vfs: check i_nlink limits in vfs_{mkdir,rename_dir,link}

New field of struct super_block - ->s_max_links.  Maximal allowed
value of ->i_nlink or 0; in the latter case all checks still need
to be done in ->link/->mkdir/->rename instances.  Note that this
limit applies both to directoris and to non-directories.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
这个提交包含在:
Al Viro
2012-02-06 12:45:27 -05:00
父节点 c16fa4f2ad
当前提交 8de5277879
修改 26 个文件,包含 46 行新增149 行删除

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@@ -121,9 +121,6 @@ static int sysv_link(struct dentry * old_dentry, struct inode * dir,
{
struct inode *inode = old_dentry->d_inode;
if (inode->i_nlink >= SYSV_SB(inode->i_sb)->s_link_max)
return -EMLINK;
inode->i_ctime = CURRENT_TIME_SEC;
inode_inc_link_count(inode);
ihold(inode);
@@ -134,10 +131,8 @@ static int sysv_link(struct dentry * old_dentry, struct inode * dir,
static int sysv_mkdir(struct inode * dir, struct dentry *dentry, umode_t mode)
{
struct inode * inode;
int err = -EMLINK;
int err;
if (dir->i_nlink >= SYSV_SB(dir->i_sb)->s_link_max)
goto out;
inode_inc_link_count(dir);
inode = sysv_new_inode(dir, S_IFDIR|mode);
@@ -251,11 +246,6 @@ static int sysv_rename(struct inode * old_dir, struct dentry * old_dentry,
drop_nlink(new_inode);
inode_dec_link_count(new_inode);
} else {
if (dir_de) {
err = -EMLINK;
if (new_dir->i_nlink >= SYSV_SB(new_dir->i_sb)->s_link_max)
goto out_dir;
}
err = sysv_add_link(new_dentry, old_inode);
if (err)
goto out_dir;

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@@ -44,7 +44,7 @@ enum {
JAN_1_1980 = (10*365 + 2) * 24 * 60 * 60
};
static void detected_xenix(struct sysv_sb_info *sbi)
static void detected_xenix(struct sysv_sb_info *sbi, unsigned *max_links)
{
struct buffer_head *bh1 = sbi->s_bh1;
struct buffer_head *bh2 = sbi->s_bh2;
@@ -59,7 +59,7 @@ static void detected_xenix(struct sysv_sb_info *sbi)
sbd2 = (struct xenix_super_block *) (bh2->b_data - 512);
}
sbi->s_link_max = XENIX_LINK_MAX;
*max_links = XENIX_LINK_MAX;
sbi->s_fic_size = XENIX_NICINOD;
sbi->s_flc_size = XENIX_NICFREE;
sbi->s_sbd1 = (char *)sbd1;
@@ -75,7 +75,7 @@ static void detected_xenix(struct sysv_sb_info *sbi)
sbi->s_nzones = fs32_to_cpu(sbi, sbd1->s_fsize);
}
static void detected_sysv4(struct sysv_sb_info *sbi)
static void detected_sysv4(struct sysv_sb_info *sbi, unsigned *max_links)
{
struct sysv4_super_block * sbd;
struct buffer_head *bh1 = sbi->s_bh1;
@@ -86,7 +86,7 @@ static void detected_sysv4(struct sysv_sb_info *sbi)
else
sbd = (struct sysv4_super_block *) bh2->b_data;
sbi->s_link_max = SYSV_LINK_MAX;
*max_links = SYSV_LINK_MAX;
sbi->s_fic_size = SYSV_NICINOD;
sbi->s_flc_size = SYSV_NICFREE;
sbi->s_sbd1 = (char *)sbd;
@@ -103,7 +103,7 @@ static void detected_sysv4(struct sysv_sb_info *sbi)
sbi->s_nzones = fs32_to_cpu(sbi, sbd->s_fsize);
}
static void detected_sysv2(struct sysv_sb_info *sbi)
static void detected_sysv2(struct sysv_sb_info *sbi, unsigned *max_links)
{
struct sysv2_super_block *sbd;
struct buffer_head *bh1 = sbi->s_bh1;
@@ -114,7 +114,7 @@ static void detected_sysv2(struct sysv_sb_info *sbi)
else
sbd = (struct sysv2_super_block *) bh2->b_data;
sbi->s_link_max = SYSV_LINK_MAX;
*max_links = SYSV_LINK_MAX;
sbi->s_fic_size = SYSV_NICINOD;
sbi->s_flc_size = SYSV_NICFREE;
sbi->s_sbd1 = (char *)sbd;
@@ -131,14 +131,14 @@ static void detected_sysv2(struct sysv_sb_info *sbi)
sbi->s_nzones = fs32_to_cpu(sbi, sbd->s_fsize);
}
static void detected_coherent(struct sysv_sb_info *sbi)
static void detected_coherent(struct sysv_sb_info *sbi, unsigned *max_links)
{
struct coh_super_block * sbd;
struct buffer_head *bh1 = sbi->s_bh1;
sbd = (struct coh_super_block *) bh1->b_data;
sbi->s_link_max = COH_LINK_MAX;
*max_links = COH_LINK_MAX;
sbi->s_fic_size = COH_NICINOD;
sbi->s_flc_size = COH_NICFREE;
sbi->s_sbd1 = (char *)sbd;
@@ -154,12 +154,12 @@ static void detected_coherent(struct sysv_sb_info *sbi)
sbi->s_nzones = fs32_to_cpu(sbi, sbd->s_fsize);
}
static void detected_v7(struct sysv_sb_info *sbi)
static void detected_v7(struct sysv_sb_info *sbi, unsigned *max_links)
{
struct buffer_head *bh2 = sbi->s_bh2;
struct v7_super_block *sbd = (struct v7_super_block *)bh2->b_data;
sbi->s_link_max = V7_LINK_MAX;
*max_links = V7_LINK_MAX;
sbi->s_fic_size = V7_NICINOD;
sbi->s_flc_size = V7_NICFREE;
sbi->s_sbd1 = (char *)sbd;
@@ -290,7 +290,7 @@ static char *flavour_names[] = {
[FSTYPE_AFS] = "AFS",
};
static void (*flavour_setup[])(struct sysv_sb_info *) = {
static void (*flavour_setup[])(struct sysv_sb_info *, unsigned *) = {
[FSTYPE_XENIX] = detected_xenix,
[FSTYPE_SYSV4] = detected_sysv4,
[FSTYPE_SYSV2] = detected_sysv2,
@@ -310,7 +310,7 @@ static int complete_read_super(struct super_block *sb, int silent, int size)
sbi->s_firstinodezone = 2;
flavour_setup[sbi->s_type](sbi);
flavour_setup[sbi->s_type](sbi, &sb->s_max_links);
sbi->s_truncate = 1;
sbi->s_ndatazones = sbi->s_nzones - sbi->s_firstdatazone;

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@@ -24,7 +24,6 @@ struct sysv_sb_info {
char s_bytesex; /* bytesex (le/be/pdp) */
char s_truncate; /* if 1: names > SYSV_NAMELEN chars are truncated */
/* if 0: they are disallowed (ENAMETOOLONG) */
nlink_t s_link_max; /* max number of hard links to a file */
unsigned int s_inodes_per_block; /* number of inodes per block */
unsigned int s_inodes_per_block_1; /* inodes_per_block - 1 */
unsigned int s_inodes_per_block_bits; /* log2(inodes_per_block) */