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ext4: add a new ioctl EXT4_IOC_CLEAR_ES_CACHE

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The new ioctl EXT4_IOC_CLEAR_ES_CACHE will force an inode's extent
status cache to be cleared out.  This is intended for use for
debugging.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o 2019-08-11 16:30:41 -04:00
parent 547b9ad698
commit b0c013e292
4 changed files with 40 additions and 0 deletions
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2
fs/ext4/ext4.h
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@ -649,6 +649,8 @@ enum {
#define EXT4_IOC_SET_ENCRYPTION_POLICY FS_IOC_SET_ENCRYPTION_POLICY #define EXT4_IOC_SET_ENCRYPTION_POLICY FS_IOC_SET_ENCRYPTION_POLICY
#define EXT4_IOC_GET_ENCRYPTION_PWSALT FS_IOC_GET_ENCRYPTION_PWSALT #define EXT4_IOC_GET_ENCRYPTION_PWSALT FS_IOC_GET_ENCRYPTION_PWSALT
#define EXT4_IOC_GET_ENCRYPTION_POLICY FS_IOC_GET_ENCRYPTION_POLICY #define EXT4_IOC_GET_ENCRYPTION_POLICY FS_IOC_GET_ENCRYPTION_POLICY
/* ioctl codes 19--39 are reserved for fscrypt */
#define EXT4_IOC_CLEAR_ES_CACHE _IO('f', 40)
#define EXT4_IOC_FSGETXATTR FS_IOC_FSGETXATTR #define EXT4_IOC_FSGETXATTR FS_IOC_FSGETXATTR
#define EXT4_IOC_FSSETXATTR FS_IOC_FSSETXATTR #define EXT4_IOC_FSSETXATTR FS_IOC_FSSETXATTR

28
fs/ext4/extents_status.c
View File

@ -1374,6 +1374,34 @@ static int es_reclaim_extents(struct ext4_inode_info *ei, int *nr_to_scan)
return nr_shrunk; return nr_shrunk;
} }
/*
* Called to support EXT4_IOC_CLEAR_ES_CACHE. We can only remove
* discretionary entries from the extent status cache. (Some entries
* must be present for proper operations.)
*/
void ext4_clear_inode_es(struct inode *inode)
{
struct ext4_inode_info *ei = EXT4_I(inode);
struct extent_status *es;
struct ext4_es_tree *tree;
struct rb_node *node;
write_lock(&ei->i_es_lock);
tree = &EXT4_I(inode)->i_es_tree;
tree->cache_es = NULL;
node = rb_first(&tree->root);
while (node) {
es = rb_entry(node, struct extent_status, rb_node);
node = rb_next(node);
if (!ext4_es_is_delayed(es)) {
rb_erase(&es->rb_node, &tree->root);
ext4_es_free_extent(inode, es);
}
}
ext4_clear_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
write_unlock(&ei->i_es_lock);
}
#ifdef ES_DEBUG__ #ifdef ES_DEBUG__
static void ext4_print_pending_tree(struct inode *inode) static void ext4_print_pending_tree(struct inode *inode)
{ {

1
fs/ext4/extents_status.h
View File

@ -248,5 +248,6 @@ extern unsigned int ext4_es_delayed_clu(struct inode *inode, ext4_lblk_t lblk,
ext4_lblk_t len); ext4_lblk_t len);
extern void ext4_es_remove_blks(struct inode *inode, ext4_lblk_t lblk, extern void ext4_es_remove_blks(struct inode *inode, ext4_lblk_t lblk,
ext4_lblk_t len); ext4_lblk_t len);
extern void ext4_clear_inode_es(struct inode *inode);
#endif /* _EXT4_EXTENTS_STATUS_H */ #endif /* _EXT4_EXTENTS_STATUS_H */

9
fs/ext4/ioctl.c
View File

@ -1115,6 +1115,14 @@ resizefs_out:
case EXT4_IOC_GET_ENCRYPTION_POLICY: case EXT4_IOC_GET_ENCRYPTION_POLICY:
return fscrypt_ioctl_get_policy(filp, (void __user *)arg); return fscrypt_ioctl_get_policy(filp, (void __user *)arg);
case EXT4_IOC_CLEAR_ES_CACHE:
{
if (!inode_owner_or_capable(inode))
return -EACCES;
ext4_clear_inode_es(inode);
return 0;
}
case EXT4_IOC_FSGETXATTR: case EXT4_IOC_FSGETXATTR:
{ {
struct fsxattr fa; struct fsxattr fa;
@ -1233,6 +1241,7 @@ long ext4_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
case EXT4_IOC_GET_ENCRYPTION_POLICY: case EXT4_IOC_GET_ENCRYPTION_POLICY:
case EXT4_IOC_SHUTDOWN: case EXT4_IOC_SHUTDOWN:
case FS_IOC_GETFSMAP: case FS_IOC_GETFSMAP:
case EXT4_IOC_CLEAR_ES_CACHE:
break; break;
default: default:
return -ENOIOCTLCMD; return -ENOIOCTLCMD;