Reconfigure a shmem filesystem. - * - * Note that we disallow change from limited->unlimited blocks/inodes while any - * are in use; but we must separately disallow unlimited->limited, because in - * that case we have no record of how much is already in use. */ static int shmem_reconfigure(struct fs_context *fc) { struct shmem_options *ctx = fc->fs_private; struct shmem_sb_info *sbinfo = SHMEM_SB(fc->root->d_sb); - unsigned long inodes; + unsigned long used_isp; struct mempolicy *mpol = NULL; const char *err; raw_spin_lock(&sbinfo->stat_lock); - inodes = sbinfo->max_inodes - sbinfo->free_inodes; + used_isp = sbinfo->max_inodes * BOGO_INODE_SIZE - sbinfo->free_ispace; if ((ctx->seen & SHMEM_SEEN_BLOCKS) && ctx->blocks) { if (!sbinfo->max_blocks) { @@ -4034,7 +4034,7 @@ static int shmem_reconfigure(struct fs_context *fc) err = "Cannot retroactively limit inodes"; goto out; } - if (ctx->inodes < inodes) { + if (ctx->inodes * BOGO_INODE_SIZE < used_isp) { err = "Too few inodes for current use"; goto out; } @@ -4080,7 +4080,7 @@ static int shmem_reconfigure(struct fs_context *fc) sbinfo->max_blocks = ctx->blocks; if (ctx->seen & SHMEM_SEEN_INODES) { sbinfo->max_inodes = ctx->inodes; - sbinfo->free_inodes = ctx->inodes - inodes; + sbinfo->free_ispace = ctx->inodes * BOGO_INODE_SIZE - used_isp; } /* @@ -4211,7 +4211,8 @@ static int shmem_fill_super(struct super_block *sb, struct fs_context *fc) sb->s_flags |= SB_NOUSER; #endif sbinfo->max_blocks = ctx->blocks; - sbinfo->free_inodes = sbinfo->max_inodes = ctx->inodes; + sbinfo->max_inodes = ctx->inodes; + sbinfo->free_ispace = sbinfo->max_inodes * BOGO_INODE_SIZE; if (sb->s_flags & SB_KERNMOUNT) { sbinfo->ino_batch = alloc_percpu(ino_t); if (!sbinfo->ino_batch)
In preparation for assigning some inode space to extended attributes, keep track of free_ispace instead of number of free_inodes: as if one tmpfs inode (and accompanying dentry) occupies very approximately 1KiB. Unsigned long is large enough for free_ispace, on 64-bit and on 32-bit: but take care to enforce the maximum. And fix the nr_blocks maximum on 32-bit: S64_MAX would be too big for it there, so say LONG_MAX instead. Delete the incorrect limited<->unlimited blocks/inodes comment above shmem_reconfigure(): leave it to the error messages below to describe. Signed-off-by: Hugh Dickins <hughd@google.com> --- include/linux/shmem_fs.h | 2 +- mm/shmem.c | 33 +++++++++++++++++---------------- 2 files changed, 18 insertions(+), 17 deletions(-)