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-rw-r--r--mm/shmem.c110
1 files changed, 67 insertions, 43 deletions
diff --git a/mm/shmem.c b/mm/shmem.c
index 40f574c06375..98aa066c00f7 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -107,6 +107,20 @@ struct shmem_falloc {
pgoff_t nr_unswapped; /* how often writepage refused to swap out */
};
+struct shmem_options {
+ unsigned long long blocks;
+ unsigned long long inodes;
+ struct mempolicy *mpol;
+ kuid_t uid;
+ kgid_t gid;
+ umode_t mode;
+ int huge;
+ int seen;
+#define SHMEM_SEEN_BLOCKS 1
+#define SHMEM_SEEN_INODES 2
+#define SHMEM_SEEN_HUGE 4
+};
+
#ifdef CONFIG_TMPFS
static unsigned long shmem_default_max_blocks(void)
{
@@ -3349,8 +3363,7 @@ static const struct export_operations shmem_export_ops = {
.fh_to_dentry = shmem_fh_to_dentry,
};
-static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo,
- bool remount)
+static int shmem_parse_options(char *options, struct shmem_options *ctx)
{
char *this_char, *value, *rest;
struct mempolicy *mpol = NULL;
@@ -3395,39 +3408,35 @@ static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo,
}
if (*rest)
goto bad_val;
- sbinfo->max_blocks =
- DIV_ROUND_UP(size, PAGE_SIZE);
+ ctx->blocks = DIV_ROUND_UP(size, PAGE_SIZE);
+ ctx->seen |= SHMEM_SEEN_BLOCKS;
} else if (!strcmp(this_char,"nr_blocks")) {
- sbinfo->max_blocks = memparse(value, &rest);
+ ctx->blocks = memparse(value, &rest);
if (*rest)
goto bad_val;
+ ctx->seen |= SHMEM_SEEN_BLOCKS;
} else if (!strcmp(this_char,"nr_inodes")) {
- sbinfo->max_inodes = memparse(value, &rest);
+ ctx->inodes = memparse(value, &rest);
if (*rest)
goto bad_val;
+ ctx->seen |= SHMEM_SEEN_INODES;
} else if (!strcmp(this_char,"mode")) {
- if (remount)
- continue;
- sbinfo->mode = simple_strtoul(value, &rest, 8) & 07777;
+ ctx->mode = simple_strtoul(value, &rest, 8) & 07777;
if (*rest)
goto bad_val;
} else if (!strcmp(this_char,"uid")) {
- if (remount)
- continue;
uid = simple_strtoul(value, &rest, 0);
if (*rest)
goto bad_val;
- sbinfo->uid = make_kuid(current_user_ns(), uid);
- if (!uid_valid(sbinfo->uid))
+ ctx->uid = make_kuid(current_user_ns(), uid);
+ if (!uid_valid(ctx->uid))
goto bad_val;
} else if (!strcmp(this_char,"gid")) {
- if (remount)
- continue;
gid = simple_strtoul(value, &rest, 0);
if (*rest)
goto bad_val;
- sbinfo->gid = make_kgid(current_user_ns(), gid);
- if (!gid_valid(sbinfo->gid))
+ ctx->gid = make_kgid(current_user_ns(), gid);
+ if (!gid_valid(ctx->gid))
goto bad_val;
#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
} else if (!strcmp(this_char, "huge")) {
@@ -3438,7 +3447,8 @@ static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo,
if (!has_transparent_hugepage() &&
huge != SHMEM_HUGE_NEVER)
goto bad_val;
- sbinfo->huge = huge;
+ ctx->huge = huge;
+ ctx->seen |= SHMEM_SEEN_HUGE;
#endif
#ifdef CONFIG_NUMA
} else if (!strcmp(this_char,"mpol")) {
@@ -3452,7 +3462,7 @@ static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo,
goto error;
}
}
- sbinfo->mpol = mpol;
+ ctx->mpol = mpol;
return 0;
bad_val:
@@ -3467,42 +3477,50 @@ error:
static int shmem_remount_fs(struct super_block *sb, int *flags, char *data)
{
struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
- struct shmem_sb_info config = *sbinfo;
+ struct shmem_options ctx = {.seen = 0};
unsigned long inodes;
int error = -EINVAL;
- config.mpol = NULL;
- if (shmem_parse_options(data, &config, true))
+ if (shmem_parse_options(data, &ctx))
return error;
spin_lock(&sbinfo->stat_lock);
inodes = sbinfo->max_inodes - sbinfo->free_inodes;
- if (percpu_counter_compare(&sbinfo->used_blocks, config.max_blocks) > 0)
- goto out;
- if (config.max_inodes < inodes)
- goto out;
/*
* Those tests disallow limited->unlimited 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.
*/
- if (config.max_blocks && !sbinfo->max_blocks)
- goto out;
- if (config.max_inodes && !sbinfo->max_inodes)
- goto out;
+ if ((ctx.seen & SHMEM_SEEN_BLOCKS) && ctx.blocks) {
+ if (!sbinfo->max_blocks)
+ goto out;
+ if (percpu_counter_compare(&sbinfo->used_blocks,
+ ctx.blocks) > 0)
+ goto out;
+ }
+ if ((ctx.seen & SHMEM_SEEN_INODES) && ctx.inodes) {
+ if (!sbinfo->max_inodes)
+ goto out;
+ if (ctx.inodes < inodes)
+ goto out;
+ }
error = 0;
- sbinfo->huge = config.huge;
- sbinfo->max_blocks = config.max_blocks;
- sbinfo->max_inodes = config.max_inodes;
- sbinfo->free_inodes = config.max_inodes - inodes;
+ if (ctx.seen & SHMEM_SEEN_HUGE)
+ sbinfo->huge = ctx.huge;
+ if (ctx.seen & SHMEM_SEEN_BLOCKS)
+ sbinfo->max_blocks = ctx.blocks;
+ if (ctx.seen & SHMEM_SEEN_INODES) {
+ sbinfo->max_inodes = ctx.inodes;
+ sbinfo->free_inodes = ctx.inodes - inodes;
+ }
/*
* Preserve previous mempolicy unless mpol remount option was specified.
*/
- if (config.mpol) {
+ if (ctx.mpol) {
mpol_put(sbinfo->mpol);
- sbinfo->mpol = config.mpol; /* transfers initial ref */
+ sbinfo->mpol = ctx.mpol; /* transfers initial ref */
}
out:
spin_unlock(&sbinfo->stat_lock);
@@ -3551,6 +3569,9 @@ static int shmem_fill_super(struct super_block *sb, void *data, int silent)
{
struct inode *inode;
struct shmem_sb_info *sbinfo;
+ struct shmem_options ctx = {.mode = 0777 | S_ISVTX,
+ .uid = current_fsuid(),
+ .gid = current_fsgid()};
int err = -ENOMEM;
/* Round up to L1_CACHE_BYTES to resist false sharing */
@@ -3559,9 +3580,6 @@ static int shmem_fill_super(struct super_block *sb, void *data, int silent)
if (!sbinfo)
return -ENOMEM;
- sbinfo->mode = 0777 | S_ISVTX;
- sbinfo->uid = current_fsuid();
- sbinfo->gid = current_fsgid();
sb->s_fs_info = sbinfo;
#ifdef CONFIG_TMPFS
@@ -3571,9 +3589,9 @@ static int shmem_fill_super(struct super_block *sb, void *data, int silent)
* but the internal instance is left unlimited.
*/
if (!(sb->s_flags & SB_KERNMOUNT)) {
- sbinfo->max_blocks = shmem_default_max_blocks();
- sbinfo->max_inodes = shmem_default_max_inodes();
- if (shmem_parse_options(data, sbinfo, false)) {
+ ctx.blocks = shmem_default_max_blocks();
+ ctx.inodes = shmem_default_max_inodes();
+ if (shmem_parse_options(data, &ctx)) {
err = -EINVAL;
goto failed;
}
@@ -3585,11 +3603,17 @@ static int shmem_fill_super(struct super_block *sb, void *data, int silent)
#else
sb->s_flags |= SB_NOUSER;
#endif
+ sbinfo->max_blocks = ctx.blocks;
+ sbinfo->free_inodes = sbinfo->max_inodes = ctx.inodes;
+ sbinfo->uid = ctx.uid;
+ sbinfo->gid = ctx.gid;
+ sbinfo->mode = ctx.mode;
+ sbinfo->huge = ctx.huge;
+ sbinfo->mpol = ctx.mpol;
spin_lock_init(&sbinfo->stat_lock);
if (percpu_counter_init(&sbinfo->used_blocks, 0, GFP_KERNEL))
goto failed;
- sbinfo->free_inodes = sbinfo->max_inodes;
spin_lock_init(&sbinfo->shrinklist_lock);
INIT_LIST_HEAD(&sbinfo->shrinklist);
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.