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linux/fs/cifs/cached_dir.h

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cifs: Move cached-dir functions into a separate file Also rename crfid to cfid to have consistent naming for this variable. This commit does not change any logic. Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Steve French <stfrench@microsoft.com>
2022-08-10 22:00:08 -05:00
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Functions to handle the cached directory entries
*
* Copyright (c) 2022, Ronnie Sahlberg <lsahlber@redhat.com>
*/
#ifndef _CACHED_DIR_H
#define _CACHED_DIR_H
cifs: Add constructor/destructors for tcon->cfid and move the structure definitions into cached_dir.h Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2022-08-11 19:04:29 -05:00
struct cached_dirent {
struct list_head entry;
char *name;
int namelen;
loff_t pos;
struct cifs_fattr fattr;
};
struct cached_dirents {
bool is_valid:1;
bool is_failed:1;
struct dir_context *ctx; /*
* Only used to make sure we only take entries
* from a single context. Never dereferenced.
*/
struct mutex de_mutex;
int pos; /* Expected ctx->pos */
struct list_head entries;
};
struct cached_fid {
cifs: enable caching of directories for which a lease is held This expands the directory caching to now cache an open handle for all directories (up to a maximum) and not just the root directory. In this patch, locking and refcounting is intended to work as so: The main function to get a reference to a cached handle is find_or_create_cached_dir() called from open_cached_dir() These functions are protected under the cfid_list_lock spin-lock to make sure we do not race creating new references for cached dirs with deletion of expired ones. An successful open_cached_dir() will take out 2 references to the cfid if this was the very first and successful call to open the directory and it acquired a lease from the server. One reference is for the lease and the other is for the cfid that we return. The is lease reference is tracked by cfid->has_lease. If the directory already has a handle with an active lease, then we just take out one new reference for the cfid and return it. It can happen that we have a thread that tries to open a cached directory where we have a cfid already but we do not, yet, have a working lease. In this case we will just return NULL, and this the caller will fall back to the case when no handle was available. In this model the total number of references we have on a cfid is 1 for while the handle is open and we have a lease, and one additional reference for each open instance of a cfid. Once we get a lease break (cached_dir_lease_break()) we remove the cfid from the list under the spinlock. This prevents any new threads to use it, and we also call smb2_cached_lease_break() via the work_queue in order to drop the reference we got for the lease (we drop it outside of the spin-lock.) Anytime a thread calls close_cached_dir() we also drop a reference to the cfid. When the last reference to the cfid is released smb2_close_cached_fid() will be invoked which will drop the reference ot the dentry we held for this cfid and it will also, if we the handle is open/has a lease also call SMB2_close() to close the handle on the server. Two events require special handling: invalidate_all_cached_dirs() this function is called from SMB2_tdis() and cifs_mark_open_files_invalid(). In both cases the tcon is either gone already or will be shortly so we do not need to actually close the handles. They will be dropped server side as part of the tcon dropping. But we have to be careful about a potential race with a concurrent lease break so we need to take out additional refences to avoid the cfid from being freed while we are still referencing it. free_cached_dirs() which is called from tconInfoFree(). This is called quite late in the umount process so there should no longer be any open handles or files and we can just free all the remaining data. Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2022-10-06 00:14:31 -05:00
struct list_head entry;
struct cached_fids *cfids;
cifs: store a pointer to a fid in the cfid structure instead of the struct also create a constructor that takes a path name and stores it in the fid. Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2022-08-31 12:49:44 +10:00
const char *path;
cifs: Add constructor/destructors for tcon->cfid and move the structure definitions into cached_dir.h Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2022-08-11 19:04:29 -05:00
bool has_lease:1;
cifs: enable caching of directories for which a lease is held This expands the directory caching to now cache an open handle for all directories (up to a maximum) and not just the root directory. In this patch, locking and refcounting is intended to work as so: The main function to get a reference to a cached handle is find_or_create_cached_dir() called from open_cached_dir() These functions are protected under the cfid_list_lock spin-lock to make sure we do not race creating new references for cached dirs with deletion of expired ones. An successful open_cached_dir() will take out 2 references to the cfid if this was the very first and successful call to open the directory and it acquired a lease from the server. One reference is for the lease and the other is for the cfid that we return. The is lease reference is tracked by cfid->has_lease. If the directory already has a handle with an active lease, then we just take out one new reference for the cfid and return it. It can happen that we have a thread that tries to open a cached directory where we have a cfid already but we do not, yet, have a working lease. In this case we will just return NULL, and this the caller will fall back to the case when no handle was available. In this model the total number of references we have on a cfid is 1 for while the handle is open and we have a lease, and one additional reference for each open instance of a cfid. Once we get a lease break (cached_dir_lease_break()) we remove the cfid from the list under the spinlock. This prevents any new threads to use it, and we also call smb2_cached_lease_break() via the work_queue in order to drop the reference we got for the lease (we drop it outside of the spin-lock.) Anytime a thread calls close_cached_dir() we also drop a reference to the cfid. When the last reference to the cfid is released smb2_close_cached_fid() will be invoked which will drop the reference ot the dentry we held for this cfid and it will also, if we the handle is open/has a lease also call SMB2_close() to close the handle on the server. Two events require special handling: invalidate_all_cached_dirs() this function is called from SMB2_tdis() and cifs_mark_open_files_invalid(). In both cases the tcon is either gone already or will be shortly so we do not need to actually close the handles. They will be dropped server side as part of the tcon dropping. But we have to be careful about a potential race with a concurrent lease break so we need to take out additional refences to avoid the cfid from being freed while we are still referencing it. free_cached_dirs() which is called from tconInfoFree(). This is called quite late in the umount process so there should no longer be any open handles or files and we can just free all the remaining data. Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2022-10-06 00:14:31 -05:00
bool is_open:1;
bool on_list:1;
bool file_all_info_is_valid:1;
cifs: Add constructor/destructors for tcon->cfid and move the structure definitions into cached_dir.h Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2022-08-11 19:04:29 -05:00
unsigned long time; /* jiffies of when lease was taken */
struct kref refcount;
struct cifs_fid fid;
cifs: enable caching of directories for which a lease is held This expands the directory caching to now cache an open handle for all directories (up to a maximum) and not just the root directory. In this patch, locking and refcounting is intended to work as so: The main function to get a reference to a cached handle is find_or_create_cached_dir() called from open_cached_dir() These functions are protected under the cfid_list_lock spin-lock to make sure we do not race creating new references for cached dirs with deletion of expired ones. An successful open_cached_dir() will take out 2 references to the cfid if this was the very first and successful call to open the directory and it acquired a lease from the server. One reference is for the lease and the other is for the cfid that we return. The is lease reference is tracked by cfid->has_lease. If the directory already has a handle with an active lease, then we just take out one new reference for the cfid and return it. It can happen that we have a thread that tries to open a cached directory where we have a cfid already but we do not, yet, have a working lease. In this case we will just return NULL, and this the caller will fall back to the case when no handle was available. In this model the total number of references we have on a cfid is 1 for while the handle is open and we have a lease, and one additional reference for each open instance of a cfid. Once we get a lease break (cached_dir_lease_break()) we remove the cfid from the list under the spinlock. This prevents any new threads to use it, and we also call smb2_cached_lease_break() via the work_queue in order to drop the reference we got for the lease (we drop it outside of the spin-lock.) Anytime a thread calls close_cached_dir() we also drop a reference to the cfid. When the last reference to the cfid is released smb2_close_cached_fid() will be invoked which will drop the reference ot the dentry we held for this cfid and it will also, if we the handle is open/has a lease also call SMB2_close() to close the handle on the server. Two events require special handling: invalidate_all_cached_dirs() this function is called from SMB2_tdis() and cifs_mark_open_files_invalid(). In both cases the tcon is either gone already or will be shortly so we do not need to actually close the handles. They will be dropped server side as part of the tcon dropping. But we have to be careful about a potential race with a concurrent lease break so we need to take out additional refences to avoid the cfid from being freed while we are still referencing it. free_cached_dirs() which is called from tconInfoFree(). This is called quite late in the umount process so there should no longer be any open handles or files and we can just free all the remaining data. Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2022-10-06 00:14:31 -05:00
spinlock_t fid_lock;
cifs: Add constructor/destructors for tcon->cfid and move the structure definitions into cached_dir.h Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2022-08-11 19:04:29 -05:00
struct cifs_tcon *tcon;
struct dentry *dentry;
struct work_struct lease_break;
struct smb2_file_all_info file_all_info;
struct cached_dirents dirents;
};
cifs: enable caching of directories for which a lease is held This expands the directory caching to now cache an open handle for all directories (up to a maximum) and not just the root directory. In this patch, locking and refcounting is intended to work as so: The main function to get a reference to a cached handle is find_or_create_cached_dir() called from open_cached_dir() These functions are protected under the cfid_list_lock spin-lock to make sure we do not race creating new references for cached dirs with deletion of expired ones. An successful open_cached_dir() will take out 2 references to the cfid if this was the very first and successful call to open the directory and it acquired a lease from the server. One reference is for the lease and the other is for the cfid that we return. The is lease reference is tracked by cfid->has_lease. If the directory already has a handle with an active lease, then we just take out one new reference for the cfid and return it. It can happen that we have a thread that tries to open a cached directory where we have a cfid already but we do not, yet, have a working lease. In this case we will just return NULL, and this the caller will fall back to the case when no handle was available. In this model the total number of references we have on a cfid is 1 for while the handle is open and we have a lease, and one additional reference for each open instance of a cfid. Once we get a lease break (cached_dir_lease_break()) we remove the cfid from the list under the spinlock. This prevents any new threads to use it, and we also call smb2_cached_lease_break() via the work_queue in order to drop the reference we got for the lease (we drop it outside of the spin-lock.) Anytime a thread calls close_cached_dir() we also drop a reference to the cfid. When the last reference to the cfid is released smb2_close_cached_fid() will be invoked which will drop the reference ot the dentry we held for this cfid and it will also, if we the handle is open/has a lease also call SMB2_close() to close the handle on the server. Two events require special handling: invalidate_all_cached_dirs() this function is called from SMB2_tdis() and cifs_mark_open_files_invalid(). In both cases the tcon is either gone already or will be shortly so we do not need to actually close the handles. They will be dropped server side as part of the tcon dropping. But we have to be careful about a potential race with a concurrent lease break so we need to take out additional refences to avoid the cfid from being freed while we are still referencing it. free_cached_dirs() which is called from tconInfoFree(). This is called quite late in the umount process so there should no longer be any open handles or files and we can just free all the remaining data. Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2022-10-06 00:14:31 -05:00
#define MAX_CACHED_FIDS 16
cifs: Make tcon contain a wrapper structure cached_fids instead of cached_fid This wrapper structure will later be expanded to contain a list of fids that are cached and not just the root fid. Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2022-08-31 12:49:42 +10:00
struct cached_fids {
cifs: enable caching of directories for which a lease is held This expands the directory caching to now cache an open handle for all directories (up to a maximum) and not just the root directory. In this patch, locking and refcounting is intended to work as so: The main function to get a reference to a cached handle is find_or_create_cached_dir() called from open_cached_dir() These functions are protected under the cfid_list_lock spin-lock to make sure we do not race creating new references for cached dirs with deletion of expired ones. An successful open_cached_dir() will take out 2 references to the cfid if this was the very first and successful call to open the directory and it acquired a lease from the server. One reference is for the lease and the other is for the cfid that we return. The is lease reference is tracked by cfid->has_lease. If the directory already has a handle with an active lease, then we just take out one new reference for the cfid and return it. It can happen that we have a thread that tries to open a cached directory where we have a cfid already but we do not, yet, have a working lease. In this case we will just return NULL, and this the caller will fall back to the case when no handle was available. In this model the total number of references we have on a cfid is 1 for while the handle is open and we have a lease, and one additional reference for each open instance of a cfid. Once we get a lease break (cached_dir_lease_break()) we remove the cfid from the list under the spinlock. This prevents any new threads to use it, and we also call smb2_cached_lease_break() via the work_queue in order to drop the reference we got for the lease (we drop it outside of the spin-lock.) Anytime a thread calls close_cached_dir() we also drop a reference to the cfid. When the last reference to the cfid is released smb2_close_cached_fid() will be invoked which will drop the reference ot the dentry we held for this cfid and it will also, if we the handle is open/has a lease also call SMB2_close() to close the handle on the server. Two events require special handling: invalidate_all_cached_dirs() this function is called from SMB2_tdis() and cifs_mark_open_files_invalid(). In both cases the tcon is either gone already or will be shortly so we do not need to actually close the handles. They will be dropped server side as part of the tcon dropping. But we have to be careful about a potential race with a concurrent lease break so we need to take out additional refences to avoid the cfid from being freed while we are still referencing it. free_cached_dirs() which is called from tconInfoFree(). This is called quite late in the umount process so there should no longer be any open handles or files and we can just free all the remaining data. Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2022-10-06 00:14:31 -05:00
/* Must be held when:
* - accessing the cfids->entries list
*/
spinlock_t cfid_list_lock;
int num_entries;
struct list_head entries;
cifs: Make tcon contain a wrapper structure cached_fids instead of cached_fid This wrapper structure will later be expanded to contain a list of fids that are cached and not just the root fid. Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2022-08-31 12:49:42 +10:00
};
extern struct cached_fids *init_cached_dirs(void);
extern void free_cached_dirs(struct cached_fids *cfids);
cifs: Move cached-dir functions into a separate file Also rename crfid to cfid to have consistent naming for this variable. This commit does not change any logic. Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Steve French <stfrench@microsoft.com>
2022-08-10 22:00:08 -05:00
extern int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
const char *path,
struct cifs_sb_info *cifs_sb,
cifs: Do not access tcon->cfids->cfid directly from is_path_accessible cfids will soon keep a list of cached fids so we should not access this directly from outside of cached_dir.c Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2022-08-11 19:51:18 -05:00
bool lookup_only, struct cached_fid **cfid);
cifs: Move cached-dir functions into a separate file Also rename crfid to cfid to have consistent naming for this variable. This commit does not change any logic. Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Steve French <stfrench@microsoft.com>
2022-08-10 22:00:08 -05:00
extern int open_cached_dir_by_dentry(struct cifs_tcon *tcon,
struct dentry *dentry,
struct cached_fid **cfid);
extern void close_cached_dir(struct cached_fid *cfid);
cifs: drop the lease for cached directories on rmdir or rename When we delete or rename a directory we must also drop any cached lease we have on the directory. Fixes: a350d6e73f5e ("cifs: enable caching of directories for which a lease is held") Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2022-10-18 17:39:10 +10:00
extern void drop_cached_dir_by_name(const unsigned int xid,
struct cifs_tcon *tcon,
const char *name,
struct cifs_sb_info *cifs_sb);
cifs: Move cached-dir functions into a separate file Also rename crfid to cfid to have consistent naming for this variable. This commit does not change any logic. Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Steve French <stfrench@microsoft.com>
2022-08-10 22:00:08 -05:00
extern void close_all_cached_dirs(struct cifs_sb_info *cifs_sb);
extern void invalidate_all_cached_dirs(struct cifs_tcon *tcon);
extern int cached_dir_lease_break(struct cifs_tcon *tcon, __u8 lease_key[16]);
#endif /* _CACHED_DIR_H */
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